WSU Tree Fruit Research & Extension Center

Postharvest Information Network

Thursday, September 1, 2016

WSU-TFREC/Postharvest Information Network/Preharvest Practices to Minimize Postharvest Decay



Preharvest Practices to Minimize Postharvest Decay


Practices

  • Use low angle nozzles to keep irrigated water off fruit on lower limbs to reduce sprinkler rot (Phytophthora cactorum). Maintain 1 ppm copper in the irrigation water.

  • Maintain good weed control and keep grass mowed. A drier orchard microclimate will reduce mucor rot, coprinus rot and scab.

  • Control woolly aphids to reduce bull's eye rot.

  • Supplement fruit calcium with foliar calcium sprays during the growing season. High calcium fruit is less prone to decay and physiological disorders than low calcium fruit.

  • Use the minimum amount of nitrogen fertilizer necessary to maintain plant vigor. High N fruit is more prone to various postharvest problems than lower N fruit. Application of N immediately postharvest may minimize fruit N while still supplying enough for fruit set and shoot growth the following year.

  • Do not use Benlate or other benzimidazole fungicides in the orchard to avoid development of resistance in the packinghouse. Resistance to Benlate will reduce the effectiveness of other postharvest fungicides including Mertect 340-F and Deccosalt 19.

  • Early season and preharvest applications of Ziram to orchards susceptible to bull's eye rot, side rot and pear scab infections will help reduce postharvest decay. Follow application instructions in EB0419, Crop Protection Guide for Tree Fruits in Washington.

  • Harvest at proper maturity. Late-picked fruit is more susceptible to decay than fruit of optimum maturity.

  • Clean bins thoroughly before filling with fruit. Steam is very effective. Remove last season's leaves and fruit parts prior to placing bins in the orchard. Decay spores survive on the wood of bins, especially where fruit has been smashed. Apple and pear scab-infected leaves survive through storage. Growers in districts without scab are advised to use only bins free of scab-infested leaves to avoid new infections.

  • Reduce bin contact with dust and dirt, which contain spores of decay fungi. Keep the bottom of bins as clean as possible. Keep staging areas mowed. Suppress dust.

  • Avoid picking fruit when it is wet.

  • Keep grounders (fallen fruit) out of bins.

  • Do not allow bins of fruit to remain in the sun. Transfer fruit quickly to the packinghouse and cold storage.

  • Handle fruit gently. Avoid bruising and stem punctures. Smooth orchard roads and driving forklifts slowly may reduce fruit injury.

  • After harvest, remove fallen fruit from orchard to prevent buildup of decay spores.

  • Apply copper at leaf-fall to help reduce bull's eye rot.

Dr. Eugene Kupferman, Postharvest Specialist

WSU Tree Fruit Research and Extension Center
1100 N. Western Ave., Wenatchee, WA 98801
Kupfer@wsu.edu

Tree Fruit Postharvest Journal 4(1):7
June 1993

Tree Fruit Research & Extension Center, 1100 N Western Ave, Washington State University, Wenatchee WA 98801, 509-663-8181, Contact Us