Statistical Models for Insect Pests in Sorghum [Sorghum bicolor (L.) Moench]
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Date
2012
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Publisher
UAS, Dharwad
Abstract
Sorghum [Sorghum bicolor (L.) Moench] is one of the most important cereal
crop in the world, because of its adaptation to a wide range of ecological conditions. It
is the fifth major cereal crop of world following wheat, rice, maize and barley in
terms of production and utilization. Sorghum adversely affected by shoot fly in
northern Karnataka, in considering the importance of the pest present study was
envisaged. Experimental data were collected from AICSIP at Dharwad and
meteorological data were collected from meteorological observatory of Main
Agricultural Research Station of Dharwad.
The linear and nonlinear models viz., quadratic, cubic, logarithmic, inverse,
exponential models were tried. Results of the study revealed that simple linear and
nonlinear models viz., cubic and quadratic models were of much informative in
explaining the relation between dates of sowing and the shoot fly.
The Correlation analysis was carried out to know the relationship existing
between weather parameters and shoot fly. In kharif season high rainfall was
negatively correlated with the egg population and high temperature (Max and Min),
high relative humidity (RH1 and RH2) were positively correlated with the egg as well
as dead heart of shoot fly in both the season. But the minimum temperature less than
20°C and low humidity had negative correlation during Rabi season.
By considering the significance of the weather parameters stepwise regression
analysis was carried out, these models were having high R square value. During
kharif season in the year 2003 models for 14 days after emergence of the crop
produced high R square value 0.986 and During rabi season model in 2005 for 14
days after emergence of the crop produced high R square value of 0.999 and hence it
was best fit, in explaining the effect of weather parameters in the development of
shoot fly.