Richard M. Turcotte

A Case Study: Walnut Twig Beetle, Pityophthorus juglandis Blackman (Coleoptera: Curculionidae: Scolytinae) in Bucks County, Pennsylvania

Thousand cankers disease (TCD) is a lethal disease caused by the fungus Geosmithia morbida (Tisserat, et al. 2009). The fungus is vectored by the walnut twig beetle (WTB; Pityophthorus juglandis Blackman (Coleoptera: Scolytidae)), which carries the fungus as it tunnels beneath the bark, causing small cankers to form (Kolařik, et al. 2011). Repeated beetle attacks and the formation of multiple cankers disrupt the vascular system, leading to dieback and eventually death of the tree. TCD is a threat to both commercial and wildland walnut (Juglans spp.) trees. While it has been known to occur throughout much of the southwestern United States, it has only recently been detected in the eastern United States. WTB was first detected in Bucks County, Pennsylvania, in July 2011 when a concerned sawmill owner sent a sample to the plant disease clinic at Pennsylvania State University. By August 2011 the Pennsylvania Department of Agriculture had confirmed the presence of both WTB and its accompanying fungus in Bucks County. Quaran tine measures were initiated to prevent the spread of TCD from walnut material originating from Bucks County. Recent molecular tests have shown that the WTB present in Pennsylvania is identical to the WTB in California (S. Seybold, U.S. Forest Service, personal communication). It is believed that the beetles arrived on in fected Claro (J. hindsii) walnut wood shipped to the sawmill owner in 2001 or 2008. The objectives of this project were to determine: 1) if WTB was established in Bucks County, 2) the distribution of WTB within Bucks county, 3) the spatial distribution of black walnut and WTB around the introduction site, 4) if distance, dbh and other abiotic and biotic factors affect infestation by WTB, and if this information could be used in developing a potential sampling plan for the detection of WTB. Volume 123, Number 4, November and December 2013 311

The Spotted Wing Drosophila, Drosophila suzukii (Diptera: Drosophilidae): A New Pest of Concern for Black Cherry, Prunus serotina, on the High Allegheny Plateau in Pennsylvania

ABSTRACT: Drosophila suzukii (Matsumura) is an invasive insect pest native to Southeastern Asia that is now reported to have established populations in North America. We used traps baited with red wine vinegar to detect and monitor D. suzukii in four black cherry (Prunus serotina Ehrh.) and maple (Acer spp.) stands in the Allegheny National Forest in northwestern Pennsylvania. Stands ranged in age from 70 to 110 years old, with average basal area from 40 to 45 m2/ha. All stands are characterized as the intermediate Allegheny hardwood forest type with black cherry being the dominant species making up > 70% of the total stand basal area at each site (Eyre, 1980). Traps were placed in the crowns of mature black cherry from May to October 2012. In total, 11,000 D. suzukii were collected. The appearance of D. suzukii on the High Allegheny Plateau in northwestern Pennsylvania could have negative implications for fruit production, dispersal, and seed viability of black cherry and other forest species. With D. suzukiis predilection toward Prunus spp. and its unusual method of oviposition, this could be a contributing factor that impacts black cherry regeneration on the Plateau.

Spatial and Temporal Distribution of Imidacloprid Within the Crown of Eastern Hemlock

Systemic imidacloprid is the most widely used insecticide to control the hemlock woolly adelgid, Adelges tsugae Annand (Hemiptera: Adelgidae), an exotic pest of eastern hemlock, Tsuga canadensis (L.) Carriére in the United States. This study was conducted to 1) determine the effect of treatment timing (spring vs. fall) and application method (trunk injection vs. soil injection) on the spatial and temporal distribution of imidacloprid within the crown of A. tsugae-free eastern hemlock using a competitive enzyme-linked immunosorbent assay (ELISA), 2) compare ELISA to gas chromatography-mass spectrometry (GC/MS) for the detection of imidacloprid in xylem fluid, and 3) determine the concentration of imidacloprid in leaf tissue using high performance liquid chromatography with tandem mass spectrometric (LC/MS/MS) detection methods. Xylem fluid concentrations of imidacloprid were found to be significantly higher for spring applications than for fall applications and for trunk injections than soil injections in the first year posttreatment. A total of 69% of samples analyzed by ELISA gave 1.8 times higher concentrations of imidacloprid than those found by GC/MS, leading to evidence of a matrix effect and overestimation of imidacloprid in xylem fluid by ELISA. A comparison of the presence of imidacloprid with xylem fluid and in leaf tissue on the same branch showed significant differences, suggesting that imidacloprid moved intermittently within the crown of eastern hemlock.

Use of Chemical Protection and Host Tree Reduction to Control an Emerald Ash Borer Infestation in West Virginia

Use of Chemical Protection and Host Tree Reduction to Control an Emerald Ash Borer Infestation in West Virginia The destruction of the ash (Fraxinus) resource in North America by the emerald ash borer has progressed rapidly since it was first identified in 2002 in and around Detroit, Michigan. A 2004 survey estimated that 15 million ash trees had been severely impacted or killed by this pest insect and by late 2005 infested ash trees were detected in Indiana and Ohio. The emerald ash borer infestation has continued to expand, currently encompassing 24 states and various locations in southern Ontario and Quebec, Canada.