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Accumulated thermal time, a key factor in affecting generation initiation and duration of top borer, Scirpophaga excerptalis Walker of sugarcane for its model-based chemical control

✍ Scribed by Arun K. Srivastava; D. C. Srivastava; O. K. Sinha; Rajesh Kumar


Publisher
John Wiley and Sons
Year
2009
Tongue
English
Weight
211 KB
Volume
17
Category
Article
ISSN
1350-4827

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✦ Synopsis


Abstract

The seasonal variation in the initiation and duration of the I–III generations of the top borer was observed and analysed during five crop cycles from 2002–2003 to 2006–2007 at Lucknow in central Uttar Pradesh. The durations of the I–III generations were significantly correlated with the accumulated thermal time (T~base~ = 10°C). Relatively higher temperature and consequently higher accumulated thermal time shortened the brood duration and early initiation of successive generations and vice versa. Based on these correlations, models were developed for predicting the initiation and duration of these generations. These models were validated for 2007–2008 crop cycle. The differences between observed and predicted duration of the I–III generation of the pest were 3, 1 and 3 days respectively reflecting high precision of the models. As the current management strategy for the chemical control of the pest is based on a calendar week, the shift of III generation initiation due to seasonal fluctuations could lead to escape from insecticide and render the chemical application pointless. The model‐based control strategy is more precise and foretells the time of application of chemical against III generation of top borer which is most damaging to sugarcane crop. Copyright © 2009 Royal Meteorological Society