Environmental Entomology (1988) 17, 385-390

Andrew M. Liebhold and Joseph S. Elkinton (1988)
Estimating the density of larval gypsy moth, Lymantria dispar (Lepidoptera: Lymantriidae), using frass drop and frass production measurements: sources of variation and sample size
Environmental Entomology 17 (2), 385-390
Abstract: At three sites on Cape Cod, Mass., successive gypsy moth, Lymantria dispar (L.), larval densities were estimated using simultaneous measurements of the number of frass pellets produced per larva (frass yield) and the number of frass pellets falling in the forest per unit area (frass drop). Estimated larval densities declined through the period of larval development at all sites. Frass yield was positively correlated with ambient temperature. Frass drop was positively correlated with the basal area of host trees immediately around the frass trap. At a low-density population, rate of frass drop exhibited a diel periodicity similar to that of larval feeding. Mean-variance relationships of frass drop measurements and density estimates indicated that frass pellets and larvae were spatially aggregated within stands. The optimal ratio of drop to yield samples and the number of replicates of each sample necessary to obtain a given level of precision decreased with increasing density.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Database assignments for author(s): Andrew M. Liebhold

Research topic(s) for pests/diseases/weeds:
surveys/sampling/distribution

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Lymantria dispar		U.S.A. (NE)