Arboriculture & Urban Forestry 43(6): November 2017 09 June 2009 near the end of crawler hatch. Three twigs with ≥20 leaves each were tagged on each of four trees and the bark and foliage was sprayed to runoff with chlorantraniliprole (0.156 ml/L) or bifenthrin (0.78 ml/L), or leſt untreated. On 23 June 2016, 14 days aſter treatment, researchers har- vested the tagged branches, brought them to the lab, and counted numbers of live settled crawlers on both abaxial and adaxial surfaces of five ran- domly chosen, fully expanded leaves per shoot, which were pooled to give a single total per shoot. Efficacy of Systemic Soil Applica- tions on Boxwood and Rose Pests Systemic applications targeting boxwood pests A trial assessing efficacy of autumn or spring soil drenches of chlorantraniliprole for systemic control of boxwood psyllid [Cacopsylla busi (L.)], and boxwood leafminer (Monarthropalpusi flavus (Schank)] was done on established boxwood shrubs (Buxus sempervirens) at the Lexington Cemetery, Lexington, Kentucky. Both pests have a single generation per year with key life history events occurring during leaf flush (hatching and feeding of psyllid nymphs; emergence and egg- laying by leafminer adults). Imidacloprid (Merit 75 WP) was included as a standard. The shrubs (0.6–0.9 m height) were located in four sections of the cemetery, were at least 100 m apart, with one shrub (replicate) per treatment in each sec- tion. The insecticides were mixed with water and applied as a basal drench using 2.33 L solution per meter of plant height at the rates listed in Table 1, without additional irrigation. Separate sets of shrubs were treated in October 2009 or April 2010. Total rainfall was 14.7 and 22.8 cm dur- ing the six week periods following the October and April applications, respectively, which was 3.8 and 7.4 cm above average for those periods. Damage from boxwood psyllids was evalu- ated on 30 July 2010 by examining 20 twigs per shrub (10 each from the upper and lower canopy) and recording the number with characteristic rosettes of cupped, stunted, terminal leaves that result from the psyllids’ feeding during leaf flush. Boxwood leafminers were sampled twice, on 04 May 2010 for larvae already in the leaves at the time of the October 2009 drench, and on 13 247 October 2010 for larvae originating from eggs laid in spring 2010. For the May sampling, research- ers collected 10 mined leaves per plant from the 2009 flush of growth and counted the number with live larvae, pupae, or exit holes. For the Octo- ber sampling, researchers removed 20 random twigs per shrub and stereoscopically examined the first five leaves on each twig for living larvae. Another trial targeting boxwood leafminer was done on heavily-infested in-ground B. semper- virens (0.6–0.9 m height) planted at a wholesale nursery in Stamping Ground, Kentucky. There were five replicates, each in a separate nurs- ery row, with skips (untreated plants) between treated ones in a given row. Rows were 2.44 m apart and separated by mowed grass. Insecticides were applied as a basal drench on 23 April or 13 May 2013, using 3.1 L solution per meter of plant height at the rates listed in Table 1, without additional irrigation. The two timings tested for possible differences in efficacy from application just before or soon after leaf flush, which is when adults emerge from the previous year’s leaves and oviposit in new leaves. Treatments included chlorantraniliprole (both treatment dates) and two standards: dinotefuran (23 April only) or thi- amethoxam (13 May only), plus untreated checks. There was 19.1 cm total rainfall from 23 April to 1 June 2013, 4.8 cm above normal for that period, and during summer the plants received occasional irrigation from the nursery’s sprinkler system, as needed to maintain vigor. Efficacy was assessed on 09 October 2013 by clipping 10 twigs per shrub from all parts of the canopy. Three fully-expanded leaves from each twig were dissected, and the number of leaves (out of 30 per plant) with live miners and living larvae per leaf was recorded. Systemic applications targeting rose pests This trial evaluated autumn soil drenches of chlorantraniliprole for reducing foliar damage by roseslug sawfly larvae and JB in the follow- ing growing season. It was conducted on estab- lished, similar-sized (about 60 cm height) hybrid tea (‘Knockout’) rose shrubs growing in several mulched beds on the university campus. The lay- out was a completely randomized design with five replicates. Treatments included chloran- traniliprole and imidacloprid (Merit 2F) at the ©2017 International Society of Arboriculture
November 2017
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