Seasonal abundance of planthoppers and natural enemies: correlation with weather parameters under direct seeded and transplanted basmati rice

The present investigations were carried out over two consecutive Kharif seasons (2019 and 2020) to study the population dynamics of brown planthopper (BPH) [Nilaparvata lugens (stal.)], white backed planthopper (WBPH) [Sogatella furcifera (Horvath)] and green leaf hopper (GLH) [Nephotettix virescens (Distant)] in basmati rice cultivar CSR 30 under field conditions at the CCS HAU, Regional Research Station, Uchani, Karnal. The maximum population of N. lugens was observed during 37th and 39th SMW (381.1 and 483.0 BPH/10 hills) and that of S. furcifera during 35th and 39th SMW (157.1 and 184.0 WBPH/10 hills) and N. virescens during 32nd SMW (5.4 and 6.3 GLH/10 hills) in transplanted rice (TPR) during Kharif, 2019 and 2020, respectively. The population of planthoppers was significantly lower in direct seeded rice (DSR), population of N. lugens [370.0 and 420.7 BPH/10 hills; S. furcifera was 255.0 and 349.0 WBPH/10 hills; and N. virescens 3.9 and 4.2 GLH/10 hills] during Kharif, 2019 and 2020, repsectively. Correlation studies revealed a positive and significant effect of mean maximum temperature and mean sunshine hours on the population of BPH, WBPH and GLH; moreover, the mean population of natural enemies viz., mirid bugs, spiders and coccinellids exhibited a highly significant and positive correlation with the mean BPH and WBPH population in DSR as well as TPR during both the years of study. The peak incidence of natural enemies (predators), mirid bugs (69.5 and 65.3 mirid bugs/10 hills) and coccinellids (1.47 and 1.23 coccinellids/10 hills) was recorded during 37th SMW, while spiders were at peak during 39th SMW (24.1 and 21.6 spiders/10 hills) in TPR and DSR during Kharif, 2019. A similar trend of natural enemy populations was observed during Kharif, 2020.