Comparative evaluation of modified neem leaf, wood ash and neem leaf extracts for seed treatment and pest control in maize (Zea mays L.)

An experiment was conducted at Akure, rainforest zone of Nigeria to evaluate the effectiveness of neem leaf, wood ash extracts, modified neem leaf extract, Apron star 42WS and Karate 720EC as seed treatment and pest control in maize. The organic treatment extracts namely neem leaf extract, wood ash extract applied at 1200ml per hectare and modified neem leaf extract (1:1 ratio 600ml wood ash + 600ml neem leaf extract) were compared with Apron star 42WS (seed treatment), Karate 720EC and control treatment (no neem leaf, wood ash extracts nor Karate), replicated four times and arranged in randomized complete block design. The results showed that there were significant differences (P 0.05) in the germination counts, insect population, number of damaged leaves, growth and yield parameters of maize under different treatments compared to the control treatment. The modified neem leaf extract performed better in germination counts, reduction of damaged leaves, insect population and yield of maize than the sole application of neem leaf and wood ash. For percentage germination counts, Apron star 42WS had 65% followed by modified neem leaf extract (57%), wood ash extract (51%), neem leaf extract (47%) respectively. Modified neem leaf extract increased the leaf area, plant height and stem girth of maize by 8%, 5% and 7% respectively compared to the neem leaf (sole) extract. Generally, modified neem leaf extract had the best values of maize growth parameters followed by Karate, neem leaf and wood ash extracts respectively. Modified neem leaf extract decreased significantly the insect population, number of damaged leaves and number of holes per plant in maize by 33%, 70% and 30% respectively compared to the neem leaf extract (sole). When compared to modified neem extract, Karate decreased the number of damaged leaves per sample plot by 33%. However, there was no significant difference between karate and modified neem extract for insect population. For yield parameters, modified neem leaf extract significantly increased the maize yield gains by 15%, 14% and 2% compared to neem leaf, wood ash extracts and karate treatments respectively. However, wood ash and neem leaf extracts did not affect significantly the maize yield. Therefore, the modified neem leaf extract applied at 1200L/ha (3L/25m2) was most effective for pest control and seed treatment in maize crop.