Managing Stone Fruit Diseases Mohammad University of Illinois babadoos@illinois.edu Tree Fruit Schools 2,3 February 2016
Updates in the Spray Guides One spray guide for all fruit crops No new fungicides for fruit ProPhyt is reported to be effective against apple diseases (SB/FS) Orondis, a newly registered fungicide by Syngenta, is excellent for downy mildew control and good for Phytophthora of vegetables
Fact Sheets on Fruit and Vegetable pathology Sites for the Fact Sheets (RPDs): - Old website: http://veg-fruit.cropsci.illinois.edu/ - New website: http://extension.cropsciences.ill inois.edu/fruitveg/diseases/
Important Stone Fruit Diseases Leaf spot of cherry Black knot of plum Brown rot of peach Bacterial spot of peach
Important Stone Fruit Diseases Leaf spot of cherry: Fungus Blumeriella jaapii
Cherry leaf spot
Defoliation caused by cherry leaf spot
Cherry Leaf Spot Disease A foliage disease Purple spots on upper leaf surface Conidia may be under leaf surface Leaf chlorosis Foliage defoliation in summer Fruit may not ripen Pathogen survivesin leavesonthefloor Spore release: early bloom for 6 weeks Favorable conditions: moist & warm Tart cherries are more susceptible
Managing Cherry Leaf Spot All commercially acceptable cultivars are susceptible Collect and destroy leaves on the floor Disease management by fungicides: Start fungicide application at petal fall Repeat application every 7 to 10 days until harvest and with one or two postharvest Effective fungicides: Bravo Weather Stik, Fontelis, Gem, Pristine, Rally
Important Stone Fruit Diseases Black knot of plum: Fungus Apiosporina morbosa
Plum black knot symptoms
Black Knot of Plum Affected plant parts: twigs, branches, fruit spurs Symptoms: swelling of bark and wood In summer: young knots become dark Spores are produced on knots Infection during bud break and 2 weeks after bloom Favorable conditions: moist & 55-77 F
Managing Black Knot of Plum Purchase disease-free trees Prune and burn all infected wood and new knots Destroy wild and neglected plums and cherries within 600 feet Fungicide applications: before bud break, pink bud, petal fall, and until 2 weeks after bloom - Effective fungicides: copper, Bravo Weather Stik, Topsin-M + captan Resistance: Japanese cultivars are less susceptible
Important Stone Fruit Diseases Brown rot of peach: Fungus Monilinia fructicola
Typical brown rot of peach in Illinois
Brown rot of stone fruit
Blossom infection by Monilinia fructicola
Brown rot of peach in Illinois
Characteristics of Brown Rot Major symptoms: blossom blight, spur blight, fruit rot Inoculum sources: mummies, twig canker
Peach brown rot and mummies
Overwintering of Monilinia fructicola
Sporulation of Monilinia fructicola in spring
Managing Peach Brown Rot Cultural practices Destroy rotted fruit Remove mommies Prune blighted twigs Disk the ground in spring to prevent spore production Remove wild and neglected stone fruit trees
Managing Peach Brown Rot Fungicide applications From pink bud until petal fall blossom blight (blossom and shoot blight) Prior to harvest fruit rot (brown rot)
Fungicide Efficacy for Peach Brown Rot Fungicide Brown R. Bloom Brown R. Fruit Fungicide Brown R. Bloom Brown R. Fruit Adament E E Pristine G G Bravo G --- Procure* G G Captan G F-G Rally* E --- Captevate E E Rovral E E Elevate E E Quash G G Fontelis E E Scala G G Indar* E E Sulfur F P Inspir Super E E Syllit* --- P Luna Sensa. E E Topguard E E Merivan E E Topsin-M* E E Orbit* E E Vangard G G P = poor; F = fair; G = good; E = excellent; --- = unknown. * = resistance reported.
Important Stone Fruit Diseases Bacterial spot of peach: Xanthomonas arboricola pv. pruni
Lesions on upper leaf surface Lesions on lower leaf surface Bacterial spot of peach: leaf symptoms
Bacterial spot of peach: leaf symptoms
Bacterial spot of peach: fruit lesions
Bacterial spot of peach: twig infection
Bacterial Spot of Peach Disease: most important disease of peaches & nectarines in Illinois Pathogen survival: in buds, cankers, cracks in barks, and leaf scars
Managing Peach Bacterial Spot Disease resistance: resistance cultivars (less susceptible) are available Sandy soil: prevent sand blowing Chemical use: copper, oxytetracycline (Mycoshield, FireLine)
Some of Resistant Peach Cultivars to Bacterial Spot Allstar, Blushingstar, Coral Star, Encore, Garnet Beauty, Glowing Star, Harmony, Loring, PF15A, PF-24-007, Raritan Rose, Red Gold, Red Heaven
Chemical Management of Peach Bacterial Spot Spray fixed copper from dormant bud through early shuck split Spray Mycoshield or Mycoshield+low ratesof copper Spray at 7-day intervals
Applications of Copper Sprays 2.0-2.5 lb Cu/A 1.5-2.0 lb Cu/A 1.0 lb Cu/A Early bud-break Pink-bud Blossoms opening NCSU
Applications of Copper Sprays 0.50 lb Cu/A 0.10-0.25 lb Cu/A (+ Mycoshield) Petal-fall Shuck-split/Shuck-off Copper phytotoxicity may begin to occur NCSU
Peach production in Illinois, 2015
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