- The New Brunswick Committee for Environmental Monitoring of Forest Insect Control Operations (EMOFICO)
Aerial application of insecticide were used in spruce budworm control operations in New Brunswick, Quebec, Newfoundland, and Maine, and smaller-scale operations in Ontario and Nova Scotia. In the New Brunswick operational spruce budworm control programs in 1980 and 1981, mainly fenitrothion was used. Aminocarb (Matacil) was also used in 1980, but on only a small proportion of the forest area treated. Other insecticides were used in experimental spruce budworm control programs in New Brunswick, and in some operational and experimental programs elsewhere. A biological insecticide based on the bacterium Bacillus thuringiensis, and various chemical insecticides including Reldan (chlorpyrifos-methyl), Sevin-2-Oil (carbaryl) and permethrin were all tested in experimental programs in New Brunswick to determine their efficacy, or environmental impact, or both.
Summarized in this report are aspects of invironmental surveillance in New Brunswick in 1980-81 of: wildlife, pollinators; forest arthropods; freshwater fauna; and insecticide analysis, distribution, and persistence and toxicology. Provincial and federal environmental regulations pertaining to insecticide use are also summarized.
Studies of the non-target impacts of fenitrothion revealed effects on songbirds (cholinesterase activity and nestling growth), arboreal predaceous insects (population density), and arboreal spiders (species diversity). No effects on perennial population density trends of arboreal predaceous insects or spiders were evidenced following either fenitrothion or aminocarb spraying. Reductions in the numbers of arboreal arthropods occurred following experimental applications of various formulations of aminocarb. The degree of reduction appeared to depend upon the formulation of aminocarb used. Studies of the impact of aminocarb on forest-dwelling birds, fish in streams, and microbial communities in ponds in New Brunswick revealed no detrimental effects; however, the rate of carbon assimilation by algae in ponds was reduced briefly.
The distribution and persistence of insecticides and some of their breakdown products in the air, and in forest, stream and pond ecosystems are described. Fenitrothion rapidly mixed in streams and was distributed to all levels of the water column. The rate of movement of aminocarb in ponds depended upon physical factors such as the wind.
After spray applications, the concentrations of both aminocarb and fenitrothion and some of their breakdown products generally declined rapidly. These compounds persisted at small concentrations for different durations (usually short) in different organisms and parts of the environment; however, instances of fenitrothion persistence at larger concentrations and for longer durations were also reported.
Components of aminocarb and fenitrothion formulations were found to differ in their toxicity to aquatic organisms. Estimates of the toxicity of insecticide formulations, which are typically established on the basis of just the active ingredient portion of the formulation, may therefore be low and safety margins may be narrower for some organisms than was previously thought. A model which facilitates the comparison of the toxicity of pesticides and their various formulations is described.
Characteristics of insecticide drift, its distribution, factors affecting drift, and models used to predict drift behavior are discussed with particular reference to the findings of the New Brunswick Task Force on Drift. Use of buffer zones was found to reduce drift deposit in non-target areas.
Recommendations of the New Brunswick Committee for Environmental Monitoring of Forest Insect Control Operations are given. These pertain to research and monitoring needs; information exchange between governments, industry and the public; budworm control strategies; and coordination of surveillance and control efforts.