Severity of thrips on chili varieties under varied weather factors and plant characteristics

The abundance and severity of the thrips Scirtothrips dorsalis were studied on the chili Capsicum frutescens L. (Solanaceae) varieties BARI Morich 1, BARI Morich 2, BARI Morich 3, BINA Morich 1, and Bogura Morich from June to December 2018. The population buildup of thrips started from third week of August with mean abundance of 1.2 thrips/shoot and continued till the fourth week of November when the mean abundance was 0.4 thrips/shoot. The highest incidence of the thrips (5.3/shoot) was recorded on the variety BINA Morich 1 in the fourth week of September whereas the thrips showed lowest occurrence (2.0/shoot) on BARI Morich 2. The abundance of thrips on the chili varieties was positively correlated with maximum temperature, minimum temperature, and relative humidity, and negatively correlated with rainfall. Thrips population exerted negative correlation with leaf trichomes, chlorophyll and moisture, and revealed positive correlation with proline. The chili varieties depicted significant differences within their leaf curl indices (LCI). BARI Morich 1, BARI Morich 2 and Bogura Morich showed <50% LCI and these varieties were categorized as moderately resistant. The varieties BARI Morich 3 and BINA Morich 1 revealed >50% LCI and these varieties were found as susceptible.