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Abstract
Aim: To develop and
validate a multi-linear regression model correlating brown planthopper (Nilaparvata
lugens) population with weather parameters specific to New Delhi
conditions.
Methodology: A weather-based
forecasting model was developed for predicting brown planthopper (BPH)
infestation for early, normal and late transplanted rice. The field data
during 2017 to 2021 were utilized for the model development and was validated
during 2022 and 2023.
Results: In early
transplanted rice, a significant negative correlation with BPH infestation
and minimum temperature (r=-0.462) and evening relative humidity (-0.387) as
well as a significant positive correlation with total sunshine hours
(r=0.447) were observed. For normal transplanted rice, BPH population was
significantly and negatively correlated with minimum temperature (r=-0.526),
evening relative humidity (r=-0.559) and rainfall (r=-0.411) while it was
significantly positively correlated with sunshine hours (r=0.390). In case of
late transplanted rice, the abiotic factor, sunshine hours (r = 0.355) alone
showed a positive correlation with BPH population. Multiple linear regression
(MLR) models were developed using data from 2017 to 2021 and validated with
2022 and 2023 data. The models were evaluated based on mean bias error (MBE),
mean absolute error (MAE), and root mean square error (RMSE). Correlation
analyses indicated significant negative correlations between BPH populations
and Tmin and RH2 in early and normal transplanting,
while positive correlations with SSH were observed. Validation showed
satisfactory accuracy for early and normal transplanting (RMSE: 0.237-0.749),
but lower accuracy for late transplanting (RMSE: 2.033-3.259).
Interpretation: These findings
show the importance of weather parameters in predicting BPH infestations,
with temperature, humidity, and sunshine hours playing significant roles. The
study highlights the necessity for integration of pest management strategies
time of planting and weather conditions to effectively mitigate BPH impacts
on rice yields.
Key
words:
Multiple regression model, Nilaparvata lugens, Rice, Weather
parameters
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