potato 5-9-12 CLEAN - Vegetableipmasia.org

ORGANIC POTATO PRODUCTION Management Option Planting Hilling Vine killing Harvest Postharvest Sanitation Notes Recommendation for Late Blight Plant on proper row spacing to ensure adequate air flow around leaves and leaf drying. Proper hilling practices reduce the exposure of tubers to spores. Proper vine-­‐killing practices reduce the exposure of tubers to spores. See Section 10.1: Vine killing. If a field has significant infection, destroy foliage by using chemicals, mowing or flaming to prevent infection of other fields including tomatoes. Foliage and vines should be completely dead and dry before harvest to avoid inoculating tubers. Providing at least 2-­‐3 weeks post-­‐vinekill prior to harvesting will improve skin set and allow many blight infected tubers to develop visual symptoms that can be graded out prior to storage or marketing. Cool tubers as quickly as possible to 50 degrees and maintain good air circulation. Maintain proper storage temperature depending on variety grown (See Section 10.4). Monitor storage potatoes for infection. Eliminate cull piles and volunteers before plants emerge in the spring. Infected shoots from these plants can provide initial inoculum for field infection. In recent years, late blight has become a greater economic problem in conventional potatoes because new strains of the late blight pathogen have developed that are resistant to metalaxyl, a widely used, conventional curative fungicide. High nitrogen rates can lead to excessive foliage that will prevent adequate airflow and thus slow foliage drying. At the time this guide was produced, the following materials were labeled in New York State for managing this pest and were allowable for organic production. Listing a pest on a pesticide label does not assure the pesticide’s effectiveness. The registration status of pesticides can and does change. Pesticides must be currently registered with the New York State Department of Environmental Conservation (DEC) to be used legally in NY. Those pesticides meeting requirements in EPA Ruling 40 CFR Part 152.25(b) (also known as 25(b) pesticides) do not require registration. Current NY pesticide registrations can be checked on the Pesticide Product, Ingredient, and Manufacturer System (PIMS website) http://pims.psur.cornell.edu/ (Reference 3). ALWAYS CHECK WITH YOUR CERTIFIER before using a new product. Table 12.4 Pesticides Labeled for Management of Late Blight Class of Compounds Product Name (active ingredient) BIOLOGICALS ActinoGrow (Streptomyces lydicus WYEC 108) Actino-­‐Iron (Streptomyces lydicus WYEC 108) Actinovate AG (Streptomyces lydicus) Product Rate 1-­‐12oz/A drench 2-­‐18oz/100lb seed* 10-­‐15 lb/A (in-­furrow)1-­‐12 oz./10 to 200 gal water per acre (soil treatment) PHI (days) REI (hours) Efficacy Comments 0 1 or when sprays have dried ? *can be applied to seed in a slurry or dry in planter box. -­‐ 4 ? Soil application. Water in after application 0 1 or until solution is dry ? Use as in furrow/soil drench. Regalia Biofungicide 2 – 4 qts 0 4 ? Apply every 5 – 7 days. Concentrate (Reynoutria sachalinensis) Serenade ASO (Bacillus subtilis) Serenade MAX (Bacillus subtilis) 6 qts/A 0 4 ? For suppression, begin applications of Serenade ASO and Serenade MAX soon after emergence and when 1-­‐3 lb/A 0 4 ? conditions are conducive to disease development. Repeat on 5 to 7 day interval or as needed. 342012