Two Species of Thrips Injurious to Apples in the Pacific Northwest1

Abstract

So-called Pansy spot or thrips injury on apples is caused by the egg laying punctures of two species of thrips: Frankliniella occidentalis and Aeolothrips fasciatus . Injury of this character produced by thrips has been reported from most of the apple growing sections of the Pacific Northwest. In some instances the grade of the fruit has been lowered fully twenty per cent. Pansy spot derives its name from the shape of a discolored area which develops about the egg punctures. The color of this pansy shaped spot varies from white through various shades of pink. Egg laying begins shortly after bloom time, continuing until the fruit has reached the size of large walnuts. The life history of the insect in the orchard is not fully known. Sprays of oil and Black leaf applied while the trees were in full bloom showed that injury can be materially reduced but do not give complete control. The Black Leaf appears to be the active ingredient in bringing about this benefit.