STUDIES ON FIELD SCREENING OF SORGHUM GENOTYPES AGAINST SHOOT FLY & STEM BORER AND THEIR MANAGEMENT WITH AQUEOUS ORGANIC EXTRACTS
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Date
2018
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Acharya N G Ranga Agricultural University, Guntur
Abstract
The present investigation entitled “Studies on field screening of sorghum genotypes against shoot fly and stem borer and their management with aqueous organic extracts” was carried out during kharif 2017-18 at Agricultural College Farm, Bapatla.
Thirty genotypeS including two resistant checks were screened under field conditions against shoot fly and stem borer both under unprotected and protected conditions and replicated twice in a Randomized Block Design. The evaluation of different genotypes against shoot fly based on data collected on dead hearts that Mahalakshmi and R 68 were found to be highly resistant and the genotypes ICSR 172, 4019, ICSR 96, NJ 2647, R 149, 73902-4-2-1, 73904-2-1, 81-52-4, 73902-4-1-2 and R 91019 were identified as resistant for shoot fly. The genotypes 73902-2-1, 73902-8-2-2, NJ 2446, ICSR 98, 73904-1-1, 4109, 73911-3-2-30, 81-1-1, 73902-2-7, R 75, R 29, 73902-1-2-1 were found to be moderately resistant, whereas the genotypes R 91014 and 4993 were found to be susceptible to shoot fly when compared to the resistant checks IS 18551 (C) and IS 2205 (C). Regarding the biophysical characters, the highest number of trichomes on adaxial and abaxial leaf surfaces were recorded in highly resistant genotypes, viz. R 68, Mahalakshmi, IS 2205 and IS 18551 compared to susceptible genotypes R 91014 and 4993 with lower number of trichomes. The genotypes Mahalakshmi, 73904-2-1, 73911-3-2-30, R 68, IS 2205 and IS 18551 were found to be glossy in nature, whereas the genotypes R 75, R-91014 and 73902-2-7 found to be nonglossy in nature.
Pertaining the stem borer infestation, the genotypes IS 2205, I 33, R 75, NJ 2647 and IS 18551 were found to be less susceptible and the remaining all the genotypes were categorized as highly susceptible. The genotype ICSR 98 showed multiple resistant to shoot fly and stem borer.
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Regarding the yield attributes, among the thirty genotypes, eight genotypes were found to be sturdy, whereas the twelve genotypes were lean in nature. The genotypes ICSR 96 was found to be sturdy, while NJ 2446 and 73902-4-2-1 were found to be lean under both protected and unprotected conditions. Among the thirty genotypes, 4993, R 91014, NJ 2647 and ICSR 98 were short stature type, whereas the remaining were having medium stature. The genotypes 73903-1-2-1, 4109, 81-52-4, 73911-3-2-30, 81-1-1, R91019, R 75, ICSR 172, 4019, R 29, R-49, Mahalakshmi, R-91014, 73903-1-2-1, 739022-5, R 149 and R 68 were categorized as medium duration and 73902-8-2-2, NJ 2446, ICSR 98, 73904-1-1, 73904-2-1, IS 2205, 73902-2-7, I 33, ICSR 96, NJ 2647, 73902-42-1, IS 18551, 73902-4-1-2 and 4993 were found to be late. The genotypes 81-1-1 (3519 kg ha-1), 73902-4-1-2 (3418 kg ha-1 ) and 81-52-4 (2870 kg ha-1) gave the high grain yield, whereas R 68 (833 kg ha-1) and R 149 (833 kg ha-1) were poor yielding genotypes under both unprotected and protected conditions.
Avoidable losses ranged from 4.76% (R-91019) to 63.64% (NJ 2647). The highest avoidable losses were recorded in genotypes NJ 2647 (63.64%), R- 49 (60.00%), R-91014 (58.33%), NJ 2446 (55.56%) and ICSR 98 (55.00%), whereas the lowest were recorded in genotypes R-91019 (4.76%), 73902-8-2-2 (5.26%), 81-1-1 (6.98%) and ICSR 172 (9.50%) when compared to the resistant check IS 18551(C) (10.89%).
The genotypes 81-1-1, 73902-2-7, 73902-4-1-2, R 68 and 73904-2-1 recorded the highest number of spiders, whereas the lowest number of spiders recorded in genotypes ICSR 98, 4993 and 73903-1-2-1, but spider population was nil in genotypes 73903-1-2-1, Mahalakshmi, R 29, 4019, R 75, R 91019 and 4109 when compared to the resistant checks IS 18551 (C) and IS 2205 (C) under unprotected condition. The maximum number of coccinellids were recorded in the genotypes NJ 2647, 4993, 4019 and R 75, whereas the lowest number of coccinellids recorded in genotypes 73903-1-2-1, 73902-42-1, ICSR 96 and 81-52-4, but coccinellids were nil in genotype R 149 when compared to the resistant checks IS 18551 (C) and IS 2205 (C). Among the natural enemy complex, coccinellid beetles and spiders were predominant in sorghum crop ecosystem. Among coccinellids, Chilomenus sexmaculata and among spiders, Neoscona sp., Hyllus sp., Argiope sp., Olios sp., male and female of Telomonia dimidiata were recorded.
Regarding the management of shoot fly and stem borer with aqueous organic extracts, chlorantraniliprole followed by NSKE @ 5% was found to be effective and significantly superior over all the treatments. Regarding the efficacy of remaining aqueous organic extracts, karanj leaf extracts @ 5% and custard apple leaf extracts @ 5% were found to be effective against shoot fly and stem borer in terms of reduction in dead hearts, larval population, leaf damage and stem tunneling. The order of efficacy of the treatments was chlorantraniliprole > NSKE @ 5% > karanj leaf extracts 5 & 10% > custard apple leaf extracts @ 5 & 10% > neem leaf extracts @ 5 & 10% > chilli pod extract @ 5 & 10% > chilli leaf extracts @ 5 & 10%.
Regarding the efficacy of aqueous organic extracts against natural enemies, chilli leaf extracts @ 5% and 10%, chilli pod extract @ 10% and neem leaf extracts @ 10% were found to be safe and recorded the highest number of natural enemies viz., spiders and coccinellids. Among the aqueous organic extracts, NSKE @ 5% recorded the highest yield (1667 kg ha-1) and statistically on par with chlorantraniliprole (1861 kg ha-1) by recording 81.81 per cent increase in yield over control. The treatments custard apple leaf extracts @ 5% (1506 kg ha-1) with 64.24, karanj leaf extracts @ 5% (1500 kg ha-1) with 63.63 and custard apple leaf extracts @ 10% (1497 kg ha-1) with 63.33 per cent yield over control respectively are statistically on par with NSKE @ 5%.
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D5761
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