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Potential barrier materials (diatomaceous earth, hydrated lime, sulfur, fumed silica, wood ash) and chemical repellents (2 essential oil-based sprays) were evaluated for their efficacy to prevent herbivory by the Florida leatherleaf slug, Leidyula floridana (Leidy, 1851) (Gastropoda: Veronicellidae) by placing a band of material around the plant tissue or by direct application to foliage. Hydrated lime and sulfur effectively prevented foliage damage compared with the other 3 materials when presented as barriers. Dusting or sprinkling these barrier materials on foliage generally did not inhibit feeding by slugs, but sprinkling hydrated lime or wood ash onto foliage significantly reduced herbivory. Two commercially available essential oil formulations were evaluated for their effectiveness at repelling L. floridana. Pure ‘N’ Natural Snail & Slug Away (a cinnamon oil-based product) was quite effective whereas Slug & Snail Defense (containing cedar oil, pine oil, peppermint oil, and white pepper) was ineffective. Contact toxicities of barrier materials and essential oil products were assessed, and compared with a metaldehyde-based bait (Corry's Slug and Snail Pellets), an iron phosphate-based bait (Ecosense Slug and Snail Pellets), and a sulfur-based bait (Ortho Bug-getta Snail and Slug Killer2). Mortality of slugs was high when slugs were exposed to metaldehyde, hydrated lime, and the cinnamon oil-based spray. Iron phosphate bait, sulfur bait, and fumed silica were less effective but provided some reduction in herbivory. Soil moisture adversely affected efficacy of barrier materials, significantly compromising functionality relative to dry soils. Water uptake from soil by barrier materials was positively correlated with foliage consumption but pH was negatively correlated. Because of the negative correlation of pH with consumption, the negative effects of soil moisture on barrier effectiveness, and the rapid physiological response of slugs to some materials, these barrier materials are perhaps better considered to be physiochemical barriers rather than physical barriers.

Repellents and feeding deterrents are underutilized tactics for plant pest damage suppression. Here I report on laboratory and screenhouse studies that assessed a copper hydroxide-based fungicide as a chemical barrier to prevent the Cuban brown snail, Zachrysia provisoria (Pfeiffer, 1858) (Gastropoda: Pleurodontidae) from accessing plants and from feeding on foliage. This snail species is considered to be one of the most important molluscs affecting plants in Florida. Studies were conducted as a follow-up to previous research with different molluscs that demonstrated the potential usefulness of copper hydroxide formulated in a commercial fungicide as a repellent. Although the residue of copper hydroxide displayed repellency to Z. provisoria in laboratory studies, it did not effectively prevent snails from climbing the sides of pots to access plants in screenhouses. Addition of 2 spreader-stickers, Bonide Turbo® and Southern Ag®, to the copper hydroxide to enhance retention of the fungicide did not improve performance. However, when copper hydroxide was applied to pots and foliage, feeding on vegetation was significantly suppressed under screenhouse conditions. I attribute these results to better fungicide residue persistence on foliage than on plastic pots. ResumenLos repelentes y disuasorios de alimentacion son tacticas pocas utilizadas para la supresion de dano de las plagas en las plantas. Aqui se informa sobre los estudios de laboratorio e invernadero con malla que evaluaron un fungicida a base de hidroxido de cobre como una barrera quimica para evitar que el caracol marron cubano, Zachrysia provisoria (Pfeiffer, 1858) (Gastropoda: Pleurodontidae) tenga acceso a las plantas e inhibir su alimentacion sobre el follaje. Se considera esta especie de caracol como uno de los moluscos mas importantes que afecta a las plantas en la Florida. Se realizaron los estudios como seguimiento de investigaciones anteriores con diferentes moluscos que demostraron la utilidad potencial del hidroxido de cobre formulado en un fungicida comercial como repelente. Aunque el residuo de hidroxido de cobre mostro repelencia a Z. provisoria en estudios de laboratorio, no evito eficazmente que los caracoles treparan por los costados de las macetas para acceder a las plantas en los invernaderos con malla. La adicion de 2 adhesivos spreader, Bonide Turboy Southern Ag, al hidroxido de cobre para mejorar la retencion del fungicida no mejoro el rendimiento. Sin embargo, cuando se aplico hidroxido de cobre a las macetas y al follaje, se suprimio la alimentacion de la vegetacion significativamente en las condiciones de invernadero con malla. Se atribuye estos resultados a una mejor persistencia de los residuos de fungicidas en el follaje que en las macetas de plastico.View this article in BioOne

We compared the lethal and sublethal effects of 2 novel Betaproteobacteria-based insecticides ( Burkholderia spp. strain A396 as Venerate® XC; Chromobacterium subtsugae strain PRAA4-1 as Grandevo® WDG) for suppression of 2 polyphagous insect pests of world-wide importance: green peach aphid, Myzus persicae (Sulzer) (Hemiptera: Aphididae), and Madeira mealybug, Phenacoccus madeirensis Green (Hemiptera: Pseudococcidae). In laboratory and screenhouse tests, the insects were exposed to residues applied by leaf dipping, or by spraying the insects and foliage. These novel products also were compared to a well-established product, spirotetramat (Movento® 240 SC). Spirotetramat was generally effective for suppression of both species of insects, and Burkholderia (Venerate) induced mortality levels that made it competitive with spirotetramat. Chromobacterium subtsugae (Grandevo) was less satisfactory, inducing only moderate levels of mortality in both species. Reproduction by aphids surviving exposure to Burkholderia was slightly affected, whereas C. subtsugae did not affect reproduction. New Betaproteobacteria-based insecticides show promise for a useful role in suppressing important insect pests such as M. persicae and P. madeirensis . Resumen Comparamos los efectos letales y subletales de 2 nuevos insecticidas basados en Betaproteobacteria (cepa Burkholderia s pp. A396 como Venerate ® XC; cepa PRAA4-1 de Chromobacterium subtsugae como Grandevo® WDG) para la supresion de 2 plagas de insectos polifagos de importancia mundial: el pulgon (afido) verde del melocoton, Myzus persicae (Sulzer) (Hemiptera: Aphididae) y la cochinilla harinosa de Madeira, Phenacoccus madeirensis Green (Hemiptera: Pseudococcidae). En pruebas de laboratorio y en una casa de malla, los insectos fueron expuestos a los residuos aplicados por la inmersion de hojas o al rociar los insectos y el follaje. Estos nuevos productos tambien se compararon con un producto bien establecido, spirotetramat (Movento® 240 SC). Spirotetramat fue generalmente efectivo para la supresion de ambas especies de insectos y Burkholderia (Venerate) indujo niveles de mortalidad que lo hicieron competitivo con spirotetramat. Chromobacterium subtsugae (Grandevo) fue menos satisfactorio, induciendo solo niveles moderados de mortalidad en ambas especies. La reproduccion de los afidos que sobrevivieron a la exposicion de Burkholderia se vio ligeramente afectada, mientras que C. subtsugae no afecto la reproduccion. Los nuevos insecticidas basados en Betaproteobacteria prometen tener un papel util en la supresion de plagas de insectos importantes, como M. persicae y P. madeirensis . View this article in BioOne

Lissachatina fulica (Bowdich, 1822) (Gastropoda: Achatinidae), also known as the giant African land snail, is a plant pest throughout much of the world, including southern Florida, where an established population of this snail was discovered in 2011. Apart from reports that it is polyphagous, food preferences and suitability are not well known. The suitability of 21 ornamental plants commonly grown in Miami, Florida, was tested using snail growth (snail shell height and snail mass) and survival. After hatching, 50 snails were reared for 70 d on each of 24 dietary treatments (21 natural diets and 3 control diets). French marigold ( Tagetes patula [Asteraceae]) was the ornamental plant diet that produced the largest snails (24 mm in shell height), producing snails equivalent in size to 2 of the control diets: romaine lettuce ( Lactuca sativa [Asteraceae]) and synthetic insect diet (gypsy moth). Plants allowing intermediate growth (> 10 mm) were cosmos ( Cosmos bipinnatus [Asteraceae]), salvia ( Salvia splendens [Lamiaceae]) , petra croton ( Codiaeum variegatum [Euphorbiaceae]), zinnia ( Zinnia elegans [Asteraceae]), Texas sage ( Leucophyllum frutescens [Scrophulariaceae]), beach sunflower ( Helianthus debilis [Asteraceae]), lantana ( Lantana camara [Verbenaceae]), kalanchoe ( Kalanchoe blossfeldiana [Crassulaceae]), and butterfly weed ( Asclepias tuberosa [Apocynaceae]). There was a strong positive correlation between survival and plant suitability, as judged by shell height ( r = 0.89). However, some plants tested, such as purslane ( Portulaca oleracea [Portulacaceae]), sunflower ( Helianthus annuus [Asteraceae]), dusty miller ( Centaurea cineraria [Asteraceae]), and oyster plant ( Tradescantia spathacea [Commelinaceae]) only provided minimal growth ( 10 mm) fueron: cosmos ( Cosmos bipinnatus [Asteraceae]), salvia ( Salvia splendens [Lamiaceae]), petra croton ( Codiaeum variegatum [Euphorbiaceae]), zinnia ( Zinnia elegans [Asteraceae]), cenizo Leucophyllum frutescens [Scrophulariaceae]), girasol de playa ( Helianthus debilis [Asteraceae]), lantana ( Lantana camara [Verbenaceae]), kalanchoe ( Kalanchoe blossfeldiana [Crassulaceae]) y la maleza mariposa ( Asclepias tuberosa [Apocynaceae]). Hubo una fuerte correlacion positiva entre la sobrevivencia y la sostenebilidad de las plantas, segun la altura de la concha (r = 0,89). Sin embargo, algunas plantas probadas, como el perejol ( Portulaca oleracea [Portulacaceae]), el girasol ( Helianthus annuus [Asteraceae]), centaurea ( Centaurea cineraria [Asteraceae]) y la planta ostra ( Tradescantia spathacea [Commelinaceae] solo proporcionaron un crecimiento minimo (

Seasonal abundance and spatial distribution of melonworm, Diaphania hyalinata L. (Lepidoptera: Crambidae), on yellow squash were studied during 4 crop-growing periods in 2014 in Homestead, Florida. The abundance of D. hyalinata larvae ranged from a minimum during Dec 2014 (1.3 ± 0.0 larvae per 2 leaves) when temperatures were relatively low (15–20 °C), to a maximum in Sep 2014 (6.6 ± 0.1 larvae per 2 leaves) when temperatures were relatively high (24–26 °C). The abundance of small larvae (L1 L2) was relatively greater, with a maximum of 7.1 ± 0.3 larvae per 2 leaves, as compared with medium-sized larvae (L3 L4) (2.4 ± 0.1 per 2 leaves) and large larvae (L5) (2.4 ± 0.1 larvae per 2 leaves) throughout the year. The abundance of large larvae was consistently low over the entire year. Diaphania hyalinata distributions tended to be aggregated (b > 1) during the crop-growing periods during May, Jun–Jul, and Sep 2014, when the population densities were relatively high, but were uniform (b < 1) during Dec 2014, when the population densities were low. A weak but statistically significant positive linear relationship existed between temperature and larval abundance. The results from this study will help squash and cucurbit growers of south Florida in monitoring melonworm infestations in the field and in developing a knowledge-based management program.

The biology of the widely occurring but poorly known terrestrial snail Allopeas gracile (Hutton, 1834) (Gastropoda: Subulinidae) was determined, emphasizing food relationships. Isolated snails reproduced without cross fertilization. These snails deposited small clusters of eggs (3–7 per d) totaling about 20 per mo once oviposition commenced (after about 50 d). The snails grew rapidly for 50 d, attaining a mass of about 25 mg, then grew more slowly, eventually attaining a mass of about 50 mg after 250 d. Hatching occurred over a wide range of temperatures. The mean duration of the egg stage decreased from 18.7 to 8.0 d as the temperature increased from 19.5 to 32.0 °C. Allopeas gracile was omnivorous, feeding on green plants (vegetables, weeds, and flowers), fungi (cultivated mushroom and sooty mold), and animal matter (dead cockroaches and earthworms), but not decaying vegetation (tree leaves). Although this species is omnivorous, many plants allowed only maintenance, not fostering rapid growth. These small snails consumed only about 1.5 cm2 per d of favored food (lettuce) at maturity, and considerably less of most plants offered. This invasive snail does not seem to be destined to be a significant pest except perhaps under restricted circumstances.

The 'cornsilk fly,' Euxesta stigmatias Loew, is an attractive, dark metallic green fly with distinctive wing patterns and wing flapping behavior commonly found throughout southern Florida agricultural communities. Its normally saprophytic life style belies its destructive nature when it comes to its preference for sweet corn ears. Entire fields may have to be passed up for harvest if they went untreated for this destructive pest or if individual treatments were missed due to weather, time or other constraints. This document is EENY-224, one of a series of the Department of Entomology and Nematology, UF/IFAS Extension. Original publication date August 2001. Revised July 2005. EENY-224/IN381: Cornsilk Fly (suggested common name), Euxesta stigmatias Loew (Insecta: Diptera: Otitidae) (ufl.edu)

Grasshopper populations on western grasslands historically have exhibited dramatic shifts in numerical abundance. Increases in abundance, alone or in combination with migration, have had devastating effects on the agricultural economy of the affected areas. This chapter reviews the important elements affecting the population ecology of western rangeland grasshoppers, and emphasizes the different or unique aspects associated with the shortgrass region. Examination of literature on grasshoppers in the Great Plains region of North America indicates that each of the three major grasshopper subfamilies is well represented throughout the region. Grasshopper phenology, in particular, vanes with location due to differences in grasshopper population composition. Although key species in the northern Great Plains exhibit considerable synchrony in hatch and development, southern regions apparently have more late-developing species. Any long-term collection of data on grasshopper occurrence demonstrates periods of great abundance interspersed by periods of rarity.

Calliphorid species form larval aggregations that are capable of generating heat above ambient temperature. We wanted to determine the relationship between volume, number of larvae, and different combinations of instars on larval mass heat generation. We compared different numbers of Chrysomya megacephala (F.) larvae (40, 100, 250, 600, and 2,000), and different combinations of instars (∼50/50 first and second instars, 100% second instars, ∼50/50 second and third instars, and 100% third instars) at two different ambient temperatures (20 and 30 °C). We compared 13 candidate multiple regression models that were fitted to the data; the models were then scored and ranked with Akaike information criterion and Bayesian information criterion. The results indicate that although instar, age, treatment temperature, elapsed time, and number of larvae in a mass were significant, larval volume was the best predictor of larval mass temperatures. The volume of a larval mass may need to be taken into consideration for determination of a postmortem interval.

The melonworm, Diaphania hyalinata L. (Lepidoptera: Crambidae), is one of the most serious insect problems affecting cucurbit production. We evaluated the relative preference and suitability of yellow squash, zucchini, cucumber, and watermelon to melonworm by measuring its oviposition, larval feeding preference, survivorship, and developmental responses in the laboratory. Whole plants were used for oviposition study, whereas host leaf discs were used for all the other studies. Watermelon feeding resulted in the longest larval development period (14.3 d), greatest prepupal weights and survivals rates (92%; first instar to adult) among the four crops. However, for watermelon, adult oviposition preference (199.5 eggs/♀), egg survival (70%), and larval feeding (4.1% defoliation) were numerically or statistically lowest, and larval head capsule widths and whole-body lengths were smallest. When differences occurred among these variables, yellow squash, zucchini, and cucumber were each typically higher (or quicker to develop) than watermelon. So why do melonworm adults not prefer watermelon, or at least select it as frequently as squash and cucumber when ovipositing? The answer likely is that there might be some variation in the important chemical components among these cucurbits. We suggest that comparison of kairomones and allomones from watermelon and related cucurbits would be very useful for determining the combination resulting in the lowest risk of damage to the more susceptible cucurbits (assuming the levels can be modified without seriously affecting the crops).

The effects of three copper-based fungicides on feeding by four terrestrial molluscs (two slugs and two snails) were assessed in laboratory choice and no-choice tests. These products functioned effectively as short-term feeding deterrents. However, a copper hydroxide-based fungicide was more persistent than copper octanate- and copper diammonia diacetate-based fungicides under field conditions. Tests with foliage treated in the field and fed to Leidyula floridana and Lissachatina fulica showed that significant feeding suppression persisted for several days. We also determined that copper hydroxide was repellent, affecting movement of L . floridana slugs independent of food. Further, we assessed copper hydroxide effects with and without iron phosphate molluscicide bait. Copper hydroxide alone significantly suppressed foliage consumption, but did not affect slug survival. Iron phosphate bait alone caused slug mortality, and significantly suppressed feeding, but only after 24 h. Significantly improved foliage protection, relative to iron phosphate bait application alone, was attained when copper hydroxide repellent was used simultaneously with iron phosphate bait. Where terrestrial molluscs are a plant protection issue, it appears that ancillary benefit can be derived from using copper hydroxide fungicides. These data provide evidence for the potential application of the “push–pull” or “stimulo-deterrent” concept relative to mollusc management; plant protection may be enhanced when attractant and repellent treatments are applied simultaneously.

Leidyula floridana (Leidy) (Gastropoda: Veronicellidae) has long been known to be a plant pest in the Caribbean region and southern Florida, though its range has expanded to include northern Florida, other Gulf Coast states, and Mexico. It is nocturnal, and often overlooked as a source of plant damage. Although polyphagous, it does not feed on all plants, and it is desirable to know what bedding plants will likely be damaged by this common herbivorous slug. To identify readily accepted bedding plants, I conducted a series of comparative trials of 7 d duration to assess the acceptance of 30 commonly grown bedding plants relative to French marigold, a plant that is commonly fed upon by slugs and snails. Several commonly grown bedding plants were shown to be very susceptible to feeding injury. In a second set of 7-d trials, I compared 14 plants from among those that were not readily accepted in the first set of trials to determine if they would remain poorly accepted when not provided with favored food. In the second set of trials, the levels of herbivory shown in the first trials were maintained, demonstrating that some bedding plants are not acceptable to L. floridana even when the slugs do not have access to acceptable food. Thus, a list of readily available bedding plants that resist herbivory by this slug has been determined, providing gardeners with slug-resistant choices. The most unacceptable species (damage rating = 1.00) were: lantana (Lantana camara L.; Verbenaceae), tickseed (Coreopsis spp.; Asteraceae), torenia (Torenia fournieri Linden ex E. Fourn.; Linderiaceae), angelonia (Angelonia angustifolia Benth.; Plantaginaceae), and snapdragon (Antirrhinum majus L.; Plantaginaceae). Additional plant species that were not very acceptable (damage rating of between 1.00 and 1.50) were blue daze (Evolvulus glomeratus Choisy; Convolvulaceae), dusty miller (Centaurea cineraria [L.] Jacq. ex Nym.; Asteraceae), viola (Viola hybrid; Violaceae), celosia (Celosia argentea L.; Amaranthaceae), and geranium (Geranium spp.; Geraniaceae). In contrast, plant species that seem to be at considerable risk of damage (damage rating 3 to 5) by L. floridana were: French marigold (Tagetes patula L.; Asteraceae), Madagascar periwinkle (Catharanthus roseus [L.] G. Don; Apocyanaceae), coleus (Plectranthus scutellarioides [L.] R. Br.; Laminaceae), petchoa (Petunia × Calibrachoa; Solanaceae), zinnia (Zinnia elegans Jacq.; Asteraceae), polka dot plant (Hypoestes phyllostachya Baker; Acanthaceae), chrysanthemum (Chrysanthemum morifolium Ramat; Solanaceae), petunia (Petunia spp.; Solanaceae), Stokes' aster (Stokesia laevis [Hill] Greene; Asteraceae), scarlet sage (Salvia splendens Sellow ex Nees; Lamiaceae), butter daisy (Melampodium paludosum Kunth; Asteraceae) and verbena (Verbena spp.; Geraniaceae). A few species were intermediate in susceptibility, namely: impatiens (Impatiens hawkeri W. Bull; Balsamaniaceae), wax begonia (Begonia × Semperflorens × Cultorum; Begoniaceae), sweet potato vine (Ipomoea spp.; Convolvulaceae), firecracker flower (Crossandra infundibuliformis [L.] Nees; Acanthceae), sweet William (Dianthus barbatus L.; Caryophyllaceae), pansy (Viola × Wittrochinana; Violaceae), purslane (Portulaca oleraceae L.; Portulacaceae), and alyssum (Lobularia maritima [L.] Desv.; Brasscaeae).

Redbay ambrosia beetle, Xyleborus glabratus Eichhoff (Coleoptera: Curculionidae: Scolytinae), is a nonnative pest that transmits the pathogenic fungus Raffaelea lauricola T.C. Harr., Fraedrich & Aghayeva (Ophiostomatales: Ophiostomataceae), which causes laurel wilt disease in trees of the family Lauraceae. Laurel wilt is present in the commercial avocado (Persea americana Mill.; Laurales: Lauraceae) growing areas of Florida and poses a potential threat to the avocado industries of California and Mexico. The life cycle of X. glabratus was studied in avocado logs at 16, 20, 24, 28, and 32 °C. Xyleborus glabratus successfully completed its life cycle at 24, 28, and 32 °C, with the greatest oviposition and development rate at 28 °C. Development of the egg and pupal stages was studied at 12, 16, 18, 20, 24, 28, 32, and 36 °C. One linear and 7 nonlinear developmental models were used to estimate the temperature-dependent development of both stages. The linear model estimated the lower threshold temperatures for egg and pupal development to be 13.8 °C and 11.1 °C, respectively, and the degree-days (DD) for egg and pupal development to be 55.1 DD and 68.2 DD, respectively. The Brier-2, Ratkowsky, Logan, and polynomial models gave the best estimates for the temperature-dependent development of the egg stages, whereas the Brier-1, Logan, and polynomial models gave the best estimates of temperature-dependent development of the pupal stages. Our results suggested that the optimal temperature for development of X. glabratus was around 28 °C, and that temperature will play an important role in the spread and successful establishment of X. glabratus.

Leidyula floridana (Leidy, 1851) (Mollusca: Gastropoda: Veronicellidae), also known as Florida leatherleaf slug, has long been known to be a pest of ornamental plants in southern Florida, and of food crops in the Caribbean region. Its geographic range is expanding, and it also has become an intermediate host for the nematode Angiostrongylus cantonensis (Chen, 1935) (Strongylida: Metastrongylidae), which can cause meningoencephalitis in humans and other primates if ingested. Thus, it is increasingly important that we understand its biology and management. We determined that about 50% survived more than 18 mo under laboratory conditions. It attained a maximum mean weight of about 13.4 g after 18 mo, but individuals as large as 28.5 g were occasionally obtained in our cultures. It burrowed in the soil or sought shelter during the daylight hours. Slugs began egg production when 3–7 g in weight, and deposited clusters of about 45 oval eggs in or atop the soil. Eggs measured about 7.4 mm in length and ...

Injury caused by picture-winged flies or corn silk flies (Diptera: Ulidiidae) is a major limiting factor of corn (Zea mays L.: Poales: Poaceae) yields in Florida. Growers have relied heavily on chemical insecticides for control of these pests. However, we are exploring other methods, such as the use of biological control by predatory arthropods, which may be factors in an integrated pest management (IPM) program. Thus, information on the distribution of the flies and their predators and responses of the predators to the flies is potentially useful. Taylor's Power Law, Iwao's Patchiness Regression, and the Index of Dispersion were used to study distribution patterns of arthropods found on sweet corn ears in 2010. Arthropod groups included eggs and larvae of Euxesta stigmatias (Loew), E. eluta (Loew), E. annonae F. (Diptera: Ulidiidae), nymphs and adults of Orius insidiosus (Say) (Hemiptera: Anthocoridae), and larvae of Anotylus insignitus (Gravenhorst) (Coleoptera: Staphylinidae). In each season i...

Phylomycus carolinianus (Bosc, 1902), (Mollusca: Gastropoda: Philomycidae) also known as Carolina mantleslug, is a widespread but poorly known terrestrial mollusc. We conducted studies to assess key aspects of its natural history. In the laboratory, its pattern of growth followed a sigmoid curve, but the growth rate was highly variable. Using a hierarchical clustering analysis of time to achieve reproductive maturity, the individual slugs could be separated into 4 discrete developmental groups: fast, intermediate, and slow-growing individuals, and also some that failed to develop completely. The 3 groups of developing slugs achieved reproductive maturity in about 129, 173, and 217 days, respectively. This developmental polymorphism suggests intra-generation risk-spreading. Reared alone or in pairs, slugs produced eggs in about 6 months; eggs numbered about 65 per cluster, though paired slugs produced slightly more eggs per cluster. Thus, these hermaphroditic slugs are capable of self-fertilizatio...

The eastern lubber grasshopper, Romalea microptera (Palisot de Beauvois) (Orthoptera: Romaleidae)[also known as R. guttata (Houttuyn)], is known to be polyphagous, but little else is known about its diet. Choice and no-choice tests were conducted to determine plant preference. In choice tests, 104 different plants were presented and relative preference was determined using ‘Romaine’ lettuce (Lactuca sativa L. var. longifolia; Asteraceae) as a standard. These included representative plants from several categories, including ornamental plants, weeds, shrubs, trees, vines, aquatic or semiaquatic plants, and vegetable crops. The grasshoppers did not display a statistically significant difference in selection, relative to ‘Romaine’ lettuce, for 20% of the plants evaluated; these should be considered very susceptible to injury because lettuce is a readily accepted plant. A few plants (3%) were more preferred than lettuce, and of course would also be at high risk for consumption. The majority of plants tested (77%) were significantly less preferred, but even some of these are at risk because, like other polyphagous insects, lubbers sometimes will feed on less acceptable plants when preferred plants are not available. A subset of these (n = 25) was also presented in no-choice tests, and the choice and no-choice responses compared. Plant preference in choice and no-choice tests was significantly correlated. A selection of ornamental plants (n = 10) that scored least-preferred in choice tests was assessed in no-choice ‘starvation’ tests, and 9 of the 10 proved to be quite resistant to grasshopper feeding. Several plants (n = 5) that produce foliage asynchronously were assessed in choice tests, with the grasshoppers preferring young foliage relative to old foliage. In field cage studies, the acceptability of plants significantly affected the efficacy of insecticide-containing baits, with significantly higher mortality found in cages containing non-preferred plants. Thus, host plant selection affects damage directly by regulating the amount of feeding, and indirectly by influencing acceptance of bait.

Since the 1960s, the USA has led all other countries in the production of sweet corn (Zea mays L.), and Florida has often led the nation, such as from 2004 to 2009. Picture-winged flies, or corn silk flies, including Euxesta stigmatias Loew, E. eluta Loew, E. annonae F., and Chaetopsis massyla Walker (Diptera: Ulidiidae), are serious pests of field and sweet corn in southern Florida. Control has focused on the use of chemical insecticides, but efforts have begun to explore other control methods, such as using predatory arthropods. We studied the timing, abundance, identification, and predatory status of ulidiids and other arthropod species associated with corn ears growing in the field in the spring, summer, and fall of 2010. Predators of ulidiids included Orius insidiosus Say (Hemiptera: Anthocoridae), Anotylus insignitus (Gravenhorst) (Coleoptera: Staphylinidae), Chrysoperla carnea Smith (Neuroptera: Chrysopidae), Zelus longipes (L.) (Hemiptera: Reduviidae), and potentially other arthropod species. Larvae of A. insignitus, C. carnea, and nymphs and adults of O. insidiosus consumed eggs and larvae of ulidiids in laboratory no-choice tests. Other than ulidiid eggs and/or larvae, O. insidiosus was the most abundant arthropod species in the silking (R1) stage of corn in all 3 seasons. Sap beetle larvae or adults (Coleoptera: Nitidulidae) were the most abundant arthropod groups in the spring blister stage (R2) and in milk stages (R3) of the spring and fall. The most abundant groups in the summer R2 and R3 stages included A. insignitus larvae and sap beetle larvae and adults, and in the summer R2, also O. insidiosus. The most abundant groups in the fall R2 were O. insidiosus, sap beetle adults, Thrips sp. (Thysanoptera: Thripidae), and mites. Chrysoperla carnea was found only in the summer, and Z. longipes only in the fall. In all 3 seasons, ulidiid eggs were more abundant than larvae in the R1 stage, but larvae usually outnumbered eggs in the R2 and R3 stages. Each of the groups, O. insidiosus and eggs and larvae of ulidiids, were most abundant in the summer followed by the fall and least abundant in the spring. These findings may help in determining spatial distributions and functional responses of these predators to further evaluate their potential to control ulidiid flies.

McPherson JE [Ed.]. 2018. Invasive Stink Bugs and Related Species (Pentatomoidea). Biology, Higher Systematics, Semiochemistry, and Management. CRC Press, Boca Raton, FL. 819 pp. ISBN 9781498715089 $149.95 (hardcover). View this article in BioOne

The snail Zachrysia provisoria (Pfeiffer) is poorly known in Florida, USA, where it predominately is viewed as a pest of ornamental plants. I evaluated its host plant relationships, foliage consumption potential, and susceptibility to several molluscicides. Many of the potential hosts, especially common ornamental plants that are planted densely as ground cover and might be expected to provide a favorable environment for snails, are not suitable for growth of young snails. Older snails, though displaying some ability to feed and damage hosts unsuitable for growth of young snails, displayed similar patterns of acceptance and growth. Several weeds were favorable for growth, suggesting that untended environments could lead to snail problems in adjacent ornamental plantings. The effect of plant condition (age) on snail feeding preference was assessed by measuring leaf consumption by snails presented simultaneously with young (green, located apically) and senescent (yellowing or yellow, located basally) leaves of a single plant species. From preferred host plants, snails chose young leaf tissue, but from less preferred plants they consumed senescent tissue. Foliage consumption potential was assessed using romaine lettuce at two constant temperatures, 24 and 32 °C. Foliage consumption increased with age (wet weight) at both 24 and 32 °C; however, the rate of consumption was higher at the lower temperature. At 24 °C, mean peak consumption was about 40 cm2 of leaf area or 12 g wet weight/day. At the less favorable high temperature of 32 °C, mean peak consumption was reduced by about 50%, to a mean of only 20 cm2 or 6 g wet weight/day. Relative consumption rate (cm2 or g foliage/g snail) diminished with age (wet weight) of the snails. Several molluscicide-containing baits were assessed. Metaldehyde-based baits induced mortality most quickly, followed by iron-based baits. A boric acid-based bait was slowest, requiring 12 days for the induction of significant levels of mortality. All baits significantly suppressed feeding, however, sometimes even in the absence of mortality.

The redbay ambrosia beetle, Xyleborus glabratus Eichhoff (Coleoptera: Curculionidae: Scolytinae), is a wood-boring pest that transmits the fungal pathogen Raffaelea lauricola, the causal agent of laurel wilt disease in American Lauraceae. This study documents the gallery formation patterns of X. glabratus as well as its life cycle and development at 25 ± 2 °C in logs of 3 natural hosts: avocado (Persea americana), redbay (P. borbonia) and swampbay (P. palustris). Females were observed to excavate galleries perpendicular to the tree trunk; galleries were characterized by a main entrance tunnel, from which branched secondary tunnels that, in turn, gave rise to tertiary tunnels. By dissecting infested logs daily, the length of time was determined for each developmental stage, and found to be comparable in all 3 hosts. Eggs were first encountered in avocado, redbay, and swampbay at 7, 11, and 10 days after gallery initiation (agi), respectively; larvae at 14, 20, and 14 days agi; pupae at 24, 26, and 26 days agi; and teneral adults at 31, 30, and 27 days agi. Despite comparable rates of development in all hosts, there were fewer progeny per female produced in avocado. Oviposition by the founding female extended over a broad time-span, and all stages were observed in the gallery at 1 month agi. Three larval instars were present, with mean head capsule widths of 0.21, 0.26, and 0.37 mm, respectively. Long term rearing of X. glabratus was achieved on swampbay logs soaked in water prior to infestation. Emergence of new females from logs was first observed at 60 d agi, indicating that teneral adults remain in hosts for ~1 month prior to dispersal. Emergence continued for up to 240 days, with maximum emergence observed between 120-150 days agi.

Chrysomya megacephala (Fabricius) is a forensically important fly that is found throughout the tropics and subtropics. We calculated the accumulated development time and transition points for each life stage from eclosion to adult emergence at five constant temperatures: 15, 20, 25, 30, and 35 ° C. For each transition, the 10th, 50th, and 90th percentiles were calculated with a logistic linear model. The mean transition times and % survivorship were determined directly from the raw laboratory data. Development times of C. megacephala were compared with that of two other closely related species, Chrysomya rufifacies (Macquart) and Phormia regina (Meigen). Ambient and larval mass temperatures were collected from field studies conducted from 2001–2004. Field study data indicated that adult fly activity was reduced at lower ambient temperatures, but once a larval mass was established, heat generation occurred. These development times and durations can be used for estimation of a postmortem interval (PMI).

Xyleborus glabratus (Coleoptera: Curculionidae: Scolytinae) is a non-native pest that transmits the causal pathogen of laurel wilt disease to plants belonging to the Lauraceae. To improve the current monitoring and survey techniques of X. glabratus, various trapping and flight behavior studies were conducted in natural areas with host species in Alachua County, Florida. Daylight flight rhythm studied at Austin Cary Memorial Forest twice in Sep 2010 using sticky traps baited with manuka lures showed that X. glabratus flies mostly between 1600 and 1800 h daylight saving time. Flight height of the beetle was determined in a trapping study using ladder-like traps. The largest number of beetles was trapped at heights of 35–100 cm above the ground. Seasonality of X. glabratus was studied in Florida from Mar 2010–Dec 2011. Three peaks of trap catches occurred during Apr 2010, Oct 2010 and Mar 2011. To find the optimal Lindgren funnel trap design for X. glabratus, a study was conducted using 4, 8, 12 and...

Natural products are usually used as a food source for the culture of terrestrial molluscs. Better uniformity, and perhaps economy, could be introduced to the culture of molluscs by using synthetic diets. I assessed acceptance by various terrestrial molluscs of several insect diets developed for culture of caterpillars, and suitability for mollusc growth. Diet selection (preference) studies were conducted with 2 species of snails (Cuban brown snail, Zachrysia provisoria; Asian tramp snail, Bradybaena similaris) and 4 species of slugs (meadow slug, Deroceras laeve; grey fieldslug, Deroceras reticulatum; dusky arion, Arion subfuscus; Carolina mantleslug, Philomycus carolinianus). The molluscs differed in their preference for insect diets, though tobacco hornworm diet and a bean-based diet often used for cutworms usually were not preferred, whereas gypsy moth, diamondback moth, and spruce budworm diets tended to be more preferred. Short-term (7-wk) developmental (weight gain) studies were conducted ...

Larvae of 11 species of picture-winged flies (Diptera: Ulididae) are known to feed on corn plants (Zea mays L.) in the western hemisphere. Larvae emerge from eggs deposited in leaf axils and corn silk to feed mostly within ears, but the primary versus secondary nature (i.e., pest status) of their infestation is not known for all of these species. Choice and no-choice tests by using a split-plot design were conducted in greenhouse and field trials to determine the pest status on sweet corn of three of these species found in Florida: Chaetopsis massyla (Walker), Euxesta eluta Loew, and E. stigmatias Loew. The main treatments (uninfested ears and ears experimentally infested with either Spodoptera frugiperda [Lepidoptera: Noctuidae] or E. eluta larvae) were applied at first silk. The subtreatments (C. massyla, E. eluta, or E. stigmatias adults caged on ears) were applied 7 d later and maintained for 10 d. All three fly species were reared from uninfested and experimentally infested ears in both choice and no-choice tests in greenhouse and field trials confirming both primary and secondary modes of ear infestation. More flies of all three species emerged from ears that were preinfested with S. frugiperda compared with uninfested ears suggesting either preference for or greater survival within ears previously infested by S. frugiperda. Fewer E. eluta and E. stigmatias emerged from ears preinfested with E. eluta in no-choice field tests, suggesting that previous infestation by this fly may negatively affect oviposition or that older fly larvae affect survival of neonate larvae. All three species studied here should be considered primary pests that can render unprotected sweet corn ears unmarketable.

Redbay ambrosia beetle (RAB), Xyleborus gla bratus Eichhoff (Coleoptera: Curculionidae: Sco lytinae), a native of Asia, was first discovered in the USA near Savannah, Georgia in 2002 (Haack 2001; Rabaglia et al. 2006). RAB is an effective vector of Raffaelea lauricola T.C. Harr., Fraedrich & Aghayeva (Harrington et al. 2008) that causes laurel wilt (LW), a lethal disease of several trees in the Lauraceae in the southeastern USA (Crane et al. 2008; Mayfield et al. 2008). Ambrosia beetle adults bore through the bark and into the xy lem (wood) where they lay eggs, then adults and larvae cultivate and feed on symbiotic ambrosia fungi that grow in the galleries. Native Persea (Laurales: Lauraceae) species appear to be pre ferred hosts. LW is responsible for high mortality of redbay [P borbonia (L.) Spreng.], swampbay [P palustris (Raf.) Sarg.], and sassafras [Sassa fras albidum (Nuttall) Nees] in Alabama, Flor ida, Georgia, Mississippi, North Carolina and South Carolina (Fraedrich et al. 2008; Hanula et al. 2008; Gramling 2010). As LW encroaches upon the Lake Wales Ridge ecosystem in south central Florida, silkbay (P. humilis Nash) is also showing susceptibility to LW and is dying. Addi tional species affected by LW include avocado (P. americana Mill.), spicebush [Lindera benzoin (L.) Blume], and other woody Lauraceae (Fraedrich et al. 2008) (Table 1). The susceptibility of 5 avocado cultivars of Mexican, Guatemalan or West Indian origin to RAB and LW was demonstrated by Mayfield et al. (2008). However, with more than 23 West In dian cultivars grown in Florida, it is necessary to determine their susceptibility. Moreover, as an adventive species to the North American conti nent, RAB might affect other valuable New World species. Most Persea species are of Mexican, Cen tral American, or South American origin. These Persea may have significant value in germplasm collections, some have been discovered recently, and some have resistance to diseases that afflict their commercial relative, the avocado (Skutch et l. 1992; Scora & Bergh 1992; Zentmyer & Schieber 1992). Thus, their susceptibility to RAB and LW warrants evaluation. Another member of the Lauraceae of much concern is the California bay laurel [Umbellularia californica (Hook. & Arn.) Nutt.], a dominant hardwood species of the U.S. Pacific Coast. Through inoculation experi ments, Fraedrich (2008) demonstrated that U. californica is susceptible to LW. With continued westward spread of LW, the host status of U. cali fornica needs to be confirmed. The 3 studies presented here evaluate sus ceptibility to RAB and LW in: 1) 13 West Indian avocado cultivars; 2) 10 non-commercial Persea spp., 1 Beilschmidia sp. (a genus related to Per sea), and 3) U. californica. First, no-choice ex periments were conducted to determine if RAB would bore into avocado cultivars not screened previously by Mayfield et al. (2008) and follow ing similar methodology. Avocado cultivars 'Ber necker', 'Beta', 'Brooks late', 'Choquette', 'Don nie', 'Dupuis', 'Hall', 'Loretta', 'Lula', 'Monroe', 'Simmonds', 'Tower 2' and 'Waldin' (4 plants each) were planted in 10-gallon pots in a screenhouse at he Plant Sciences Research and Education Unit, University of Florida (UF), Citra, Florida in VI 2008. Two plants of each cultivar were infested by enclosing 4 newly emerged 9 RAB (UF colony reared) within a mesh sleeve on the lower trunk. Two plants per cultivar were uninfested controls. Entrance holes and perseitol (white exudate from wounds) were monitored for 4 wk. Severity of wilt symptoms was scored using the following LW in dex: 0 = no wilt; 1 = wilt, no leaf necrosis; 2 = wilt, 10% necrosis or defoliation; 3 = wilt, 30% necrosis/ defoliation; 4 = 50% necrosis/defoliation; 5 = 75% necrosis/defoliation; 6 = 100% necrosis/defoliation

Eleven species of picture-winged flies (Diptera: Ulidiidae: Lipsanini) have been reported attacking maize [Zea mays L. (Poaceae)] ears in the Americas. Four of these species are sweet corn pests in America north of Mexico: Chaetopsis massyla (Walker), Euxesta annonae (Fabricius), E. eluta Loew, and E. stigmatias Loew. Adults of these four species appear at the beginning of each season following maize-free periods, suggesting other plants act as food sources for maintenance and development of these flies. Studies were conducted in Florida, USA, to evaluate the suitability of several crop and non-crop plants commonly occurring near maize plantings as developmental hosts for these flies. Laboratory trials were conducted using laboratory colonies of C. massyla, E. eluta ,a ndE. stigmatias to determine their developmental rates and pupal survivorship on roots, stems, leaves, or fruits of 14 cropandweedspecies.Allthreeflyspeciescompleteddevelopment onalltestedcrops(Brassicaoleracea L., Capsicum chinense Jacquin, Capsicum annum L., Carica papaya L., Persea americana Mill., RaphanussativusL.,SaccharumofficinarumL., andSolanumlycopersicumL.)andweedspecies [Amaranthus spinosus L., Portulaca oleracea L., Sorghum halepense (L.), and Typha spp.], except for Daucus carota L. roots and Solanum tuberosum L. tubers. Findings of the current study suggest that the presence of multiple host crops in areas surrounding maize fields may help explain the occurrence of thesemaize-infestingulidiidsimmediatelyafterprolongedabsencesofmaize.

The redbay ambrosia beetle (RAB), Xyleborus glabratus Eichhoff (Coleoptera: Curculionidae: Scolytinae), is an adventive pest of Lauraceae in the southeastern U.S. This wood-boring insect vectors a lethal fungus, Raffaelea lauricola T. C. Harr., Fraedrich & Aghayeva, the causal agent of laurel wilt (LW) disease. The vector-pathogen complex is responsible for extensive mortality of native Persea trees in South Carolina, Georgia, and northern Florida, and now poses an imminent threat to the avocado (Persea americana Mill.) industry in south Florida. While chemical control of the vector is not viewed as the primary solution, control tactics should be made available to Florida avocado growers. Field and laboratory tests were conducted using avocado bolts, potted avocado trees, and field grown swampbay trees (Persea palustris (Raf.) Sarg.) treated with contact and systemic insecticides. Zeta-cypermethrin + bifenthrin and lambda-cyhalothrin + thiamethoxam provided the most consistent control of Scolytin...

Several species of Ulidiidae (Diptera) are primary pests of maize (Zea mays L.). The ability to distinguish their immature stages would be useful for biological studies where their distributions overlap. Morphology of the immature stages was examined for three Ulidiidae that attack maíze in the southeastern United States: Chaetopsis massyla (Walker), Euxesta eluta Loew, and Euxesta stigmatias Loew. Egg, larval, and pupal characters were measured and described with the aid of light and scanning electron microscopy. Because of considerable overlap in character states, only a few traits in each stage could be used to separate these three species. C. massyla eggs had pores restricted to the posterior end, but the pores were evenly distributed in the two Euxesta species. Eggs of the two Euxesta species could not be differentiated. Larval mouth hooks of C. massyla had a distinct tooth on their ventral surface, whereas this tooth was lacking in E. eluta and E. stigmatias. Fewer oral ridges were observed on C. massyla larvae than on E. eluta or E. stigmatias. Posterior spiracular slits were apparent in E. stigmatias versus obscure in E. eluta larvae. The length and spinule arrangements on creeping welts could be used to separate E. eluta and E. stigmatias larvae. Posterior spiracular plates of C. massyla puparia were trapezoidal versus ovoid in the two Euxesta species. Puparium color varied significantly among the three species.

BACKGROUND: The deterrent effect of seven commercial compounds against Schistocerca americana (Drury) nymphs and Diaprepes abbreviatus L. adults, two important citrus pests, was investigated. Extracts of three Florida local plants were also tested as deterrents. Antifeedant activity was assayed using a leaf-disk bioassay in choice and no-choice tests. The residual activity of the commercial compounds that significantly deterred the insects was assayed by applying them to foliage of citrus plants exposed to three time intervals of sunlight. RESULTS: Sabadilla, azadirachtin and ryanodine effectively deterred S. americana, whereas rotenone, sabadilla and ryanodine reduced the feeding activity of D. abbreviatus. Methanol and methylene chloride extracts of Ceratiola ericoides Michaux deterred D. abbreviatus, but only methylene chloride extract dissuaded S. americana. Methanol extract of Ardisia crenata Sims functioned as a feeding deterrent against both S. americana and D. abbreviatus, but only the latter species was deterred by methylene chloride extract of A. crenata. Extracts of Illicium parviflorum Michaux ex Ventetat only dissuaded the insects in choice bioassays. Rapid loss of effectiveness was observed under field conditions. Sabadilla was the only compound that maintained its antifeedant properties in the field, but only against S. americana. CONCLUSION: Based on their deterrency, some of the commercial products and plant extracts have potential for use as substitute crop protectants against the pest species tested. Copyright © 2011 Society of Chemical Industry

The picture-winged fly Euxesta stigmatias Loew (Diptera: Ulidiidae) has been a serious pest of sweet corn (Zea mays L.) in Florida since 1930. Several other species in the family are known to infest corn grown in the Caribbean, Central America, and South America. Surveys were conducted throughout Florida to evaluate species richness and distribution of corn-infesting Ulidiidae. Adults were sampled with sweep nets and reared from fly larvae-infested corn ears collected from representative corn fields in 16 and 27 counties in 2007 and 2008, respectively. Four Ulidiidae species were found in corn fields using both sampling techniques. Euxesta eluta Loew and Chaetopsis massyla (Walker) were found throughout the state on field and sweet corn. Euxesta stigmatias was only found in Martin, Miami-Dade, Okeechobee, Palm Beach, and St. Lucie Counties on field and sweet corn. Euxesta annonae (F.) was found in sweet corn in Miami-Dade, Okeechobee, and Palm Beach Counties, but field corn was not sampled in the...

The picture-winged fly Euxesta stigmatias Loew (Diptera: Ulidiidae) has been a serious pest of sweet corn in Florida since the 1930s and had been considered the only fly infesting Florida corn. In a sweet corn variety trial to evaluate E. stigmatias resistance in 2007, adult Chaetopsis massyla (Walker) (Diptera: Ulidiidae) was reared from the ears. Choice and no-choice trials were conducted in 2007 and 2008 to determine the pest nature of C. massyla on corn. In no choice tests, C. massyla pairs were caged on uninfested corn ears in green house and field trials. In choice tests, field collected corn ears were held for fly emergence. No choice tests showed that C. massyla could infest and complete development in ears that had no previous damage. Chaetopsis massyla emerged from corn ears with and without prior infestation by other insect species in choice tests. Subsequently, C. massyla were reared from corn ears collected from locations throughout the major sweet corn growing region of southern Flo...

The effects of three bio-insecticides Azatrol [neem: 1.2% azadirachtin A and B], Molt-X [neem: 3% azadirachtin], and Conserve SC [spinosad; 11.6% spinosyn A and spinosyn D], applied at different concentrations were evaluated on Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) under both laboratory and greenhouse conditions. Laboratory bioassays demonstrated that both neem-based insecticides were repellent to adult whiteflies in a dose-dependent manner. The amounts and frequency of honeydew excretion were significantly reduced up to 0.95 by foliar application of these insecticides at the labeled rate, as compared to untreated plants, with the neem products displaying greater effects on food uptake than spinosad. Reduced fecundity and egg hatch also were associated with these bio-insecticides. The bio-insecticides decreased significantly the survival of nymphs, egg hatch and adult emergence when applied systemically via the roots. However, the impacts of neem-based insecticides on all parameters tested were greater than that of spinosad. The results indicate that the biologically based formulations tested were effective in suppressing whitefly abundance and acting as an efficient repellent, though they were not able to completely inhibit food intake. The repellent and antifeedant activities of such natural products render plants unattractive to B. tabaci , thus potentially reducing the incidence of viral diseases transmitted by this pest. The systemic properties of these formulated biopesticides minimize their rapid degradation by strong ultraviolet light and their adverse effects on non-target organisms.

Infestation of sugarbeet plants by bean aphid, Aphis fabae Scopoli, significantly affected intraplant allocation of carbohydrate and protein. Aphids caused a decrease in nonstructural carbohydrate concentration in stem tissue, but an increase in leaf blade and root tissue. Nitrogen levels were higher in young leaf and stem tissue of plants infested by aphids, but lower in old leaf blade and root tissue. Aphid infestation caused a reduction in sucrose content in sugarbeet roots of 0.86% per day. Economic injury levels were calculated based on sucrose value and aphid suppression costs, and were shown to vary with length of aphid infestation or time until harvest. Sequential sampling plans, based on the binomial distribution, were developed for determining when aphid infestation levels exceeded the economic injury level. Zusammenfassung uber einige Wirkungen des Befalls von Zuckerruben durch die Blattlaus Aphis fabae Scop. auf den Kohlenhydrat- und Eiweisgehalt der Pflanzen sowie Moglichkeiten zur Bestimmung der wirtschaftlichen Schadensgrenze Der Befall von Zuckerruben durch A. fabae beeinfluste in signifikanter Weise die intraplantare Verteilung von Kohlenhydraten und Eiweisen. Die Blattlause verursachten eine Verminderung der nichtstrukturellen Kohlenhydratkonzentration im Stengelgewebe, jedoch eine Zunahme im Blatt- und Wurzelgewebe. Der Stickstoffgehalt war in jungen Blattern und im Stengelgewebe der von Blattlausen befallenen Pflanzen erhoht, dagegen in alten Blattern und im Wurzelgewebe vermindert. Der Blattlausbefall fuhrte weiterhin zu einer Senkung des Zuckergehalts der Zuckerrubenwurzel von 0,86% pro Tag. Die wirtschaftliche Schadensgrenze wurde auf der Grundlage des Zuckergehalts sowie der Kosten von Gegenmasnahmen kalkuliert. Sie variierte mit der Lange des Befalls und der Zeit bis zur Ernte. Es wurde ein Probesammlungs-Plan auf der Grundlage der bionomischen Verteilung entwickelt, um den Punkt zu bestimmen, wo die Befallshohe die wirtschaftlich tragbare Schadensgrenze uberschreitet.

Diaprepes abbreviatus L. is a highly polyphagous root weevil that causes damage to several fruit crops, ornamental plants, and other naturally occurring plants in Florida. Haeckeliania sperata Pinto is a gregarious endoparasitoid that attacks D. abbreviatus eggs. We hypothesized that the reproductive success of H. sperata is affected by the host plant of D. abbreviatus. Six host plants with varying degrees of pubescence were used to determine the effect of leaf trichomes on the searching behavior and success of parasitism by H. sperata. No-choice tests showed that H. sperata was able to parasitize Diaprepes eggs laid on the six host plants. However, the plants with a high trichome density on their leaves had a lower percent of parasitism than the plants with smoother leaves. Removing trichomes from a host plant showed that the presence of some leaf trichomes had a negative effect on the overall searching efficiency of H. sperata. The presence of trichomes decreased the total distance traveled and increased the total search time of H. sperata females, resulting in a lower searching speed. Multiple regression analysis was used to establish the relationship between percent parasitism and leaf trichome density, leaf thickness, and the searching speed of H. sperata. Searching speed was the best predictor of percent parasitism; this parameter could be used to predict the suitability of host plants for the establishment of H. sperata. Our findings suggest that the reproductive success of H. sperata is affected by the host plant of D. abbreviatus.

Summary • Brake fern, Pteris vittata , not only tolerates arsenic but also hyperaccumulates it in the frond. The hypothesis that arsenic hyperaccumulation in this fern could function as a defense against insect herbivory was tested. •F ronds from control and arsenic-treated ferns were presented to nymphs of the grasshopper Schistocerca americana . Feeding damage was recorded by visual observation and quantification of the fresh weight of frond left uneaten and number of fecal pellets produced over a 2-d period. Grasshopper weight was determined before and after 5 d of feeding. • Grasshoppers consumed significantly greater amounts of the frond tissue, produced more fecal pellets and had increased body weight on control plants compared with grasshoppers fed arsenic-treated ferns. Very little or none of the arsenic-treated ferns were consumed indicating feeding deterrence. In a feeding deterrent experiment with lettuce, sodium arsenite at 1.0 m M deterred grasshoppers from feeding whereas 0.1 m M did not. In a choice experiment, grasshoppers preferred to feed on lettuce dipped in water compared with lettuce dipped in 1.0 m M sodium arsenite. • Our results show that arsenic hyperaccumulation in brake fern is an elemental defense against grasshopper herbivory.

Azadirex (azadirachtin and other biologically active extracts from neem trees) has been shown to have considerable potential to be used in integrated pest management systems based on its growth regulator/insecticide properties. Less well known are the antifeedant properties. The feeding-deterrent properties of a commercial azadirex formulation (Azatrol EC) were evaluated using both no-choice and choice tests, the American grasshopper, Schistocerca americana (Drury), and four host plants [savoy cabbage, Brassica oleracea variety capitata L.; cos (romaine) lettuce, Lactuca sativa variety longifolia Lam.; sweet orange, Citrus sinensis variety Hamlin L.; and peregrina, Jatropha integerrima Jacq.]. These studies demonstrated that azadirex application can significantly affect the feeding behavior of grasshoppers. Some degree of protection can be afforded to plants that differ markedly in their innate attractiveness to the insect, although the level of protection varies among hosts. The tendency of grasshoppers to sometimes feed on azadirex-treated foliage suggests that it will be difficult to prevent damage from occurring at all times, on all hosts. No evidence of rapid habituation to azadirex was detected. Rapid loss of efficacy was observed under field conditions, suggesting that daily retreatment might be necessary to maintain protection of plants from feeding.

The relationship between mouthpart structure and diet has been known for years. This connection between mouthpart morphology and specific food types is incredibly pronounced in the class Insecta (Snodgrass 1935). As insects have evolved and adapted to new food sources, their mouthparts have changed accordingly. This is an extremely important trait for evolutionary biologists (Brues 1939) as well as systematists (Mulkern 1967). Isley (1944) was one of the first to study grasshopper mouthparts in detail. He described three groups of mandibles according to general structure and characteristic diet. These three groups, still used today, were graminivorous (grass-feeding type) with grinding molars and incisors typically fused into a scythe-like cutting edge, forbivorous (forb or broadleaf plant-feeding type) which have a molar region consisting of a depression surrounded by raised teeth and sharp interlocking incisor teeth, and herbivorous (mixedfeeding type) that have characteristics of both of the aforementioned groups. The original findings by Isley (1944) have since been proven to be widespread in grasshoppers. Additional studies have been conducted by Snodgrass (1928), Gangwere (1965, 1966), Gangwere et al. (1976), and Patterson (1984) in North America; Lieberman (1968) and Gangwere & Ronderos (1975) in South America; Williams (1954), Kaufmann (1965), and Gangwere & Morales (1973) in Europe; Gangwere & Spiller (1995) and Gangwere et al. (1998) in the Mediterranean islands; Feroz & Chaudhry (1975), Gapud (1968), and Kang et al. (1999) in Asia; and Chapman (1964) in Africa. The relationship between grasshopper mouthparts and food is far from precise. Mulkern (1967) was convinced that only the grossest determinations could be made between mandibular structure and diet (i.e., graminivorous, forbivorous, and herbivorous). Occasionally, grasshoppers with forb-feeding mandibles regularly feed on grasses or vice versa (Chapman 1964). Nevertheless, there is some value in assessing mouthpart structure relative to predicting diet and habitat of grasshoppers, especially for the many rare or non-economic species that are unlikely to be studied in detail. Thus, the morphological characteristics and structural adaptations of the mouthparts of 36 of the 71 grasshoppers occurring in Florida were examined. Grasshoppers were collected from various habitats throughout north-central Florida in 2001 and 2002. Thirty-six of the most common Floridian grasshopper species were identified with the taxonomic key found in Smith et al. (2004) and frozen until examination. Mandibles were removed from thawed specimens by lifting the labrum and pulling out each mandible separately with forceps. Only young adults were used in an effort to avoid confusion of mandible type due to mandible erosion (Chapman 1964; Uvarov 1977). An example of moderate erosion can be seen in Figure 1 (I). This process was replicated with 10 individuals from each species. After air-drying, each mandible was glued to the head of a #3 or #2 insect pin, depending on its size, for easier manipulation, and examined microscopically. We used Isley's (1944) description of mandible types and their adaptive functions to divide the mandibles into 3 major categories: forbivorous (forb-feeding), graminivorous (grass-feeding), and herbivorous (mixed-feeding). Mandibles were lightly brushed with 80 percent ETOH and distilled water in an effort to remove most of the sand and debris adhering to the mouthparts. Photographs were taken with the Syncroscopy Auto-Montage system (University of Florida, Entomology and Nematology Dept.). The mandible structure of 36 species of grasshopper, from five subfamilies (Acridinae, Cyrtacanthacridinae, Gomphocerinae, Oedipodinae, and Romaleinae), found in Florida was microscopically examined. These grasshoppers were collected from a variety of habitats including disturbed freshwater marsh, high pine, swamp, and oak hammocks. All grasshoppers had distinctive mouthparts that could be described as forbivorous (forb-feeding type), herbivorous (mixed-feeding type), or graminivorous (grass-feeding type) (Fig. 1, A-L). A list of each species studied and the mandible type is given in Table 1. Of the subfamilies examined, the Cyrtacanthacridinae demonstrated the most diversity in mandible type; however, most of them displayed either herbivorous or forbivorous mandibles, indicating a tendency toward forb-feeding. These grasshoppers can be found in a wide range of habitats, usually in dense vegetation or woodland areas, and are quite active in both walking and flying. It is interesting to note that both the grasshoppers in this subfamily that did display graminivorous type mandibles (L. marginicollis and S. vitreipennis) also have extremely slender, elongated bodies and can be found on the edges of ponds or in freshwater marshes (Isley 1944; Squitier & Capinera 2002b; Smith & Capinera 2005). These grasshoppers typically grasp the stems of emergent grass or grass-like vegetation such as sedges or cattails, blending in almost perfectly.

Host-plant preferences were assessed by field measurement of grasshopper abundance in relation to measurements of floral community and by laboratory host-plant preferences. Correlations between grasshoppers and plants (biomass and percentage cover) were based on data gathered at 29 study sites in five distinct Florida habitats (including disturbed, freshwater marsh, high pine, oak hammock, and swamp). Relationships among plants in these habitats and 10 abundant grasshopper species were examined to clarify differences in grasshopper assemblages among habitats. The grasshoppers studied were Aptenopedes sphenarioides Scudder, Chortophaga australior (Rehn and Hebard), Eritettix obscurus (Scudder), Melanoplus bispinosus Scudder, Melanoplus querneus Rehn and Hebard, Paroxya clavuliger (Serville), Schistocerca americana (Drury), Schistocerca ceratiola Hubbell and Walker, and Spharagemon crepitans (Saussure). In addition to correlations among individual plants and the abundance of grasshoppers, multiple regression analysis was used to assess how groups of plants were related to grasshopper abundance. These analyses identified grasshopper-plant associations, but some plants were found to be host plants, whereas others were indicators of preferred habitats (indicator plants). Host-plant preferences were determined in the laboratory using five plant-choice tests to help distinguish between host and indicator plants. The 10 grasshopper species examined for laboratory host-plant preferences were the same species scrutinized in the field study. In almost every case, grasshoppers showed specific plant preferences, and the preference studies successfully distinguished between host plants and indicator species. Similar results were obtained whether biomass or percent cover measurements were used to assess the floral community, although percent cover is much easier and faster to determine.

A dichotomous key is presented to aid in the identification of the adult stage of the 71 grasshopper species known to occur in Florida. Reflecting recent research one subspecies, Schistocerca alutacea rubiginosa (Scudder), has been elevated to species status Schistocerca rubiginosa (Harris) in this key.

Through laboratory choice tests involving 19 plant species, we assessed the host selection behavior of six grasshopper species: Stenacris vitreipennis (Marschall) (glassywinged toothpick grasshopper), Leptysma marginicollis (Serville) (cattail toothpick grasshopper), Gymnoscirtetes pusillus Scudder (little wingless grasshopper), Paroxya clavuliger (Serville) (olivegreen swamp grasshopper), Paroxya atlantica Scudder (Atlantic grasshopper), and Romalea microptera (Beauvois) (eastern lubber grasshopper). This grasshopper assemblage is commonly associated with semi-aquatic habitats in the southeastern United States. These poorly studied species display both graminivorous (S. vetreipennis and L. marginicollis) and mixed graminivorous-forbivorous feeding habits (the remaining species), the nature of which are fairly predictable based on examination of mouthpart morphology, but not entirely consistent with the tendency of cyrtacanthacridine species to feed on forbs.

A year-long survey was conducted to assess the grasshopper species assemblage in various natural and anthropogenic habitats in Florida. Distribution, density, and relative abundance data were collected, providing insight into habitat preference and resource utilization. Of the 70 species known to occur in Florida, 52 species were collected in one or more habitats. The number of different species found in each habitat, in descending order of species richness, were: sandhill, 34; freshwater marsh, 27; scrub, 26; roadside, 26; lakeside, 22; disturbed areas, 22; pasture, 19; pine plantation, 19; old fields, 18; flatwoods, 13; salt marshes, 11; oak hammock, 9; crops, 8; coastal scrub, 6; cutthroat seep; 5; and coastal strand, 5. Common species, and the number of habitats they were found to occupy, include Schistocerca americana, 12; Aptenopedes sphenarioides, 10; Dichromorpha viridis, 8; Melanoplus propinquus, 8; Paroxya atlantica, 8; Achurum carinatum, 7; Amblytropidia mysteca, 7; Chortophaga austral...

Grasshopper occurrence and abundance in several natural and anthropogenic habitats found in north Florida were surveyed for a one-year period to determine periodicity of adult and nymphal stages. Thirty species were sufficiently abundant to assess at least some elements of their phenology. A high proportion (36%) of the species overwintered as adults, and 27% of the species overwintered as nymphs. Three species were found to overwinter in both the adult and nymphal stages. The period of peak nymphal abundance varied among species and was found to include spring, summer, autumn, and winter. The method of data collection used in this study was inadequate to ascertain definitively the number of generations, but six species are suspected of being multivoltine in Florida.

The milkweed assassin bug, Zelus longipes (L.) (Hemiptera: Reduviidae), is a generalist predator and a potential biological control agent of picture-winged flies (Diptera: Ulidiidae), which cause considerable economic damage to sweet corn yields in Florida. We studied the potential of Z. longipes as a biocontrol agent of four ulidiid pests in corn fields: Euxesta stigmatias Loew, Euxesta eluta Loew, Euxesta annonae F., and Chaetopsis massyla Walker. Within-plant and within-field distributions of Z. longipes and ulidiids and functional responses of Z. longipes to ulidiid prey were determined. Highest numbers of Z. longipes and ulidiids in the R1, R2, and R3 corn stages were generally in the basal or middle leaves at 09:00 h EST, ears at 13:00 h EST, and top and tassel at 17:00 h EST. Hence, there seemed to be a coordinated migration of Z. longipes and ulidiids from the lowest to the highest parts of the corn plant during the day. Within the corn field, aggregated (clumped) distributions were most common for Z. longipes and ulidiids especially in the later R2 and R3 stages based on Taylor's power law, Iwao's patchiness regression, index of dispersion, and Lloyd's patchiness indices of dispersion. However, predator and prey populations were lower in the R1 stage, and there were inconsistent results for dispersion indices among times of day and between predators and prey. Ulidiid distributions in R1 were mostly regular (uniform) at 13:00 h EST, but aggregated at 09:00 h and 17:00 h. However, Z. longipes R1 distributions were mostly aggregated at 13:00 h, but random or regular at 09:00 h and 17:00 h EST. Handling times for male and female Z. longipes were 1.0-1.39 h and 0.67-0.97 h, respectively, and each had a type II functional response to E. stigmatias, E. eluta, and E. annonae and consumed about five flies per day. Although the population abundance of Z. longipes can vary between seasons, it appears to be a promising biocontrol agent of ulidiid flies in corn.

Entomopathogenic nematodes are generally considered beneficial organisms. However, they can affect beneficial insects such as parasitoids. The infectivity of Steinernema carpocapsae (Mexican strain) to Cardiochiles diaphaniae Marsh, a solitary internal wasp parasitoid of melonworm, Diaphania hyalinata (L.), and pickleworm, D. nitidalis (Stoll), was determined under laboratory conditions. S. carpocapsae induced 100% infection in melonworm hosts during exposure periods of 6, 24, 36, and 48 h. The number of nematodes penetrating the host was proportional to the length of exposure period, and the emergence rate of wasp parasitoids was inversely proportional to exposure time. Though only 0–10% of immature C. diaphaniae were parasitized by nematodes within hosts, newly emerged and, to a lesser degree, cocoon-spinning wasp larvae were readily infected by nematodes. In contrast, pupae of C. diapahaniae in completely formed cocoons were resistant to infection. S. carpocapsae adversely affected C. diaphaniae developing in melonworm principally by causing the premature death of the host before the wasp could complete its development. If the wasp larvae were 6 or 7 d old when the melonworm host was parasitized by nematodes, then all the wasp larvae died. However, if the wasp larvae were 8 d old when nematodes parasitized the melonworm, then 39–92% of the melonworms successfully produced wasp parasitoids. Many wasp larvae that emerged from nematode-parasitized melonworms did not form cocoons, and died within 24 h of emergence. However, only a small proportion of the larvae contained nematodes as determined by dissection. The percentage of infected parasitoids and the proportion of emerged parasitoid larvae dying increased as the exposure time to nematodes increased. Overall, S. carpocapsae nematodes are somewhat compatible with parasitoids because they do not kill all parasitoids, and the pupal stage is resistant to infection. However, the direct and indirect mortality of wasps caused by nematodes could result in some interference with biological suppression.

Many photoactive dyes are relatively nontoxic to vertebrates despite their insecticidal properties. Several photoactive dyes known to be toxic to some groups of insects were evaluated at various concentrations for toxicity to American and migratory grasshoppers in laboratory and field studies. Rose bengal and phloxine B were effective at inducing mortality of grasshoppers when applied at 2 and 5% to bran bait, though erythrosin B and uranine were ineffective. Partial replacement of phloxine with uranine in dye mixtures resulted in no significant loss of efficacy. Some indication of feeding inhibition was observed at high dye concentrations, so minimum effective dosages, probably 2%, are optimal. Phloxine B and rose bengal appeared to be stable upon exposure to sunlight, and able to withstand at least 24 h of sunlight without significant degradation. Dyes such as phloxine B could be a viable grasshopper control agent for small or medium-sized grasshopper species because mortality can be induced by consumption of a single flake dusted with 5% dye, and yet pose little hazard to vertebrates. Large species such as American grasshopper must consume several flakes before mortality is induced.