Plodia interpunctella (Lepidoptera: Pyralidae): Spatial Relationship Between Trap Catch and Distance from a Source of Emerging Adults

Abstract

The Indianmeal moth, Plodia interpunctella (Hübner), was selected as a representative stored-product moth to test the validity of contour mapping of trap catch for pest monitoring in warehouses and retail stores. Three experiments, each replicated five times, were conducted in a 3.2 by 9.0-m aluminum shed. Each experiment involved placing pupae at a single release point (source) and recording the numbers of emerging adult males captured after 24, 48, and 72 h in each of four pheromone-baited sticky traps. The experiments differed only with respect to the point of release. Distribution of trap catch reflected the general distribution of moths in the shed; and consecutive contour maps tracked their dispersal from the source. As emergence and dispersal progressed, cumulative trap catch increased throughout the shed, but it remained highest near the source. The observed spatial patterns of trap catch relative to sources of infestation and the inverse relationship of trap catch to distance from a source support the validity of contour mapping as a means of monitoring stored-product moths and locating foci of infestation. The relationship between trap catch and distance from a source of infestation was well described by two-parameter exponential decay, both in P. interpunctella and in the previously studied Lasioderma serricorne (F.). Analysis of data from retail pet stores also showed exponential decline in trap catch of P. interpunctella with distance from centers of infestation.

Distribution, abundance, and seasonal patterns of Plodia interpunctella (Hübner) in a commercial food storage facility

“…However, it is sometimes difficult to interpret moth capture data because of various factors that affect trap performance (Arbogast et al, 2005;Nansen et al, 2008). Interpretation of trapping data is especially difficult in food warehouses because of the constant movement of commercial food products into and out of the building and among different locations within facility.…”

Using a population growth model to simulate response of Plodia interpunctella Hübner to temperature and diet

“…Temperatures during the cooler months are unlikely to eliminate populations of P. interpunctella (Kaliyan et al 2007a, b;Johnson 2007), especially in climate-controlled facilities that allow population levels to remain high throughout the year. Although the model does not account for movement of individuals in or out of populations, sampling and monitoring can be used to estimate seasonal population fluctuations and pinpoint sources of infestation in food processing and manufacturing situations (Doud and Phillips 2000;Arbogast et al 2005). The rapid growth of P. interpunctella populations on both optimal and sub-optimal diets indicates the need for regular sampling to quickly treat problem areas to avoid rapid population growth.…”

Contour Mapping and Number of Point Observations

“…In a recent issue of the Journal of Economic Entomology, Arbogast et al (2005) published an article upon which we are compelled to comment. The authors state that their article was in part ".…”

“…However, there were problematic aspects of the article that could set a precedent if perpetuated by others in the future, so we felt it necessary to raise our concerns. Arbogast et al (2005) released insects at a single point into a shed and then generated contour maps (Figs. 2Ð 4) of interpolated trap captures derived from counts made at four traps located in the same shed.…”

“…A sample size of four is generally an inadequate number of samples for statistical inference, whether the objective is to measure differences in an analysis of variance or to interpolate spatially dependent samples in a map. Figures 2Ð 4 in Arbogast et al (2005) are examples of extracting too much information from too few observations. A simple alternative would have been to present the same data as bubble plots with either size, shape, or color of discrete dots indicating the magnitude of trap captures (Bailey andGatrell 1995, Nansen et al 2003).…”