246 chokecherry tree on 2 May 2016, enclosing them in arenas as above, and challenging them with cohorts of five ETC (four fourth instar, one third instar) per arena. By then most of the ETC in central Ken- tucky had abandoned their tents for pupation, but researchers were able to collect enough tents with still-active larvae from black cherry trees in shaded locations to use in the assay. Aſter the 24-hour feeding period, ETC mortality, fecal pellet pro- duction, and defoliation were evaluated as above. Control of roseslug sawfly on rose This trial was conducted on potted roses (Knock- out® variety Radrazz PP#11836, about 61 cm tall) in 11.4 L pots, with six shrubs (replicates) per treat- ment. Treatments were chlorantraniliprole (0.312 ml/L), carbaryl (2.5ml/L), and untreated control. The insecticides were applied with a hand-held spray bottle on 01 May 2012, thoroughly wetting all adaxial and abaxial leaf surfaces of the whole shrub. Plants were held in the greenhouse for 24 hours to allow residues to dry, and then moved outdoors. There was no rain between treatment and the first (three days) challenge. Challenges were made at 3, 7, 14, and 21 days aſter application. Late-instar bristly roseslug sawfly larvae were hand-collected from rose plantings in Lexington, Kentucky, immediately before each challenge and set up in the assays the same day. For each chal- lenge, six sets of three undamaged connected leaflets were removed from plants. Leaflets were placed on moistened filter paper in a 9 cm Petri dish, and five roseslug larvae were placed on the surface of the leaflets. Test arenas were main- tained at 26°C on a 14:10 light:dark cycle. Ros- eslugs were assessed for mortality aſter 24 hours, and then feeding damage (leaf area consumed) was measured as described for the JB trials. Foliar sprays targeting lace bugs, aphids, and soft scale crawlers A trial comparing efficacy of 1- or 7-day-old foliar spray residues of chlorantraniliprole and bifen- thrin against hawthorn lace bugs was conducted on mature (>10 years old; 4–5 m tall) hawthorn trees (Crataegus viridis ‘Winter King’) on the University of Kentucky campus in 2016. On 03 August 2016, twigs with 5–10 leaves were tagged and sprayed to runoff at label rates (Table 1). There ©2017 International Society of Arboriculture Redmond and Potter: Acelepryn Control of Horticultural Pests were six sets of twigs for each treatment and chal- lenge date, blocked and distributed across six trees, with twigs within trees at least 1 m apart and non- sprayed twigs as checks. Another set of twigs was tagged and treated as above on 10 August 2016. On 11 August 2016, one leaf was removed from each twig; then the detached leaves with field-weathered residues (or checks) were placed into individual Petri dishes on moistened filter paper. There were six replicates per treatment and timing. Adult lace bugs were collected by beating branches of a heavily infested unsprayed hawthorn at a different cam- pus location. Ten active adults were placed on the abaxial side of each leaf, leaves were then inverted, and the lidded plates were held at 25°C under a 14:10 light:dark cycle. Aſter 24 hours, the insects were gently brushed off the leaves, leaves were removed, and the bugs were allowed three hours to crawl out of the open dishes and disclose their status as live and mobile. Bugs still in the dishes aſter three hours were probed, and those not capa- ble of crawling or flipping over were scored as dead. Another trial compared efficacy of chloran- traniliprole and bifenthrin sprays against olean- der aphids (Aphis nerii) on small (10–15 cm tall) greenhouse-grown swamp milkweed (Asclepias incarnata var. ‘Ice Ballet’) plants in 10 cm × 10 cm pots. The plants were infested by placing field-collected swamp milkweed shoots with high numbers of aphids in the flats amongst the test plants and allowing the aphids to estab- lish for four days before the trial. On 29 August 2016, 24 shoots, enough for eight replicates plus untreated checks, were selected and blocked by initial infestation level. Individual plants were gently sprayed to runoff using a hand-held spray bottle so that no aphids were physically knocked off the plants. Plants with aphids were then held in an incubator as described in the lace bug trial. Surviving aphids were counted after 48 hours. Researchers also evaluated chlorantraniliprole as a foliar spray targeting active and newly settled oak lecanium scale nymphs that hatch from eggs laid by females on twigs and then move to leaves upon which they settle and feed from late spring through summer. The study site was a heavily- infested planting of mature willow oaks (Quer- cus phellos) in a parking lot on the University of Kentucky campus. The application was made on
November 2017
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