In maize cultivation, the major biotic stress affecting yield was infestation by stem borers, which results in annual yield loss ranging from 25-78 per cent. The various insecticides including botanicals, biorationals, whorl application and foliar spray of conventional insecticides are evaluated for their bio efficacy against reduction of leaf injury and dead hearts damage by maize stem borers for two seasons during 2017-18. Among the various insecticides evaluated, the least per cent leaf injury and per cent dead heart was recorded with whorl application of carbofuran 3G @ 10 Kg ha-1
at 14 days after germination and recorded 68.36, 73.30 and 65.47, 72.48 per cent reduction of leaf injury over control at 7 and 14 DAT during Kharif
seasons respectively. With respect to reduction of per cent dead hearts over control also carbofuran 3G only recorded significantly highest control over other treatments with an average of 64-78 per cent reduction. The insecticides chlorantraniliprole 0.4% GR @ 10 Kg ha-1
and chlorantraniliprole 18.5%SC @ 150 ml ha-1
also found on par with carbofuran 3G in reduction of leaf injury and dead hearts damage by maize stem borers. Further, the botanical Azadirachtin
(10000 ppm) @ 150ml ha-1
also exerted an average of 50 per cent reduction of dead hearts over control. The order of efficacy of treatments in reduction of stem borer damage infesting maize represents T7
: Carbofuran 3G > T6
: Chlorantraniliprole 0.4% GR > T5
: Chlorantraniliprole 18.5%SC > T4
: Novaluron 10% EC > T1
(10000ppm) > T2
: B.bassiana >
T3: B. thuringiensis.
The highest kernel yield was also recorded in Carbofuran 3G (5895 & 5750) with 44.10 and 45.57 per cent yield advantage over control during Kharif and Rabi
, 2017-18 respectively. The highest cost: benefit ratio was evinced in insecticidal treatment with carbofuran 3G (1:1.35 & 1:1.21) followed by Chlorantraniliprole 0.4% GR (1:1.14 & 1:1.11). Hence, insecticidal schedule embracing the application of Carbofuran 3G -Azadirachtin
(10000ppm)- Chlorantraniliprole 0.4% GR/ Chlorantraniliprole 18.5%SC will combat with the pest infestation and may offer superior control.
D Sudha Rani, Ch. Naga Satya Sri, K Anand Kumar and MN Venkatesh. Economic evaluation and efficacy of various insecticides against maize stem borers. J Pharmacogn Phytochem 2018;7(3):15-20.