At least eight races of stem canker are present in the eastern United States. The first few weeks following bud break are critical in the infection cycles of mummy berry and twig blight , two of the most serious blueberry diseases. Infected terminals quickly die back 2 to 6 inches and destroy fruiting potential for an average of 6 buds per twig. Twig blight can be controlled with two or three applications of Benlate. Sprays should be applied at 7-10 day intervals from bud swell through full bloom.
Spores infect new leaves just as they begin to unroll from the bud.
These insects can usually be controlled with a single pre-bloom spray applied just as fruit buds begin to swell. Chemical control of fruit rot is best achieved with two or three applications of Captan at 10-14 day intervals beginning at full bloom. Benlate and Funginex are not very effective against these diseases. Although fungicide applications may continue well past bloom, insect control is the primary consideration in the weeks immediately following petal fall. Of all insect pests, those active just after bloom represent the greatest potential injury to a blueberry crop because they damage the fruit or transmit disease.