Potential of Jatropha seedcake for control of root-knot nematodes (Meloidogyne spp.) in tobacco
Jatropha seedcake is reported to be efficient in the control of root-knot nematodes (Meloidogyne spp.) in crops such as tomato. In this study, five application rates of Jatropha seedcake were explored for control of nematodes in tobacco seedbeds. Plots received Jatropha seedcake at the rates of 0.75 kg/m2, 1.5 kg/m2 and at 3.0 kg/m2. There was also a standard chemical control, Herbifume (a.i. Metham sodium) at the rate of 100 ml/m2 while another plot had neither Jatropha or Herbifume as a Nil control. The trial was a randomised complete block design with four replicates at two locations in Central Malawi for two seasons from 2014 to 2016. Results showed that at both locations Jatropha treatments reduced nematode root galls by 44% at eight weeks after germination compared to the non-treated plot. On the other hand, Herbifume was 50% more efficient in controlling galling than the Jatropha treatments but in the latter, the seedlings also exploited the nutritive benefits of the cake to stay relatively healthy, vigorous and strong. It was therefore the finding of this study that Jatropha seedcake at the rate of 1.5 kg/m2 effectively controlled root galling. It is possible to reduce dependence on costly synthetic chemicals to more eco-friendly bio-sources such as those from Jatropha seedcake for the benefit of Malawi tobacco farmers for increased productivity and reduced cost of production.