Scots Pine, Control of Spring Generation Crawlers of a Pine Needle Scale, Carroll Co., OH, 1983

Abstract

Abstract Pinus sylvestris (2.5 to 3 m high) growing in an abandoned block of Christmas trees were chosen for evaluating toxicity of candidate insecticides against spring crawlers. Trees heavily infested with newly hatched crawlers were sprayed 20 May, using a KWH backpack mistblower operating at maximum rph to deliver ca 700 ml of finished spray to three sides of four, single-tree replicates per treatment. Skies were sunny with 21°C temperature and winds gusting to 24 kph. The strong wind gusts precluded application to the downwind side of the trees. All crawlers had hatched and were settled first instars when treatments were applied. Treatment effectiveness was evaluated 26 to 27 May by collecting infested needle fascicles from the middle of the sprayed portion of each tree. Fascicles were placed in coin envelopes and transported under refrigeration to the laboratory where the viability of the first 100 nymphs observed under a dissecting scope was determined. Counts were always made from at least three fascicles.