Distribution of the European Pine Shoot Moth, Its Parasites, and Associated Insects in Red Pine Trees and Stands

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Twenty species of parasites and associated insects were reared from shoots of red pine, Pinus resinosa Ait., infested with the European pine shoot moth, Rhyacionia buoliana (Schiffermuller), at Oakland, Md. In trees 7 ft tall, Hyssopus thymus Girault was more abundant than Exeristes comstockii Cresson, but the reverse was true in trees half that height. Total parasitism and parasitism by H. thymus and Eurytoma pini Bugbee were greater in the lowest ⅓ than in the topmost ⅓ of the tree; E. comstockii and associated insects of uncertain status—lepidopterans, coleopterans, and the dipteran Oscinella conicola (Green)—were most abundant in the topmost ⅓. Of Itoplectis conquisitor (Say) only males were reared. Usually only 1 shoot moth larva was found per shoot, but occasionally there were as many as 5; more than 1 larva per shoot occurred more often in the topmost than in the lowest ⅓ of the trees. Trees 3½ ft tall had a higher infestation rate than those 7 ft tall. Lammas shoots were infested at the same rate as normal shoots. In 3½-ft trees, 23% of the shoots were in the lowest ⅓ and 24% in the topmost ⅓ of the tree; in 7-ft trees, 50% and 10%, respectively.