Subunits of Sample for Estimating Aphid Abundance on Potatoes

Abstract

From a 2-year field study 2 subunits of sample were found suitable for estimating populations of wingless aphids of 4 spp. (Aphis abbreviate, Macrosiphum solanifolii, Myzus persicae, and M. solani) on potatoes in Maine. These are (1) the terminal and 2 opposing basal leaflets of a leaf in each of the 3 standard positions on each sample plant - one within each of the top, middle, and bottom thirds of the plant''s height - and (2) one-half of each of these leaflets. Factors for converting to the 3-whole-leaf-per-plant basis the numbers of aphids found when using these sub-units are ((no. aphids i 38.1) x 100) and ((no. aphids [image]- 19.05) x 100) for leaflet and half-leaflet subunits, respectively. These subunits are resorted to when the total number of wingless aphids of all spp. on 3-whole-leaves-per-plant average 100 and 500, respectively.