Prune: When completely dormant in December or January, remove at least half of current year’s growth on mature trees. To identify fruiting wood, see our Fruit Tree Pruning Care Guide.
Spray: Three dormant sprays at the end of November, December and January. Use Master Nursery Pest-fighter Year-Round Spray Oil and Microcop. Copper products must contain at least 80% copper. Follow label directions for appropriate quantities. The last spraying must be before any color shows in the flower buds.
Always check with your Nursery Professional to properly diagnose problems before undertaking additional sprays.
Peach Leaf Curl:
- Spray: Control is best achieved by three dormant sprays described above, the most important of which is January’s. Research shows that growing season measures, such as picking off infected leaves or blasting leaves with water, yield no favorable results.
Brown Rot Blossom Blight:
- Symptoms: Brown rot is the most common and serious blossom and fruit disease of stone fruits. The first symptom is the browning and withering of blossoms. Dead blossoms often cling to twigs for a long time. Sunken brown areas called cankers may develop around twigs at the base of infected flowers. Sticky, amber colored droplets of pitch may develop at the base of infected flowers or from the cankers.
Especially on the fruit of peaches and nectarines, brown rot may develop around the seed. This may not be visible on the outside. As the rot progresses, small insects may enter the base of the fruit to lay eggs. See Control below.
- Control: Spray trees again with Liqui-Cop before flower buds swell and again at pink bud stage. Do not apply Liqui-Cop after pink bud stage or when trees are in leaf OR spray with Ortho Garden Disease Control or Daconil (Chlorothalonil) or Ortho Rose Pride (Triforine) at pink bud and again at full bloom stage. If cool, moist weather persists, a third application will be needed at petal fall. If the fruit had brown rot during the previous year, it should be sprayed again one to three weeks before harvest. Prune to allow good ventilation. Remove infected twigs and branches as soon as they become evident. DO NOT COMPOST.
- Sanitation: Remove and destroy affected buds and blossoms during bloom. Remove and destroy maturing fruit when symptoms appear. In August or September, remove and destroy mummies and fallen fruit. DO NOT COMPOST.
- Fruit Thinning: See section below on Fruit Thinning. Thinning fruit reduces spread of brown rot spores among fruits.
- Irrigation Methods: Use basin or drip irrigation to avoid wetting blossoms, foliage and fruit (see below).
Fertilize: Use Master Nursery Fruit Tree & Vine Food twice a year, around Memorial Day and Labor Day. A lawn fertilizer containing iron and sulfur may also be used especially if the leaves show symptoms of chlorosis. If you prefer organic fertilizers, use Dr. Earth Fruit Tree Fertilizer two to three weeks earlier. Water all fertilizers in immediately after application.
Water: At planting, construct a soil basin at the drip line of the tree. As the tree matures, extend the basin to the span of the drip line. Flood weekly during the first year and then at 2 to 4 week intervals when the tree is mature. If a drip system is used, place hosing along the tree’s drip line with emitters on 18 inch centers. This system will also need to be adjusted as the drip line expands. Keep in mind that a large, mature tree may consume up to 200 gallons of water per week in July and August.
Fruit Thinning: Thin fruit when it reaches 1 inch in diameter. Leave one fruit every 6 to 8 inches of shoot growth. Thinning is especially helpful if the tree is affected by brown rot.
Other Comments: Watch for oozing of amber-colored gum on twigs, branches or trunk, which may indicate the presence of borers or fungus. Bring several leaf and twig sample to Wegman’s Nursery for evaluation whenever these or other symptoms appear.
Paint trunks and lower branches of young or non-vigorous trees with a one to one mixture of white interior latex paint and water to prevent sunburn injury and reduce borer infestations. Apply the paint mixture from 2 inches below the soil surface to 3 feet above.
Adapted from Ogawa and English (1991), Diseases of Temperate Zone Tree Fruit & Nut Crops, UC Extension Publication 3345; and from Flint (1998), Pests of the Garden and Small Farm, 2nd Edition, UC Extension Publication 3332.
