G. it. Ent., 5 (28): 289-295
August 31, 1991
Spatial distribution pattern of the cutworm, Agrotis ipsilon (Hufn.)
(Lepidoptera: Noctuidae)
in the maize field
by
ABHIJEET NAG & PARAS NATH
Abstract - The spatial distribution pattern of cutworm, Agrotis ipsilon (Hufn.), larvae in the maize field was studied. Several methods, such as the index of dispersion (I), the coefficient of variation (c.v.), the index of clumping by David & Moore (IDM), the index of Lexis (ILex), Charlier's coefficient (ICh), Green's index (IG), Morisita's index (Ig), Cole's index (IC), Lefkovitch's index (ILef), exponent k and its reciprocal 1/k as index of dispersion were computed. The mathematical model (negative binomial) and the relationship between variance and mean were tried. These methods confirm the aggregative nature of cutworm larvae distribution, which is attributed to different factors, mainly to habitat heterogeneity and behaviour of the insect.
