Efficacy of selected botanicals against rice insect pests under green house and field conditions.
Greenhouse studies showed that the oils of Mahua (Bassia datilalia) and Pinnai (Calophyllum inophyllum) were highly toxic to brown planthopper (BPH) nymphs and were superior to Maravetty (Hydnocarpus wightiana). Oil of Pinnai and neem affected orientation and settling of BPF. Pinnai was superior to neem and Mahua in antifedant effects against BPH. They also disrupted the growth of BPH and green leafhopper (GLH). Neem seed kernal water extract (NSKWE) spray adversely affected the growth of BPH (at 5000 ppm) and GLH (at 25000 ppm). NSKWE as seedling root dip was more efficient than sprays. Neem seed kernal suspension (NSKS) 3% level inhibited the growth of GLH nymphs. Field studies Tevealed thaf neem cake (150 kgfha) incorporated in soil and followed by neem oil (3%) spray at 10 days interval effectively checked leaf folder incidence. However, 3% sprays of neem oil, Mahua oil, Pinnai oil and neem seed kernal suspension did not show consistant effectiveness against stem borer, (Scirpophaca incertulas), gall midge (Orseolia oryzae) and whorl maggot (Hydrellia philippines).