Arboriculture & Urban Forestry 40(3): May 2014 Arboriculture & Urban Forestry 2014. 40(3): 135–142 135 The Effect of Sticky Bands on Cankerworm Abundance and Defoliation in Urban Trees Chanthammavong Noukoun, Gregory Bryant, and Steven D. Frank Abstract. Defoliation by insects can reduce tree growth, increase mortality, and increase herbivory of neighboring plants. In North Carolina, U.S., fall cankerworms (Alsophila pometaria) and spring cankerworms (Paleacrita vernata) are important early-season defo- liators and have become more common in recent years. Female fall and spring cankerworm adults are wingless and climb tree trunks to mate and deposit egg masses. Therefore, sticky bands made by wrapping paper bands around trees and covering them with Tangle- Foot™ can intercept female moths as they climb, preventing oviposition and reducing subsequent larval abundance and defoliation. The authors hypothesize that sticky bands reduce cankerworm larvae and defoliation in the canopy when compared to unbanded trees. To test this hypothesis, cankerworm abundance and defoliation were measured on willow oaks with zero, one, and two bands. It was found that trees with two bands captured an average of 38.69% more moths than single banded trees. As a consequence, two-band trees had the least larvae in the canopy. It was found that larval abundance, sampled early in the season with trays of soapy water, was cor- related with canopy defoliation at the end of the season. However, tree bands did not affect total canopy defoliation. Although many cities use sticky bands as part of cankerworm management, the authors did not find evidence for their efficacy when defoliation is low. Key Words. Alsophila pometaria; Cankerworms; Defoliation; North Carolina; Paleacrita vernata; Tree Mortality; Quercus phellos; Willow Oak. Defoliation by insects can reduce tree growth, increase mortality, and increase herbivory of neighboring plants (Kulman 1971). Immature leaves are vulnerable to folivorous insects, such as winter moths (Operophtera brumata) and autumnal moths (Epirrita autumnata), because they are more nutritious and have less defensive compounds than mature leaves (Feeny 1970; Feeny 1976; Haukioja et al. 1978; Haukioja et al. 1985). Early-season defoliation of immature leaves can increase susceptibility to secondary pest outbreaks and environmental stress (Rhoades 1983; White 1984; Potter and Redmond 1989). It also forces trees to utilize stored energy sources and nutrients to flush secondary leaves, which can reduce tree growth and survival. For example, early-season defoliation of conifers reduces basal area in proportion to foliage loss (Kulman 1971; Mill- er and Wagner 1989). Early-season defolia- tion also increases stem dieback and mortality, and decreases stem diameter of oak seedlings (Wright et al. 1989). Defoliation of oaks by gypsy moth (Lymantria dispar L.) larvae causes a proportional reduction in trunk growth and increases mortality (Minott and Guild 1925; Turner 1963; Naidoo and Lechowicz 2001). In North Carolina, U.S., two early-season defo- liators, fall cankerworms (Alsophila pometaria L.) and spring cankerworms (Paleacrita vernata Peck), cause damage to urban trees (Lyttle 2012; Shaf- fer 2012). Both species have become more com- mon in recent years, increasing the chance of tree health decline aſter consecutive years of defolia- tion. Cankerworms pupate from late spring to late fall (autumn) in the litter and soil beneath trees. Fall and spring cankerworm adults emerge in late fall and early spring, respectively. Both spe- cies have wingless moths that climb tree trunks to mate and deposit egg masses of up to 400 eggs into crevasses along the branches in the crown (Porter and Alden 1924). The moths die shortly aſterward (Porter and Alden 1924). Larvae hatch in spring, just aſter bud break, and begin feeding on foliage. Aſter 4–6 weeks, larvae drop from trees to pupate in the soil (Baker 1972; Johnson and Lyon 1991). Larvae disperse by descending from ©2014 International Society of Arboriculture
May 2014
| Title Name |
Pages |
Delete |
Url |
| Empty |
Search Text Block
Page #page_num
#doc_title
Hi $receivername|$receiveremail,
$sendername|$senderemail wrote these comments for you:
$message
$sendername|$senderemail would like for you to view the following digital edition.
Please click on the page below to be directed to the digital edition:
$thumbnail$pagenum
$link$pagenum
Your form submission was a success. You will be contacted by Washington Gas with follow-up information regarding your request.
This process might take longer please wait
