- Nash, Robley W.
Maine Forestry Department
- Peterson, John W.
USDI, Bureau of Sport Fisheries and Wildlife
- Chansler, John F.
USDA Forest Service
Application operations were preceded by extensive planning and pre-cautionary measures. Base was at the Presque Isle Airport with the full operations crew living together as a unit at nearby facilities. The two applications were made in the period May 29 - June 15 inclusive. Direct costs were $1.194 per acre, addition of indirect costs or overhead brought this figure to $1.355.
Men assigned to hazardous areas at the airport facility were monitored for exposure to the insecticide chemical. Three blood tests were made on each man for plasma cholinesterase activity, the results showing no toxic exposure of any individual to the insecticide. The total aspect of equipment, drum, and area decontamination was supervised. A recommendation concerning elimination of drum decontamination was made.
Effects of the insecticide treatment throughout the treated area were determined from pre- and post-treatment foliage collections from trees at 86 locations scattered throughout the treatment area. A reduction in survival of 84% in survival was not sufficient to alter the course of the infestation in the treated area, for a comparison of egg masses in the 1969 and 1970 surveys showed only a slight reduction in the treated area. Outside the treated area the epidemic budworm infestation expanded in size and intensity. The treatment was successful in preserving much current foliage, especially on those trees most severely damaged in recent years. The treated area was sufficiently improved in overall tree condition that treatment was not recommended for 1971.
Intensive monitoring of budworm populations on five heavily infested plots showed that when the prescribed dosage reached the target tree a substantial amount of current foliage is saved. The prescribed dosage did not effectively suppress populations but left sufficient survivors to produce generally heavy levels of new egg masses. The first application has the greatest impact on foliage protection with relatively little effect on population reduction. Whereas the second application has the greatest impact on population reduction with little effect on foliage protection. The data suggests that a higher dosage in the second application (5th instar) would provide better population control.
The broad spectrum of Accothion is evident from the knockdown of predaceous and parasitic arthropods, including spiders, and parasitic Diptera and Hymenoptera. Spruce budworm parasites killed, include Meteorus trachynotus and Glypta funiferanae. The spiders and parasitic dipterans were not identified and may also contain species which attack budworm. There were no striking differences in the mortality of budworm larvae harboring parasites at the time of spraying.
Populations of stream invertebrates were monitored by bottom and/or drift sampling in six sprayed and six unsprayed streams. No reductions were detected in the variety of invertebrates collected. Total numbers collected were reduced somewhat, however. The reductions were statistically significant only for the Chironomidae, and these reductions appeared in all sprayed streams. Reductions in other taxa were restricted to one of the six sprayed streams, and it is suggested that this stream may have received an overdose of spray application. The impact of Accothion on aquatic invertebrates appear minor in comparison to some other pesticides, e.g. DDT.
Observations in the spray area were made on reactions to Accothion of a great variety of species of flora and fauna present. Accothion showed observable effects on some insects but not on other insects; nor on plants, birds, minnows in a confined pool, tadpoles, frogs, toads, and salamanders.
Two brooks located inside the spray area and one, serving as a control, located outside the spray area were studied to evaluate short-term changes in pre-spray and post-spray population estimates were evident. No mortality occurred in brook trout held in live cages throughout the study. Fish mortality at the site of blocking seines was high in one of the sprayed brooks and in the control brook. Most of this mortality is believed to have been caused by high flows coupled with spawning movements of many of the minnow species. The second application of Accothion may have contributed to a high mortality of common shiners. Samples of book trout, white suckers, common shiners, creek chubs, and redbelly dace, will be analyzed for pesticide residues.
Pre- and post-spray bird censuses were conducted in both the spray and control area. Evening grosbeaks were apparently attracted to the budworm infestation area as 196 were recorded in the spray area as compared to 38 in the control area. An intensive carcass search covering an estimated 90 linear miles of tote road within the spray area disclosed no bird mammal or amphibian mortality or signs of aberrant behavior. One dead parula warbler was found in the spray area. A very depressed brain cholinesterase value strongly suggested that death was caused by Accothion. Two applications of Accothion at a rate if two ounces per acre did not cause significant bird, mammal or amphibian mortality.
Free-flying sapsuckers were used to monitor the effects of Accothion on bird mortality and behavior. Observations of 74 birds were made, before and after spraying, at nine nesting territories in the sprayed area and at four in the unsprayed area. Sapsucker nestlings were banded and placed in nest-blocks, where normal nesting activities continued. Nestlings fledged and lived normally in their home territories. The spray apparently did not cause sapsucker mortality. Some mortality occurred but was probably caused by nest disturbance and predators.
Samples of grass forage, milk, and soil were chemically analyzed and showed the presence of Accothion up to 1.1 ppm. on grass, no presence in milk, and no presence in soil.