Interpretation of trap catch for detection and estimation of stored-product insect populations

Methods available for interpretation of trap catches of stored-product insects are discussed. Trap efficiency must be determined to convert trap catches into absolute densities. Much of the variation in trap catch may be attributable to variation in trap efficiency in response to environmental factors rather than to actual changes in insect population density. Therefore, regression equations for calculating trap efficiency over a range of environmental conditions may be needed to convert the number of insects caught to absolute densities. Calculating the probability of detection or the accuracy of estimation insures that trap catches are not extrapolated beyond the limits of their resolution. Insect population dynamics models are useful in predicting future insect population densities from trap catches and in relating trap catches to developmental stages not trapped. Interpretation of trap catch must begin with careful planning of a trapping program if these three methods of interpreting trap catch are to be fully utilized to provide correct conclusions in research programs and appropriate decisions in management programs.