1a. Objectives (from AD-416)
Specific objectives for this cooperative research include: 1)Determine efficacy and residual activity of registered insecticides against chilli thrips and other invasive pests; 2)Develop baseline data of chilli thrips to spinosad (Conserve) and chlorfenapyr (Pylon) for future resistance monitoring efforts; 3)Determine direct impact and residual activity of insecticides against key beneficial organisms used for biological control of thrips and other invasive pests; and 4)Develop model pesticide rotation programs for chilli thrips and western flower thrips. These rotations will be developed based on residual activity, labeled restrictions on frequency of application and impact on key beneficial arthropods.
1b. Approach (from AD-416)
The approach of this cooperative research project is to evaluate registered pesticides alone and in rotation on different floral and ornamental host plants such as knock-out roses and hawthorne for efficacy against chilli thrips (Scirtothrips dorsalis) and their impact on predatory mites, (Amblyseius swirskii and Neoseiulus californicus ) for development of BMPs. In order to minimize reliance on spinosad and the attendant problems that this poses for western flower thrips management, efficacy trails will be conducted to find additional materials for chilli thrips control and their impact on beneficials. We fully expect to find pesticides that have lost their efficacy on WFT but not to chilli thrips. Bioassays will be conducted to determine susceptibility baseline data for chilli thrips to the most important compounds. Data will be used to develop robust IPM programs and BMPs for thrips control in general and Scirtothrips dorsalis in particular.
3. Progress Report
This project is related to Objective 5: Chilli Thrips. The objective of this cooperative research project is to evaluate registered pesticides alone and in rotation on different floral and ornamental host plants for efficacy against chilli thrips and their impact on predatory mites for development of Best Management Practices (BMPs) that will benefit growers. A chilli thrips website was developed (http://mrec.ifas.ufl.edu/lso/thripslinks.htm) for growers and researchers alike to access the most current information including a large gallery of plant damage photos, host lists, research and regulatory articles, powerpoint presentations, links to other thrips websites, management guidelines and documents from the National Chilli Thrips Task Force, all of which can easily be downloaded by the end-user. The chilli thrips website averaged 39 page loads per day and 14,444 total for the period July 1, 2008 through July 7, 2009 with a total page loads to date of 30,984. Trials from Florida and Texas determined eleven pesticides with 7 different modes of action were effective for controlling chilli thrips and include acephate, spinosad, abamectin, flonicamid, chorfenapyr, pyridalyl and the neonicotinoids acetamiprid, clothianidin, dinotefuran, imidicloprid and thiamethoxam. Two species of phytoseiid mite were evaluated as predators of the chilli thrips. In leaf disc assays, gravid females of Neoseiulus cucumeris and Amblyseius swirskii both fed on chilli thrips at statistically similar rates. Larvae were the preferred host by both mite species, consuming on average 2.7/day, compared with 1.1- 1.7 adults/day in no choice tests. Adult thrips were rarely consumed in subsequent choice tests when larvae were also present. Mite fecundity was statistically similar for both species feeding on thrips larvae (greater than 1.3 eggs/day) but significantly less for A. swirskii restricted to a diet of adult thrips (0.5 eggs/day). In greenhouse tests with infested pepper plants, both mite species established and reduced thrips numbers significantly over 28 days following a single release (30 mites/plant). However, A. swirskii was the more effective predator, consistently maintaining thrips below 1 per terminal leaf, compared with up to 36 for N. cucumeris and 70 in control treatments. Similar results were obtained for plants maintained outside in the landscape, where A. swirskii continued to reproduce and control thrips up to 63 days post release. After publication of the predatory mite study, ARS posted a news release about the research entitled A Biocontrol for a Wide-Ranging Thrips http://www.ars.usda.gov/is/pr/2009/090428.htm and the University of Florida, IFAS posted one entitled Predatory mite could put the bite on invasive crop pest, UF researcher says http://news.ufl.edu/2009/04/28/thrips/ with the same release date. Traffic on the chilli thrips website has dramatically increased since the news releases. Progress was monitored through email, conference calls, site visits to research facilities as well as stationing the postdoctoral research associate hired thru this SCA in Fort Pierce.