Copper Materials. On apples and pears where fire blight was present the previous season, a dormant application of Bordeaux mixture or fixed copper materials may be beneficial. Spray thoroughly in the spring just before green tissue appears. Where bacterial spot has been a problem on peaches, an application of fixed copper just as the leaves begin to fall in the autumn may help reduce damage from this disease the next season. Copper materials applied during the growing season can damage apple leaves and fruit and cause complete defoliation of peaches and other stone fruits.
Streptomycin. Streptomycin is an antibiotic of limited use, but is important for apple and pear varieties with a history of fire blight problems. Although streptomycin is commonly used in commercial apple orchards and is not a restricted-use pesticide, it may be difficult for home fruit growers to obtain. In addition, the timing and number of required sprays are critical to achieve effective control and to avoid problems with resistance. For all of these reasons, growers should select varieties with some natural resistance to fire blight and employ cultural practices that reduce the risk of infection.