Development of Time-Efficient Method for Estimating Aphids Density Using Yellow Sticky Traps in Cucumber Greenhouses

The presence-absence model (PAM) was implemented to estimate the mean population density of Aphis gossypii Glover on grid-sticky traps in commercial cucumber greenhouses. The grid consisted of 4 by 6 cells (24cells per trap), each cell in size of 4cm² (2 by 2cm). The PAM described the relationship between the number of occupied cells and the number of aphids in a natural logarithmic scale reasonably well, and most trap cases were within 95% confidence limits of the predicted model. The distribution pattern of aphids on each trap was confirmed mostly nonrandom (75.3% of total traps) by Morisita's index, whereas the pattern among the traps was random according to PAM. The time cost for estimating the mean density of aphids by the PAM method was more efficient, compared to the whole trap counting method. This study demonstrated that the cell-occupied method based on the presence-absence model could be successfully implemented for estimating mean density of aphids in cucumber greenhouses.