Search

Over two growing seasons, Isomate GBM-Plus tube-type dispensers releasing the major pheromone component of grape berry moth, Paralobesia viteana (Clemens) (Lepidoptera: Tortri- cidae), were evaluated in vineyards (Vitis spp.) in Michigan, New York, and Pennsylvania. Dispensers were deployed in three different density-arrangement treatments: 124 dispensers per ha, 494 dis- pensers per ha, and a combined treatment with 124 dispensers per ha in the vineyard interior and 988 dispensers per ha at the vineyard border, equivalent to an overall density of 494 dispensers per ha. Moth captures and cluster infestation levels were compared at the perimeter and interior of vineyards receiving these different pheromone treatments and in vineyards receiving no pheromone. Orien- tation of male moths to pheromone-baited traps positioned at the perimeter and interior of vineyards was reduced as a result of mating disruption treatments compared with the nontreated control. These Þndings were consistent over both years of the study. Disruption of male moth captures in traps varied from 93 to 100% in treated vineyards, with the 494 dispensers per ha application rates providing signiÞcantly higher level of disruption than the 124 dispensers per ha rate, but only in 2007. Mea- surements of percentage of cluster infestation indicated much higher infestation at perimeters than in the interior of the vineyards in all three regions, but in both sample positions there was no signiÞcant effect of dispenser density on cluster infestation levels in either year. The contrasting results of high disruption of moth orientation to traps in vineyards that also had low levels of crop protection from this pheromone treatment are discussed in the context of strategies to improve mating disruption of this tortricid pest.

We develop individual-based Monte Carlo methods to explore how climate change can alter insect voltinism under varying greenhouse gas emissions scenarios by using input distributions of diapause termination or spring emergence, development rate, and diapause initiation, linked to daily temperature and photoperiod. We show concurrence of these projections with a field dataset, and then explore changes in grape berry moth, Paralobesia viteana (Clemens), voltinism that may occur with climate projections developed from the average of three climate models using two different future emissions scenarios from the International Panel of Climate Change (IPCC). Based on historical climate data from 1960 to 2008, and projected downscaled climate data until 2099 under both high (A1fi) and low (B1) greenhouse gas emission scenarios, we used concepts of P. viteana biology to estimate distributions of individuals entering successive generations per year. Under the low emissions scenario, we observed an earlier emergence from diapause and a shift in mean voltinism from 2.8 to 3.1 generations per year, with a fraction of the population achieving a fourth generation. Under the high emissions scenario, up to 3.6 mean generations per year were projected by the end of this century, with a very small fraction of the population achieving a fifth generation. Changes in voltinism in this and other species in response to climate change likely will cause significant economic and ecological impacts, and the methods presented here can be readily adapted to other species for which the input distributions are reasonably approximated.

Diapause in insects occurs in response to environmental cues, such as changes in photoperiod, and it is a major adaptation by which insects synchronize their activity with biotic resources and environmental constraints. For multivoltine agricultural insect pests, diapause initiation is an important consideration in management decisions, particularly toward the end of the growing season. The grape berry moth, Paralobesia viteana (Clemens), is the main insect pest affecting viticulture, and this insect responds to postsummer solstice photoperiods to initiate diapause. Because the range of grape berry moth extends from southern Canada to the southern United States, different populations are exposed to different photoperiodic regimes. We quantified the diapause response in grape berry moth populations from Arkansas, Michigan, New York, Pennsylvania, Texas, and Virginia, and observed latitudinal variation in diapause initiation. Populations from Michigan, New York, and Pennsylvania responded significantly different than those from Arkansas, Texas, and Virginia. We also observed, as a consequence of our experiments, that the timing of our laboratory studies influenced grape berry moth's response to photoperiod, ceteris paribus. Experiments that were conducted when grape berry moth would be naturally in diapause resulted in a significant higher proportion of diapausing pupae at photoperiods (i.e., > 15 h) that generally do not induce diapause, suggesting that attention should be paid to the timing of behavioral and physiological experiments on insects. This relationship between photoperiod and diapause induction in grape berry moth across geographic regions will provide applicable knowledge to improve pest management decisions.

Most transgenic corn seed is now treated with systemic neonicotinoid insecticides. To address potential direct nontarget effects of these combined technologies, 16 Carabidae species from 10 genera (Agonum, Amara, Anisodactylus, Bembidion, Chlaenius, Harpalus, Patrobus, Poecilus, Pterostichus, and Scarites) field-collected from corn were directly exposed to Bacillus thuringiensis (Bt) Cry toxin-laden pollens and seed treatments in feeding and defined-dose bioassays. All adults readily fed on field or sweet corn pollens that expressed coleopteran-specific Cry3Bb1 or lepidopteran-targeting Cry1Ab/c, and no significant toxicity was observed. Adult survivorship ranged from 47 d for the predator Pterostichus melanarius (Illiger) to a year for the more omnivorous Scarites quadriceps Chaudoir, feeding solely on pollen containing 30–90 μg Cry3Bb1/g and water. In contrast, commercial doses of neonicotinoid seed treatments (imidacloprid, thiamethoxam, or clothianidin) elicited nearly complete mortality for ...

We studied the effects of inundative releases of the egg parasitoid Trichogramma minutum Riley (Hymenoptera: Trichogrammatidae) on economic injury by grape berry moth, Endopiza viteana (Clemens) (Lepidoptera: Tortricidae). Trichogramma minutum originally collected from natural host populations near North East, Pennsylvania, was mass produced in tobacco hornworm hosts and Mediterranean flour moth. We released T. minutum in border rows, where grape berry moth infestation is typically high, of experiment field station and commercial vineyards from 1996 to 1999. We recorded significant reductions in economic injury in plots where parasitoids were released. In vineyards with low to moderate grape berry moth abundance, four releases during the growing season were adequate in reducing damage at harvest to below 3%. In high-risk vineyards, T. minutum releases reduced damage to levels below 15%. The use of buckwheat as a cover crop to provide nectar in combination with parasitoid releases showed potential benefits in parasitoid activity. A biocarrier and Biosprayer™ were used in mechanized parasitoid-release operations, and no adverse effect on parasitoid emergence was recorded from parasitized eggs using this approach.

Thegrapeberry moth, Endopiza viteana (Clemens) feeds on wild and cultivated Vitis spp., causing economic damage in the latter. We studied incidence of pheromone trap catch data, and combined this with previous work on development and diapause to construct a comprehensive model of thetemporal dynamics of E. viteana. We explored the behavior of this model in six eastern United States locations along Lakes Erie and Michigan, the Finger Lakes in New York, and in Missouri and Virginia. Voltinism of E. viteana is insuenced by the accumulated growing degree-days before the postsummer solstice photoperiod at which eggs develop exclusively into diapausing pupae. Our model generally predicted two full and a partial third generation in Geneva, NY, whereas partial fourth generations existed in vineyards along Lakes Erie and Michigan. In more southern latitudes, such as Missouri and Virginia, the absence of a partial fourth generation would be rare. Also, our model suggested the presence of clinal latitudinal variation in diapause induction, with southern populations of E. viteana responding to shorter daylengths than northern populations. These predictions, based on average 10-yr surface temperatures (1991Ð2000), are supported by past observations and explain the variability in voltinism from year to year that has been reported in the northeastern United States and Niagara Peninsula of Canada.

We collected grape berry moth, Endopiza viteana (Clemens) (from cultivated and wild Vitis along Lake Erie in Pennsylvania and New York), and measured carbaryl susceptibility in first instars. A model of susceptibility was based on the concentration-mortality curve of laboratory-maintained colonies originating from wild Vitis with no prior history of carbaryl exposure, and a noncommercial vineyard with modest previous exposure to carbaryl. We estimated LC50 and LC90 for susceptible grape berry moth larvae at 45.4 and 2319 microg/ml, respectively. Bioassays on field-collected larvae from commercial vineyards in both states, where grape growers were abiding by current pest management guidelines for carbaryl use, revealed carbaryl resistance ratios from 7 to 71 at the LC50 level. With the loss or restriction of alternative chemical control tactics in the Food Quality Protection Act era, resistance management programs for grape berry moth should be immediately developed and implemented to regain the efficacy of this once effective insecticide and other related chemical compounds.

We studied pupal diapause maintenance and termination in Endopiza viteana, a pest of commercially grown grapes. We observed considerable variation in diapause intensity, which ranged from 5.5 to 10 mo under natural temperatures and photoperiods. Adult males tended to emerge from diapause slightly earlier than females, suggesting that E. viteana may be protandrous. In the field, low temperatures maintained diapause in overwintering pupae, and adult emergence began at ≈148 degree-days accumulated from 1 January. Photoperiod did not influence diapause termination in E. viteana. Overall, most adults emerged in spring at roughly the same time, regardless of the date at which pupae entered diapause; however, emergence was extended over a 6-wk period. Moreover, eggs oviposited by late-emerging females may experience photoperiods that would lead to diapause in pupae. Under natural conditions, extended adult emergence may result in overlapping generations; accordingly, coordinating the timing of control t...

During a survey for natural enemies of thegrape berry moth (GBM) Endopiza viteana(Clemens) in northwestern Pennsylvania, wefound that Trichogramma minutum Riley isthe only native egg parasitoid with thepotential to limit berry damage by preventingegg hatch. Natural parasitism, however, wasfound to be unreliable for providing economicpest suppression. Early season populations ofthe parasitoid are extremely low and may be theresult of inadequate alternative host eggs foroverwintering. Also, wild grapes and theirwooded habitats were found to be favored byT. minutum. Parasitism was low incultivated grapes and in wild grapes growingclose to commercial vineyards (possibly due tothe deterrent effect of insecticides) andhighest in sites ≈1.5 km from commercialvineyards. Adult T. minutum emergingfrom GBM eggs were exceptionally small andshowed little vigor. Parasitized eggs oftenfailed to produce adult parasitoids. Pre-adults in such eggs had poorly formed mouth-parts or lacked them altogether. Inundativereleases of laboratory-reared T. minutumin border rows of vineyards are suggested as apossible alternative to the current practice ofapplying carbamate and organophosphateinsecticides, which are inimical to beneficialarthropods.

Xylophagous insects often thrive on nutritionally suboptimal diets through symbiotic associations with microbes that supplement their nutritional requirements, particularly nitrogen. The wood-feeding cerambycid Anoplophora glabripennis (Motschulsky) feeds on living, healthy host trees and harbors a diverse gut microbial community. We investigated gut microbial contributions to larval nitrogen requirements through nitrogen fixing and recycling (urea hydrolysis) processes, using a combination of molecular, biochemical, and stable isotope approaches. Genes and transcripts of conserved regions of the urease operon (ureC) and nitrogen fixing (nif) regulon (nifH) were detected in A. glabripennis eggs and larvae from naturally infested logs and from larvae reared on artificial diet. Significant nitrogen fixation and recycling were documented in larvae using (15)N2 gas and (15)N-urea, respectively. Subsequent (15)N-routing of incorporated recycled nitrogen into larval essential and nonessential amino acids was shown for (15)N-urea diet-fed larvae. Results from this study show significant gut microbial contributions to this insect's metabolic nitrogen utilization through nitrogenous waste product recycling and nitrogen fixation.

We modeled development in grape berry moth, Endopiza viteana (Clemens), which exploits wild and cultivated Vitis. Laboratory experiments were used to derive the temperature-dependent developmental curve for eggs, larvae, and pupae. We used linear interpolation to estimate stage-specific base temperature thresholds and degree-day requirements under laboratory conditions. We also estimated parameters of the Logan and Lactin nonlinear developmental models. Lastly, we conducted field experiments to evaluate the conventional degree-day model, which has a base threshold of 10°C; an improved degree-day model that was based on our laboratory observations; and nonlinear developmental models in predicting seasonal grape berry moth development. We concluded that the Logan nonlinear model provided the best estimates of grape berry moth field development, and an improved degree-day model should use 8.41°C as a minimum base temperature threshold and 423.9 as the egg-to-adult degree-day requirement. Also, after...

Photoperiod influences diapause induction in the grape berry moth, Endopiza viteana (=Polychrosis viteana), and eggs and neonates (

The grape cane gallmaker, Ampeloglypter sesostris (Leconte), is a native weevil that infests new shoots of wild and cultivated grapes (Vitis spp.). Females oviposit on the tender portions of new shoots, producing a reddish gall that can expand the shoot to twice its normal diameter. These galls can be quite numerous in eastern vineyards, and their effects are unknown. We studied the spatial distribution of grape cane gallmaker and its impact on berry size, sugar content, and nutrient and mineral uptake. We observed spatial trends in grape cane gallmaker distribution in vineyards adjacent to woodland margins, with the trend emanating from the woodline. In vineyards without woodland margins, there was little spatial dependency in grape cane gallmaker distribution in individual years. However, grape cane gallmaker density on a single vine was spatially cross-correlated between 2 yr. The presence of galls did not significantly affect berry quality, or the uptake of nutrients and minerals, and we conclude that grape cane gallmaker does not negatively impact berry quality or mature vine vigor.

The toxicity of cryolite (sodium aluminofluoride) against the Colorado potato beetle, Leptinotarsa decemlineata (Say), was determined by feeding larvae on cryolite-treated potato foliage. At 48 h, the LC50 was 15.3 and 18.5 µg/cm2 for 1st and 3rd instars, respectively. Larvae consumed less foliage at higher concentrations, and the reduction of leaf consumption was correlated to the concentration of cryolite. A feeding choice test indicated that cryolite does not repel or inhibit larval feeding. Field tests showed that the effectiveness of cryolite was stable at 2 hand 1 d after application but variable after 2 d, and that cryolite toxicity was dependent on the application rate and rainfall. Significantly less mortality caused by cryolite was observed at the rate of 6.5 kg/ha than at 12.9 kg/ha. Larval mortality was also significantly lower when 0.64 cm of simulated rainfall was applied compared with the treatments without rain.

The Colorado potato beetle, Leptinotarsa decemlineata (Say), is one of 13 insect and mite species in which development of insecticide resistance has become “critical.” In this paper, we review methods for controlling this important agricultural pest while managing insecticide resistance. Many of these strategies were incorporated into an integrated pest management (IPM) program for northeastern potato growers and encapsulated in a knowledge-based expert system (PotatoES). Three years of field trails evaluating the IPM expert system’s ability to act as a surrogate for a human specialist, its capability to manage Colorado potato beetle resistance development in experimental and commercial fields, and its impact on crop yields and production economics were conducted. Comparison of management recommendations made by PotatoES with those of a human IPM specialist demonstrated a high degree of agreement. Under experimental field conditions, Colorado potato beetle insecticide resistance development was always best managed in populations controlled with the IPM program. In commercial production settings, the expert system resulted in similar (under low insect pressure) or superior (under higher insect pressure) control of resistance development compared with grower practices. Implementation of the IPM program in commercial production was more expensive than standard practices, but resulted in higher crop yields and greater net profits. These results demonstrate the potential utility of know ledge-based approaches to integrated resistance management by showing that these systems can capture and faithfully represent the specialized crop, insect, and disease management knowledge of experienced individuals; manage resistance better than traditional insecticide application regimes; manage a crop profitably; and be practically used as a treatment in a field trial and, as such, be validated in terms of their worth in agricultural decision support.

Five insecticide application regimes were evaluated to investigate their influence on development of insecticide resistance in field populations of Colorado potato beetle, Leptinotarsa decemlineata (Say). These regimes included season-long sequential esfenvalerate applications; two alternate uses of esfenvalerate, azinphosmethyl, endosulfan, oxamyl, and Bacillus thuringiensis ssp. tenebrionis ; an integrated pest management (IPM) program; and one early season esfenvalerate application. Response of Colorado potato beetle from each treatment to four insecticides was determined at the beginning and end of the growing season. Afilter-paper technique was used to estimate the concentration response relationship for first instars, and a topical application bioassay was used to measure response of adults. Differences in esfenvalerate susceptibility existed among treatments in the early season; these differences were correlated with frequency of esfenvalerate applications during the previous season. Populations from all field treatments at the end of season showed an increase in resistance to esfenvalerate and endosulfan but not to azinphosmethyl or oxamyl. Increases in resistance generally were related to the frequency that a specific chemical was applied. We observed significant correlations between increase in esfenvalerate resistance and number of esfenvalerate applications in a given regime; 10 applications resulted in a 3.6-fold increase. Direct selection by esfenvalerate appeared to be the primary factor in development of resistance in these populations. Consequently, we suggest that reduction of repeated pyrethroid use is critical for limiting resistance development. The lowest increase in esfenvalerate resistance was found in the IPM treatment, indicating that this management strategy was also effective in retarding resistance development.

The grape beny moth, Endopiza viteana (Clemens), is the key pest of cultivated grapes in the eastern United States and Canada (Gleissner 1943; Ker 1990). Laboratory techniques have been developed for large-scale rearing of this tortricid (Taschenberg 1951, 1969) using grape berries of Vitis vinifera L. (Vitaceae) and locally grown varieties. The use of grape berries is unsatisfactory because berries attract fruit flies, develop mold, and rot rapidly at normal laboratory temperatures (Taschenberg 1969). In this paper, we describe a diet for rearing E. viteana and the process that was undertaken in its development.