Management of Flower Thrips in Florida Strawberries with Steinernema feltiae (Rhabditida: Steinernematidae) and the Insecticide Sulfoxaflor

Abstract

Flower thrips (mainly Frankliniella spp.) (Thysanoptera: Thripidae) are common in Florida strawberries, causing bronzed fruit and reduced yields. As control relies on just a few insecticides, there is a need to evaluate novel management options and insecticides. The entomopathogenic nematode Steinernema feltiae (Filipjev) (Rhabditida: Steinernematidae) has been shown to be effective on flower thrips larvae in other plants, and the new insecticide sulfoxaflor has been effective on thrips in other crops. In winter 2016, S. feltiae was evaluated at 2 foliar application rates (2.47 and 4.94 billion infective juveniles per ha) in combination with and without the insecticide spinetoram by counting thrips in strawberry flowers and assessing numbers of damaged fruits. A second experiment was conducted to compare sulfoxaflor, spinetoram, and S. feltiae applications based on flower thrips thresholds. High and low S. feltiae rates did not reduce or suppress thrips and did not reduce fruit damage. Sulfoxaflor reduced thrips by 60 to 70% compared to the reduction caused by spinetoram. Hot, dry conditions likely limited the survival and effectiveness of S. feltiae. Sulfoxaflor appears to be a promising insecticide for flower thrips, and may reduce reliance on spinetoram by strawberry producers.