Project Overview

S21-009

Project Type: IPM Centers Grant

Funds awarded in 2021: $29,816.00

Grant Recipient: University of Florida

Region: Southern

State: Florida

Cooperating States: none

Project Coordinator:

Dr. Hugh Smith

University of Florida

Managing Asian bean thrips (Megalurothrips usitatus), a newly established invasive pest of legumes 

Reports

Commodities

Vegetables: beans

Target Pests

Target Pests: other

Practices

Pest Management: monitoring/scouting, pesticide application timing, pesticide resistance management, pesticides

Proposal abstract:

A new invasive pest of legumes, the Asian bean thrips (Megalurothrips usitatus), has become established in south Florida, and threatens several economically important agricultural commodities in the southeast, including snap bean, specialty Asian legumes (pigeon pea, lablab bean, yard-long bean, others), soybean and peanut. The Asian bean thrips damages crops by feeding and laying eggs on foliage, flowers and bean pods. Unlike most other pests of legumes, Asian bean thrips causes significant damage to plants in their early vegetative stages, causing bean growers to apply insecticides earlier and more intensively in the crop cycle. Asian bean thrips has been detected in several south Florida counties, but is primarily associated with the Homestead agricultural area south of Miami, where significant infestations have occurred in snap beans and lablab bean, a specialty Asian legume. Fundamental information needed to develop monitoring and management plans for Asian bean thrips is lacking. We propose gathering basic information on the relative importance of snap bean, lablab bean, yard-long bean and pigeon pea as hosts of Asian bean thrips to better understand where it is most abundant throughout the growing season. We will compare leaf, flower, and pod samples from these crops to catches on yellow and blue sticky traps to lay the foundation for an effective monitoring system. Season-long monitoring data will be related to information on yield collected in collaboration with growers to assess the relationship between pest density and economic damage. In addition, year-long sampling of legumes will provide information on the abundance and species of Orius and other important thrips predators in different crops. We will survey the pest management practices and priorities of snap bean and specialty legume growers in south Florida to gather information on the insecticide mode of action groups used and the intensity of use. Asian bean thrips will be collected from infested fields and screened for susceptibility to insecticides commonly used to manage thrips. These include spinetoram (Radiant), cyantraniliprole (Exirel), acetamiprid (Assail), tolfenpyrad (Torac) and methomyl (Lannate) for adults, and novaluron (Rimon) and spirotetramat (Movento) for larvae. The top labeled rate is used in a laboratory bioassay to determine if these materials are effective for management. This information, used in conjunction with information on insecticide use patterns and natural enemy data collected from growers and farms, will be used to outline priorities for an Asian bean thrips management plan. Two workshops will be given to provide growers, scouts, Extension agents, and other crop protection professionals training in the identification and management of Asian bean thrips in the context of an overall pest management plan for south Florida legumes. This project will build on current research and outreach efforts to monitor Asian bean thrips and assess its susceptibility to chemical control.

Project objectives from proposal:

Planned Outputs

Anticipated Outcomes

Problem or Priority targeted

Survey snapbeans, lablab, pigeon pea and yard-long bean for thrips. Target flowers, new growth, old leaves, pods.
Evaluate yellow and blue traps to monitor thrips in these four commodities.
Determine if a correlation exists between trap counts, information collected from different plant parts and economic damage.
Collect information from growers on pest management practices in four commodities.
Screen Asian bean thrips collected from these commodities for susceptibility to key insecticides.
Provide monitoring and management guidelines to legume growers in south Florida.
Offer two trainings on identification and management of Asian bean thrips.

Growers, researchers, Extension agents and crop protection professionals will improve their understanding of:

the most effective method for monitoring Asian bean thrips using plant inspection and sticky traps;
host preferences of Asian bean thrips among economically important legume crops in south Florida, including importance of alternate hosts as source of infestations in snap bean;
the role of alternate hosts as sources of thrips predators; and
the potential of alternate hosts to serve as a source of insecticide-resistant thrips.

As a result of improved understanding of multiple factors influencing monitoring of Asian bean thrips and the damage it causes, this project will provide the foundation for a management plan for this new invasive pest.

We are addressing the lack of monitoring and management information needed to develop an integrated management plan for a newly established pest of legumes in the southeast, the Asian bean thrips, Megalurothripsusitatus.

Indicators and Milestones

	Planned Outputs
Milestone	Person or organization responsible	Planned completion date
1. Quantify density of Asian bean thrips, other thrips species and thrips predators on i) yellow and blue sticky traps and ii) leaves, flowers and pods of snap bean, lablab bean, yard-long bean and pigeon pea on at least four farms of each commodity in the Homestead agricultural area.	Graduate Student, Smith, Hodges	This activity will occur year-round as hosts are available, but the final quantification of data from this one-year project will occur during the fourth quarter.
2. Rate thrips damage to harvestable pod on sixteen survey sites described in Milestone 1.	Graduate Student, Smith, Hodges	First quarter and in subsequent project periods pending the crop phenology and host availability.
3. At least six snap bean growers and six specialty legume growers respond to survey on season-long insecticide use in crops.	Graduate Student, Frey, Smith, Hodges	Second Quarter
4. Thrips populations from twelve snap bean farms and twelve specialty legume farms are bioassayed using a maximum dose test for susceptibility to at least seven key insecticides.	Graduate Student, Smith, Hodges	First quarter and in subsequent project periods pending the crop phenology and host availability.
5. Offer two workshops on identification and management of Asian bean thrips	Graduate Student, Frey, Smith, Hodges	First and final quarter
	Anticipated Outcomes
Milestone	Person or organization responsible	Planned completion date
1. Growers and crop protection professionals can optimize thrips monitoring in legumes (indicator 1) and predict densities that will result in economic loss (indicator 2).	Graduate Student, Smith, Hodges	Fourth Quarter
2. Growers, crop protection professionals and researchers use information on insecticide selection pressure (indicator 3) and insecticide susceptibility data (indicator 4) to design insecticide resistance guidelines for thrips in legumes.?	Graduate Student, Smith, Hodges	Fourth Quarter