Synanthedon scitula (Harris)
The adult is bluish black with yellow bands and has clear wings (A), resembling a wasp. Larva is creamy white to pink with a sclerotized reddish head (B).
Most fruit-growing states and provinces in eastern North America.
Attacks apple and plum. Larva is present throughout the whole season. It digs tunnels in the trunk or in burr knots (less serious, but indicative of potential problems) of trees, creating accumulations of reddish frass at the tunnel exits and causing loss of tree vigor (C).
The larva resembles that of peachtree borer (Synanthedon exitiosa) and lesser peachtree borer (S. pictipes), which are much larger and do not attack apple.
Species presence and flight activity can be monitored with pheromone traps. Keep area around the trunk weed-free and open to sunlight to decrease tendency for burrknot development. Protect base of trees: mound soil around trunk (but not so high as to allow scion rooting), install mosquito netting, use white latex paint trunk for protection; destroy larvae with a knife or a metallic skewer. When required, use broad-spectrum insecticides as a trunk spray against established infestations before bloom and before egg-laying begins around the time of fruit set.
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