Development of peach leaf curl ceases when young tissue is no longer developing or when weather turns dry and warmer (79° to 87°F). The higher the MCE, the greater the amount of copper and the more effective the product will be. Peach leaf curl disease is spread by rain droplets. 2006. Wetness from rain, dew, or irrigation for more than 12.5 hours at temperatures below 61°F is needed for infection. Calif. Plant Pathol. Periods of cool, wet weather, when leaves are first opening on the tree, favor the disease. The ascospores are released into the air, carried to new tissues, and bud (divide) to form bud-conidia. Accessed Jan. 21, 2011. There are fewer resistant nectarines, although Kreibich is one such variety. Although symptoms of leaf curl are seen primarily in spring as new leaves develop, there is little you can do to control the disease at this time. Res. The fungus grows between leaf cells and stimulates them to divide and grow larger than normal, causing swelling and distortion of the leaf. Oakland: Univ. Watch a video about making a protective cover for a peach tree.. If a tree is severely affected with peach leaf curl this can stunt its growth, so consider thinning fruit later in the season. When using pesticides, always read and follow the label for usage, rates, toxicity, and proper disposal. Be aware that repeated annual use of copper products over many seasons can result in a buildup of copper in the soil, which eventually can become toxic to soil organisms, and if it moves into waterways, can harm some aquatic species. Unfortunately, we cannot provide individual solutions to specific pest problems. For apricots, spraying at 90% leaf fall and again as buds show pink is recommended. Peach leaf curl symptoms can cause leaves to curl and distort. (See the Resistant Varieties section below.) Nat. The entire area below the tree canopy should be covered with mulch. Therefore consider planting a peach, apricot, nectarine or almond tree in a 15 to 18 inch diameter pot. T. deformans is found in the United States, Europe, Asia, Africa, Australia, and New Zealand. Redhaven peach and most cultivars derived from it are tolerant to peach leaf curl, whereas Redskin peach and cultivars derived from it range from susceptible to highly susceptible to the disease. Calif. Plant Pathol. 1979. Leaf Curl Control in Peaches and Nectarines. Later affected leaves turn yellow or brown and can remain on the tree or may fall off; they are replaced by a … Peach leaf curl reduces the amount of leaves and fruit produced by peach and nectarine trees. Keep your eye on the tree and if a tear develops in the fleece after particularly bad weather, repair the damage properly. Pests of the Garden and Small Farm: A Grower’s Guide to Using Less Pesticide, Pacific Northwest Plant Disease Management Handbook: An Online Guide to Plant Disease Control, © 2019 Regents of the University of California, Division of Agriculture and Natural Resources. The basic concept is to remove old wood to make room for new shoots to form. Nat. In that way no fleece is needed as the tree is sheltered from the winter rains. Calif. Agric. Although leaves can be infected, symptoms might not appear if temperatures remain above 69°F. Fixed copper products include tribasic or basic copper sulfate, cupric hydroxide, and copper oxychloride sulfate (C-O-C-S), but currently only liquid products containing copper ammonium complex products with 8% MCE (e.g., Kop R Spray Concentrate [Lilly Miller brands] and Liqui-Cop [Monterey Lawn and Garden]) are available to consumers. Make sure the tree is well watered and does not stand in a carpet of weeds and grass. The fungus causes the growing cells at the leaf margins to multiply quickly and randomly, which results in the puckered, curled, distorted appearance. Peach leaf curl control for home gardeners in the San Francisco Bay Area. The loss of leaves and the production of a second set result in decreased tree growth and fruit production. Thorough coverage with any fungicide is essential to obtain adequate disease control. Phytopathology 96:155–163. Maximum infection occurs when trees are wet for 2 or more days. To prevent peach leaf curl, use resistant peach and nectarine varieties where possible. Eventually a film of bud-conidia is formed on the tree’s surface. Feed the tree monthly with a suitable foliar feed, obtainable from garden centres. Red plant pigments accumulate in the distorted cells. Though uncommon, symptoms on fruit can occur, making the surface corky and cracked. Did your peach, nectarine, apricot or almond look odd with reddened, screwed up, puckered leaves?.