Comparison of Foliage Treatments Used Commercially to Control the Colorado Potato Beetle in Irish Potatoes, 1979

'Pungo' Irish potatoes were planted, 10 in spacing in 3-ft rows at Atlantic, VA on Apr 15. Temik 15G was applied to the entire area at 3 lbs ai/acre in-furrow at planting. Following “breaking” of the Temik granulars around Jun 7, as indicated by widespread apperance of potato beetle larvae, plots were established for the purpose of comparing treatments used on a commercial basis for potato beetle control. Plots were 3 rows wide × 50 ft long with adjacent untreated rows and randomized In complete blocks with 4 replications. The first spray was applied on Jun 14, at which time there were approximately 10 potato beetle larvae/hill; additional treatments were made on Jun 27 and Jul 7. The sprays were applied with a D. B. Smith 5-gal, knapsack, hand-operated, compressed-air sprayer at the rate of 75/gal/acre (40 psi) using a D. B. Smith #E - 147 adjustable cone nozzle. In evaluating the various insecticidal treatments, direct counts of the number of potato beetle larvae/10 hills and late season foliage injury ratings were utilized. The several categories for foliage injury ratings are as follows: 1) only occasional chewing, necessary to look very close to see evidences of feeding damage; 2) Visible signs of feeding but less than 10% of the leaves severely injured; 3) Severe feeding up to 25% of foliage; 4) Heavy feeding on up to 50% of foliage; 5) Practically 100% of foliage severely damaged, plants nearly defoliated; and Def. - Plants completely defoliated. Yields were taken on Jul 20.