Spatial distribution pattern of important alfalfa aphids in north of lorestan province

Pea Aphid (Acyrthosiphonpisum Harris( ,Blue Alfalfa Aphid (Acyrthosiphonkondoi Shinji and Kondo ) andSpotted Alfalfa Aphid (TherioaphismaculataBuckton( of the important aphids alfalfa is include recently given their damage , they have been forced to use chemical pesticides in some parts of the province. determining the spatial distribution of this insect is an important factor in designing a suitable sampling plan and comprehensive pest management program . there for the spatial distribution pattern of this insect in borujerd county  in 2015-2016 using distribution indices. For the experimentation and analysis of the result the regression method (Iwao , Taylor) was used . the result showed that the distribution of aphids in random . based an the values of (r ) the model (Iwao) was more appropriate than (Taylor) to show the relationship between variance and mean the data of this research can be useful in designing appropriate sampling program to stimate the populations of aphids and also to stimate population parameters.