Peach and Nectarine Insects, Mites, and Diseases

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At least 20 different insects, mites and diseases may attack peach trees. Unfortunately, they are not all present at the same time but appear at different times throughout the growing season. This makes it difficult to apply two or three sprays and harvest unblemished fruit.

If the suggestions given below are followed carefully, it may be possible to obtain a high percentage of clean fruit. The proper timing of the application and complete coverage of all plant surfaces is as important as using the correct pesticide. It is important to cover both the upper and lower surfaces of the leaves.

Do not apply any insecticides when the plants are in flower. Protect the pollinators.

A general purpose mixture containing one or two insecticides and a fungicide can be used to control most of the pests of peaches. It is available premixed or it can be mixed from individual ingredients available from most garden supply outlets.

It is important to read and follow all label instructions when using any pesticide.

Growth Stage Pest/Disease Remarks
Dormant-after leaves
drop in late fall or before buds swell in the spring.
Peach leaf curl, Bacterial spot PLC-Causes thickening and deforming of the leaves into conspicuous folds that are yellowish at first and then turn pinkish-red. Use a copper fungicide. A copper bactericide is recommended for the bacterial spot Xanthomonas campestris pv. pruni at 7-10 day intervals.
Bud Swell. Mites or scale. A previous problem with mite or scale will warrant and application of Horticultural Oils or Insecticidal Soap.
Pink-when flower buds show pink. Brown rot, plant bugs. Fungicide or insecticide. 
Bloom-open flowers present.  Blossom blight
(brown rot). 
A prior problem with brown rot, a bloom period longer than seven days, or a wet period during flowering may make it necessary to protect the blossoms, young fruit and spurs with a fungicide on a 3 to 5 day interval. Infection can take place in 6 to 7 hours at 45º if the trees are wet.
Petal Fall-no flowers remain open. Brown rot, plant bugs. Fungicide or insecticide, especially if problem was present last year
Shuck Split-1/2 of young fruit is exposed by the splitting of the shuck.              Brown rot, curculio, Oriental fruit moth, plant bugs.  Apply the cover sprays only if weather conditions and/or the presence of pests warrant their use.
First to Second Cover
7-14 day interval.
Same as Shuck Split            Same as above.
Third Cover and Summer Sprays
14 day interval as needed until harvest. 
Peach tree borer, same as Shuck Split.  Gummy or sawdust-like material at the base of the tree. The larva of the clearwing can injure or kill the tree if not controlled. Similar signs appearing on the branches may be the lesser peach tree borer. These pests may be controlled by applying insecticides to the trunk bark in mid-June, early mid-July and in early August.

For pesticide information or other questions please call toll free: 877-486-6271.
Despite good cultural practices, pests and diseases at times may appear. Chemical control should be used only after all other methods have failed.

Revised by UConn Home and Garden Education Center 2016.