What are organic solutions for managing brown rot in peaches?
Answer: Symptoms of brown rot in peaches include the following: ? Two to three weeks before harvest, earlier infection (as early as bloom and petal fall) of the fruit by the fungus Monilinia fructicola becomes apparent as the fruit softens, approaching ripeness, causing rot both at harvest and in storage.? Often occurs in warm, humid climates.? More prevalent in the eastern United States than in the west. ? Blossom blight during bloom is an indicator for extensive brown rot later in the season.Organic growers have traditionally relied on sulfur or sulfur-containing fungicides to control brown rot, and nothing better has yet been developed. The first application of sulfur should be done at the “pink” stage, just before the petals open. Applications should be repeated at seven-day intervals, especially if rain occurs, for a total of three applications. Two other applications should also be made?one at petal drop, the other at sepal drop (usually about 10 to 14 days after petal drop). The crop is still susceptible to infection later in the season, but treatments during the early “critical” stage will reduce the amount of crop loss without leaving a sulfur residue at harvest. Augmenting sulfur with Surround? WP Crop Protectant provides better disease control than sulfur alone. Harvested fruit is also susceptible to brown rot infection. To prevent infections at harvest and during storage, peaches should be picked and handled with care to avoid punctures and skin abrasions on the fruit. Any damaged fruit should be discarded, since wounds facilitate entry of the fungus. Rapid cooling or hydrocooling to remove field heat prior to refrigeration at 0 to 3? C will also help reduce infection.For more information, see the ATTRA publications Peach Diseases Identification Sheet and Peaches: Organic and Low-Spray Production.