Spray Schedule*
I. Dormant (late winter – early spring)
A. Disease Management
1. Remove all dead and diseased wood as well as any remaining dried or mummified fruit.
2. To control fire blight, remove any visible cankers and blight-infected wood. Spray the trees with a mixture of dormant oil (1 gal./50 gal. water) and soluble copper powder (approx. 1 lb./ 50 gal. water) or liquid copper (1/2 to 2 gal./ 50 gal. water).
B. Pest Management
1. Spray with dormant oil to control overwintering mite and aphid eggs and scale insects.
2. Early emergence of aphids can be controlled with spot spraying of insecticidal soap or dilute concentrations of summer oil.
II. Green tip (new buds just beginning to show green tissue)
A. Disease Management
1. Outbreaks of apple scab can be prevented by successive applications of copper/sulfur mix or Bordeaux spray. Repeat if necessary after very wet, rainy periods. (DO NOT spray sulfur within 30 days of an oil application).
2. Powdery mildew infections of young leaf tissue can be controlled with sulfur.
B. Pest Management
1. Dilute applications of a summer oil at green tip to ½” green are highly effective against scale, European red mite and rosy apple aphid eggs. Again, do not apply oil in conjunction with sulfur applications. Rely instead on insecticidal soap or Pyganic© for early season insect control.
2. Place pheromone traps at green tip to detect presence of Oriental fruit moth.
III. Tight cluster to pink tip (fruit buds well expanded and showing first signs of pink blossoms)
A. Disease Management
1. For scab and powdery mildew, use same fungicides as mentioned above for disease management during green tip.
2. Cedar apple rust can be a serious problem in many areas with major infestations occurring in spring. There are no real effective organic controls available although a solution of copper and sulfur combined can have some positive effect. Removal of all cedar trees within 1/4 mile is sometimes the only option.
B. Pest Management
1. Put out pheromone traps for codling moth, leafrollers, tentiform leafminers and tufted apple bud moth. When insect pests reach threshold limits, spray with Pyganic© and/or Neem oil.
2. Be on the lookout for early season tent caterpillars and other lepidopteron (moths) larvae. Spray with BT (Dipel©) to eliminate these pests.
IV. Bloom (trees in full flower)
A. Disease Management
1. Continue monitoring for fungal diseases (scab, mildew, rusts, etc.) Use the recommended organic fungicidal sprays as previously mentioned, but try to avoid spraying any fungicides at full bloom to lessen disturbance to pollinating insects if at all possible.
2. Now is the time to move against fire blight. A combination of cultural practices and spray programs can control this devastating bacteria but diligence and perseverance are a key. Examine all trees closely for signs of fresh outbreaks, old infected tissue and dead twigs or branches. Prune to remove all infected material and remove from orchard and burn. Spray with a very dilute solution of Bordeaux or copper and repeat at 4 – 5 day intervals. Another option is to spray with Agrimycin© or Streptrol© (Streptomycin) beginning at first bloom and continuing at weekly intervals until petal fall. (Streptomycin will likely be removed from the list of approved organic products soon. Contact your local County Cooperative Extension agent for more information.)
B. Pest Management
1. DO NOT spray insecticides of any kind during bloom but continue to monitor pheromone traps and note species of insects and the number of individuals trapped.
V. Petal Fall (all blossoms have fallen from tree)
A. Disease Management
1. If not controlled effectively in the orchard earlier, secondary outbreaks of apple scab can occur now and should be treated with sulfur and copper.
2. To control summer diseases (scab, powdery mildew, fruit spot, sooty blotch, flyspeck) dilute applications of mixed sulfur/copper or Bordeaux spray can provide some control, but require repeated sprays at two to three week intervals.
B. Pest Management
1. Many of the common soft-bodied insects and many other pests (European red mite, rosy apple aphid, tentiform leafminer, potato leafhopper and white apple leafhopper) are emerging in numbers now and can be controlled with a dilute application of summer oil. Apply either early morning or late afternoon and do not apply when temperature is over 85.
2. One insect of great concern in some areas is the plum curculio. Most organic insecticides exert minimal control over this pest. Repeated applications of Neem oil and Pyganic© can help reduce the numbers somewhat but will not completely eradicate the insect. (An application of Imidan© (1 lb./50 gal. water) at petal fall and repeated in two weeks can be very effective against this pest. [Please note Imidan© is not a registered organic control product.])
3. Fruitworms, canker worms and tent caterpillars can be effectively controlled with BT (Dipel©).
VI. Summer Sprays (post-bloom applications)
A. Disease Management
1. Continue to observe for outbreaks of scab and fire blight and treat accordingly. For summer fungal diseases such as sooty blotch and flyspeck, very limited control can be obtained with sulfur and copper. As these are “blemish” diseases which do not affect the growth or quality of fruit, strict control is optional.
B. Pest Management
1. There are numerous insect pests which reach their height of activity in the summer months. Codling moths emerge in April to late May. Pyganic©/Neem oil combination sprays work quite well to reduce their numbers. Rosy apple aphid and green apple aphid are easily contained by spot applications of insecticidal soaps. White apple leafhoppers and potato leafhoppers are somewhat difficult to control and may require full strength applications of Pyganic©/Neem oil combination sprays but apply sparingly with caution. Tentiform leafminers usually do not reach levels where severe damage can be inflicted. In most cases, a couple of pheromone traps placed in the orchard in April can reduce their numbers to tolerable levels. Dogwood borers are a sporadic but extremely troublesome pest. If left unchecked they can easily destroy a young tree in a couple of seasons. Though very difficult to eradicate, they can be held in check by painting the lower tree trunk with white latex paint into which Rotenone and diatomaceous earth have been mixed.
VII. Post Harvest
1. After the growing season is over and the harvest is completed, it is advisable to conduct a thorough clean-up in the orchard. Remove any dead branches and other debris which may have fallen and accumulated around the trees. Collect all dead and mummified fruit and remove from the orchard. It is very important to remove all litter and debris where insects may overwinter or in which disease pathogens may lie dormant ready to emerge the following season.
(* This suggested spray schedule is solely intended to provide basic guidelines for the implementation of a sound spray program for the care and maintenance of apple trees. It is not meant to address all the potential pest and disease problems you may encounter as a grower. For more information relevant to your region, visit your local County Cooperative Extension office.)
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