An Evaluation of the Insecticidal Properties of Neem (Azadirachta indica) In Controlling Diamondback Moth (Plutella xylostella. (L) In Cabbage Cultivars in Obudu Cattle Ranch Resort, Cross River State, Nigeria

An experiment was conducted at Obudu Cattle Ranch in northern Cross River State of Nigeria, to evaluate the insecticidal properties of extract from neem seeds in controlling the deleterious activities of diamond back moth (Plutella xylostella) in cabbage farms. An experimental farm was established in a 30 by 10m plot of land, and the design of the experiment was a Completely Randomized Design (CRD) with a 3 by 5 factorial lay out. 3 cultivars of headed cabbage (B. Oleracea germmifera: white, Green and Red) were cultivated one to a plot with 5 beds per plot. A bed represented a subplot. There were 15 beds in a plot, 3 plots in a block and 3 blocks in a replicate, with each replicate having 45 beds. The entire lay out was replicated 3 times. Cabbage seedlings of 3 cultivars were transplanted from a 30 day nursery to already prepared beds at the planting distance of 70 cm within and 0.5 m between rows. There were 5 stands in a bed, 25 stands in a plot, 75 stands in a block, 225 stands in a replicate and 675 stands in the entire experimental plot. A solution of extract from neem seeds was prepared and applied in five different volumes (0, 2, 4, 6 and 8 liters ai/ha) to the cabbage cultivars, 2 weeks after transplanting to prevent early attacks on the fresh leaves of the cabbage by Diamond Back Moth (DBM). The main treatments were the cultivars while the sub-treatments were the 5 volumes of neem seed extract applied. Data were taken at maturity of the crop for the number of fruits per plot, weight of fruit in grammes per plot and the fruit yield in tons per hectare (t/ha). All data generated were subjected to analysis of variance and the main separated by least significant difference at (p=0.05) level of probability. Findings revealed that the crude extract of neem seeds at 6 and 8 lit/ha has the efficacy to repel Diamond back month effectively, thereby resulting to higher yields of the crop, especially the white cultivar. It was recommended that farmers should adopt the use of biopesticides such as neem seed extract at volumes of 6 and 8 liters ai/ha in controlling DBM in cabbage farms. They are safer and environmentally friendly.