Classification of Thrips Injury and Other Similar Injuries of Fig Fruits

Abstract

This study aimed to distinguish between thrips (Thysanoptera) injury and other similar injuries on the internal parts of fig (Ficus carica L.) fruits. The symptoms that have been regarded as typical of thrips injury are internal browning of the fruit, with an irregular, glossy yellow pattern on the drupelets from the style to ovary and wilting of the stylar tips. The detection rate of thrips increases as the area affected by these abnormalities expands and becomes more visible, supporting the conventional perception that these symptoms are caused by thrips. However, in the presence of minor injuries that are not easily observed as a disorder, thrips are often not detected. I classified the main minor injuries in many fig cultivars into four types according to symptoms: A, uniform yellowing of the styles or stylar tips; B, uniform yellowing of the entire drupelet (from style tip to ovary); C, browning of the styles without a glossy yellow pattern; and D, fusing and browning of the styles without a glossy yellow pattern. Blocking thrips by sealing the ostioles with glue did not change the rates of occurrence of type A, type C (in certain cultivars), or type D symptoms. These symptoms are therefore likely to be caused by something other than thrips.