Directorate of Rice Research, Rajendranagar, Hyderabad-500030.
The studies conducted at the Directorate of Rice Research (DRR) to know the antennal response of male YSB using Electroantennograph (EAG) and Taichung native (TN1) plant extracts revealed a definite influence in eliciting greater moth response with 1.24 and 1.16mv antennal deflection with 30’and 60 day old seedlings respectively and meager 0.37mv with solvent alone. The plant extracts in solvents methanol and hexane produced significantly highest antennal deflection (1.64 and 1.22, v respectively) and lowest response was recorded in dichloromethane (0.85mv). Maximum response over EAG was recorded with Pusa Basmati plant extract in methanol in combination with 3:1 pheromone blend of (Z) 11-hexadecenal and (Z) 9-hexadecenal, respectively with a response of 1.61mv closely followed by Pusa Basmati plant extract in hexane added to 3:1 pheromone blend (1.29mv), which were on par and superior over 3:1 pheromone blend alone in combination with other plant extracts.
Preliminary field studies conducted at DRR farm with antioxidant Vitamin E alone and in combination with 3:1 pheromone blend revealed that even Vitamin E alone is able to attract YSB male moths towards the traps. Even though higher moth catch was recorded with 3:1 pheromone blend with BHT it was on par with Vitamin E alone treatment. Further field studies were conducted based on the EAG responses of plant extracts (TNI and Pusa Basmati) and trap catches with Vitamin E. Commonly used 3:1 blend + BHT mixed with Pusa Basmati plant extract in methanol elicited highest response by capturing 133.33 YSB male moths pertrap followed by 3:1 blend + Vitamin E (102 moths/trap) at Medchal. At DRR farm also 3:1 + BHT + Pusa Basmati plant extract in methanol was significantly superior over all the other treatments with 31.5 moths per trap, even at low densities followed by 3:1 + BHT (20.50 moths/trap). At karjat the treatment 9:1 + Vitamin E caught significantly higher number of moths (33.20/trap) followed by 3:1 + BHT + Pusa Basmati plant extract in methanol (29.80 moths/trap) and both were on par. The catch of3:l + Vitamin E treatment was also significantly higher than 3:1 +BHT. All these results suggest that both antioxidant Vitamin E and Pusa Basmati Plant extracts have the ability to improve the attractancy of extensively used 3:1 pheromone blend when added to it almost by two to three times. Further, there is need to identify chemical components that are present in the Pusa Basmati plant extracts which are actually responsible for this attraction and thus further strengthen mass trapping technique for managing YSB.
