TAXONOMIC NOTES ON THE GENUS MONELLIOPSIS (HEMIPTERA: APHIDIDAE: CALAPHIDINAE) WITH DESCRIPTIONS OF THREE NEW SPECIES

Abstract

The Canadian Entomologist 132: 119 -133 (2000) The Douglas-fir beetle, Dendroctonus pseudotsugae Hopkins, attacks Douglas-fir, Pseudotsuga menziesii (Mirb.) Franco (Pinaceae), throughout western North America. Periodic outbreaks cause increased mortality of its host. Land managers and forest health specialists often need to determine population trends of this insect. Bark samples were obtained from 326 trees distributed over 21 stands during a 2year period in late winter to early spring of 1997 and 1998 in the Colorado Front Range. The variance to mean relationship of brood adults was examined using the Taylor power law, and a fixed-precision sampling plan was developed using Green's method. Stop lines and minimum number of samples required to estimate brood adult density per 0.046 m2 with precision levels of 0.1, 0.2, and 0.3 were calculated. A resampling simulation conducted with an independent data set indicated that desired precision levels were not met. Theoretical precision levels were adjusted until desired precision levels were achieved. Average number of samples needed to estimate brood adult densities up to 25.1 adults per 0.046 m2 with precision levels of 0.09, 0.2, and 0.3 were 91, 20, and 8, respectively. For densities greater than 25.1 brood adults per 0.046 m2, conservative estimates are obtained with 72, 15, and 6 samples for precision levels of 0.09, 0.2, and 0.3, respectively. An emergence ratio can be obtained by dividing the estimated density of brood adults by twice the number of gallery starts. This system provides the user with an immediate assessment of the population trend of Douglas-fir beetle. The data collected compare favorably with data from other Douglas-fir beetle outbreaks reported in the literature. The use of this plan outside the Colorado Front Range, or by sampling at a different height, should be cautioned until additional data from other locations and sampling heights are examined. Negron JF, Schaupp WC, Johnson E. 2000. Mise au point et validation d'un plan d'tchantillonnage sCquentiel i precision prt-Ctablie pour l'estimation de la densite des adultes i l'tmergence chez le Dendroctone du Douglas, Dendroconus pseudotsugae (Coleoptera : Scolytidae). The Canadian Entomologist 132 : 119-133. (0,02) et 6 (0,03) Cchantillons ont Ct C obtenues.Un rapport B 1'Cmergence peut Ctre calculC en divisant la densit6 estimCe d'adultes par deux fois le nombre de galeries commencCes. Ce systkme fournit B I'utilisateur une estimation immCdiate de la tendance demographique du dendroctone. Ces donnCes se comparent favorablement B celles obtenues au cours d'CvidCmies de dendroctones mentionnCes dans la littCrature. L'utilisation de ce plan en dehors de cette chaine de montagnes, ou I'Cchantillonnage B d'autres hauteurs est B dCconseiller si I'on n'obtient pas d'abord des donnCes additionnelles sur d'autres IocalitCs et hauteurs d'Cchantillonnage. [Traduit par la RCdaction] . Taylor's power law. Environmental Entomology 27: 191-201 Wald A. 1947. Sequential analysis. New York: Wiley Volume 132...