Yellow Jacket nest size and nuisance problems will greatly increase over the next month. First year grape vines should receive no additional fertilizer this month. Cut back on the frequency of watering to allow for improved winter hardiness. Powdery mildew has already been a problem on Lilac bushes located in shady areas. Zinnia and other flowers become more susceptible as the evenings get cooler.
Powdery mildew is more prevalent when cool nights follow warm days.
Week 4 Cluster Flies begin to move into buildings seeking overwintering shelter. Seal buildings to avoid later problems. Early Blight will be a problem on tomato plants. The lower leaves are the first to be infected. A light application of nitrogen fertilizer helps keep these leaves healthy and less susceptible to blight.