Performing Department
(N/A)
Non Technical Summary
Invasive thrips, Thrips parvispinus (Karny) (Thysanoptera: Thripidae), poses a serious threat to the ornamental and vegetable industries, especially pepper in the US. Since 2020, this pest has caused serious crop losses in pepper fields and Mandevilla spp. in South Florida. The ornamental nursery growers responded with repeated insecticide applications at close intervals (three applications per week), which increase the risk of resistance development in T. parvispinus populations. The growers outside South Florida are concerned with potential spread and infestation and crop loss. No management tactics have been developed for T. parvispinus, and growers have no clear strategy to tackle this pest in their facilities/farms once detected other than resorting to repeated insecticide use. This proposal is a muilt-disciplinary, multi-commodity and multi-state effort to determine the distribution of T. parvispinus, characterization of feeding damage, and develop IPM tactics, such as cultural (pruning and mulching), biological (minute pirate bug, green lace wing and predatoy mites), and chemical control in ornamental systems and pepper fields.
Animal Health Component
100%
Research Effort Categories
Basic
0%
Applied
100%
Developmental
0%
Goals / Objectives
To determine the extent of T. parvispinus occurrence in Georgia through a survey of ornamental nurseries and commercial pepper fieldsTo characterize the damage to key ornamental crops and pepper typesTo determine the integrated effects of cultural, chemical, and biological control tactics on T. parvispinus and damageExtension of the newly generated information to clientele
Project Methods
1. To determine the extent of T. parvispinus occurrence in Georgia through a survey of ornamental nurseries and commercial pepper fields (Participants: Joseph, Schoeller, Yu, LaForest) A survey will be conducted for three consecutive years through collaboration with greenhouses, nursery growers, and field pepper growers in Georgia. Three greenhouse facilities will be randomly selected yearly in north, central, and south GA (9 sites total). Five additional nursery sites and pepper fields will be selected for surveying in South Georgia. Facilities with large operations will be selected for the survey; they move plant materials more often or are distributed to many retail facilities. The PDs will work with the University of Georgia's extension system and industry groups such as the Georgia Green Industry Association to identify the facilities.2. To characterize the damage to key ornamental crops and pepper cultivars (Participants: Joseph, Schoeller, Yu, Revynthi)To characterize the damage, we will evaluate the relationship between T. parvispinus densities and damage and document how damage symptoms vary by host plants. Laboratory colonies of T. parvispinus will be established and reared on beans in screened cages under greenhouse or containment conditions based on the pest regulation in each state. Three densities of first and second instars and adults (mixed) will be tested on different hosts and laboratory conditions. The three densities of T. parvispinus tested will be 0, 1, 5, and 10 thrips per host. The hosts tested will include Mandevilla, Gardenia, Hibiscus, Rosa, Tagetes, Chrysanthemum spp., bell pepper, banana pepper, jalapeno pepper, and mini sweet pepper. Leaf discs of 24 mm diameter will be taken from the leaves of each host plant and placed on wet cotton wool in Petri dishes. Thrips larvae will then be transferred to the leaf discs and allowed to feed for 24 h. After 24 h, the damaged area will be measured using the free software Image J (Ataide et al. 2024). Ten replicates per host plant, thrips stage, and density will be performed. From these experiments, we can determine the susceptibility of each host in relation to the thrips stage and density. The results of these experiments will create the baseline information to conduct a greenhouse experiment. The most impacted hosts from thrips feeding (based on the lab experiment) will be then evaluated under greenhouse conditions. Only the density and stage that caused the highest damage will be tested in these experiments. The leaf-feeding damage will be quantified by calculating the proportion of leaf disc (d = 24 mm) area damaged (scarred) by the thrips. The proportion of damaged area will be analyzed with a Generalized Linear Model (GLM) with a host, density, thrips stage, and their interaction as factors. Data analysis will be performed in R version 4.1.3.3.To determine the integrated effects of cultural, chemical, and biological control tactics on T. parvispinus and damage (Participants: Joseph, Schoeller, Yu, Sparks, Revynthi, Mou, and Mészáros)Both adults and larvae feed on various plant parts. When flowers are present, adults are found on flowers. Because the T. parvispinus larvae are mostly found feeding on growing terminal leaves, physically removing the leaves could reduce the population size. Thrips predators, A. swirskii, O. insidiosus, and C. carnea will be evaluated. Four experiments will be conducted. The first two experiments will be conducted in a greenhouse using gardenia plants (3.7 L containers), where either pruning or predators will be integrated with biorational insecticides. The third experiment will be conducted on pepper, where potential insecticides on T. parvispinus will be evaluated. The fourth experiment will be conducted in the greenhouse on containerized gardenia plants, where various mulch treatments will be integrated with insecticide treatments. The colonies of T. parvispinus will be held in screened cages (60 cm dimensions, 300 µm aperture) on pepper and housed in climate-controlled rooms (25 ± 2°C, 70 ± 5% RH, 12:12 L:D photoperiod) under an artificial light regime.4. Extension of the newly generated information to clientele (Participants: Joseph, Schoeller, Yu, Sparks, Campbell, LaForest, Revynthi, Mou, and Mészáros)A series of Extension activities will be conducted as part of this objective. The activities will be:1. outreach presentations directed for the producers with newly generated information;2. organize annual grant advisory committee meetings with stakeholders;3. T. parvispinus-specific grower virtual meeting for stakeholders from the ornamental and pepper industries and4. develop a one-page extension article on T. parvispinus recommendations for producers.The Georgia and Florida county extension agents will be updated during the annual winter/summer conference. Extension agents will be trained on identifying T. parvispinus, biology, ecology, monitoring and potential risk factors, and sampling plans for larval and adult stages, which will ultimately warrant management decisions such as the timing of insecticide applications. The PD, extension Co-PDs, and graduate students will lead the presentations.