potato 5-9-12 CLEAN - Vegetableipmasia.org

factORGANIC POTATO PRODUCTION five of each color on each wing. The beetles are 3/8 inch long by 1/4 inch wide and convex in shape. The eggs are yellowishorange and deposited in masses that contain between 20 and 40 eggs. Larvae are small, humpbacked, and red with two rowsof black spots on each side of their body. See Cornell H sheet (Reference 96), HUlife cycle photosUH (Reference 97) and an olderbut informative HUfact sheetUH (Reference 98). Adults and larvae feed on leaves and stems. Adults hibernate in the ground in andnear potato fields, emerge in the spring and disperse to solanaceous host plants where they feed and give rise to 1 or 2 larvalgenerations in upstate New York. (Reference 93).Risk assessment: Colorado potato beetle is a serious pest of potatoes. If left uncontrolled, it can devastate yields withreductions up to 90%. Most varieties can tolerate moderate defoliation (up to 30%) in the early season without affecting yield.Next to leafhopper, this is the most serious insect pest of potatoes.Management Option Scouting/thresholds Recommendation for Colorado Potato Beetle Take a representative sample of the field weekly. Sample five vines at five sites. For fields of an acre or less, this constitutes your entire sample. Compute means and compare to thresholds below. For larger fields, count the number of adults, small larvae (less than 1/4 inch), and egg masses. Count egg masses with less than ten eggs as half an egg mass. If the number of CPB in a particular life stage falls within the range given below or if the field is >30 acres, sample 25 more vines. The basic sample unit should be a plant "hill" until plants are 12 inches in height and a single main stem the remainder of the season. Life stage Number of CPB counted on 25 vines LOW INTERMEDIATE HIGH Stop Sample 25 Stop Compute Mean more vines Compute Mean Small larvae 200 Large larvae 68 Adults 23 If mean counts are lower than values given above, sample again next week. If any counts are higher than the values given above, sample 25 more plants and compute the means. Don't sample more than 50 vines per field. Report mean numbers of adults and larvae per 50 vines. If mean values exceed threshold values, apply insecticide. If thresholds are not reached but hot spots are found, flag hot spots and apply insecticide. Thresholds/50 vines Egg masses Small larvae Large larvae 4 with at least 25% of the earliest deposited egg masses hatched or in the process of hatching 76 31 Resistance management Given the phenomenal ability of the CPB to develop resistance to insecticides, a major goal in managing this pest is to delay the onset of resistance. Entrust Naturalyte Insect Control is very vulnerable to resistance development because it is so effective that it is tempting to overuse it. Do not rely exclusively on Entrust Naturalyte Insect Control for CPB control. Employ all possible cultural practices to minimize the number of insecticide sprays applied. Rotate with other insecticides. Before July 15 Overwintered Adults (trap cropping and then flaming or vacuuming; floating row cover; trench trapping) 1st Larval Generation (Focus your Entrust Naturalyte Insect Control use on this important stage) 602012