Contents
Bacterial Canker (Pseudomonas syringae)
Phytophthora Root, Crown, And Collar Rots
Black Cherry Fruit Fly, Cherry Fruit Fly
Table 38. Pesticide Spray Table – Cherries
Table 39.
Growth Regulator Uses in Cherries
Diseases
Bacterial
Canker (Pseudomonas syringae)
• Pesticide Application Notes
[1.1] The pathogen causing bacterial canker is favored by cool, wet weather (spring and fall). It can invade leaf scars in fall and fresh pruning wounds in spring if pruning is done under cool, wet conditions.
The optimum timing and effectiveness of copper applications for control of bacterial canker is not known under New York conditions. Label directions specify one application in the fall “before heavy rains begin” and another at late dormant. A third application is also labeled for use shortly after harvest in orchards where disease is severe, although this application should be avoided on sweet cherries in New York due to the potential for leaf injury. Several other commercial copper formulations in addition to those listed may be labeled for this use on cherries. Although they have not been tested, research on other crops suggests that most copper formulations should give comparable rates of control at comparable rates of metallic copper.
Black
Knot
• Biology & Cultural
[2.1] Black knot has become an increasingly important problem on sour cherries in recent years. It is a difficult disease to control completely, but good sanitation—removing and destroying infected (knotted) limbs as they appear (make pruning cuts at least 6-8 in below visible swellings), destroying infected fence row trees and adjacent abandoned orchards (when possible)—is critical. Fungicide sprays are unlikely to provide satisfactory control without good sanitation practices. The most critical time for protecting against infection with fungicides is between white bud and shuck split. Black knot infection periods require rain and temperatures above 55° F; thus, fungicide sprays are most likely to be beneficial under these conditions.
Refer to the reference materials list at the end of this publication for a Fact Sheet containing more details on the biology and management of this disease.
• Pesticide Application Notes
[2.2] Bravo is the most effective fungicide for black knot control. Note that a minimum 10-day re-treatment interval is specified on the label.
Brown
Rot (Blossom blight)
• Biology & Cultural
[3.1] Blossom blight is most likely to occur when the weather is warm (above 60° F) and wet during bloom or when large numbers of fruit were not harvested the previous year. Blossom blight may also be serious at lower temperatures if prolonged wetting periods occur. Blossom sprays on tart cherries may often be reduced or eliminated if none of these conditions occur. Blossom blight is much more serious on sweet cherry than on sour cherry.
[3.2] Sweet (but not sour) cherry fruit are very susceptible to brown rot for the first few weeks after they set. Protection is therefore important at this time, particularly in wet weather.
Refer to the reference materials list at the end of this publication for a Fact Sheet containing more details on the biology and management of this disease.
• Pesticide Application Notes
[3.3] When used at a rate of 10 oz/100 gal, Rovral provides 24-48 hr kickback activity against blossom blight infections. Only 2 sprays of Rovral are allowed per season. Indar, Orbit, and Elite also have significant kickback activity. For resistance management purposes, it is recommended that the SI fungicides (Elite, Indar, Orbit) should not be used routinely throughout the season for BOTH blossom blight AND fruit rot control.
[3.4] More than one blossom blight spray is rarely needed unless disease pressure is extreme.
[3.5] Young sweet cherry fruit are very susceptible to brown rot. Thus, a petal fall spray is recommended on sweet cherries if weather is wet; much less necessary on sour cherries.
[3.6] Do not use chlorothalonil (Bravo, Applause, Concorde, Echo, Equus) after shuck split; may resume use after harvest. Chlorothalonil has much longer residual activity than other fungicides labeled at shuck split, and is recommended if prolonged protection is needed. Indar is the most effective fungicide against brown rot on cherries.
[3.7] Fruit becomes increasingly susceptible to brown rot during the last 3 wk before harvest. It is therefore recommended that spray intervals be tightened during this period and that superior brown rot fungicides be used if disease pressure is high (warm and wet), especially on sweet cherries.
Indar is the most effective fungicide for control of brown rot under high disease pressure, and provides excellent residual activity. It may be applied at 7–10-day intervals as needed. Orbit, Elite, and Pristine are also excellent brown rot fungicides with no preharvest interval restrictions. Sulfur, captan plus sulfur, and ferbam plus sulfur do not provide adequate control on sweet cherries. The maximum allowable rate of 4 lb/A for captan is inadequate on trees greater than 10 ft tall, particularly on sweet cherries.
Leaf
Spot
• Pesticide Application Notes
[4.1] Primary leaf spot infections can occur from petal fall until after harvest; it is, therefore, important to maintain adequate spray deposits prior to infection periods (see Table 11) throughout this time. Chlorothalonil fungicides (Bravo, Applause, Concorde, Echo, Equus) have the longest residual activity. They also provide some control of black knot.
Rubigan, Indar, and Elite have approximately 3 days of after-infection activity, and can be used in this manner when necessary. However, leaf spot has shown resistance to SI fungicides in some orchards in Michigan, and regular use of post-infection timing will spread selection for resistance. Thiophanate-methyl (Topsin M) is no longer recommended for use on cherries because of widespread brown rot resistance and suspected leaf spot resistance. Captan may cause leaf injury on Schmidt, Emperor Francis, and Giant sweet cherries if used between petal fall and harvest. Sulfur has short residual activity and must be reapplied frequently in wet seasons. Syllit has little effect against brown rot.
[4.2] Do not use chlorothalonil (Bravo, Applause, Concorde, Echo, Equus) after shuck split; may resume use after harvest. Chlorothalonil has much longer residual activity than other fungicides labeled at shuck split, and is recommended if prolonged protection is needed.
[4.3] Do not use captan on sensitive sweet cherry varieties in the preharvest sprays. Do not use chlorothalonil between shuck split and harvest.
[4.4] Do not use copper on sweet cherries.
Phytophthora
Root, Crown, And Collar Rots
• Biology & Cultural
[5.1] Cherry rootstocks are significantly more susceptible to Phytophthora root, crown, and collar rots than are apples. Mahaleb is more susceptible than Mazzard or Colt. The main defenses against these diseases should be providing good soil drainage through proper site selection and physical manipulations such as tiling or planting on berms; in marginal sites or very wet years, berms are much more effective than tiling. Highly susceptible rootstocks (e.g., Mahaleb) also should be avoided on marginal sites. However, Ridomil will provide additional protection in wet years, on marginal sites, or in wetter sections of the orchard. See comment 5.2 about applications.
Refer to the reference materials list at the end of this publication for a Fact Sheet containing more details on the biology and management of this disease.
• Pesticide Application Notes
[5.2] Ridomil applications should be made just before growth starts in the spring and at 2–3-month intervals thereafter if soil conditions are very wet. Apply to the soil beneath the tree canopy in sufficient water to ensure good coverage (material is moved into the soil by subsequent rain or irrigation). Do not apply Ridomil to newly planted trees. See label for further details.
Powdery
Mildew
• Pesticide Notes
[6.1] To control mildew, include an appropriate fungicide in each spray from 2nd fruit fly spray through the postharvest application. Nova is most effective.
[6.2] Do not use copper on sweet cherries.
X-Disease
• Pesticide Application Notes
[6.1] Refer to “Early Spring” section in Pesticide Spray Table for Peaches and Nectarines.
Insects
And Mites
American
Plum Borer
• Biology & Cultural
Refer to the reference materials list at the end of this publication for a Fact Sheet containing details on the biology and management of this pest.
• Pesticide Application Notes
[8.1] Application recommended against newly emerging adults, shortly after petal fall. If fresh borer activity is noted in early July, follow up with an additional application by mid-July. Apply as a coarse, low-pressure spray to give uniform coverage of tree trunks and lower limbs. Avoid Lorsban contact with foliage in sweet cherries; 50WS and 75WG formulations not labeled in sweet cherries. Rate of *Baythroid products for lesser peachtree borer: 1.4-2.0 fl oz/A; for American plum borer: 2.4-2.8 fl oz/A.
[8.2] The July and August lesser peachtree borer sprays will additionally provide control of 2nd brood American plum borer. Refer to comment [12.2].
Black
Cherry Aphid
• Pesticide Application Notes
[9.1] Prebloom spray recommended, just before blossoms open, and during summer if needed. Because of toxicity to bees, Sevin is not recommended for prebloom aphid treatments. Suggested action threshold: 4 infested terminals/tree.
[9.2] No separate spray recommended at petal fall. See comment [14.1].
[9.3] Lorsban not labeled for foliar use on sweet cherries.
Black
Cherry Fruit Fly, Cherry Fruit Fly
• Biology & Cultural
Refer to the reference materials list at the end of this publication for a Fact Sheet containing details on the biology and management of these pests.
• Pesticide Application Notes
[10.1] Make 1st spray 7 days after flies emerge (when Early Richmond starts to color); 2nd and 3rd sprays at 7- to 10-day intervals. Sevin is recommended as an emergency treatment near harvest. *Imidan is for use on tart cherries only; not registered for black cherry fruit fly.
[10.2] Frequent applications (7–10-day intervals) of Surround and maximal coverage (minimum of 100 gal/A) are advised in New York while there is active foliar growth.
[10.3] Use of *Imidan and Lorsban on tart cherries only.
European
Red Mite
• Biology & Cultural
Refer to the reference materials list at the end of this publication for a Fact Sheet containing details on the biology and management of this pest.
• Pesticide Application Notes
[11.1] Apply oil against overwintering eggs.
[11.2] Do not apply *Vendex more than 2 times per season.
[11.3] Use lower rate of †Nexter for European red mite, higher rate for twospotted spider mite; postharvest use only. †Nexter not registered for use in Nassau or Suffolk Counties.
[11.4] Apollo and Savey limited to 1 application per season.
Lesser
Peachtree Borer
• Biology & Cultural
Refer to the reference materials list at the end of this publication for a Fact Sheet containing details on the biology and management of this pest.
• Biological & Non-chemical Control
[12.1] In orchards where lesser peachtree borer is the primary borer pest, hang pheromone ties at 100/acre in late May before flight begins.
• Pesticide Application Notes
[12.2] For Lorsban and pyrethroids, apply as a coarse spray to trunk and lower limbs in up to 3 sprays; June 1-10, July 7-15, and August 1-10. Do not spray fruit; 6-day PHI for *Lorsban 4EC, 21 days for Lorsban 75WG, 14 days for *Asana and *Warrior, 3 days for *Ambush and *Pounce. For *Thionex, a single spray post-harvest. The July and August sprays will additionally provide control of 2nd brood American plum borer.
Obliquebanded
Leafroller
• Biology & Cultural
Refer to the reference materials list at the end of this publication for a Fact Sheet containing details on the biology and management of this pest.
• Pesticide Application Notes
[13.1] Apply in early July when larvae are small (approximately 360-450 DD [base 43° F] after 1st trap catch.
[13.2] Lorsban not labeled in sweet cherries.
Plum Curculio
• Biology & Cultural
Refer to the reference materials list at the end of this publication for a Fact Sheet containing details on the biology and management of this pest.
• Pesticide Application Notes
[14.1] Apply sprays when last petals are falling (early fruit set) and at 8- to 10-day intervals. Use 2-3 sprays in Western New York, 3-4 in Eastern New York. *Imidan is for use on tart cherries only; causes severe foliage injury to sweet cherries. Sevin and *Imidan will also control black cherry aphid.
[14.2] Frequent applications (7–10 day intervals) of Surround and maximal coverage (minimum of 100 gal/A) are advised in New York while there is active foliar growth.
[14.3] Not labeled for use on sweet cherries.
Storage
Rots
• Pesticide Application Notes
[15.1] A postharvest treatment with Scholar SC via flooders, T-jet, or similar system for control of storage rots is recommended for fruit coming from orchards where sporulating brown rot was observed, or when one hopes keep fruit in cold storage for a few days prior to sale. Holding tanks in postharvest treatment equipment must have excellent agitation to keep fungicides in suspension. Solutions must be replenished regularly as directed on the product label. Never exposed treated fruit to direct sunlight. This will cause the fungicide to break down.