MANAGEMENT OF CHILLI THRIPS, SCIRTOTHRIPS DORSALIS HOOD (THYSANOPTERA: THRIPIDAE): EFFECTIVENESS OF NEONICOTINOIDS AND SPINOSYNS AND INEFFECTIVENESS OF PYRETHROIDS

Abstract

The chilli thrips, Scirtothrips dorsalis Hood, is a newly introduced pest of fruits, ornamentals and vegetables. Currently, this pest is causing severe damage to landscape and bedding ornamentals in Florida. Growers are using various insecticides to control this pest without any prior knowledge about their effectiveness. It is imperative to have knowledge based insecticidal management programs which may include the use of insecticides in order to avoid deleterious effects on natural enemies and other benign organisms. In the present study, we investigated the effectiveness of neonicotinoid, spinosyn and pyrethroid insecticides applied in various formulations and with different methods. Imidacloprid provided significant reduction of Scirtothrips dorsalis when applied as Admire® as a soil drench or when applied as Provado® to the foliage. Thiamethoxam (Actara®) was more effective when used as a foliar application than when applied as a soil drench (as Platinum®). Foliar application of dinotefuran (Venom™) provided significant reduction of S. dorsalis on pepper. Acetamiprid (Assail®) applied to the foliage of pepper plants did not provide significant reduction of S. dorsalis in the present study. The spinosyns, spinosad (SpinTor®) and spinetoram (Radiant®), when applied to the foliage, were highly effective against S. dorsalis larvae and adults. Neither adult nor larval chilli thrips were substantially suppressed by any of the following pyrethroids: cyfluthrin (Baythroid®), zetacypermethrin (Mustang®), cyhalothrin-lambda (Warrior®), or esfenvalerate (Asana® XL). This information has significant bearing on the efforts of the fruit, ornamental and vegetable industries to protect their crops from damage by S. dorsalis infestations. Moreover, this information will enable growers to use neonicotinoid insecticides more selectively to avoid the decimation of populations of natural enemies.