No abstract

Trials were conducted on a naturally infested Austrian pine planting in a residential area located in Ft. Collins, CO. Individual plots consisted of infested terminals arranged in a RCB design with 4 replications. Treatments were made 22 Jun using a pump mister applied to point of run-off. Evaluations were made by sampling 4 needle bundles (2 needles apiece) and determining the number of dead and living aphids.

Trials were conducted at a Golden, CO golt course on Scotch pine that were heavily infested with striped pine scale. Applications were made 4 Aug to point of run-off on individual infested terminal branches. Plot design was a RCB with 4 replications. At the time of treatment nymphs were in the second instar; at evaluation males were beginning to emerge. Plots were evaluated by counting the total number of nymphs on 10 needle bundles collected randomly on 10 Sep.

Trials were conducted at a Golden, CO golf course on Scotch pine thai were heavily infested with striped pine scale. Treatments were applied 8 Jul, to point of run-off, using a hand-pumped mister. Individual plots consisted of single terminals with a RCB plot design, involving 5 replications. Plots were evaluated 30 Aug by removing 15 needle bundles from each treatec! terminal and counting all living scales on the needles.

Plots were established using a series of street trees, approximately 60-ft (24 inch DBH), which lined a municipal park in Denver, CO. Two different injection techniques were employed in the trial. Arbor, capsules (Tree Technologies, Inc.) were applied 30 Jun by drilling a series of holes in the root flare of the tree. Rate of application was one capsule per 6 inch of circumference at breast height. Individual capsules contained either 5 ml of Bay NTN 33893 200SL (imidacloprid) or 4 ml of Avid (abamectin), which were allowed to drain completely. Direct trunk injections were made 26 Jul using a modified syringe that placed 1 ml of insecticide under the bark of the trunk. Injection sites were similarly made at intervals of 6 inches of tree circumference at breast height. Plot design was a RCB with 4 replications. No sampling was conducted during 1993, since treatments were applied after considerable defoliation had occurred. Plots were sampled twice during the 1994 season following the first and second generations of the elm leaf beetle. Leaves from 4 branches per tree were evaluated for amount of defoliation (skeletonizing). The rating system was: 0 = No damage present, 1 = 1-10% skeletonizing per branch, 2 = 11-20% skeletonizing per branch, 3 = 21-30% skeletonizing per branch, 4 = 31-40% skeletonizing per branch, 5 = 41-50% skeletonizing per branch, 6 = 51-60% skeletonizing per branch, 7 = 61-70% skeletonizing per branch, 8 = 71-80% skeletonizing per branch, 9 = 81-90% skeletonizing per branch, 10 = 91-100% skeletonizing per branch.