A D-Vac Calibration Technique

Removal samples from an irrigated pasture were used as a calibration technique for the D-Vac. Plots 4 m2 were enclosed with a frame, and 1 initial and 3 removal samples were taken. Equations are given for computing the population and probability of collecting an insect. For leafhopper adults, leafhopper nymphs, Orius insidiosus (Say), and corn flea beetle, Chaetocnema pulicaria Melsheimer, calibrations (m2/linear m) were 0.405, 0.328, 0.272, and 0.490, respectively. A suction sampler, the D-Vac, is widely used for sampling insect populations. It is now generally recognized that samples thus obtained are not directly quantitative but must be calibrated against actual populations determined by other methods. The techniques of removal trapping (Moran 1951) provide a means for making a calibration using the D-Vac as the only sampling device.