Arboriculture & Urban Forestry 40(3): May 2014 ers visited trees twice per week from Novem- ber 26, 2012 until March 28, 2013 to count the female fall and spring cankerworm moths stuck to the sticky bands. Moths were removed from the bands with a stick as they were counted. To determine how many moths climbed past the first sticky band and to determine if two bands were more effective than one, researchers compared the number of moths captured on trees with one band and two bands over the season with repeated measures ANOVA in the Mixed Procedure of SAS v. 9.3. Site was included as a blocking factor. To determine how sticky bands affect canker- worm larvae abundance in tree canopies, canker- worm larvae were counted on 4, 8, 18, and 25 of April 2013. Two 60 cm branches were clipped from each tree and beaten onto a 60 cm × 60 cm white beat sheet. Researchers counted the larvae on the sheet and examined the branch to count larvae that were not dislodged by beating. Larval abundance was also sampled by placing a 30 cm × 60 cm black tray (filled with 3–5 cm of soapy water) on the ground below each tree to capture larvae as they dropped from the canopy. The trays were deployed nine times between April 18 and April 30, 2013; the lar- vae were counted aſter 12–24 hours. All counts were converted to larvae per 12 hours for analysis. The number of larvae was compared with repeated mea- sures ANOVA in the Mixed Procedure of SAS v. 9.3 (SAS 2012). Site was included as a blocking factor. To determine how sticky bands affect defoliation, leaf damage was estimated on each branch collected during beat sampling. Two observers estimated the percent of the total leaf area that was missing from each branch. Researchers used the mean of the four observations (two branches with two observations each) as the data for analysis. On May 7, 2013, the total defoliation of each study tree was estimated. Two observers examined each tree from one point of view and recorded the percent of leaf area missing, then moved 180 degrees around the tree and recorded a second estimate. The mean of the four observations was used as the data for analysis. Percent defoliation was compared with ANOVA in the Mixed Procedure of SAS v. 9.3 with site included as a blocking factor. To determine if percent canopy defoliation was related to larval abundance, researchers tested the correlation between the mean number of counted from beat samples on each tree and percent larvae 137 defoliation. The correlation between the mean num- ber of larvae collected in trays per 12 hours (mean of all dates) from each tree and percent defoliation was also tested. Finally, researchers tested the correla- tion between the mean larvae collected in trays per 12 hours on the first three sample dates and percent defoliation to determine if early-season abundance predicted end-of-season damage. All correlations were tested in the Corr Procedure of SAS v. 9.3. RESULTS AND DISCUSSION The mean (±SEM) DBH did not differ between trees with no bands (84.8±13.9), one band (73.6±13.3), or two bands (74.5±14.2; F2, 30 = 0.21; P = 0.810). The first female fall cankerworm adult was caught on a sticky band on November 30, 2012. Over the next four months, researchers captured 16,498 fall cankerworm moths (Figure 1). The most moths (2,810) were captured on December 28. Forty-one spring cankerworm moths were cap- tured between January 11, 2013 and March 21, 2013. Figure 1. Total capture of female fall cankerworm moths (all sites combined) on sticky bands on each sample date from November 30, 2012 to March 22, 2013. The number of cankerworm moths captured on sticky bands varied significantly over time (F21, 430 = 16.30; P < 0.0001), but contrary to the hypoth- esis, two bands did not capture significantly more moths than one band (F21, 430 = 1.04; P = 0.308), = 0.85; P = 0.654). On two-band trees, 38% of moths were captured on the upper band. This nor was there a significant interaction (Figure 2; F21, 430 ©2014 International Society of Arboriculture
May 2014
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