Defining thrips injury and damage relationships in strawberries to determine economic injury levels and economic thresholds

Flower thrips are pests of numerous fruit and vegetable crops. In Florida strawberries valued currently at US$400 million, several species feed and reproduce in the flowers. Understanding the relationship between thrips injury and damage in strawberry is needed to develop species-specific and stage-specific economic injury levels and economic thresholds over a range of market price conditions. The western flower thrips (Frankliniella occidentalis), F. bispinosa, and F. tritici are species that can be found in Florida strawberry crops. For each species, 0, 2, 4, 8, 16 and 32 females were confined on plants with one flower for 2, 5, or 10 days for a total of 18 treatments. Injury to the fruit was characterized and quantified after about 21 days. Little injury was observed for either species even when 32 thrips were confined on flowers/small fruits for 10 days showing that Florida strawberries can tolerate high numbers of flower thrips without economic damage. The data from these experiments were used to determine economic injury levels and economic thresholds for each species in strawberries. The economic thresholds are being used as part of an effective, sustainable integrated pest management program for strawberries.