Relationship between gypsy moth (Lepidoptera: Lymantriidae) pheromone trap catch and population density: comparison of traps baited with 1 and 500 micrograms (+)-disparlure lures
1993
Thorpe, K.W. | Ridgway, R.L. | Leonhardt, B.A.
The relationship between the number of male gypsy moths, Lymantria dispar (L.), captured in pheromone traps and subsequent egg-mass density in the area surrounding each pheromone trap was determined for traps baited with either 1 or 500 micrograms of (+)-disparlure. Traps were located along transects that extended from within diflubenzuron-treated spray blocks, in which gypsy moth populations were low (252.0 egg masses per ha), to adjoining areas with high populations (3,390.4 egg masses per ha) that had either been treated with Bacillus thuringiensis Berliner or left untreated and that were associated with defoliation of oak, Quercus spp. Traps containing low-dose lures captured means of 5.4 and 32.9 moths in the low and high gypsy moth population density areas, respectively. Traps containing high-dose lures captured means of 431.1 and 874.4 moths in the low and high density areas. Trap captures for both lure doses were significantly correlated with subsequent egg-mass density. Numbers of surviving female pupae under burlap averaged 0.16 and 1.11 per cm in the low- and high-population density areas, respectively. Pupal numbers were also significantly correlated with subsequent egg-mass density. Functional relationships between trap catches and subsequent egg-mass densities for traps containing low- and high-dose lures are given, which explain 60 and 65% of the variation, respectively.
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