Historical pesticide applications for the treatment of eastern spruce budworm infestations in New Brunswick.

Pesticides have been used in Canada since 1945 as part of large-scale aerial spray applications to control insect pests on forested lands. Some of the pesticides used historically were efficacious, nonselective, persistent, and have led to serious impacts on the environment. A well known, and extensively documented example is the large-scale aerial spray programs in New Brunswick, Canada. From 1952 to 1993, 97% of the 6.2 million ha of the forested lands of New Brunswick were treated with at least one application of one insecticide, the majority of which were applied to control outbreaks of eastern spruce budworm (Choristoneura fumiferana). The most well known insecticide was dichlorodiphenyltrichloroethane (DDT), applied from 1952 to 1968, which still persists in treated soils and adjacent water bodies, and caused the individual and cumulative ecosystem effects that can still be measured today. The insecticides that replaced DDT were nonpersistent and unlikely to be found today. However, during the years of application some of the insecticides were likely to have impacted local ecosystems to some degree. To aid future studies on the efficacy and environmental impact of these insecticides we created a digital spatial data set of known pesticide application in New Brunswick forestry from 1952 to 1993. The data set includes active ingredient, formulation, application rate, tank mix, aircraft type, and other ancillary information. The current version of the data is available on the New Brunswick Department of Natural Resources and Energy Development, GIS Open Data Page and in the supplemental material. Use of the data set for academic and educational purposes is encouraged, provided that both this data paper and the data source are properly cited; the Government of New Brunswick should be acknowledged as the data source (Open Government License http://www.snb.ca/e/2000/data-E.html).

The Use of UAS to Release the Egg Parasitoid Trichogramma spp. (Hymenoptera: Trichogrammatidae) Against an Agricultural and a Forest Pest in Canada.

The egg parasitoid Trichogramma spp. (Hymenoptera: Trichogrammatidae) is a widely used biocontrol agent against lepidopteran pests. Historically, Trichogramma were deployed either by plane or by using cardboard cards on which parasitized eggs are glued and manually installed at sites. Plane deployment is costly and card installation is time consuming, but the use of Trichogramma has been shown to be efficient against several pests. In 2016 and 2017, a research project investigated the potential use of unmanned aerial system for distributing Trichogramma as biocontrol agents against two major pests: an agricultural pest of maize, the European corn borer, Ostrinia nubilalis (Hübner) (Lepidoptera: Crambidae), and a forest pest, the eastern spruce budworm, Choristoneura fumiferana (Clemens) (Lepidoptera: Tortricidae). Exposure duration of parasitized eggs to field conditions (temperature, predation, etc.) in maize fields influenced the Trichogramma's emergence rate, suggesting that timing of parasitoid releases with their emergence is essential. Although parasitism of naturally occurring eggs in maize fields could not be compared due to the low density of the European corn borer, parasitism of sentinel eggs by Trichogramma was more prominent in plots with unmanned aircraft systems (UAS)-releases compared to control plots. For spruce budworm, treatment with Trichogramma increased egg parasitism and there was no difference between the deployment by UAS and by Trichocards. We discuss these results in the context of pest biology and management. We also discuss the advantages and shortcomings of both methods and offer insights into where future work might go to further leverage the use of UAS in managing these important pests.