EFFECT OF COMMONLY USED BOTANICALS ON THE YIELD AND YIELD CONTRIBUTING CHARACTERS OF CABBAGE BY CONTROLLING TOBACCO CATERPILLAR Spodoptera litura (FAB.)

The experiment was conducted in the field of Sher-e-Bangla Agricultural University farm, Sher-e-Bangla Nagar, Dhaka, Bangladesh during the period from November 2013 to February 2014 to study the effectiveness of commonly used botanicals on the growth and head formation of cabbage by managing tobacco caterpillar, Spodoptera litura (fab.). using variety was cabbage Hatlas-70. The experiment comprised of the following treatments- T₁: Neem oil @ 6 ml/L of water, T₂: Neem oil @ 5 ml/L of water, T₃: Neem oil @ 4 ml/L of water, T₄: Mehgoni seed kernel @ 200 mg/L of water, T₅: Neem leaf extract @ 200 mg/L of water, T₆: Neem seed kernel extract @ 200 mg/L of water and T₇: Untreated control. Treatments were applied at 7 days intervals starting from the first initiation of the pest attack. The experiment was laid out in Randomized Complete Block Design (RCBD) with three replications.  It was revealed that the maximum thickness of head (13.28 cm) was recorded in T₁, while the minimum thickness (10.56 cm) was found in T₇ (untreated control). The maximum diameter of head (11.34 cm), the highest gross yield per plant (2.02 kg), and The highest marketable yield per hectare (65.56 ton) was recorded in T₁ treated plot, while the minimum diameter (9.34 cm), the lowest gross yield per plant (1.52 kg) and the lowest marketable yield per hectare (42.96 ton) observed in T₇ treatment respectively. The highest benefit cost ratio (3.52) was estimated for T₁ and the lowest (1.86) for T₄ treatment under the trial. From the findings it was revealed that spraying of Neem oil @ 6 ml/L of water at 7 days interval was more effective among the commonly used botanicals for reduction of cabbage plant infestation by tobacco caterpillar.