URBANA, IL – Taking a little time this spring to care for your fruit trees will improve their performance and quality all season, according to University of Illinois Extension horticulture educator Richard Hentschel.
“Fruit tree care should start well ahead of any signs of spring growth,” Hentschel says. Dormant oil sprays, which suffocate insect pests living in or on bark, should be thoroughly applied to trunks and branches as soon as the weather is expected to remain above freezing for 24 to 48 hours. Hentschel advises that dormant oil is the easiest spray for the control of scale insects.
Early spring fruit tree pruning depends on location and species. Fruit trees vary in their cold sensitivity, with apricots and sweet cherries representing the most cold-sensitive and apples being the most cold-hardy. Intermediate species, in order from most sensitive to least sensitive, include peaches, nectarines, plums, pears, and sour cherry.
“If you are attempting to grow a cold sensitive tree in northern Illinois, you would expect to find more winter dieback than with the same species in the southernmost part of the state,” Hentschel explains. “Also, flower buds are more sensitive than vegetative buds, so you may have a peach tree that grows every year, but only flowers and fruits after a mild winter.”
Hentschel says that pruning is easier while the fruit tree is dormant and you can easily see branch structure. If the fruit tree is still young, creating scaffold branches is the priority. Scaffold branches should start at about 24-30 inches from the ground, allowing for three sets of scaffolds for a mature fruit tree about 6 feet tall. Scaffold branches should be trained horizontal by holding them down or using branch spreaders. Hentschel adds that good strong scaffold branches will be able to support the fruit load expected as trees grow. Older fruit trees already bearing need to be pruned for water sprouts and suckers and to limit annual scaffold growth.
“Choosing a training system will depend on the kind of fruit tree you have,” Hentschel says. “European plums, apples, apricots, pears, sour cherries, and sweet cherries use the central leader system. Japanese plums, peaches, and nectarines use the open center system.”
Early spring disease management should include a fungicide treatment when leaf and flower buds are swelling and beginning to show just a hint of color. Early treatments will protect the very young and tender tissues from fungal spores floating through the air from their overwintering sites, such as fruit tree leaf litter or an alternate disease host plant.
“The key for good disease management is understanding that any treatments are only protective in nature and must be applied before any disease symptoms are present,” Hentschel says. “Different trees require different treatment courses. The length of the spray schedule is shortest for cherries, then early peaches and apricots, then the later peaches and summer apples, then plums and pears, and finally fall and winter apples.”