Seasonal incidence, biology and management of Ocimum leaf folder, Orphanostigma abruptalis (Walker) on sweet basil (Ocimum basilicum Linn.) through botanical insecticides
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Date
2022
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DRPCAU, PUSA
Abstract
The present investigation entitled “Seasonal incidence, biology and management of Ocimum leaf folder, Orphanostigma abruptalis (Walker) on sweet basil (Ocimum basilicum Linn.) through botanical insecticides” was studied in Kharif 2021 in the field of Herbal Garden, Hi-tech unit and laboratory of Dr. Rajendra Prasad Central Agricultural University, Pusa (Samastipur) Bihar.
In the course of research, the study of seasonal incidence of ocimum leaf folder, O. abruptalis on sweet basil revealed that the larval population exhibited significant a non- significant relationship with Standard Meteorological Week (SMW). The incidence of ocimum leaf folder were observed from 39th SMW which was (2.33 larvae/ 5 plants) while the peak population of this pest was recorded at 47th SMW (11.00 larvae/ 5 plants) afterwards the population of leaf folder started gradually decreasing by maturity of the sweet basil crop.
The correlation studies with leaf folder population in relation with weather parameters where larva of ocimum leaf folder were negatively non- significant correlated (-0.14NS) with maximum temperature whereas positively non-significant correlated (0.53NS) with minimum temperature, while positive and non-significant
correlation (0.48NS) with morning relative humidity whereas negatively significant correlation (-0.59*) with evening relative humidity and non-significant & negatively correlated (-0.39NS) with rainfall.
The studies on biology of ocimum leaf folder were conducted in ambient conditions. The incubation period of eggs was 3-6 ((mean 4.0±0.89) days. The larva goes through five instars (four moultings) to complete its larval period. A full matured caterpillar was 16.80 mm long and body width was 2.03 mm. and total larval period was completed within 9-14 (mean 10.4 ±1.72) days. The adult male lasts for 7-9 days while female moth remains for 9-12 days. The total life cycle of this pest was completed within 25-36 (mean 30.2± 3.54) days.
The observations on botanical insecticides efficiency of different treatments on mean larval population of ocimum leaf folder the treatment Azadirachtin 1.5 % @ 0.75 litre/ha was observed highly effective treatment which counted leaf mean larval population (4.44/ 5 plants) followed by the succeed productive treatment was neem oil 2 % @ 10 litre/ha was observed the mean population (4.87/5 plants). This was found statistically at par with NSKE 5 % @ 25 kg/ ha recorded (5.09 larva/ 5 plants) followed by karanj oil 2 % @ 10 litre /ha which was recorded (5.51 larva/5 plants) and castor oil 2 % @ 10 litre /ha (5.57 larva/ 5 plants)> tobacco decoction 5 % @ 25 kg/ha (5.74 larva/5 plants) which was better than control plot (8.14 larva/5 plants).