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Several insecticides are labeled for control o£ cranberry and 

 cherry fruitworms on blueberry. Two or 3 applications of carbaryl 

 (Sevin*) or malathion are recommended and labeled for their control. 

 Guthion and parathion are also labeled but should not be used un- 

 less all safety precautions are scrupulously followed. 



Blueberry maggot or fruitf ly is closely related to the apple 

 maggot. It is primarily a pest of ripe berries in contrast to 

 cranberry and cherry fruitworms. Winter is spent in the pupal stage 

 close to the surface of the soil. Flies emerge from the puparia 

 from late June until late in the summer. The flies are black with 

 characteristic black bands on the wings and are about the size of 

 horseflies. About a week or 10 days after emergence, flies start 

 to lay eggs. Ripe or nearly ripe berries are preferred, but they 

 will lay eggs in green fruit when abundant or when ripening fruit 

 is absent or scarce early in the summer. Eggs are inserted just 

 under the skin of the berry. These hatch into tiny colorless mag- 

 gots in about 5 days and feed in the berry for about 3 weeks. They 

 first feed and soften the center of the berry, but as they grow, 

 they feed within the entire berry, turning the contents into purple 

 juice and seeds. Full grown maggots are white and about 1/4 inch 

 long. When through feeding, the maggots drop to the ground and 

 form puparia in which they remain until the following growing sea- 

 son. In fact, they have insured their survival in case of crop 

 failure, by delaying the emergence of a small percentage of flies 

 from their puparia until the second of even the third growing sea- 

 son after they entered the soil. 



Maggot control is complicated by the long flight and egg lay- 

 ing period of the flies and by the fact that infestation occurs 

 during the picking period. This calls for several applications of 

 a short-lived, low toxicity insecticide. Malathion sprays or dusts 

 every 10 days beginning about July 4 are safe, effective and short- 

 lived enough to not interfere with the harvest schedule. In fields 

 where maggot has been difficult to control, applications every 7 

 days may be necessary for adequate control. 



Japanese beetles may cause injury when they congregate on the 

 ripening berry clusters to feed. They score the berries, which then 

 shrivel and become worthless. Beetles also feed on tender terminal 

 leaves, leaving them a network of veins. The latter injury can be 

 important in heavy infestations. Carbaryl (Sevin*) sprays or dusts, 

 applied as necessary, are recommended for Japanese beetle control. 



Present occasionally during the summer on individual bushes 

 or branches may be Datana worms and fall webworms. Datana worms 

 feed in colonies of many individuals with no web or nest. When 

 the worms are large, they can strip a branch or small bush almost 

 overnight, it seems. The full grown caterpillar is about 2 inches 

 long with a dark head and body, a yellowish neck and yellow stripe 

 running the length of the body. When disturbed, the worms raise 



*Trade name 



