Potential New Insecticides for the Control of Western Flower Thrips (Thysanoptera: Thripidae) on Sweet Pepper, Tomato, and Lettuce

Abstract

New pesticides are required to maintain effective resistance management strategies for control of western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae). We tested the efficacy of acetamiprid, and thiamethoxam, two neonicotinoids that represent a newer class of insecticides for the control of thrips. We also tested chlorfenapyr, a pyrrol compound, and a lower than registered rate of the biopesticide spinosad. Laboratory bioassays were used to predict the relative efficacy of insecticides against F. occidentalis and to forecast likely field rates. Two doses within the calculated LC99.99 range were used to predict field rates and trial rates of 0.5 g and 1.0 active ingredient (AI)/liter acetamiprid, 0.025 and 0.05 g (AI)/liter chlorfenapyr, 0.3 and 0.6 g (AI)/liter thiamethoxam, and 0.01 g (AI)/ liter spinosad were tested in the greenhouse against pepper, lettuce, and tomato. With the exception of acetamiprid, field trial doses predicted from laboratory bioassay translated to effective field efficacy. All products controlled F. occidentalis at the rates trialed and so have potential to augment current chemical controls. Increasing mortality correlated with increasing acetamiprid concentration in a greenhouse lettuce trial, suggesting that the higher trial rate (1.0 g [AI]/liter) may be required in some lettuce crops. The lower than registered (0.01 g [AI]/liter) rate of spinosad also significantly reduced F. occidentalis numbers and is a viable control option that may be useful in specific integrated pest management programs. The implications of introducing neonicotinoids into existing insecticide resistance management strategies for F. occidentalis are discussed.

Managing Western Flower Thrips (Thysanoptera: Thripidae) on Lettuce and Green Peach Aphid and Cabbage Aphid (Hemiptera: Aphididae) on Broccoli with Chemical Insecticides and the Entomopathogenic Fungus Beauveria bassiana (Hypocreales: Clavicipitaceae)

“…(2 There were minor variations in the efficacy of various insecticides from 2011 to 2012, but acetamiprid could not control F. occidentalis in both years. Acetamiprid, which was used as a grower standard in the current studies, effectively controlled F. occidentalis in laboratory and greenhouse studies on lettuce, pepper, and tomato in an earlier study by Broughton and Herron [18]. Results indicate possible resistance to acetamiprid and suggest a need for rotating insecticides from different modes of action groups both as a means of resistance management and to achieve effective control.…”

Management strategies for western flower thrips in vegetable greenhouses in Iran: a review

“…Spinosad acts either upon contact or ingestion (Cloyd 2009). No other insecticide class provides this level of control (Funderburk et al 2000;Broughton & Herron 2009). The unique mode of action of spinosyn-based insecticides and their translaminar properties have made them highly effective against WFT (Demirozer et al 2012).…”

Management Strategies for Western Flower Thrips and the Role of Insecticides

“…Neonicotinoids, which have been used since the 1990's to manage various types of other sucking insect pests, have recently received attention for a potential role in western flower thrips management. In experimental trials in Australia, Broughton and Herron (2009) found that two neonicotinoids, acetamiprid and thiamethoxam, were as effective as spinosad against larvae and adults of western flower thrips in pepper and lettuce. However, none of the tested insecticides, including spinosad, were effective in reducing the abundance of western flower thrips adults in tomato.…”

“…Likewise, the pyrrrol chlorfenapyr is registered for greenhouse ornamental and vegetables in the USA, but is approved for use in other situations globally. It has shown efficacy comparable to spinosad in greenhouse trials conducted in Australia (Broughton & Herron, 2009). Both pyridalyl and chlorfenapyr have translaminar properties.…”