potato 5-9-12 CLEAN - Vegetableipmasia.org

ORGANIC POTATO PRODUCTION Table 12.4 Pesticides Labeled for Management of Late Blight Class of Compounds Product Name (active ingredient) (hydrogen peroxide/dioxide) POST HARVEST TREATMENT StorOx 2.0 (hydrogen peroxide/ peroxyacetic acid mixture) Product Rate 0.25-­‐0.33 fl oz/gal (weekly/preventative) 1 ¼ -­‐ 2 ½ fl. oz./gal (postharvest spray); 1:100 – 1:1000 (post harvest process/packing line) PHI (days) REI (hours) Efficacy Comments until dry (field) treatment. For weekly or preventative treatments, apply lower rate every five to seven days. At first signs of disease, use curative rate then resume weekly preventative treatment. 0 0 ? Post harvest treatment of tubers. * = Restricted-­‐use pesticide. Restricted-­‐use pesticides can only be purchased by certified applicators and used by certified applicators or someone under the direct supervision of a certified applicator. PHI = pre-­‐harvest interval, REI = restricted entry interval. -­‐ = pre-­‐harvest interval isn't specified on label. Efficacy: 1-­‐ effective in half or more of recent university trials, 2-­‐ effective in less than half of recent university trials, 3-­‐not effective in any known trials, ?-­‐ not reviewed or no research available +/-­‐ = May be ineffective under high disease pressure; ++++=highly effective. 12.5 Verticillium Wilt, Verticillium albo-atrum and V. dahliaeTime for concern: Mid-season to harvest, in cool soils.Key characteristics: Wilt symptoms result from the growth of the fungi in the water-conducting tissues of the tuber, root andstem. Yellowing, wilting, and defoliation are the first symptoms, which typically occur on one side of a leaf or one side of theplant. These symptoms may be more apparent at higher temperatures when the plants are trying to transport more water.When affected stems are cut diagonally at the base, brown streaks are visible (Reference 55). Infected tubers develop a lightbrown discoloration of the vascular tissue. Wilting and chlorosis of the foliage is similar to Fusarium wilt. Laboratory isolationof the fungus is necessary for positive identification. Verticillium survive as microsclerotia in the soil. See Cornell generalHUfactsheetUH (Reference 55).Yield losses are more severe when lesion nematode (Pratylenchus penetrans) is also present, even at low soil populationlevels; the nematode/verticillium complex is called early dying.Relative risk: Sandy soil is a risk factor; uncommon in heavier soils of Upstate NY.Management Option Scouting/thresholds Crop rotation Resistant varieties Cultivation/Hilling Recommendation for Verticillium Wilt Record the occurrence and severity of Verticillium wilt. Thresholds have not been established for organic production Rotation with grains reduces soil populations. The pathogen survives for several years without a host crop and will infect and reproduce on many weeds. Plan a minimum of 3-­‐4 years without tomato, eggplant or pepper and maintain good weed control in rotational crops. For tuber symptoms, late-­‐maturing varieties are more resistant than early-­‐maturing varieties. See Section 6: Varieties. Superior is particularly susceptible, while Atlantic is tolerant, Genesee is resistant, and Reba is moderately resistant. Avoid late cultivation and hilling of susceptible varieties, because root pruning increases risk of infection. 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. 362012