Thripidae

About: Thripidae is a research topic. Over the lifetime, 2254 publications have been published within this topic receiving 38086 citations.

Western Flower Thrips (Thysanoptera: Thripidae) Resistance to Insecticides in Coastal California Greenhouses

Abstract: Field populations of western flower thrips, Frankliniella occidentalis (Pergande), showed high levels of resistance in laboratory tests to four classes of insecticides Commonly used for insect control in ornamentals. The resistance ratios (RR at LC90) to the pyrethroids permethrin and bifenthrin were very high, ranging from 138-fold (Bifenthrin, San Diego-1 [SD-1] location) to 8,716-fold (Permethrin, SD-1) Compared with a susceptible strain (UC89). Piperonyl butoxide significantly synergized permethrin up to 50-fold (SD-2), indicating that mixed-function oxidizes are a Cornponent of the overall resistance mechanism. There was moderate to high intensity of resistance to methomyl, a carbonate; RR values ranged from 41-fold (SD-1) to 378-fold (SD-2). Field resistance to chlorpyrifos, an organophosphate, was Comparatively low, with the RR values ranging from 17-fold (Santa Barbara-2 [58-2]) to 31-fold (SD-2). Although not registered for western flower thrips control, abamectin (a macro cyclic lactone) showed low to high levels of resistance (RR values ranging from 18-fold [SD-1] to 798-fold [S8-1]). The development of resistance to abamectin is the first documented case of resistance to this chemical in the field. In a separate field trial conducted at SB-1, all the chemicals tested including chlorpyrifos (microencapsulated formulation) performed poorly. Maximum adjusted control was only 53% (Pounce), confirming the field failure for all the insecticides tested at this greenhouse. Resistance to Commonly used insecticides and the likelihood of losing many more registrations emphasize the need for better and practical pest management strategies.

Thrips Vectors of Tospoviruses

Abstract: Tospoviruses belong to the sole phytovirus genus, Tospovirus , in the family Bunyaviridae . Tospoviruses are known to be exclusively transmitted by thrips belonging to the family Thripidae and subfamily Thripinae. Of the known 1,710 species of Thripidae only 14 thrips species are currently reported to transmit tospoviruses. Thrips-transmitted tospoviruses cause severe yield losses to several economically important crops in the United States and worldwide. For instance, a single Tospovirus ( Tomato spotted wilt virus ) alone caused an estimated $1.4 billion in losses in the U.S. over 10 years. Global trade and associated movement of plant materials across borders have introduced tospoviruses and their vectors into newer areas. Advances in serological and molecular techniques have also led to identification of new tospoviruses. This scenario has also initiated new vector-pathogen interactions between introduced and native thrips species and tospoviruses. The goal of this manuscript is to provide a comprehensive and updated list of thrips species that serve as vectors of tospoviruses along with information pertaining to common names, key diagnostic characters, distribution, important crops economically affected, and thrips and Tospovirus -induced symptoms. The manuscript is prepared with special emphasis to the U.S., but information pertaining to other countries is also included.

Distinct levels of specificity in thrips transmission of tospoviruses.

Abstract: Various thrips species were tested for their ability to transmit different tospovirus species using a petunia leaf disk assay system. Transmission efficiencies were determined for four species of thrips and four tospovirus species : tomato spotted wilt virus (TSWV), impatiens necrotic spot virus, tomato chlorotic spot virus (TCSV), and groundnut ringspot virus (GRSV). Frankliniella occidentalis appeared to be the most efficient vector for the four tospovirus species tested. A dark form of E schultzei transmitted three (TSWV, TCSV, and GRSV) of the four tospoviruses, whereas a light form of this species transmitted TSWV and TCSV rather poorly. E intonsa, which has been documented as vector of TSWV, although transmission data were not presented, transmitted TSWV efficiently and TCSV at a very low frequency. Strikingly, only one of four populations of Thrips tabaci from different geographic regions was able to transmit one of the tospoviruses tested (TSWV) and this at a low efficiency. Enzyme-linked immunosorbent assay (ELISA) showed that virus could be readily detected in transmitting adult thrips. Viral antigen also could be detected in some individuals that did not transmit virus to petunia leaf disks, but the amount of virus detected was consistently lower than those of transmitters. Positive ELISA values were found only for thrips-tospovirus combinations in which virus transmission could occur, whereas negative ELISA scores were observed for all individuals from thrips-virus combinations in which no virus transmission took place, indicating that acquisition of the virus did not result in replication and accumulation of these viruses in thrips.

Biology and Ecology of the Western Flower Thrips (Thysanoptera: Thripidae): The Making of a Pest

Abstract: In the past 30 years, western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), has become one of the most important agricultural pests worldwide. Certain biological attributes of this insect predispose it to be a direct pest across a wide range of crops. In addition to the direct damage it can cause, this species is an efficient vector of Tomato spotted wilt virus and other Tospoviruses. This review addresses questions regarding the biological and ecological attributes of western flower thrips that have enabled it to become a significant pest and make it so difficult to manage. These important life history traits include western flower thrips polyphagy and a tendency to reside and feed in concealed areas of flowers and fruits. Consequently, large populations can develop and disperse into a wide range of crops. The larvae and adults feed in a similar manner and can share the same host plant resources. The relatively short generation time and haplodiploid sex determination also contribute to the pest status of this species. These life history traits interact in complex ways to make western flower thrips one of the most significant and difficult to manage pests in the world.

Evaluation of phytoseiid predators for control of western flower thrips on greenhouse cucumber

Abstract: Ten predatory mite species, all phytoseiids, were evaluated for control of western flower thrips (WFT), Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), on greenhouse cucumber. This study was done to further improve biological control of thrips on this crop. Neoseiulus cucumeris (Oudemans) is at present used for biological control of thrips in greenhouses. Compared to this species, Typhlodromalus limonicus (Garman & McGregor), Typhlodromips swirskii (Athias-Henriot) and Euseius ovalis (Evans) reached much higher population levels resulting in a significantly better control of thrips. T. limonicus was clearly the best predator of WFT. Also Euseius scutalis (Athias-Henriot) increased to higher populations levels than N. cucumeris, but without controlling the thrips, probably because of an unequal distribution of this predator on the plant. Iphiseius degenerans (Berlese), Neoseiulus barkeri (Hughes), Euseius finlandicus (Oudemans) and Typhlodromus pyri (Scheuten) did not establish better than N. cucumeris. A non-diapausing exotic strain of N. cucumeris did not differ from the North European strain. The best performers in this study were all of sub-tropical origin. T. limonicus, T. swirskii and E. ovalis have good potentials for controlling not only thrips but also whiteflies. Factors affecting the efficacy of phytoseiids on greenhouse cucumbers are discussed.