As a rule, blueberries require the least amount of pesticide of all fruit crops. The best approach is to apply no pesticide to new plantings until some problem develops. Watch plants closely for any symptoms of disease (dieback or fruit rot) or insect damage, and begin spraying when appropriate. Some fruit loss can be expected the first year that mummy berry disease or fruit rot develops. In subsequent years, this can be controlled with fungicides.
Probably the most common problems associated with blueberries are nutrient deficiencies related to soil pH requirements and water imbalance due to lack of proper mulching. Common symptoms of nutrient deficiency are yellow (chlorotic) leaves and stunted growth. For specific information on blueberry culture, see Ohio State University Extension Bulletin 591, Growing and Using Fruit at Home.
Cultural Practices for Disease and Insect Control
Before the buds break in the spring, the area beneath and immediately around the plants should be raked thoroughly to collect or bury any mummified fruits from the previous year's crop. This will help reduce the incidence of mummy berry disease. Avoid excessive nitrogen fertilization, which increases plant susceptibility to the Botrytis fungus (blight). To reduce fungal canker diseases, prune out and destroy dead twigs, branches and stems.
Table 18. Spray Schedules for Pest Control on Blueberry.