Control of Peachtree Rorer on Tart Cherry, 1988

Abstract

Abstract Materials were applied to 5-yr-old ‘Montmorency’ tart cherry trees in a commercial orchard near Sutton’s Bay, Mich. Treatments consisted of trees replicated 5 times in a completely randomized design. Materials were applied dilute to runoff to the lower trunk and to the soil in a 1-ft radius around the trunk until each area was soaked. Dates of application were 25 May (petal fall)–peak first-generation American plum borer emergence, 17 Jun–peak lesser peachtree borer emergence, and 25 Jul–peak peachtree borer emergence. Trees were evaluated by digging up the soil around the trunks with garden trowels to a depth of 10 inches and carefully examining the soil for larvae. Then the crown and upper roots were carefully examined for old and new damage and larvae. New damage was distinguished from old by the presence of fresh reddish frass and gummosis. Old damage had either no frass or dark brown frass and no gummosis. Extensive surface damage and tunneling meant that the larvae often had to be excavated with hammers and wood chisels from the roots. A damage rating of 0-3 was assigned for no, slight, moderate, and heavy damage and averaged as an index of values 1-3. This index does not distinguish between old and new damage.