Management Of Western Flower Thrips Research Articles

Invasion Biology, Ecology, and Management of Western Flower Thrips.

Western flower thrips, Frankliniella occidentalis, first arose as an important invasive pest of many crops during the 1970s-1980s. The tremendous growth in international agricultural trade that developed then fostered the invasiveness of western flower thrips. We examine current knowledge regarding the biology of western flower thrips, with an emphasis on characteristics that contribute to its invasiveness and pest status. Efforts to control this pest and the tospoviruses that it vectors with intensive insecticide applications have been unsuccessful and have created significant problems because of the development of resistance to numerous insecticides and associated outbreaks of secondary pests. We synthesize information on effective integrated management approaches for western flower thrips that have developed through research on its biology, behavior, and ecology. We further highlight emerging topics regarding the species status of western flower thrips, as well as its genetics, biology, and ecology that facilitate its use as a model study organism and will guide development of appropriate management practices.

Returns to research and outreach for integrated pest management of western flower thrips infesting French bean and tomato in Kenya

AbstractThrips,Frankliniella occidentalis(Pergande), is a major invasive pest that causes extensive yield losses in French bean and tomato in Kenya. Thrips management is based on the application of pesticides. In addition to increased environmental risks associated with pesticides, frequent use of these chemicals increases production costs and pesticide resistance. Furthermore, exports are restricted due to non-compliance to maximum residue levels in important consumer export markets, especially the European Union (EU). This study was conducted to estimate the potential benefits of the effectiveness of theicipe-developed strategy for control of western flower thrips before dissemination of the technology in Kenya, using the economic surplus model. We calculated the benefit–cost ratio, the Net Present Value (NPV) and the Internal Rate of Return (IRR) using Cost–Benefit Analysis (CBA). Assuming a maximum conservative adoption rate of 1% and a 10% discount rate for the base deterministic scenario, the NPV of the research was estimated at US$2.2 million, with an IRR of 23% and a BCR of 2.46. Sensitivity analyses indicated that the NPV, IRR and BCR increased at an increasing rate as adoption rates increased. However, as elasticities of supply and demand increased, the NPV, IRR and BCR increased at a decreasing rate. The findings demonstrate that farmers from developing countries can gain when they obtain access to suitable pest management innovations such as integrated pest management technologies. Consequently, investment in IPM technologies for suppression of western flower thrips should be enhanced.

Western Flower Thrips Management in Marigolds, 2014

The WFT is an ornamental pest that causes scarring of leaf tissue and flower surfaces through its feeding action, and vectors plant pathogens. The objective of the experiment was to assess efficacy of candidate insecticides in reducing WFT density on Marigolds relative to that of water-only applications. The trial was conducted at the Biological Control Facility greenhouse at Texas A&M University in College Station. Marigolds ( Tagetes erecta L., cv ‘Discovery Yellow’, donated by Benary, Dekalb, IL) were germinated en masse and transplanted individually into 4 inch pots with Sunshine Complete Mix #1 soil (Sun Gro Horticulture, Agawam, MA) on 16 May approximately 1 wk after germination. Plants were placed into two 6 by 4 by 4 ft rearing cages …

Western flower thrips management in greenhouse production systems in the 21stcentury: alternative strategies need to be considered

Western flower thrips management in greenhouse production systems in the 21^stcentury: alternative strategies need to be considered

The combined effect of soil‐applied azadirachtin with entomopathogens for integrated management of western flower thrips

AbstractPerformance of soil application of azadirachtin products with entomopathogens was evaluated as single treatments, in multiple combinations and in different concentrations against the soil stages of western flower thrips, Frankliniella occidentalis (Pergande), in French beans Phaseolus vulgaris L. Treatments consisted of NeemAzal‐T solution, neem pellets, Steinernema carpocapsae (Weiser) Nemastar®, isolates of Metarhizium anisopliae (Metschnikoff) Sorokin (IPP 2539 and ICIPE‐69) and Beauveria bassiana (Balsamo) – Naturalis®. All treatments were analysed for the number of emerging adults, while emerged adults in fungi‐based treatments were analysed additionally for the retarded development of mycosis as a possible cause of secondary mortality. Possible interactive effects in combined treatments were analysed using a generalized linear model (GLM) approach, and three levels of dose–response combinations of the selected treatments were further tested. Bioassay results of the single treatments indicated between 43% and 60% reduction in adult emergence with NeemAzal‐T solution thus proving to be the most efficient. However, most cadavers with entomopathogenic fungi (EPF) treatments showed the development of mycosis. Therefore, the reduction in adult emergence attributed to the EPF was altogether >87%. Combined treatments with Steinernema, Metarhizium (ICIPE‐69), NeemAzal‐T and neem pellets resulted in total reduction in adult emergence of 95–97% when late mortality by mycosis was considered. Of the treatment combinations, two showed synergistic, four additive and one an antagonistic response. Combining low concentration of entomopathogenic nematode (EPN) (100 IJ/cm2) with NeemAzal‐T resulted in satisfactory control compared to the operational dose of EPN, while the highest concentration of M. anisopliae (108 conidia) combined with Steinernema showed the best performance with 74% reduction in adult emergence.

Optimizing Western Flower Thrips Management on French Beans by Combined Use of Beneficials and Imidacloprid.

Western flower thrips (WFT), Frankliniella occidentalis (Pergande), is an important pest of vegetable crops worldwide and has developed resistance to many insecticides. The predatory mites Neoseiulus (=Amblyseius) cucumeris (Oudemans), the entomopathogenic fungus Metarhizium anisopliae (Metsch.), and an insecticide (imidacloprid) were tested for their efficacy to reduce WFT population density and damage to French bean (Phaseolus vulgaris L.) pods under field conditions in two planting periods. Metarhizium anisopliae was applied as a foliar spray weekly at a rate of one litre spray volume per plot while imidacloprid was applied as a soil drench every two weeks at a rate of two litres of a mixture of water and imidacloprid per m2. Neoseiulus cucumeris was released every two weeks on plant foliage at a rate of three mites per plant. Single and combined treatment applications reduced WFT population density by at least three times and WFT damage to French bean pods by at least 1.7 times compared with untreated plots. The benefit-cost ratios in management of WFT were profitable with highest returns realized on imidacloprid treated plots. The results indicate that M. anisopliae, N. cucumeris, and imidacloprid have the potential for use in developing an integrated pest management program against WFT on French beans.

Impacts on Natural Enemies and Competitor Thrips of Insecticides against the Western Flower Thrips (Thysanoptera: Thripidae) in Fruiting Vegetables

Newer, selective insecticides with few negative impacts on natural enemies and competitor species are needed for effective, sustainable management of the western flower thrips, Frankliniella occidentalis (Pergande). The purpose of this study was to evaluate the impacts on natural enemies and competitor thrips species of insecticides used for control of western flower thrips in fruiting vegetables. Trials with tomato (Solanum lycopersicum L.) and with pepper (Capsicum annuum L.) were conducted to evaluate insecticide treatment effects on western flower thrips and natural enemies at the North Florida in 2008, 2009, 2010 and 2011. A number of insecticides from different classes showed moderate to high efficacy against western flower thrips. The broad-spectrum insecticides acetamiprid, methomyl, and tolfenpyrad demonstrated activity against the pest, while also reducing populations of the key predator of thrips in pepper, Orius insidiosus (Say) (Hemiptera: Anthocoridae). Insecticides that showed little impact on populations of O. insidiosus were cyantraniliprole, flonicamid, spirotetramat, and terpenes. Although only moderately active against the western flower thrips, they would be valuable additions to existing management programs for pepper. Insecticides with activity against western flower thrips also showed activity against Frankliniella tritici (Fitch). This non-damaging congener species is a beneficial because it out-competes the western flower thrips, especially in tomato where O. insidiosus is not a major factor in western flower thrips management. Numerous insecticides were identified with activity against the western flower thrips that are suitable for use in integrated pest management programs of fruiting vegetables.

Frankliniella occidentalis (Pergande) integrated pest management programs for fruiting vegetables in Florida

The spread of the western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), resulted in the worldwide destabilization of established integrated pest management programs for many crops. Efforts to control the pest and the thrips-vectored tospoviruses with calendar applications of broad-spectrum insecticides have been unsuccessful. The result has been a classic '3-R' situation: resistance to numerous insecticides; resurgence of the western flower thrips populations as a result of natural predators and native competitor thrips being eliminated; replacement by various other pests. This paper reports on integrated pest management programs for fruiting vegetables that are effective, economical, ecologically sound and sustainable. The components include the following: define pest status (economic thresholds); increase biotic resistance (natural enemies and competition); integrate preventive and therapeutic tactics (scouting, ultraviolet-reflective technologies, biological control, compatible insecticides, companion plants and fertility); vertically integrate the programs with other pests; continually communicate latest science-based management tactics with end-users. These programs have been widely implemented in Florida and have significantly improved the management of western flower thrips and thrips-transmitted viruses.

Single versus multiple releases of predatory mites combined with spinosad for the management of western flower thrips in strawberry

Western flower thrips, Frankliniella occidentalis (Pergande), is a major pest of strawberry and other horticultural and ornamental crops. Biological control of F. occidentalis with predatory mites is recommended as an additional management strategy to chemical control in glasshouse and protected crops. However, it is not known whether multiple (two or three) species releases of predatory mites are more effective than single species releases. The effect of an application of spinosad followed by mite releases could further increase suppression of F. occidentalis. In a series of trials in the glasshouse, we evaluated three commercially available predatory mite species, Typhlodromips montdorensis (Schicha), Neoseiulus cucumeris (Oudemans) and Hypoaspis miles (Berlese). Strawberry plants were sprayed once with either spinosad at the recommended rate or with water. F. occidentalis adults were released onto plants 24 h after spraying, and mites were released six days later. Spinosad significantly reduced F. occidentalis compared to the control (water). T. montdorensis, N. cucumeris and H. miles significantly reduced F. occidentalis compared to the ‘no mite’ treatment. Spinosad had no effect on T. montdorensis and N. cucumeris, as their numbers did not differ between the spinosad and control treatments; H. miles was not recovered. When mites were released after an application of spinosad, greater suppression of F. occidentalis was achieved than with releases of predatory mites alone. When released as a double species combination, ‘ T. montdorensis and H. miles’ was the most effective combination. There was no difference in efficacy between releases of ‘ T. montdorensis and H. miles’ or ‘ T. montdorensis, N. cucumeris and H. miles’. We conclude that multiple species releases are more effective than single species releases, and that biological control of F. occidentalis with predatory mites can be used together with spinosad.

Investigation into the apparent failure of chemical control for management of western flower thrips, Frankliniella occidentalis (Pergande), on plums in the Western Cape Province of South Africa

Western flower thrips (WFT), Frankliniella occidentalis (Pergande), causes russetting, pansy spot and silvering damage on plums. Despite routine insecticide applications for thrips control, some plum producers report economic losses due to pansy spot damage, pits and holes that render fruit unfit for export. Six commercial plum orchards in two climatic regions in the Western Cape Province, South Africa, were monitored to determine (1) why current management practices based on monitoring and insecticide applications failed to prevent damage in some orchards, and (2) whether WFT is responsible for pitting damage. Western flower thrips was the dominant thrips species in all orchards, though low numbers of Frankliniella schultzei Trybom also occurred. Blue sticky traps were more efficient for monitoring WFT and F. schultzei than yellow traps. Insecticide applications early in bloom and unfavourable weather conditions for thrips flight contributed to very low numbers of WFT on sticky traps during the flowering and fruit set periods. Flower dissections, however, revealed varying levels of oviposition damage to ovaries and fruitlets. Dissections confirmed that WFT enter flowers to lay eggs in the ovaries and other flower parts before petals are fully open. No consistent significant relationship between sticky trap counts and WFT oviposition damage to plums were found, therefore no treatment threshold level could be recommended. Insecticide applications during bloom limited thrips feeding damage, but were too late to prevent oviposition damage. Some oviposition sites developed into typical pansy spots, whilst others formed holes or pits that increased in size as the fruit matured. After insecticide applications ended, and as air temperature increased, WFT populations increased. Weeds and wild vegetation in and around orchards provide a continuous source of potential infestation for as long as the fruit remains attractive and vulnerable to WFT. As oviposition damage by WFT can occur before flowers open, and because of the risk to pollinators when insecticides are applied during flowering, a purely chemical control strategy does not appear to be feasible. A new approach to WFT management is required.

Education and Training to Increase Adoption of IPM for Western Flower Thrips,Frankliniella occidentalis(Thysanoptera: Thripidae)

ABSTRACT The University of Florida, IFAS, IPM Florida and Southern Plant Diagnostic Network (SPDN) are cooperatively developing education and training to increase integrated pest management (IPM) of western flower thrips (WFT), Frankliniella occidentalis (Pergande). Management of WFT is exacerbated by difficulty in identifying thrips species and by their development of insecticide resistance. Education and training will emphasize workshops on identification of thrips; insecticide resistance management protocols; description of the effects of insecticides on natural enemies, i.e., Orius spp., and use of the “Grower's IPM Guide for Florida Tomato and Pepper Production”. Thrips identification aids, such as a national field-based identification deck currently under development by the SPDN and the North Central IPM Center (NCIPMC), will be useful to Florida growers. This kind of information will be delivered through Extension programs, including workshops, in-service training, field days, and classroom educati...

ANALYSING INDUSTRY NEEDS TO FINE TUNE IPM PROJECT ACTIVITIES

As a first step to better targeting the activities of a project for improving management of western flower thrips, Frankliniella occidentialis, (WFT) in field grown vegetable crops, we surveyed growers, consultants and other agribusiness personnel in two regions of Queensland. Using face-to-face interviews, we collected data on key pests and measures used to manage them, the importance of WFT and associated viral diseases, sources of pest management information and additional skills and knowledge needed by growers and industry. Responses were similar in the two regions. While capsicum growers in one northern Queensland district had suffered serious losses from WFT damage in 2002, in general the pest was not seen as a major problem. In cucurbit crops, the silverleaf whitefly (Bemisia tabaci biotype B) was considered the most difficult insect pest to manage. Pest control tactics were largely based on pesticides although many respondents mentioned non-chemical methods such as good farm hygiene practices, control of weed hosts and regular crop monitoring, particularly when prompted. Respondents wanted to know more about pest identification, biology and damage, spray application and the best use of insecticides. Natural enemies were mentioned infrequently. Keeping up to date with available pesticide options, availability of new chemicals and options for a district-wide approach to managing pests emerged as key issues. Growers identified agricultural distributors, consultants, Queensland Department of Primary Industries staff, other growers and their own experience as important sources of information. Field days, workshops and seminars did not rank highly. Busy vegetable growers wanted these activities to be short and relevant, and preferred to be contacted by post and facsimile rather than email. In response to these results, we are focusing on three core, interrelated project extension strategies: (i) short workshops, seminars and farm walks to provide opportunities for discussion, training and information sharing with growers and their agribusiness advisors; (ii) communication via newsletters and information leaflets; (iii) support for commercialisation of services.

Sequential Sampling Plans for Western Flower Thrips (Thysanoptera: Thripidae) on Greenhouse Cucumbers

The development of cost-effective and reliable sampling programs for the management of western flower thrips, Frankliniella occidentalis (Pergande), on greenhouse cucumbers is important for getting growers to adopt economic injury levels and economic thresholds. The objectives of this study were to develop two sequential sampling plans. A fixed-precision sequential sampling plan was designed for estimating F. occidentalis adult density at a fixed-precision level on cucumber flowers. Also, a sequential sampling plan for classifying thrips population levels as below or above economic thresholds was developed to assist in decision making for the timing of pesticide applications. Both sequential sampling plans were validated using a resampling simulation technique on nine independent data sets ranging in density from 1.25 to 12.95 adults per flower. With the fixed-precision sampling plan, average means obtained in 100 repeated simulation runs were within the 95% CI of the estimated mean for all data sets. Appropriate levels of precision for the different population densities were recommended based on the simulation results. With sequential sampling for classifying the population levels of thrips in terms of an economic threshold, it has the advantage of requiring smaller sample sizes to determine the population status when the population densities differ greatly from the critical density (i.e., economic threshold). However, this plan needs a great number of samples when population density is close to the critical density. In this case, use of a combination of both sampling plans is recommended.