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Adelges tsugae Annand (Hemiptera: Adelgidae), a nonindigenous insect pest of hemlock (Tsuga spp.) (Pinaceae) in eastern North America, spends most of its life cycle within an ovisac, which resembles a woolly white mass on twigs. We evaluated the probability of detecting adelgid wool with Velcro®-covered balls when taking an increasing number of samples per tree (field sampling) and number of trees per simulated stand. We examined the relationship between the detection of adelgid wool using this technique and the incidence of A. tsugae-infested twigs by sampling lower-crown branch tips of the same trees. We found that the probability of detecting wool with ball sampling increased with number of ball samples per tree, with number of trees per simulated stand, and with increasing incidence of ovisacs in the lower crown. When sampling an individual tree, we found that 20 ball samples per tree achieved a targeted precision level of 0.75, but when sampling a stand, we found that 10 ball samples per tree took the least time for the range of simulated A. tsugae infestations we tested. These sample sizes are recommended for detection of A. tsugae infestations on an individual tree and in a hemlock stand. [ABSTRACT FROM AUTHOR]

Adelges tsugae Annand (Hemiptera: Adelgidae) has caused extensive mortality of hemlocks (Tsuga (Endlicher) Carrière; Pinaceae) in the eastern United States of America and was discovered recently in Nova Scotia, Canada. We evaluated the use of a Velcro-covered racquetball as a sampling device for A. tsugae wool. Specifically, we report on improvements to an earlier design and evaluate several factors seen in routine sampling that influence the ability of the ball to trap and retain adelgid wool. Velcro was found to be critical for trapping and retaining adelgid wool on the ball during flight and landing. Wooden beads, inserted in the ball, reduced deflection during flight and bounce during landing. Higher probability of trapping wool on the ball was associated with an ascent through the crown, with increasing diameter and density of ovisacs on branch tips, and with increasing abundance of woolly twigs on the forest floor. Higher probability of retaining wool on the ball was associated with Velcro surface area and with amount and location of wool loaded on the ball. These modifications improved detection surveys for A. tsugae in general. [ABSTRACT FROM AUTHOR]

Discovery of the non-native Anoplophora glabripennis Motschulsky (Coleoptera: Cerambycidae) in Ontario, Canada, in 2003 led to the implementation of an eradication programme. The plan consisted of removing all infested trees and all trees belonging to a genus considered suitable for complete development of this wood-borer that were found within 400m of an infested tree; however, many of the trees within that 400m belonged to genera for which suitability for development of A. glabripennis was questionable or unknown. We visually inspected over 3000 such trees annually for the three years following removal of infested trees. All but one tree were unattacked: an ash (Fraxinus excelsior Linnaeus (Oleaceae)) tree had signs of oviposition and early-instar development, but not of adult emergence. Before that survey, we had found only one other species with questionable suitability, a little leaf linden (Tilia cordata Miller (Malvaceae)) that had many signs of oviposition, but no evidence of full development, suggesting resistance to A. glabripennis. Both of these trees were within 200m of the most heavily infested maple (Acer platanoides Linnaeus (Sapindaceae)) tree found in that infestation, suggesting that colonisation of trees with questionable or unknown suitability might occur mostly where population pressure is high. [ABSTRACT FROM AUTHOR]

Agrilus planipennis (Coleoptera: Buprestidae), is causing extensive mortality of ash (Fraxinus Linnaeus; Oleaceae) in North America. Once detected in an area, resource managers require methods to obtain estimates that could improve management decisions. We studied the within-crown and within-branch distribution and abundance of A. planipennis feeding galleries by sampling 3-m-long branches from asymptomatic urban ash trees and subdividing each branch into 12 sections of 25 cm each. We found galleries in all 12 sections of some, but not all, branches. Section was a significant source of variation in A. planipennis gallery density/m² of branch surface area. A comparison of predictive power and efficiency of estimates for samples of increasing length, and for samples of the same length but consisting of different combinations of sections, revealed that those based on the two basal 25-cm sections of a branch from the lower-crown or mid-crown of an asymptomatic tree were less accurate and precise than those based on more sections, but were the most cost effective. Whittling more sections per branch, irrespective of the combinations of branch sections per length, improved predictive power but reduced cost effectiveness. We also observed that crown level was not important, and aspect was only marginally so, when estimating gallery abundance per sampled branch. [ABSTRACT FROM AUTHOR]

Detection of the exotic hemlock woolly adelgid, Adelges tsugae Annand (Hemiptera: Adelgidae), in the crown of eastern hemlock, Tsuga canadensis (Linnaeus) Carrière (Pinaceae), relies mainly on two techniques: (1) sampling of branches from the lower half of the crown using pole pruners; and, (2) visual examinations of accessible foliage from the ground. As a result, infestations starting elsewhere than the lower crown may be missed because the upper crown is out of reach for both techniques. We developed a novel technique called ball sampling, and evaluated its sensitivity at detecting a range of A. tsugae ovisac densities as estimated by pole pruning branch tips of T. canadensis. We launched racquet balls covered with VELCRO® patches of hooks through branches and examined them for the presence of wool produced by A. tsugae. Ball sampling was as effective as pole pruning at detecting infestations in individual trees. If A. tsugae abundance on branches was ⩾0.1 per 10 cm of twig length, as estimated by branch-tip sampling, ball sampling always detected wool in 10 or fewer samples. This technique has the potential to improve detectability of A. tsugae infestations because it can effectively access foliage that is typically inaccessible to other ground-based detection tools. [ABSTRACT FROM PUBLISHER]

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Copyright of Canadian Entomologist is the property of Cambridge University Press and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Entomologist is the property of Cambridge University Press and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)