Effect of Neem and False Yam botanicals on Parasitic Nematodes of Yam (Dioscorea spp)

Abstract

A field experiment was conducted in two locations within the Yendi district of Northern Ghana. The objectives were: to assess the effect of leaves of neem and false yam on yam leaf diseases, dry rot and tuber cracking, and to evaluate the effect of pounded Neem seed and False yam leaves on yam nematodes population in the soil, and tuber yield.The experiment was laid in Randomized Complete Block Design (RCBD) in three replications. Each experimental unit consisted of ten mounds. In all, there were three treatments: False yam leaves, Neem seed and Control. A local yam variety of Dioscorea cayenensis, ‘Labreko' setts, were planted on mounds at 100 cm x50 cm planting distance. Data were collected on nematode numbers, the incidence of mottling, mosaic and anthracnose on yam leaves at ten weeks after emergence, dry rot and cracking on the yam tubers at harvest, and tuber yield.The result showed that false yam leaves and Neem seed statistically had the same effect on the control of cracking on yam tubers. However the control was significantly different from the botanicals (P<0.05) and recorded higher score of tuber cracking than the botanicals. There were significant difference (P<0.05) between Jashee and Pashee locations in the occurrences of yam parasitic nematodes. The botanicals also had significant effect on nematode number, both Neem seed and False yam leaves reduced parasitic nematode population than the untreated mounds. False yam leaves significantly reduced nematode number more than Neem seed. Neem seed reduced nematode number by 29% as compared to 67% by False yam. Tuber yield was not significantly affected by the botanicals.The study showed that Neem seed and False yam leaves had thesame effect on the reduction of cracking on yam tubers. Cracking which affected the quality of yam tubers was more in the control than in the botanicals, this suggests that both Neem seed and False yam leaves could be a better option to farmers in the control of tuber cracking. This study also shows that when one milk tin, in quantity, of the botanicals were used, it emerged that false yam leaves reduced nematode numbers more than Neem seed; suggesting that two milk tins of Neem seed and one milk tin of False yam leaves may be the effective levels to suppress parasitic nematode in yam.