Issue link: https://read.dmtmag.com/i/514197
www.goodfruit.com GOOD FRUIT GROWER JUNE 2015 37 will close stomata and shut down their evaporative cooling system, allowing more rapid heating of fruit. Rosenberger recommends that orchardists facing bitter rot problems: —Remove dead wood during winter. —Remove rotted fruit on the ground after harvest. —Consider irrigating to soil-saturation ahead of heat waves. —Consider applying fresh fungicide ahead of heat waves. —Consider avoiding calcium sprays just prior to predictions of temperatures above 90˚F. —Consider overhead sprinkler irrigation, refl ective coatings, or hail nets to reduce sunlight intensity. The best fungicide for bitter rot control is captan, applied at full rate at 10- to 14-day intervals, especially ahead of warm, wet weather, Rosenberger said. Pristine (boscalid, pyraclostrobin), Merivon (Xemium, also known as fl uxapyroxad, with pyr- aclostrobin), and Flint (trifl oxystrobin) are moderately effective, but should be used along with captan under high disease pressure. Two molds Honeycrisp is prone to postharvest rots that infect wounded tissue. Gray mold (Botrytis cinerea) is easier to control than blue mold (Penicillium expansum) and should be controlled with postharvest drenching or fogging. Blue mold, on the other hand, can be made worse by drenching. If fruit must be drenched, Rosenberger said, include Penbotec (pyrimethanil) or Scholar (fl udioxonil) in the drench solution. Blue mold spores, which come from decayed fruit, contaminate soil, bins, and storages and survive year to year. Spores in drench solutions infect apple wounds, and spores in storage rooms get blown about during storage fi lling. Rosenberger recommends these steps for control: —Minimize puncture wounds, perhaps by clipping stems. —Sanitize storage bins and storage rooms that will be used for holding Honeycrisp. Quaternary ammonia, the standard treatment, is very effective if surfaces are warm. Sodium hypochlorite is ineffective unless exposure time is longer than 15 minutes, especially if bins or treated surfaces are cool at the time of treatment. —Manage storage and packing to avoid contamination by spores. • Heat injury and drought stress can predispose Honeycrisp to bitter rot. Left: Bitter rot likes hot, humid weather in mid- to late summer and can spread rapidly if the fruit is not protected by fungicides. Right: White rot inoculum is always present in older trees, so fungicide protection is needed from petal fall to harvest—especially after July. PHOTOS COURTESY OF DAVID ROSENBERGER Helicopter Aerial Spraying SERVICES: • Farm Ground / Crop Land "Crop-dusting" • Noxious Weeds in Pastures and Rangeland • Water Ways, Marshes, Lakes, and Ponds • Aerial Seeding and Fertilizing • Fruit Orchards • Timber and Forestry • Cherry Drying Providing excellence in precision aerial applications throughout the Pacific Northwest. CALL FOR A QUOTE! 208-743-5411 Office 208-790-1122 Doug Lohman MORE INFO AT www.LohmanHelicopter.com LOW. SLOW. ACCURATE. Minimize drift, maximize yields and profits.