Maize Entomology Laboratory, Department of Plant Breeding and Genetics, Punjab Agricultural University, Ludhiana - 141 004, Punjab, India
*E-mail: jindal_ento@pau.edu
Online published on 13 June, 2013.
Distribution of Atherigona naqvii Steyskal eggs within- and between-plants were determined on germinating spring maize crop at two sites in Punjab. Variance to mean ratio, parameter k of the Negative Binomial distribution and Taylor's power law were used to describe the spatial distribution of eggs. Further, the observed distributions were compared to the Poisson and Negative binomial distributions. Stem base was the first choice of flies to lay eggs, although eggs were also deposited on leaves and soil with increase in egg densities per plant. Samples from different crop stages revealed that eggs were placed randomly among maize plants, though slight aggregation was noticed at higher egg densities. About 3.92 and 12.64% of the samples showed deviation from Poisson distribution and have s2/m ratios different from one at site 1 and site 2, respectively. Further 72.72% of the samples (s2 > m) agreed with Negative binomial distribution. Parameter k also showed that distribution is largely random at both the sites. Taylor's power law revealed that the between-plant distribution of shoot fly eggs was random (b = 0.99 – 1.10, r2= 0.53 – 0.99, p d" 0.0001) except on three crop stages.
Spatial distribution, sampling plan, maize, Atherigona naqvii, eggs
