Influence of Weathier Parameters on Pests and Diseases of Soybean [Glycine max (L.) Merill]
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Date
2013
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Publisher
UAS, Dharwad
Abstract
Soybean is a major oilseed crop of India. Pests (Spodoptera litura and Cydia
ptychora) and diseases (rust and purple seed stain) are major threat for the cultivation of
soybean crop in India. The present study was envisaged by considering the importance of
these two major insect pests and diseases. Experimental data were collected from AICRP on
Soybean of Dharwad regarding pests and diseases of regions like Dharwad, Kalaghatagi,
Bailhongal and Hukkeri. Meteorological data were collected from meteorological observatory
of Main agricultural research station Dharwad. Assistant Executive Water Gauge Office Sub-
Division-2, Dharwad for Kalaghatagi region, A.R.S Bailhongal for Bailhongal region and
A.R.S Hukkeri for Hukkeri region.
Several simple linear and nonlinear regression models were tried. The incidence of
Spodoptera litura was more associated with maximum temperature and Cydia ptychora with
maximum and minimum temperature. The incidence of rust was associated with maximum
and purple seed stain was associated with relative morning humidity in all the regions. The
present study demonstrated that in few cases cubic model and in few other cases quadratic
model was more suited for all weather parameters. Multiple linear regression (MLR) models
were also tried, theses models were having high R2 values both in case of pests and diseases
and hence MLR is an improved model over the above models in explaining the variation in
development of pests and diseases.
The presence of insect pests and diseases caused yield reduction, there exist some
relationship between insect variables, diseases variables and yield loss. Present study reveals
that there is linear relationship exists between the insect variables, disease variables and yield
loss in soybean.