The thrips Frankliniella tritici (Fitch) occurred in great abundance early in May, 1954, in orchards of tree fruits in Essex County, Ontario. Observations during the first three weeks of May showed that this insect was abundant on the foliage and blossoms of apple, sweet and sour cherries, plum, and peach. Sweet cherry, European plum, and peach suffered the greatest attack. On sweet cherry and plum large numbers of eggs were inserted in blossom stems, styles and apices of the ovaries. From 30 to 50 per cent of the blossoms of sweet cherry and plum were destroyed, apparently because of disruption of tender tissues by the large numbers of eggs inserted in them; a considerable number of the fruits remaining on the trees were injured by feeding of adults and immature stages of the thrips (Fig. 1).