Population densities of Bemisia tabaci adults and nymphs from Regulation of dynamics and densities of whitefly Bemisia tabaci by agricultural landscapes in south China

This method divides the seasonal activity into three periods: early, main and late, and formally identifies the start and end for each of these, as well as the date of the seasonal activity peak. First, the numbers observed were summed and the three cardinal points were the dates when 25, 50 and 75% of the total densities were reached. These also divided the curve into four segments. The start of the main activity period was from the date when the cumulative densities reached 25% of the total (the start of the second quartile on the vertical axis), and the end was the date when 75% (the end of the third quartile on the vertical axis) was reached. The formally defined early activity period extended from the start of the census to the beginning of the main activity period, and the likewise formalized late activity period lasted from the end of the main activity period until the end of the observations, when activity stopped. Census data were initially subjected to a one-way ANOVA with agriculture landscape types as the main effect. To reduce the impact of occurrence time on the population densities of B. tabaci, the activity period of B. tabaci was divided into early, main and late activity period by quartile method. Differences in B. tabaci densities were compared among agriculture landscape types in the same activity period, as well as densities in different positions of the tomato plants, constrained by landscape type (identified as above) by Least Significant Difference. The significance threshold was P=0.05 in all tests. Data analyses were performed using SPSS 20.0.