Detection of Hemlock Woolly Adelgid (Hemiptera: Adelgidae) Infestations with Sticky Traps

We deployed sticky traps underneath the crown of eastern hemlock, Tsuga canadensis (L.) Carrière, to assess their sensitivity at detecting crawlers (1st instar nymphs) of the non-native hemlock woolly adelgid, Adelges tsugae Annand (Hemiptera: Adelgidae). We found these traps more sensitive at detecting infested trees with low densities of A. tsugae than branch-tip sampling with pole pruners. We observed two peaks of crawler abundance at all sites: these peaks likely represented the timing of the progrediens and sistens crawler stages of A. tsugae. Deployment of sticky traps in treated and high-risk stands may prove useful at detecting residual and new infestations, respectively

Improvement of Pheromone Trapping in Low Density Populations of \u3ci\u3eChoristoneura Pinus Pinus\u3c/i\u3e (Lepidoptera: Tortricidae)

Pheromone baited bucket traps (e.g., Multipher) are popular as a monitoring tool for the jack pine budworm, Choristoneura pinus pinus Freeman (Lepidoptera: Tortricidae), in Canada. However, there is no evidence to support their use when budworm populations are low. We therefore evaluated the capture rate of bucket traps at two placement heights (2 vs 6 m) in two jack pine forests in 2011, having low (≤5 fifth instars per mfoliated branch length) budworm populations. Compared to wing traps (e.g., Pherocon 1C), the trap design used initially to evaluate efficacy of the C. pinus pheromone, bucket traps caught fewer C. pinus and capture rates of both trap designs did not differ significantly between the two heights tested. Loss of bucket traps at 2 m, due to black bears, suggested that higher placement of traps was warranted to maintain the integrity of the array. However, wing traps are recommended due to their ability to consistently catch more moths when C. pinus populations are low

Effect of a severe cold spell on overwintering survival of an invasive forest insect pest

Cold temperatures can play a significant role in the range and impact of pest insects. Severe cold events can reduce the size of insect outbreaks and perhaps even cause outbreaks to end. Measuring the precise impact of cold events, however, can be difficult because estimates of insect mortality are often made at the end of the winter season. In late January 2023 long-term climate models predicted a significant cold event to occur over eastern North America. We used this event to evaluate the immediate impact on hemlock woolly adelgid (Adelges tsugae Annand) overwintering mortality at four sites on the northern edge of the insects invaded range in eastern North America. We observed complete mortality, partial mortality and no effects on hemlock woolly adelgid mortality that correlated with the location of populations and strength of the cold event. Our data showed support for preconditioning of overwintering adelgids having an impact on their overwintering survival following this severe cold event. Finally, we compared the climatic conditions at our sites to historical weather data and previous observations of mortality in Nova Scotia. The cold event observed in February 2023 resulted in the coldest temperatures observed at these sites, including the period within which hemlock woolly adelgid invaded, suggesting cold conditions, especially under anthropogenic climate forcing, may not be a limiting factor in determining the ultimate northern range of hemlock woolly adelgid in eastern North America

Data from: Effect of a severe cold spell on overwintering survival of an invasive forest insect pest

<p>Data from a study of a servere cold event in February 2023 on the survival of hemlock woolly adelgid (<em>Adelges tsugae</em> Annand) from four populations in Canada. Cold temperatures can play a significant role in the range and impact of pest insects. Severe cold events can reduce the size of insect outbreaks or in some cases even cause outbreaks to end. Measuring the precise impact of cold events, however, can be difficult because estimates of insect mortality are often made at the end of the winter season. In late January, 2023 long-term climate models predicted a significant cold event to occur over eastern North America. We used this event to evaluate the immediate impact on hemlock woolly adelgid overwintering mortality at four sites on the northern edge of the insects invaded range in eastern North America. We observed complete mortality, partial mortality and no effect of the cold event that correlated with the location and strength of the cold event. Our data also showed lack of support for preconditioning of overwintering adelgids as impacting their overwintering survival following this severe cold event. Finally, we compared the climatic conditions at our sites to historical weather data. The cold event observed in February 2023 resulted in the coldest temperatures observed at these sites, including the period within which hemlock woolly adelgid invaded these sites, suggesting cold conditions, especially under anthropogenic climate forcing, may not be a limiting factor in determining the ultimate northern range of hemlock woolly adelgid in eastern North America.</p><p>Insects were collected from infested trees at 4 sites in 2 Canadian provinces immediately before and immeditely after a severe cold spell. The health and status of the insects (live/dead) was determined in a laboratory. The survival was then compared to observed temperature data extracted from Environment and Climate Change Canada weather stations. </p&gt