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Limb jarring samples were taken in four experimental apple orchards (one completely unmanaged; one with horticultural management and no pest management; one with horticultural management, no pest management, and interplanted with peach and sour cherry; and one under conventional commercial management practices) at hourly intervals over a 24-h period at four times in 1991. A total of 1,176 individual predators belonging to seven orders and 22 families was collected. The most abundant species was Coniopteryx sp. (Coniopteryigidae: Neuroptera), and the most abundant family was Coccinellidae (Coleoptera). A total of 396 adult parasitoids was collected from 26 families of Hymenoptera and one Diptera family, with Encyrtidae being the most abundant. All other individuals were classified as potential food items and were identified only to order or, in some instances, family. A total of 5,812 potential food items was collected. Diversity of predators and parasitoids was greatest in May and June. Diversity of predators was highest on apple trees that were inter-planted with peach and cherry trees, whereas parasitoid diversity was greatest on peach trees and on insecticide treated apple trees. Chrysopids (Neuroptera), clerids (Coleoptera), and Leptothrips mali (Fitch) (Phlaeothripidae: Thysanoptera) were most commonly collected at dawn or during the night, suggesting that their role in orchards may be underestimated by sampling only during daylight hours. With the exception of Scelionidae and Platygastridae (Hymenoptera), parasitoids were most commonly collected during the night. Results indicate that peach trees are attractive to both predators and parasitoids and therefore may be a valuable addition to apple orchards to enhance the abundance of biological control species.

Degree-day models were developed for predicting different levels of attack by slash pine flower thrips, Gnophothrips fuscus (Morgan), on female strobili (flowers) and for predicting the appearance of different morphological stages of flower development. The models were based on 5-yr data collected from a north Florida slash pine, Pinus elliottii Engelmann variety elliottii, seed orchard. Different starting dates and lower threshold temperatures for models were compared. Starting dates included the 1st annual incidence of temperatures below 4.4 degrees C (40 degrees F) and a range of biofix dates (20 November through 10 December). Lower threshold temperatures were compared over a range of -1.1-12.8 degrees C (30-55 degrees F). Degree-day models with a 4.4 degrees C (40 degrees F) lower threshold temperature appeared to be suitable predictors of the appearance of stage 2 flowers and the 50% level of attack by slash pine flower thrips. These models should facilitate implementation of insecticide application programs based on predicting levels of thrips attack and flower phenology.

Thrips inhabiting leaf galls on noncultivated Vaccinium species were surveyed throughout Georgia. Frankliniella caudiseta Sakimura & O'Neill was present on V. tenellum Aiton, and V. myrsinites Lam. Blueberry thrips, Frankliniella vaccinii Morgan, was only collected from V. arboreum Marsh. Catinathrips similis Nakahara occurred on V. tenellum and V. myrsinites . However, C. vaccinicola Nakahara was collected only on V. arboreum. Haplothrips rectipennis Hood, a predaceous species, was found on all Vacciniurn species. F. vaccinii and C. vaccinicola were both capable of initiating gall formation on plants in the spring. Both species may coexist in the same gall and are univoltine on mature growth during a season. However, in cutover areas where new plant growth was generated during the summer, 1 additional generation was produced. Adult terebrantians became active during April. Larvae were abundant during May and June. On 2nd-growth plants, larvae were abundant during July and August and adults were collected in October. The predator H. rectipennis colonized galls during May. Larvae of this species became abundant during May and June. One generation was produced. Adults remained in the galls until leaves dropped from the plants, usually in October. Thrips significantly reduced shootlength, bud formation, and fruit production of both V. arboreurn and V. myrsinites . These observations have implications for blueberry plant improvement efforts.

Schinus terebinthifolius Raddi (Sapindales: Anacardiaceae) is a non-native perennial woody plant that is one of the most invasive weeds in Florida, Hawaii, and more recently California and Texas. This plant was introduced into Florida from South America as a landscape ornamental in the late 19th century, eventually escaped cultivation, and now dominates entire ecosystems in south-central Florida. Recent DNA studies have confirmed two separate introductions of S. terebinthifolius in Florida, and there is evidence of hybridization. A thrips, Pseudophilothrips ichini s.l. (Hood) (Thysanoptera: Phlaeothripidae), is commonly found attacking shoots and flowers of S. terebinthifolius in Brazil. Immatures and occasionally adults form large aggregations on young terminal growth (stems and leaves) of the plant. Feeding damage by P. ichini s.l. frequently kills new shoots, which reduces vigor and restricts growth of S. terebinthifolius. Greenhouse and laboratory host range tests with 46 plant species in 18 families and 10 orders were conducted in Parana, Brazil, and Florida. Results of no-choice, paired-choice, and multiple-choice tests indicated that P. ichini s.l. is capable of reproducing only on S. terebinthifolius and possibly Schinus molle L., an ornamental introduced into California from Peru that has escaped cultivation and is considered invasive. Our results showed that P. ichini s.l. posed minimal risk to mature S. molle plants or the Florida native Metopium toxiferum L. Krug and Urb. In May 2007, the federal interagency Technical Advisory Group for Biological Control Agents of Weeds (TAG) concluded P. ichini s.l. was sufficiently host specific to recommend its release from quarantine.

Insects in the order Thysanoptera are known for their haplodiploid reproduction, with most species reproducing by arrhenotoky. A few species, however, have only female populations and reproduce by thelytoky. Seven thrips species reproducing either by arrhenotoky [Frankliniella occidentalis (Pergande), Echinothrips americanus Morgan, Suocerathrips linguis Mound and Marullo, Gynaikothrips ficorum (Marchal)] or thelytoky [Hercinothrips femoralis (O.M. Reuter) and Parthenothrips dracaenae (Heeger)] or showing both reproduction modes (Thrips tabaci Lindeman) were screened for the presence of Wolbachia using 16S rDNA and ftsZ gene primers. The arrhenotokous reproducing species E. americanus, G. ficorum, and S. linguis tested positive for Wolbachia. The bacterium was not detected in F. occidentalis or T. tabaci; even the thelytokous population of T. tabaci was free of Wolbachia. Wolbachia was found in the thelytokous reproducing species H. femoralis and P. dracaenae. Antibiotic treatment of H. femoralis induced the production of males that copulated with females. The results confirmed Wolbachia to be present in thelytokous reproducing thrips species and proved the presence of the bacterium for the first time in some arrhenotokous reproducing thrips species.

The functional responses of all feeding stages of Leptothrips mali (Fitch) to various densities of selected Panonychus ulmi (Koch) stages were determined in the laboratory at 23.9 ± 1°C. Functional response data were obtained for the following L. mali-P. ulmi combinations: first-stage larvae of L. mali with P. ulmi eggs and adults, second-stage larvae or adult female L. mali with adult P. ulmi. To estimate the relationship between the number of prey killed and prey density for the selected predator-prey combinations, various mathematical models were fit to the data. No functional response was found when first-stage larvae were provided adult female P. ulmi. A sigmoid curve best explained the relationship in all other situations. Search rate increased between the two lowest prey densities when adult thrips were provided adult mites. No such increase was observed with other L. mali-P ulmi combinations; search rate remained constant. Therefore, for these other stages, the type III response obtained cannot be explained on the basis that the search rate increases over an initial range of low prey densities. A possible explanation may be interference-stimulation of the predator by the prey above some threshold prey density.

The interspecific interactions of 5th-instar Orius insidiosus (Say) and 2nd-instar larvae of another mite predator, Leptothrips mali (Fitch), was studied in the laboratory. L. mali is a potential prey for O. insidiosus , but has a defensive anal secretion which repels predator attacks. Most contacts between well-fed O. insidiosus and L. mali resulted in mutual avoidance. Most attacks by O. insidiosus were unsuccessful, especially if the approach was from the rear. Contact with the thrips' anal secretion resulted in immediate repelling of O. insidiosus , with subsequent cleaning activity lasting 1 to 3 min. This study indicates that these two predators are compatible, especially in the presence of another food source such as the European red mite.

The effectiveness of Liothrips urichi Karny introduced to control the noxious weed Clidemia hirta (L.) D. Don was studied at three sites on Oahu, Hawaii. Vegetative C. hirta infested with L. urichi showed greater mortality after 1 mo and significantly shorter internode diameters among the survivors at 4 mo than uninfested plants. L. urichi had no effect on plant height in the field but stunted the growth of young potted C. hirta in greenhouse studies and caused a significant increase in terminal leaf drop. No effect on production of floral buds, flowers, or berries occurred at any field site over 11 mo. L. urichi was restricted to sunny or partly sunny sites and never occurred in heavily shaded areas. Higher thrips infestations occurred during the fall and winter and lower infestations during the summer. Percentage of damaged tips also fluctuated seasonally, but the degree of damage to individual leaves was not seasonal.

The host specificity of Amynothrips andersoni O'Neill was determined in a series of feeding behavior and starvation tests conducted in the laboratory in Argentina and Uruguay. The host plant spectrum tested involved 21 different plant species belonging to 5 families and 11 genera. A slight amount of adult feeding (1–2%) was obtained on the test plant, Polygonum aviculare L., but was not observed to occur on field plants. Observation and study of 46 plant species in nature also demonstrated an absence of thrips or their feeding. The results of these laboratory tests and observations confirm earlier observations indicating that this thrips is associated only with Alternanthera philoxeroides (Mart.) Griseb. and A. hassleriana Chod.

Predation on Liothrips urichi , introduced to Hawaii to control the weed Clidemia hirta (L.) D. Don, was studied in field-cage exclusion experiments. Thrips in open cages (exposed to predation) experienced >40% mortality compared to