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United States Department of Agriculture

Agricultural Research Service

Related Topics

Research Project: Biologically Based Techniques for Control of Insect Pests

Location: Insect Behavior and Biocontrol Research Unit

2012 Annual Report


1a.Objectives (from AD-416):
To develop and improve the biologically based technolgies used for the area-wide control of disease-vectoring thrips and migratory Lepidoptera, such as, the invasive cactus moth. The particular methods of interest are classical, inundative and conservation biological control of both insects and plants, particularly the latter that serve as pathogen reserviors, and the sterile insect technique (SIT). The systems for investigations will serve as models for testing hypotheses regarding novel biologically based Integrated Pest Management (IPM) techniques. Results of this research are not limited to specific pests but will have broad applicability to other systems. The cooperator will provide the needed expertise in spatial ecology and detection techniques to analyze the spread and movement of pests and natural enemies and thus facilitate development of managment programs, including optimal biological control agent release strategies.


1b.Approach (from AD-416):
A principle obstacle to better control the disease-vectoring thrips and whiteflies is the lack of information concerning weeds, sometimes invasive, pathogen reserviors, and the movements of insects between these reservoirs and crops. There is also a dearth of knowledge on natural enemies and their impact in crop and non-crop situations. The cooperator will develop new methods, including genetic, that will determine the presence of infections and the consequences of infection on insect behavior and ecology, and the spread of disease. Subsequently, the efficacies of biological control agents, of both plant reservoirs and pests, will be screened in collaboration with the Principal Investigator. The cooperator and the ADODR will also examine the dispersal behavior and efficacy of sterile males of the invasive cactus moth to optimize release strategies and will develop other tactics to prevent its further spread. Techniques will include mark-recapture and measures of physiological flight capacity. The potential of other control approaches, especially biological control, will also be examined.


3.Progress Report:

Research conducted under this specific cooperative agreement is related to Objective 1 of the parent project by seeking to understand the role of weeds as reservoirs for thrips and tomato spotted wilt virus, and how weed management may benefit management of those pests. Research on leafminers benefits addresses Objective 1 and 2 of the parent project by fostering the development of comprehensive integrated pest management (IPM) programs for vegetable crops that are also attacked by thrips and whiteflies. Improved biological control of leafminers will minimize disruption to IPM programs for management of these key pests.

Two master’s students at the FAMU Center for Biological Control are working with the research team. The tropical soda apple (TSA) work will be the basis for a M.S. thesis for one student and the leafminer work the basis for the other student.

Tropical soda apple is a key noxious weed pest of pastures in the southern USA and can harbor insect transmitted viruses of vegetable crops. One of the key viruses it can harbor is the thrips-vectored tomato spotted wilt virus (TSWV). Scientists with the Center for Biological Control, Florida A&M University have initiated studies in cooperation with scientists with USDA-ARS-CMAVE to determine if western flower thrips (WFT) can transmit TSWV from infected TSA, a known reservoir of the virus, and the level at which WFT is found inhabiting stands of naturally growing TSA. Additional aspects of the study are to establish the effect that crop pollens may have on ovipositional rate of thrips on TSA.

Although the leafminers Liriomyza sativae and L. trifolii (Diptera: Agromyzidae) are already important pests in U.S. horticultural and ornamental crops, additional pest species of Liriomyza pose invasive threats to the U.S. In particular, Liriomyza huidobrensis, the pea leafminer, which is closely related to these species, is considered by APHIS to be a pest of quarantine significance that poses a high risk for introduction into the U.S. Florida is particularly concerned by the threats posed from invasive species.

Given this possibility of introduction, it is critical to proactively develop management tactics for the pea leafminer should it become established in the US. It is well established that in many cases hymenopteran parasitoids of leafminers can provide acceptable control in the absence of insecticide spraying. Most of these parasitoid species that attack L. sativae and L. trifolii are also able attack the pea leafminer. Thus, improved biological control has the potential to reduce the use of harmful agrochemicals in vegetable fields and mitigate pest pressure from invasive species. Surveys have been initiated to determine the prevalence of L. sativae and L. trifollii in vegetable production in Tallahassee, FL. Multiple vegetable species in Solanaceae (pepper, eggplant, tomato, tomatillo), Cucurbitaceae (squach, pumpkin), Brassicaceae (cabbage, turnip, mustard), Malvaceae (cotton, okra), Amaranthaceae (spinach), Leguminacea (bean, pea) are some of the families being surveyed for leafminers and associated parasitoids.

The goal in this project is to provide information on plant-leafminer-parasitoid associations in order to explore food web dynamics involving leafminers established in Florida, and to relate these to potential hosts of the pea leafminer. These data will enable predictions of which parasitoids would be most suitable to target for conservation/augmentation for various crops that may be attacked by the invasive pea leafminer.


Last Modified: 10/25/2014
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