WITHIN·FIELD SPATIAL DISTRIBUTION AND SAMPLING PLANS FOR LARVAE AND PUPAE OF DIAMONDBACK MOTH, PLUTELLA XYLOSTELLA 1. (LEPIDOPTERA: PLUTELLIDAE) IN ETHIOPIAN HEAD CABBAGE FIELD
Keywords:
Action threshold, Brassica oleracea var. capitata, enumerative sampling, sequential sampling, spatial distributionAbstract
Sampling statistics of three life stages of Diamondback moth (DBM), Plutella xy.lostel{a L.,
young larvae, mature larvae and pupae were· calculated on head cabbage (Brassica olenlcea L. var.
capitata L.) in Ethiopia. Iwao's mean crowding regression was used to analyze spatial patterns and to
derive sampling plans. The model accounted for 82%, 87% and 91 % of the variation in mean crowding
to mean relationship of young larvae, mature larvae and pupae of OBM, respectively. Distribution of all
the three stages was contagious. Values of the intercept were not different from zero for all the three
~tages indicating that the basic components of the population are Single individuals. Enumerative and
action threshold-related sequential presence-absence sampling plans for population studies as well as
decision making ill integrated OBM control programs in cabbage field is developed