Insect-pests Dynamics and Developing Weather Based Forewarning Models for Rice Crop Insect-pests in the State of Chhattisgarh, India

Abstract

Globally, rice is the second most widely consumed cereal next to wheat, and it has occupied an area of 163.2 million hectares, with a total production of 719.7 million tonnes. Rice (Oryza sativa L.) is the world’s most important food crop and is the staple food for 50% of the global population. The main objectives of the investigation are to study the effect of weather parameters on the population dynamics of yellow stem borer, BPH and RLF in rice crop and to develop a weather-based forewarning model. To study the relationship between weather parameters and rice leaf folder population, dataset of collected for weeks 27th SMW to 48th SMW were subjected to correlation analysis using data analysis tool-pack of Microsoft Excel and free flow diagrams. From our investigation of effect of weather parameters on population dynamic, we figured out that weeks with declining rainfall (i.e. from last week of September), accompanied by declining humidity is found favorable for infestation of C. medinalis. Adults mate only once and up to 150 eggs are laid per female. Each female lays 1-3 egg masses. Egg masses are usually laid on leaf tips but they are also laid on the base of the stems. Favourable temperature for egg laying of YSB is 24 – 29°C and relative humidity 90-100%, Egg period varies from 5-9 days. The number of moults and larval duration (30-40 days) depends on the prevailing temperature which ranges from 17- 35°C. From the results it can be concluded that Yellow Stem Borer population is showing high build-up and peak activity during 3rd week of September to 1st week of October and this is verified through light trap catch data also. In the life cycle of the insects in second generation (larva development) peak population reaches if there is matching favourable temperature ranging from 24-31°C. Another parameter relative humidity (90-95%) is also found to be favourable in second generation insect development. This study investigates the dynamics of insect-pest4s affecting rice crop in the state of Chhattisgarh, state has diverse agro-climatic zones, resulting in various soil types. The major zones are the Chhattisgarh Plains, the Northern Hills Zone, and the Bastar Plateau. Key soil types include red-yellow soil (Matasi), red sandy soil (Tikra), laterite soil (Bhata), and black soil (Kanhar).