IMPORTANT MASSACHUSETTS HIGHBUSH BLUEBERRY INSECTS 



William E. Tomlinson, Jr. 

 Cranberry Experiment Station, East Wareham 



Cultivated highbush blueberries are subject to the attacks 

 of many insect pests, d£ which some of the more damaging can seri- 

 ously reduce productioi or adversely affect the marketability of 

 the crop by their presence in the berries when picked. Growers 

 should be familiar with the different pests, their potential for 

 harm to the crop or plant, and the control methods that can be 

 used against them. 



During the pruning operation is an ideal time to be on the 

 watch for insect stem galls , stem borers, and scale insects . Insect 

 stem galls are hard, kidney-shaped callus tissue deformations of 

 blueberry twigs and stems. Galls vary considerably in size, depend- 

 ing on the number of gall wasp larvae they contain. They may be 

 numerous enough to reduce the fruitfulness of a bush if not con- 

 trolled. The galls are formed when the small black wasp lays her 

 eggs in the soft new wood. The eggs hatch and form cells in which 

 the larvae feed. A secretion given off by the larvae apparently 

 causes the formation of the galls. The larvae overwinter in the 

 galls, change to pupae, and transform to adults within the galls 

 in the spring. The adult wasps emerge from the galls at the time 

 twig and stem growth is underway. Removal of galls any time they 

 are noticed, but not later than during winter and early spring 

 pruning is all the control necessary. Be sure to destroy the galls 

 or remove them far enough from the planting to insure that there 

 is no chance of wasp emergence to reinfect new growth. 



Stem borer is a beetle grub that tunnels in stems of blueberry. 

 Flagging of shoots in mid-summer is the first sign of borer attack. 

 Examination reveals 2 parallel rows of punctures about half an inch 

 apart girdling the stem several inches from the tip. An egg is 

 laid just under the bark between the rows of punctures by the stem 

 borer beetle. The grub that hatches tunnels in the stem for 3 years 

 before producing an adult beetle. The first year the grub tunnels 

 only a few inches but the second year it may tunnel the whole length 

 of the stem down to the crown. The third year it may start to tun- 

 nel up another stem from the crown before transforming to an adult 

 in July or August. 



The beetle is slender, about 5/8 of an inch long, yellow, with 

 dark antennae nearly as long as the body. The wing covers are yel- 

 low with black edges. The grub is also yellow, attaining a length 

 of about 5/8 of an inch when full grown. Pupation occurs in the 

 tunnel in a cell plugged with sawdust. 



The flagged tips, the weakened appearance of infested stems 

 during the growing season and the emission of elongate yellow frass 



