Population dynamics of rice whitebacked planthopper, Sogatella furcifera and natural enemies of planthoppers in Godavari Delta of Andhra Pradesh State.

摘要

Field studies during Kharif 2001 and 2002 and Rabi 2002 and 2003 at A.P. Rice Research Institute, Maruteru to understand the population dynamics of whitebacked planthopper (WBPH) Sogatella furcifera and natural enemies of plant hoppers in Krishna-Godavari zone of Andhra Pradesh, India revealed that WBPH was present only during Kharif season. WBPH nymphal population was significantly correlated with spider and mirid bug population (r=0.572 to 0.841). WBPH nymphal population and brown planthopper (BPH) nymphal population were significantly correlated (r=0.615 to 0.995) indicating their coexistence. Mirid bugs (Cyrtorhinus lividipennis) and spiders as a group were present both during Kharif and Rabi seasons. Mirid bugs appeared in considerable numbers only 8-9 weeks after substantial WBPH and BPH nymphal population existed in the field. Spider populations were high from the beginning of the season but could not cope up with the dramatic rise in the WBPH and BPH populations. The LT catches of WBPH showed positive correlation with WBPH nymphal population present in the field. Among the weather parameters, minimum temperature showed consistent and significant negative correlation (-0.473 to -0.877) with mirid bugs indicating that increase in minimum temperature may adversely affect mirid bug population during Kharif. During Rabi minimum temperature and sunshine hours were positively correlated with BPH field population and spider population.