Spatial distribution pattern and sampling plan for the blister midge, Erosomyia indica Grover (Cecidomyiidae: Diptera) in India.
Verghese A., Tandon P. L., Prasada Rao G. S.
Author Affiliation: Indian Institute of Horticultural Research, Hessaraghatta Lake, Bangalore-560 089, India.
Insect Science and its Application 9 : 515-518
Abstract : Studies on the spatial distribution and sampling of infestation by the cecidomyiid Erosomyia indica [E. mangiferae], were carried out in a mango orchard at Bangalore, Karnataka, India. The spatial distribution of infestation on the panicles was studied using the parameters variance-mean ratio, and Lloyd's index of patchiness. It was found that the midge infestation tended to follow a random distribution pattern. The infestation was not significantly different between the sections of the canopy delineated horizontally and vertically. However, infestations in east lower, south lower and south upper were significantly correlated to the total infestation. The sample sizes were apportioned to these sections using regression analysis, thus arriving at a sectional random sampling plan for better precision estimates. For the data on percentage infestation, angular transformation was found to be satisfactory. These results have application in field studies leading to the management of the pest on mango.