[1.1] Bacterial spot is devastating disease of peaches and nectarines as well as plums, prunes and apricots. This disease is most likely to be a problem on susceptible varieties (e.g., Autumnglo, Babygold 5, Redhaven, California white-fleshed varieties, nectarines). Any variety developed in drier climates and then grown in the more humid climate of NY has a strong likely hood of being susceptible. Also, this disease will be more severe in the warmer southern portions of NY, in wet years, in orchards with lighter (sandy) soils, and in windy orchard sites. The bacterial spot pathogen, Xanthomonas arboricola pv. pruni infects leaf scars at leaf drop and overwinters in infected twigs. Bacteria populations subsequently multiply during warm weather and ooze out during spring rains. Immature tissues are less susceptible to the bacterial infection, and as such, infections will not begin until petal fall/shuck split. Early season copper applications are quite effective for controlling the bacterial populations, but also likely to induce phytotoxicity if one is not careful. Moreover, copper phytotoxicity can cause symptoms similar to that of bacterial spot. Do not plant susceptible peach varieties near plums, prunes, or apricots. Prunes, plum, and apricots are also susceptible to bacterial spot, and no materials are registered for use on bacterial spot of prunes, plum, and apricots.

• Pesticide Application Notes

[1.2] Where susceptible varieties are planted, a delayed dormant application of copper my help reduce bacterial spot disease pressure for the season. Along these lines, if applications of copper were made to manage peach leaf curl, these applications will substitute for those needed for bacterial spot. Apply copper with caution. Peaches are very susceptible to copper injury, especially after bud break. Copper phytotoxicity will be exacerbated by cool wet weather and environmental acidity.

[1.3] Where control is needed, apply sprays of Mycoshield or Flameout every 7-–10 days from shuck split until 3 wk before harvest. The applications immediately after shuck split are the most important for protecting the fruit. Thorough coverage is essential.

[1.4] Low rates of copper can be applied post-bloom at 7-14 day intervals to reduce harvest damage and build of bacterial populations in susceptible varieties. Do not make more that six such applications. Take caution with post-bloom copper applications. These copper applications may result in phytotoxicity if no rains occur between applications. If copper sprays are applied under acidic conditions (e.g., with LI-700 or other acidifiers) these may be more phytotoxic than copper applied alone.

Brown Rot (Blossom Blight)

• Biology & Cultural

[2.1] Blossom blight is most likely to occur when the weather is warm (above 60° F) and wet during bloom or when significant numbers of fruit were left unharvested the previous year. Blossom blight may also be serious at lower temperatures if prolonged wetting periods occur. However, blossom sprays on peaches may often be reduced or eliminated if these conditions do not occur. Nectarines are more susceptible to brown rot than most peach cultivars.

[2.2] Good insect control is important to prevent formation of entry points for the brown rot fungus. Pay special attention to control of plum curculio, oriental fruit moth, and tarnished plant bug. Fruits thinned after pit hardening are likely to become infected on the orchard floor and provide a source of inoculum for spread to ripening fruits in the tree; in contrast, fruits thinned prior to pit hardening are much less likely to do so.

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

[2.3] When used at a rate of 10 oz/100 gal dilute, Rovral provides 24–48 hr kickback activity against blossom blight infections at 68° F. Only 2 applications of Rovral are allowed per year. Orbit, Indar, and Elite also have significant kickback activity.

[2.4] More than one blossom blight spray is rarely needed unless disease pressure is extreme.

[2.5] If a previous brown rot spray was applied, a petal fall application is necessary on peaches only if warm and wet weather persists.

[2.6] Fruit are very susceptible to infection for the first 3 wk after shuck split; therefore, the shuck split and 1st cover sprays are important for controlling brown rot, particularly in wet weather. Chlorothalonil (Bravo, Echo) has longer residual activity than captan or sulfur, but do not use Chlorothalonil after shuck split. Indar is highly effective.

[2.7] Elite, Indar and Orbit are not registered for use until 3 wk before harvest. Fruit becomes increasingly susceptible to infection the last 3 wk before harvest. It is therefore suggested that spray intervals be tightened up during this period and that Elite, Indar, or Orbit be used if disease pressure is high.

• Pesticide Resistance

[2.8] For resistance management purposes, the SI fungicides (Indar, Elite, Orbit) should not be used routinely throughout the season for BOTH blossom blight AND fruit rot control. Where peaches within the same block ripen over an extended season, continued use of SI fungicides as preharvest sprays for successive varieties will also create selection pressure for fungicide resistance. Use captan or Pristine to break the string of preharvest SI fungicides applied to varieties with varied ripening or harvest dates.

Peach Leaf Curl

• Pesticide Application Notes

[3.1] Leaf curl sprays are especially important in years following crop failures because inoculum can build in orchards that do not receive brown rot sprays. Leaf curl sprays can be applied anytime between leaf fall and bud swell. Treatment applied after bud swell may not provide 100% control. Fixed copper compounds applied at leaf fall should also improve bacterial spot control by reducing the inoculum that overwinters in leaf scars. Several other commercial copper formulations in addition to those listed may be labeled for this use on peaches. Although they have not been tested in NY, research on other crops suggests that most copper formulations should give comparable rates of control at comparable rates of metallic copper.

Peach Scab

• Biology & Cultural

[4.1] Peach scab is caused by the fungal pathogen, Cladosporium carpophilum, and is phylogenetically closely related to the apple scab pathogen. This pathogen survives in lesions on twigs and in the textural features of the bark. The infective spores (conidia) are produced shortly before shuck split and for several weeks thereafter. The spores are unable to infect immature fruit immediately; the dense pubescence of immature fruit prevents spore infection for nearly a month after petal fall. Once infection has taken place, lesions will develop fairly slowly (e.g. 40-70 day incubation period). If spring weather is particularly warm and wet, lesions can during appear a few weeks after shuck split. In order to protect against infection, initiate management programs at shuck split.

This disease has been restricted to the more southern portions of the state, but may become a larger problem if we continue to experience warmer winters. This disease is also likely to show up on late maturing varieties, and following years when spring frosts destroy the crop, but no fungicides are applied for disease management. In the absence of management, peach scab inoculum can build up considerably.

• Pesticide Application Notes

[4.2] Where control is needed, apply sprays at 10- to 14-day intervals beginning at shuck split and continuing until 6 wk before harvest. Spray intervals can be lengthened during extended periods of dry weather. Bravo or Echo applied at shuck split will provide at least 14 days of protection for young fruits.

Perennial (Cytospora, Valsa) Canker

• Biology & Cultural

[5.1] Perennial canker is the most destructive disease of peach trees in New York and other cold-climate regions. Infections usually become established in pruning wounds or winter-injured tissue, from which they slowly expand and girdle the infected trunk or limbs. The most common point of entry is small, weak shoots that develop in the centers of the trees, then become killed during the winter. Thus, the most effective means of controlling this disease is to prune trees so that their centers are open. Other control practices include establishing new plantings at a distance from old, cankered blocks; training to promote wide crotch angles (reduced breakage and winter injury); delaying annual pruning until bloom or later, to allow pruning cuts to “heal” quickly; and standard horticultural practices to promote winter hardiness. Some fungicides applied for brown rot control after pruning may help protect these wounds from infection, but such benefits are unproven and likely to be minor. This disease is controlled almost entirely through horticultural practices.

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.

Phytophthora Root, Crown, And Collar Rots

• Biology & Cultural

[6.1] Peach rootstocks are significantly more susceptible to Phytophthora root, crown, and collar rots than are apples (peach is similar to cherry in susceptibility). The main defense 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. Ridomil will provide additional protection in wet years, on marginal sites, or in wetter sections of the orchard. See comment

[6.2] 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 pest.

• Pesticide Application Notes

[6.2] 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 assure good coverage (material is moved into the soil by subsequent rain or irrigation). See label for further details.

Powdery Mildew (Rusty Spot)

• Biology & Cultural

[7.1] Only a problem on certain susceptible varieties (e.g., Rio-Oso-Gem, Redskin). Can be particularly severe if peaches are planted adjacent to mildew-susceptible apple cultivars.

• Pesticide Application Notes

[7.2] Where disease has been a problem, add sulfur to each spray from petal fall through pit hardening. This rate of sulfur may be combined with 1 lb captan/100 gal in the early cover sprays for brown rot protection. When applied for brown rot control, the SI fungicides (Elite, Indar, Orbit) also should provide control of powdery mildew.

Prunus Stem Pitting Virus

• Biology & Cultural

[8.1] Prunus stem pitting virus is spread from broadleaf weed species to trees by the dagger nematode. The virus is seed-transmitted and enters orchards via windblown seeds from infected weed species. Broadleaf weeds in the sodded row middles should be controlled annually using 2,4-D after harvest to minimize the potential sources of virus in the orchard.

X-Disease

• Biology & Cultural

[9.1] The only effective control for X-disease of peach, nectarine, and cherry is the destruction of infected host plants within a 500-ft radius of the orchard. Chokecherry (Prunus virginianae) and wild sweet cherry seedlings are the wild hosts that provide most of the inoculum for leafhopper vectors of this disease. Wild black cherry (Prunus serotina) is not a host for X-disease. Infected sweet and tart cherry trees (particularly those on Mazzard rootstock) and wild sweet cherry seedlings can also serve as inoculum sources, but leafhoppers cannot acquire the disease from infected peach or nectarine trees. Where X-disease is a concern, new peach and nectarine plantings should be isolated from plantings of sweet cherries that might harbor X-disease.

All chokecherry and wild sweet cherry seedlings within 500 ft of peach, nectarine, and cherry orchards should be eradicated either by physically removing the plants or through use of brush killers. Chokecherries often grow in hedgerows, along fences and property lines, along the margins of woodlots, and in overgrown meadows where they can be managed with brush killers. DO NOT USE BRUSH KILLERS WITHIN THE ORCHARD. Where chokecherries have been removed or treated with brush killers, check for regrowth of chokecherry sprouts during the season following treatment. Some broadleaf weeds can also harbor the X-disease pathogen, and weeds encourage high populations of X-disease vectors. To minimize risks of X-disease, stone fruit orchards should be treated annually (in autumn) with 2,4-D herbicide to eliminate broadleaf weeds in the grass ground cover.

• Pesticide Application Notes

[9.2] Method of Hyvar application: Spread granules around the base of the stump or brush clump. Hyvar is a soil sterilant. Growth of most vegetation will be prevented in the treated area for several years. Do not apply near ditches or where surface water may carry the material to desirable plants.

[9.3] To increase activity of Krenite, add one quart of spray oil/100 gallons. Krenite will not affect current season’s foliage, but it will prevent the treated plants from breaking bud in the spring. DO NOT ALLOW KRENITE TO DRIFT ONTO CROP PLANTS. Krenite affects only woody plants, and only those parts of the plant that are sprayed. Thus, it acts like a “chemical pruner.” It is not active in soil.

[9.4] Peach and nectarine trees with X-disease can be treated therapeutically by injecting trees with oxytetracycline (an antibiotic) in the fall after harvest. Oxytetracycline kills or suppresses the pathogen in the tree phloem and prolongs the life and productivity of infected trees. Infected trees usually require annual treatment to maintain disease suppression, but some trees recover completely after two successive years of treatment. Peach and nectarine trees in later stages of decline (i.e., X-disease symptoms throughout the canopy) will not recover and should not be treated. Oxytetracycline has not been proven effective for treating cherry trees. Oxytetracycline should only be applied to peach and nectarine trees that have symptoms of X-disease; it should never be applied to healthy trees or used as a preventive for X-disease.

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

[10.1] Apply spray against newly emerging adults, shortly after petal fall. Apply as a coarse, low-pressure spray to give uniform coverage of tree trunks and lower limbs. Particularly a problem in trees with split trunks from Cytospora canker or winter injury. Will also contribute to control of peachtree borer and lesser peachtree borer; see comment [17.3]. Only 1 application of Lorsban permitted per season.

[10.2] 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.

Cottony Peach Scale, European Fruit Lecanium Scale

• Pesticide Application Notes

[11.1] Low rate of oil during dormant period for European fruit lecanium, high rate for cottony peach scale.

[11.2] 1 application at completion of crawler hatch in mid-June, directed to leaf undersides, trunk, and scaffold limbs.

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

[12.1] High rate of oil during dormant period.

[12.2] Apply as mites appear in summer; use lower rate of †Nexter for European red mite, higher rate for twospotted spider mite. †Nexter not registered for use in Nassau or Suffolk Counties. Acramite, Savey and Apollo limited to 1 application per season.

Green Peach Aphid

• Pesticide Application Notes

[13.1] Apply spray postbloom, before excessive leaf curling occurs.

Japanese Beetle

• Biology & Cultural

[14.1] Primarily a problem in southern part of Hudson Valley from mid-July to mid-August.

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

[15.1] 3 sprays: end of May (shuck split), 1st hatch (mid-late June: 360 DD43 after 1st trap catch), and 2 wk later. Best results obtained if materials are alternated.

Oriental Fruit Moth

• 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

[16.1] Pheromone disruption is economically justified if 2–3 sprays are normally applied, and if no other insecticide sprays are routinely needed for other pests after petal fall. For this reason, disruption may not be economical for the 1st brood, as plum curculio sprays at this time normally would also control oriental fruit moth. Pheromones should be applied in mid-June before initiation of the 2nd flight; the need for re-application depends on residual field life of specific formulations: Isomate-M 100, 90 days; Checkmate and 3M Sprayable, 14 days. The residual life of the 3M sprayable deposit can be extended by the addition of a spreader-sticker such as Nu-Film-17 at 1 pt/A. Border insecticide sprays may be needed in orchards adjacent to sources of adult immigration or in other high pressure situations.

• Pesticide Application Notes

[16.2] Against adults, beginning at petal fall. Use 2 applications at a 10-14-day interval. Pyrethroids will also control plum curculio, lesser peachtree borer, and tarnished plant bug. Sevin will not control lesser peachtree borer. *Imidan not registered for lesser peachtree borer.

[16.3] Summer sprays should be timed to start approximately at the 10% hatch point, 175-200 DD (base 45° F) after the first adult catch of the second brood, with a second application in 10-14 days. In high pressure blocks, a final spray should be applied 2 wk before harvest to control late season larvae. Suggested action threshold: Avg. of >10 adults/week caught per pheromone trap.

Peachtree Borers (Including 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

[17.1] Hang pheromone ties at 100/acre in late May before flight begins.

• Pesticide Application Notes

[17.2] Against adults, when first shucks start to split. Will also control plum curculio, oriental fruit moth, and tarnished plant bug. Sevin will not control lesser peachtree borer. *Imidan not registered for lesser peachtree borer.

[17.3] 3 sprays of pyrethroids to trunk and scaffold limbs against larvae: June 1–10, July 7–15, and August 1–10. 1 application of Lorsban or *Thionex, from July 20 to Aug. 1 OR immediately after harvest, may be substituted for the 3rd spray; do not apply either material to fruit. Only 1 application of Lorsban permitted per season. *Baythroid not labeled for peachtree borer. Suggested action threshold: 1st emergence of adults plus 8 days or 1–2 larvae/tree. Note: Preplant dipping of roots and crowns of peach tree seedlings before planting has given complete control of the peachtree borer for the 1st growing season and has reduced borers during the 2nd season. *Thionex, 2 2/3 qt of 3EC formulation/40 gal, is preferred because it stays in suspension and eliminates the need for constant agitation during treatment. SPECIAL PRECAUTIONS: Wear full PPE to avoid exposing skin to insecticide. Dispose of excess material with extreme care. *Thionex is extremely toxic to fish and wildlife.

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

[18.1] Against adults, when first shucks start to split; continue at 7- to 10-day intervals. Use 2–3 applications in Western New York, 3–4 in Eastern New York. Will also control oriental fruit moth, lesser peachtree borer, and tarnished plant bug.

[18.2] 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.

Tarnished Plant Bug, Stink Bug

• 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. Satisfactory control requires adequate management of orchard weeds that attract this pest and act as alternate hosts.

• Monitoring & Forecasting

[19.1] Apply spray as insects appear. Suggested action threshold: At pink, 3 bleeding sites/tree or cumulative capture of 7 adults by late pink stage (white sticky-board trap); at petal fall, 3 bleeding sites/tree.

[19.2] Most catfacing injury is caused before shuck split. Later season feeding generally results in only minor surface scarring.

• Pesticide Application Notes

[19.3]At 10-day intervals as needed in July and August. Suggested action threshold: 3 bleeding sites/tree.

Western Flower Thrips

• Biology & Cultural

Drought conditions and high temperatures may encourage damaging populations in nectarines, particularly in the Hudson Valley region. Adults move from alternate weed or crop hosts to fruit just prior to and during harvest, feed on the fruit surface in protected sites, such as in the stem end, the suture, under leaves and branches, and between fruit. Feeding results in silver stipling or patches; injury is particularly obvious on highly colored varieties.

• Pesticide Application Notes

[20.1] In orchards with severe infestations, a petal fall application may be warranted against thrips feeding in fruit clusters. Control using SpinTor may be improved by addition of an adjuvant.

[20.2] An application after the first harvest may prevent subsequent losses; however, an additional application may be needed if pressure is severe. Note PHI. Control may be improved by addition of an adjuvant.

Storage Rots

• Pesticide Application Notes

[21.1] A postharvest treatment with Scholar SC via dipping, 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.

Pest Management Guidelines A Cornell Cooperative Extension Publication	Cornell Guide for Pest Management of TreeFruits
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