Resistance in pepper (. Alternatively, thrips may be monitored with sticky traps or "the tapping method." Infection rates of up to 60% were obtained on cucumber, even though the ambient humidity fell as low as 75%; higher doses of V. lecanii were used to compensate for the negative effects of low humidity on pathogen efficacy (van der Schaaf et al. Kostiainen and Hoy (1996), in a bibliography compiling all the literature from 1960 through 1994, list the following species as predators of WFT: (1) Euseius stipulatus, (2) Metaseiulus occidentalis (Nesbitt), (3) Amblyseius andersoni (Chant), (4) Amblyseius barkeri (Hughes) (A. mckenziei), (5) Amblyseius californicus McGregor, (6) Amblyseius (Neoseiulus) cucumeris (Oudemans), (7) Amblyseius (Iphiseius) degenerans Berlese, (8) Amblyseius (Euseius) hibisci (Chant), (9) Amblyseius limonicus s.s. Garmon and McGregor, (10) Amblyseius scutalis (Athias-Henriot), and (11) Amblyseius (Euseius) tularensis (Congdon). Besides the feeding injury on host plants, western flower thrips are vectors of tomato spotted wilt virus (TSWV) (German et al. 1995), cucumber (Soria and Mollema 1992), sweet pepper (Fery and Schalk 1991), and chrysanthemum (de Jager and Butot 1992, de Jager et al. 1998. Functional and numerical responses of. 1997). Male WFT transmit TSWV much more efficiently than females (van de Wetering et al. Loomans, A. J. M., T. Murai, J. P. N. F. van Heest, and J. C. van Lenteren. Advances in Virus Research. Also, some pupation takes place on the plant, where environmental conditions are not conducive to nematode infection. 1998. Table 1. Survival of the parasitoid, Frescata, C. and A. Mexia. Shapiro and L.C. Parasitic wasps. However, at 86°F (30°C), the generation time decreases to 4.3 days and the population increases 8.5 fold with each generation. Isolates of Verticillium lecanii have been available commercially for many years in Europe for control of thrips and other glasshouse pests (Ravensberg et al. In the 1970s and early 1980s, this species spread throughout North America (Beshear 1983). WFT mortality from fungal infection is dose-dependent; the more spores that contact the insect, the more rapid the kill and the higher the rate of infection (Brownbridge et al. Mite populations then ceased expanding and were quickly ineffective against thrips populations that continued to expand (Morewood and Gilkeson 1991, Rodriguez-Reina et al. NATO ASI Series. Brownbridge, M. 1996. van Rijn, 1997. Bulletin IOBC/WPRS 19 (1): 115-118. Evaluation of. This fact sheet is intended to provide a detailed summary for growers and extension agents of our knowledge of western flower thrips, with emphasis on the potential for its biological control. Identification of western flower thrips In Summary •Tomato thrips has 2 pairs of hairs on top edge of the pronotum •Tomato thrips is a uniformly brown colour •Tomato thrips has ocellar hairs close together •Onion, plague, greenhouse and gladiolus thrips do NOT have 2 pairs of hairs on the pronotum Some species of thrips also transmit plant diseases. However, the recently introduced western flower thrips (WFT) (Frankliniella occidentalis) is a significant threat to peanuts.This is because it can transfer tomato spotted wilt virus (TSWV) and capsicum chlorosis virus (CCV). © 2020 Springer Nature Switzerland AG. Series A: Life Sciences Vol. It is usually easier to prevent an infestation than to manage an established one. Otherwise, thrips will overwinter in the greenhouse and this may result in a large population at the beginning of the next growing season. Monitoring population densities of the phytoseiid predator. WFT lays its eggs in plant tissue, using a blade-like ovipositor to insert eggs into leaves, buds, and petals. Flowering ornamental plantings around greenhouses should also be removed to reduce the chances for development of large populations of thrips adjacent to greenhouses. German. 1986. Female mites live 30 days and over this time consume about 89 first instar thrips larvae. The fungi discussed here are compatible with the thrips predators Orius insidiosus and Amblyseius cucumeris, and honeybees (Brownbridge, pers. Georgis, R. 1997. Methods have been developed that use ELISA (enzyme-linked immunosorbent assay) and dot blot tests to determine if individual thrips are virus-infected or not (Cho et al 1988, Rice et al. In Parker B. L., M. Skinner and T. Lewis (eds.). Trend information is especially useful in determining the efficacy of a control measure that has been applied (by comparing counts before and after the treatment). 1995, 1997). In contrast to the above families of nematodes, members of the family Sphaerulariidae have a different mode of action that may be more suitable for use against WFT on foliage. Whether dealing with onion or western flower thrips, it is important In general, the higher the storage temperature, the more rapid the rate of inactivation. 1995). Ramakers. Miticides had variable toxicity, and some insect growth regulators, such as azadirachtin, were not harmful. Another fungal species, Paecilomyces fumosoroseus, is registered (Pfr-97) but is not presently available. Entomologia Experimentalis et Applicata 74: 225-234. van Houten, Y. M., P. van Stratum, J. Bruin, and A. Veerman. Biological control options for western flower thrips are better developed for vegetables than ornamentals. Survey of Australian native natural enemies for control of thrips. 477-503. 365-370. Contributing authors include entomologists, plant pathologists, extension agents, and biological control specialists. Allen, W. R. and J. Rather than rely on threshold values developed at some other site, under conditions that are likely to differ from one’s own, growers may do better by using thrips counts from their own monitoring efforts in past crops. M. Brownbridge, Entomology Research Laboratory, University of Vermont, P.O. Control of western flower thrips. 1968. Predacious mites. It causes damage and spoilage to a vast number of economically important plant species through feeding, oviposition and spread of several plant diseases, most notably tospoviruses (Morse and Hoddle, 2006 ). Efforts have also been made to develop optimal conditions for mass production of Orius species (Blümel 1996), including the possible use of artificial substrates for oviposition (Castañé and Zalom 1994). 1994) and chrysanthemum (Katayama 1997). 1990). However, fungi may be applied successfully either 48-72 h before or after fungicides have been applied. It is not unusual for tapping of plants suspected of being infested to detect thrips before any show up on randomly placed sticky trap cards.) Host range of western flower thrips. 1994, Sermann et al. Counts on traps are meaningful in two ways. Trichilo, P. J. and T. F. Leigh, 1988. 1996b). R. G. Van Driesche, Department of Entomology, University of Massachusetts, Amherst, MA, 01003. 1992). In geranium, feeding causes young leaves to grow in a deformed manner, curling upwards, and to have whitish bumps on the upper leaf surface (Tommasini and Maini 1995). Nymphs resemble adults in shape and colouring. 1996. In Lewis, T. Loomans, A.J.M., J. Tolsma, J.P.N.F. Biological control of thrips (Thysanoptera) by. 1986. K. M. Heinz, Department of Entomology, Texas A and M University, College Station, Texas, 77843. Resistance among Lycopersicon species to. 1996. Damaged plant cells collapse, resulting in deformed plant growth, flower deformation, or silvered patches and flecking on expanded leaves. A threshold of 10 thrips per bloom is used in California. Growth and survivability of the entomopathogenic fungus. Less work has been done to explore the ability of Orius species to suppress WFT damage in floral crops, compared to the previously discussed vegetable and fruit crops. Growers should also try to avoid buying thrips-infested plants and introducing them into their greenhouses. A., T. D. Paine, J. Hessein, N. A. and M. P. Parrella. Box 53400, Burlington, VT, 05405. Monitoring. On cucumber, control is not reliable with A. cucumeris; however, use of either A. limonicus or A. degenerans provides effective control. Reservoir weed hosts of tomato spotted wilt virus. Montserrat, M., C. Castañé & S. Santamaria. Gill, S. 1994. Loomans, A. J. M., T. Murai and I.D. 1995a, Loomans and van Lenteren 1996, Castineiras et al. The viruses then multiply inside the salivary glands and other tissues of the thrips (Wijkamp et al. Diapause in the predacious mites, Rosin, F., D.I. Immaraju et al. Thrips as Crop Pests. 1995. 1992. We also thank Dr. D. Peters (Dept. Place traps near doors, vents, and over thrips-sensitive plants. 341-346. Several species of Orius bugs have been tested for control of WFT on sweet pepper and cucumber, including O. tristicolor (Gilkeson et al. Careful studies of the minimum day length tolerated before induction of diapause have found great variation among Orius species. This biology suggests that T. nicklewoodi might be effectively transmitted within a WFT population on plants. CAB Commonwealth Institute of Parasitology. Plant Disease 70(11): 1014-1017). (ed.). According to experts, they are impossible to distinguish from other thrips species with the naked eye. Bulletin IOBC/WPRS 19(1): 47-50. Abdominal tip Western flower thrips: extreme tip black. Biological control of the western flower thrips. To date, two species of parasitoids, Ceranisus menes and C. americensis have been investigated to assess their potential to suppress WFT in greenhouse crops (Loomans et al. Invasion and development of, Sermann, H., U. Kästner and W. Hirte. Large : Identification to species is critical for determining which management actions to use as onion and western flower thrips are susceptible to different insecticides and depending on the crop, may or may not require treatment. 1993. 1996. Consequently, the crop plant on which mites are expected to provide biological control of a pest can strongly influence their success or failure. Damage: The western flower thrips feeds on the flowers and foliage by inserting its modified left mandible into the tissue, and sucking the fluids from cells. Siddiqui, M. F. 1985. Nematodes in the families Steinernematidae and Heterorhabditidae seem poorly suited for biological control of WFT because they are ineffective on foliage and can only be used against thrips in soil. Specifically, van den Meriacker (1994) found that for O. insidiosus the critical photoperiod was between 11 and 12 hours, and for O. majusculus it was between 14 and 16 hours. Molting is an important factor in insect resistance to infection, especially in an insect like WFT in which the time between molts is short. Plant Disease 74: 274-276. Clarkson, J.M. While providing some reduction, such results have suggested that Orius species tested so far on ornamentals provide too little control to be acceptable and are uneconomical for use (Parrella and Murphy 1996). of Virology, Wageningen, the Netherlands) for information on virus transmission and Peter Krauter for assistance in editing and Sean Werle for redrawing Figures 1 and 2. Bulltein IOBC/WPRS 19(1): 15-18. In addition, invasion by WFT (and its replacement of onion thrips as the pest of greatest concern) redirected the need for control to this new thrips species, whose biology differs from that of onion thrips. The western flower thrips [Frankliniella occidentalis (Pergande)] is an invasive pest insect in agriculture. TSWV has a very wide host range, and the only thrips that transmits the virus in a persistent way. Heinz, F., M. P. Parrella, and J. P. Newman. 1993. Ravensberg and M. Malais. Because most WFT pupate in soil or potting media, an alternative to foliage application is to apply pesticides to soil (Helyer et al. 1991. Artificial oviposition substrate for rearing, Castineiras, A., R. M. Baranowski and H. Glenn. 1998. However, its eggs were relatively sensitive to low humidities. Then, rotate to a third class of insecticides, and finally, return to the original material and repeat the whole process. Journal of Economic Entomology 91: 671-677. Parrella, M. P. 1995. Flower buds may abort in heavy infestations. Also, an in-greenhouse rearing process (called the "banker plant system") has been developed (Ramakers and Voet 1996). Wijkamp, I., J. van Lent, R. Kormelink, R. Goldbach and D. Peters. Products can be rendered totally inactive within a few weeks or less at such temperatures. Catches of cylindrical and flat traps, of the same area, do not differ. Tospoviruses: diagnosis, molecular biology, phylogeny, and vector relationships. Thrips management and biological control. A non-diapausing strain of the subtropical species A. limonicus was identified in laboratory tests as having the highest predation and oviposition rates of five candidate species (van Houten et al. Charnley, A.K., B. Cobb and J.M. In contrast, on plants which are not producing pollen, or on short cycle crops in which time for population increase is lacking, mites may fail to provide biological control of pests. Past published records of WFT predators (Riudavets 1995, Sabelis and van Rijn 1997) and parasitoids (Loomans and van Lenteren 1995; Loomans et al. Effect of temperature on development and oviposition of western flower thrips, de Klerk, M. L. and P. M. J. Ramakers. 1986. In a subsequent comparison of A. cucumeris and A. limonicus in a cucumber greenhouse in Holland, A. limonicus was able to suppress WFT populations, whereas A. cucumeris was not (van Houten 1996). Fungal entomopathogens recovered from Vermont forest soils. 1996. The first occurs during the bloom period when adult and larval thrips feed in flower parts and on the developing fruitlet under the shuck. (ed.) 1995). Early detection is important because symptoms of feeding often go unnoticed until serious damage has occurred. Chemical control. Prior to 1989, only one WFT-vectored tospovirus (TSWV) was known. Loomans, A. J. M. and J. C. van Lenteren. Monitoring of the western flower thrips, Schreiter, G., T. M. Butt, A. Beckett, S. Vestergaard, and G. Mortiz. Parker. Loomans, A.J.M. The relative suitabilities of cucumbers, tomatoes, and sweet peppers for foraging of O. insidiosus have been compared and cucumber found to be somewhat less suitable (Ferguson and Schmidt 1996). There is some doubt whether this mite can successfully complete its life cycle solely on a diet of WFT (for above details, see references cited in Riudavets 1995, and Sabelis and van Rijn 1997). 1996. Fransen and Tolsma (1992) found that release of one O. insidious per chrysanthemum plant every other week reduced thrips damage from 40-90% in untreated controls to 5-20%. The taxonomists who study phytoseiid mites currently do not agree as to the generic placement of species and the same mite may appear in different articles with different generic names (e.g., Amblyseius degenerans and Iphiseius degenerans). Tospoviruses strike the greenhouse industry: INSV has become a major pathogen on flower crops. Two new natural enemies of western flower thrips in California, pp. Western flower thrips will … 67-73, In Proceedings of the 6th International Colloquium on Invertebrate Patholology and Microbial Control. (1995) using M. anisopliae, although better control was obtained when the fungus was applied before rather than after pupation. Eggs, for example, are laid in host plant tissue and are thus protected from contact with the pathogen. On peppers, releases totaling 1-2 predators per plant resulted in good thrips control over several months, providing initial thrips numbers were low. 1995. In 1989, a new serotype was discovered in impatiens that became known as TSWV-I (for impatiens), in contrast to the common strain first characterized from lettuce that was known as TSWV-L (for lettuce). 1992. 19: 153-156. 115-126. Use a given effective insecticide for several generations of WFT (3-4 weeks), then rotate to another insecticide with a different mode of action (different chemical class) for several WFT generations. Thrips parasitoids are found in three families (Eulophidae, Trichogrammatidae, Mymaridae) and several genera. 1992. Thrips as Crop Pests. Allen, W. R. and A. Sex ratio patterns and population dynamics of western flower thrips (Thysanoptera: Thripidae). Entomologia Experimentalis et Applicata, 83: 73-80. Shipp et al. In addition, B. bassiana and M. anisopliae inoculum levels actually increased over time, potentially providing a long-term control of thrips pupae in soil. Laboratory methods to mass rear and synchronize the developmental stages of WFT have been developed (see Loomans and Murai 1997 for a review). For more precision, sticky traps may be used. The critical photoperiod for diapause induction is 12.5 hours day light, given a day temperature of 72°F (22°C) and night temperature of 63°F (17°C). H. Glenn van Houten, Y. M., T. nicklewoodi infects but does not kill thrips.. Faster rates of development the salivary glands and other thrips species can peanuts... Plant for use in population monitoring of the western flower thrips in greenhouse crops Helyer... Achieved through use of fungal pathogens for insect control in greenhouses a wide of. More resistant than adults, presumably because fungal inoculum is shed when the fungus was before. Various tests ( Tomalek 1991, 1994 ; Helyer et al Houten van! 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