PEST MANAGEMENT OF DOUGLAS-FIR TUSSOCK MOTH, ORGYIA PSEUDOTSUGATA (LEPIDOPTERA: LYMANTRIIDAE): MONITORING ENDEMIC POPULATIONS WITH PHEROMONE TRAPS TO DETECT INCIPIENT OUTBREAKS

Abstract

The numbers of Douglas-fir tussock moths (Orgyia pseudotsugata) (Lepidoptera: Lymantriidae) caught in sticky, delta-shaped pheromone traps baited with different concentrations of synthetic lures were compared with egg-mass densities and subsequent defoliation throughout a population cycle. A lure containing 0.01% pheromone by weight in the form of a 3 × 5-mm polyvinylchloride rod provided more consistent catches than pheromone concentrations of 0.0001, 0.001, 0.1, or 1.0%. Trap saturation occurred when >40 moths per trap were caught. To achieve a standard error of 30%, 6 traps were required at each site. There was a poor correlation between numbers of moths caught and egg-mass density or defoliation estimates in the following generation, but a threshold density was found that provides a warning of an incipient outbreak. Ground surveys for egg masses are recommended to confirm suspected infestations after continuous increases in moth catches for 2 to 3 years or if an average of 25 moths or more per trap has been caught.

Douglas-Fir Tussock Moth- and Douglas-Fir Beetle-Caused Mortality in a Ponderosa Pine/Douglas-Fir Forest in the Colorado Front Range, USA

“…This mortality was concentrated in the larger diameter classes, portraying the preference of the insect for larger diameter trees [16,20,22]. Douglas-fir tussock moth populations have a propensity to concentrate around initial infestation sites [36,37], so the distribution of DFTM-related tree mortality is probably associated with spatial location of early infestation foci. Douglas-fir tussock moth dispersal primarily through "ballooning" of larvae to nearby trees.…”

The influence of Canadian research on semiochemical-based management of forest insect pests in Canada

“…Years of research led to the development of an operational pheromonebased monitoring system for the spruce budworm, Choristoneura fumiferana (Clemens) (Lepidoptera: Tortricidae) that can predict densities of larvae in the subsequent generation (Sanders 1988). In monitoring programmes for Douglas-fir tussock moth, Orgyia pseudotsugata (McDunnough) (Lepidoptera: Erebidae), pheromone trap capture combined with egg-mass surveys predict population concentrations and potential defoliation in Douglas-fir stands (Shepherd et al 1985). Pheromone-based monitoring is particularly useful for monitoring forest insect pests that go through cyclical changes in population density in which insect abundance can increase quickly and result in widespread damage.…”

“…Lure type and pheromone dose both can influence the active space (Byers 2008) of the pheromone plume and dictate the distance from which moths can be attracted and the period over which the lure remains attractive. A pheromone dose that is consistently effective at different population densities (Sanders 1986a), but does not necessarily elicit the highest trap capture, should be used (Shepherd et al 1985). In fact, trap capture in low-dose pheromone-baited traps is easier to enumerate and can better reflect the actual population density than high-dose traps that capture more insects.…”

“…Moths captured in traps baited with a low pheromone dose (10 µg) targeting the western hemlock looper, Lambdina fiscellaria lugubrosa Guenée (Lepidoptera: Geometridae) predicted egg counts in the subsequent generation better than traps baited with higher doses (Evenden et al 1995a). Similarly, moth capture in traps baited with a moderate pheromone dose of 0.01% pheromone by weight in polyvinyl chloride (PVC) rods best reflected population trends at various densities of the Douglas-fir tussock moth (Shepherd et al 1985). The operational pheromonemonitoring programme for spruce budworm was developed using PVC pellets loaded with 0.03% synthetic pheromone (Sanders 1981(Sanders , 1988.…”

Monitoring and testing different doses of disparlure for Indian gypsy moth, Lymantria obfuscata, in a temperate region of India (Kashmir Valley)

“…They can be used, in combination with other methods, to provide estimates of population densities and to monitor populations for the implementation of envi-ronmentally sound management strategies (Sanders, 1988), with examples including insect pests of forest (Granett, 1974;Shepherd et al, 1985;Evenden, 2005) and agricultural ecosystems (Shelton and Wyman, 1979;Tingle and Mitchell, 1981;Ngollo et al, 2000). Also, disruption of chemical communication between the sexes can also be an option for control (Hussain et al, 2014) Studies have been conducted on the use of disparlure [(Z)-7,8-epoxy-2-methyloctadecane], sex pheromone of L. dispar L., for monitoring population dynamics (Schwalbe and Mastro, 1988;Webb et al, 1988), but no such reports are available for L. obfuscata, which is considered to be one of the most destructive defoliators of hardwood trees in Kashmir.…”