Stone Fruit Programs


Major Diseases

Bacterial canker or gummosis
Bacterial canker or gummosis (Pseudomonas syringae) is a serious disease of cherry in the Pacific Northwest. It is particularly damaging to young trees and can result in replanting issues if un-managed. Spread of the pathogen is favored by cool, moist weather. Optimum timing for control of bacterial gummosis is in late winter before trees break of dormancy, spring frost, and wet weather occur. In the Fall, apply most materials before autumn rains or after October 1.

Brown rot
Brown rot is a serious disease of stone fruit when wet conditions occur in the orchard. The disease is caused by the fungus Monilinia fructicola although other species (i.e. M. laxa and M. fructigena) have been reported in other regions. There are both floral and fruit phases of the disease. Brown rot is explosive and highly favored by rain events during bloom (blossom infection) and immediately prior to harvest (fruit infection). Many fungicide materials are effective on both brown rot and powdery mildew. Use the products list on the Bloom table for brown rot, as they are effective, and mildew sprays are not recommended at this stage of tree growth. Neither iprodione nor fenbuconazole are first-rate powdery mildew materials. Always follow fungicide resistance management guidelines. Current resistance management guidelines are available at https://www.frac.info

Coryneum blight (shothole)
Coryneum blight or shothole, caused by Wilsonomcyes carpophilus, is a fungal disease of minor importance in the Pacific Northwest. The fungus overwinters in twig cankers. Spores are produced on canker surfaces during early spring rains (or over-the-canopy irrigation) and are splashed to foliage and fruit where they germinate, infect, and cause small lesions. The lesions are small and circular. Necrotic lesion centers may drop giving heavily infected leaves a "shothole" appearance. The disease is managed using fungicide programs early in the growing season.

Peach leaf curl
Peach leaf curl, which is caused by the fungus Taphrina deformans, is a relatively common disease of minor economic importance. The disease first appears as reddish areas on the leaf surface; these areas eventually pucker, blister, and become severely deformed. Defoliation may occur. Symptoms typically appear about 2 weeks after bud break. Wet and and cool weather during and immediately after bud break favors the disease.

Pear scab
Scab, caused by the fungus Venturia pyrina on pear, is major disease of pear fruit in many growing regions, especially those with high rainfall. Typical scab symptoms include gray-brown to blackish lesions on leaves and fruit. Because of the semi-arid conditions during the growing season in central Washington, scab risk is low. However, some microclimates in the north of the state can be conducive to scab and therefore, management is recommended. Pear scab can cause problems in growing regions north of Washington and in Hood River, Oregon but it is rarely seen in central and south Washington State.

Powdery Mildew (Stone Fruit)
Powdery mildew of soft fruit is caused by a fungus (Podosphaera pannosa) different from the powdery mildew of cherry. If unmanaged losses due to powdery mildew can become quite severe. The fungus attacks both fruit and foliage and survives winter on bud scales. Conidia produced on bud scales serve as primary inoculum. Fruit are most susceptible to infection prior to pit hardening. The disease is managed with fungicide spray programs.

Major Insects

Leafrollers (Pandemis, Obliquebanded)
Pre-bloom applications of pesticides can be effective and will also conserve natural enemies for leafroller and biological control agents of other pests, such as aphids. If treatments for leafrollers were applied at pink and/or bloom, sampling to determine the density of surviving leafrollers should be completed prior to deciding to apply additional controls at this timing. Most products listed act primarily as stomach poisons versus direct contact to residues, therefore, complete coverage is very important to achieve maximal control. Repeating an application of any product should be based on the leafroller population surviving previous treatments. Use the leafroller models on the WSU Decision Aid System (https://decisionaid.systems) for the optimum timing. Additional Details

Peach twig borer
Use the phenology model on the the WSU Decision Aid System (https://decisionaid.systems) to time insecticides.

Plum aphids
Several different aphid species can attack stone fruit. They are generally not a problem when a regular spray program is used to control other insects. The most effective of these programs would be a delayed-dormant spray of oil with an appropriate pesticide. After the aphids become active and leaves begin to curl they are more protected and harder to control. Attempts at late season control can disrupt predators.
Low populations in the orchard early in the season may be beneficial in attracting predators. Later in the season, predators and migration to summer hosts should keep populations at acceptable levels. Aphids returning from summer hosts in the fall lay overwintering eggs on stone fruit. Fall-applied aphicides may prevent egg-laying, and thus next year’s spring population. Additional Details

San Jose scale
San Jose scale can be a minor pest if adequately controlled, or escalate into a major problem if not. It primarily infests the trunk and limbs, but scale crawlers will settle on the fruit. Damage to this season’s crop may become serious, but ultimately the infestation of wood may cause death of limbs or the entire tree. Oil plus an organophosphate in the delayed dormant spray provide control; if the organophosphate is omitted (oil only), monitor the trees carefully and add one of the listed materials if scale become numerous. Additional Details

Shothole borer
Good sanitation (removing large wood prunings and woodpiles from the orchard) is the best management tactic. Insecticides are only effective against adults. Beetles begin flying in late April and are active through May. The second generation flight begins in late July or early August. Yellow sticky traps placed on orchard borders will detect adult beetle activity. Spraying the border trees (rows) with high water volumes will protect the remainder of the orchard in many situations where external sources are the primary problem. Additional Details

White apple leafhopper
Adults fly from late May until frost. Monitor nymphs on the underside of leaves. Egg parasitoid Anagrus spp. attacks overwintering and summer eggs. Only control this indirect pest when necessary. Carbaryl, if used for apple thinning, is also a very effective leafhopper material but the canopy spray technique may not provide adequate coverage for leafhopper control. Additional Details

Spray Schedule

Dormant

Coryneum blight (shothole)

16 Product Choices

Applications and Notes » 

Peach leaf curl

13 Product Choices

Applications and Notes » 

Delayed dormant

Cutworms

2 Product Choices

Applications and Notes » 

European red mite

4 Product Choices

Applications and Notes » 

Green peach aphid

6 Product Choices

Applications and Notes » 

San Jose scale & Lecanium scale

14 Product Choices

Applications and Notes » 

Prebloom

Brown rot

30 Product Choices

Applications and Notes » 

Coryneum blight (shothole)

32 Product Choices

Applications and Notes » 

Grape mealybug, mealy plum aphid, leaf curl plum aphid

8 Product Choices

Applications and Notes » 

Leafrollers (Pandemis, Obliquebanded)

20 Product Choices

Applications and Notes » 

Lecanium scale

8 Product Choices

Applications and Notes » 

Oriental fruit moth

4 Product Choices

Applications and Notes » 

Peach twig borer

24 Product Choices

Applications and Notes » 

Peach silver mite

1 Product Choices

Applications and Notes » 

Bloom

Brown rot

37 Product Choices

Applications and Notes » 

Cutworms

1 Product Choices

Applications and Notes » 

Leafrollers (Pandemis, Obliquebanded)

4 Product Choices

Applications and Notes » 

Petal fall

Brown rot

40 Product Choices

Applications and Notes » 

Coryneum blight (shothole)

24 Product Choices

Applications and Notes » 

Pear scab

1 Product Choices

Applications and Notes » 

Powdery Mildew (Stone Fruit)

28 Product Choices

Applications and Notes » 

Grape mealybug, mealy plum aphid, leaf curl plum aphid

12 Product Choices

Applications and Notes » 

Green peach aphid

8 Product Choices

Applications and Notes » 

Leafrollers (Pandemis, Obliquebanded)

25 Product Choices

Applications and Notes » 

Oriental fruit moth

28 Product Choices

Applications and Notes » 

Peach twig borer

28 Product Choices

Applications and Notes » 

Western flower thrips

14 Product Choices

Applications and Notes » 

Shuck fall

Brown rot

34 Product Choices

Applications and Notes » 

Coryneum blight (shothole)

28 Product Choices

Applications and Notes » 

Powdery Mildew (Stone Fruit)

33 Product Choices

Applications and Notes » 

Leafrollers (Pandemis, Obliquebanded)

28 Product Choices

Applications and Notes » 

Summer

Earwigs

4 Product Choices

Applications and Notes » 

Grape mealybug

8 Product Choices

Applications and Notes » 

Grasshoppers and Mormon crickets

4 Product Choices

Applications and Notes » 

Leafrollers (Pandemis, Obliquebanded)

26 Product Choices

Applications and Notes » 

McDaniel spider mite, twospotted spider mite, European red mite

19 Product Choices

Applications and Notes » 

Oriental fruit moth

28 Product Choices

Applications and Notes » 

Peach silver mite

3 Product Choices

Applications and Notes » 

Peach twig borer

24 Product Choices

Applications and Notes » 

Peachtree Borer

6 Product Choices

Applications and Notes » 

Plum rust mite

2 Product Choices

Applications and Notes » 

San Jose scale

5 Product Choices

Applications and Notes » 

Shothole borer

8 Product Choices

Applications and Notes » 

White apple leafhopper

4 Product Choices

Applications and Notes » 

Brown rot

35 Product Choices

Applications and Notes » 

Powdery Mildew (Stone Fruit)

30 Product Choices

Applications and Notes » 

 

Preharvest and harvest

Brown rot

33 Product Choices

Applications and Notes » 

Powdery Mildew (Stone Fruit)

18 Product Choices

Applications and Notes » 

Oriental fruit moth

24 Product Choices

Applications and Notes » 

Peach twig borer

24 Product Choices

Applications and Notes »