Damage to Tomato Fruit by The Western Flower Thrips (Thysanoptera: Thripidae)

Abstract

Cosmetic fruit damage on tomato recently has resulted in downgrading and cullout of freshmarket fruit in the southeastern U.S. The damage consists of small indentations that are sometimes surrounded by a light-colored halo; it began at the same time that western flower thrips, Frankliniella occidentalis (Pergande), populations moved into the geographical area. In addition to F. occidentalis, populations of other Frankliniella spp. commonly inhabit tomato flowers in the region. An understanding of the cause of the damage and its association with Frankliniella spp. is necessary to implement management programs. The objectives were to determine if thrips species inhabiting tomato flowers cause the newly observed cosmetic damage, and to determine the relationship between number of scars per fruit and thrips densities on tomato flowers and small fruit. Results showed that damage was caused by oviposition of female F. occidentalis inhabiting either flowers or small fruit. Other Frankliniella species were not found to cause cosmetic fruit damage. The relationship between the number of scars per tomato fruit and density per flower of F. occidentalis was evaluated by using regression. The relationship was quadratic, although the amount of variation explained by the model was very low (r2 = 0.07). Our research revealed that management efforts should focus on reducing populations of female F. occidentalis to nondamaging levels.