[Three-dimentional distribution pattern dynamics of Erythroneura sudra and its natural enemy Erigonidum graminicola]

Investigations on the Erythroneura sudra and Erigonidum graminicola populations in three layers (upper, middle and lower) and four directions (east, south, west and north) of peach tree crown showed that both of them had aggregated spatial distributions in these 7 part, because 5 parameters used to analyze the distribution reached required standard. Each insect was attracted by the others, as the parameter (alpha) in Iwao formulation m* = alpha + beta x - (1971) was positive. The average density of aggregation was the biggest in its middle layer and east direction, and the smallest in its lower layer and south direction. The biggest average density of aggregation appeared in mid-September.