The Persistence of Fenitrothion Insecticide in Red Maple (Acer rubrum L.) and White Birch (Betula papyfifera (Marsh.)) Deer Browse

Abstract

From May 15 to November 15, 1977, vegetation plots were monitered on a constant basis in order to obtain the concentration of fenitrothion in red maple and white birch deer browse. The data obtained indicates that the concentrations tend to be as high as 21.413 ppm for the red maple and 19.371 ppm for the white birch immediately following the spray application. However, the concentrations are below 0.010 ppm 120 days following the application. Fenitroxon was detected in two of the samples taken from the sprayed plots. None was detected within the control plots. There is no evidence in the literature that a concentration of fenitrothion of the magnitude detected would have obvious effects on deer populations during their winter yarding. Fenitrothion, 0, Odimethyl O-(4 nitro-m-tolyl) phosphorothioate, has been used since 1969 tocontrol spruce budworm (Choristoneura fumiferuma (Clemens)) in the forest of the Canaan Game Reserve, New Brunswick, Canada. Various workers (Shishido et al. 1972, Miyamoto 1969, Nigam et al. 1971) have previously shown the short persistence and fate of fenitrothion in a natural Author is with the Biology Department, Universite de Moncton, Moncton. N.B., EIA 3E9. Canada. This study was conducted under support funds received from Forest Protection Limited and the Conseil de Recherche de I’llniversid de Moncton. Their support is greatly appreciated. 1 also thank the staff of the Chemistry Department, particularly Dr. Victorin Mallet for his assistance with the analytical work. I am also grateful toall who have assisted me during the project. environment. Furthermore Yule and Duffy (1972) and Sundaram (1974) demonstrated that fenitrothion can persist in a coniferous forest in concentration rangingfrom 0.80 to 0.14 ppm over a 5-year period. This project evaluated residual concentrations of fenitrothion and its oxygen analogue in red maple (Acer rubrum) and white birch (Eerulupupyriferu (L.)). Previous studies by CrOte (1976) and unpublished data obtained by the author from monitoring deer yards in southeastern New Brunswick indicate that red maple and white birch play an important role in the diet of the white-tailed deer (Odocoileus virginianus (Zimmerman)) during the winter yarding. It was anticipated that a high concentration of fenitrothion might have a negative effect on the intestinal rumen flora and consequently disrupt the energy requirements of the deer during their winter yarding. Study Area and Methods The field experiments were located in the Canann Game Reserve area 34 km northwest of Moncton within longitude 65” 30’ and latitude 46O 20’. The experimental spray plot was located 5 m from Alward Brook inside spray block 279 of the 1977 spray program. The control plot was located along the south side of the Canaan River approximately 17 km from the sprayed plot. The control plot was not sprayed during the 1975, 1976, and 1977 programs. JOURNAL OF RANGE MANAGEMENT 35(l), January 1992 65 The sampling plots were surrounded by forested aeas dominated by red spruce (Piceu rubens (Moench)), and black spruce (Picea mariuna (L.) (M.11)). Logging of these species occurred 10 years ago in areas where the experimental plots were established. A young growth of red maple and white birch varying from 1.5 to 3 m in height formed the major, lower vegetation within the plots. The upper canopy was composed of mature red maples, grey birch (Bet& populifolia (Marsl.)), and aspen (Populus tremuloides (Michx.)). Both habitats selected were identical in vegetation composition, All sampling plots were located in areas where deer browsing had been observed during the winters of 1975 and 1976. The sprayed plots were treated with twoaerial applications of three ounces active ingredient/ hectare of fenitrothion in an oil emulsion between May 26 and June 3, 1977. pesticide. The light concentration which appeared following the spray programs is more than likely due to aerial drift. The oxygen analogue of fenitrothion, fenitroxon, was detected in only two samples taken from the sprayed plots at concentrations of 0.004 and 0.15 ppm; no detection was obtained from the control samples. Results from both samples of browse indicate a persistence of the pesticide throughout the entire sampling period within the sprayed plots. However the concentration available to the deer during the browse period is considered to be below 0.010 ppm. Table 1. Fenitrothion residues in red maples (Acerrubrwn) and white birch (Betda ptq&fera) deer browse for the 1977 aerial budworm spray pro-