Studies on Buprofezin and Synthetic Pyrethroids Against Hoppers in Rice

In green house studies buprofezin (an insect growth regulator) at a concentration of 0.01% exhibited high degree of persistent toxicity to nymphs of rice brown planthopper (BPH), white backed planthopper (WBPH) but moderate against green leafhopper (GLH). Synthetic pyrethroids, cypermethrin (0.005%) and deltamethrin (0.0025%) showed moderate efficacy against BPH and WBPH but were highly effective against GLH. The combinations of cypermethrin +buprofezin and deltamethrin + buprofezin were highly effective against all the three hopper pests. Buprofezin was safe to nymphs and adults of mirid bug (MB) but synthetic pyrethroids and combination treatments were relatively more toxicto MB. In field studies, cypermethrin(50 g.a.i.ha⁻¹ and deltamethrin 25 g.a.i.ha⁻¹) caused BPH resurgence but, when used in combination with buprofezin (100 g.a.i.ha⁻¹) resulted in good control of BPH and leaf folder similar or superior to monocrotophos (500 g.a.i.ha⁻¹) without detriment to the predatory mirid bug. In view of relatively low mammalian toxicity, combinations of cypermethrin + buprofezin and deltamethrin + buprofezin can be used effectively against BPH, GLH and leaf folder in integrated pest management programmes in rice.