Scientific validation of two indigenous plants used for traditional storage pest management in Manipur

Abstract

Goniothalamus sesquipedalis and Isodon ternifolius are two well-documented ethnobotanically important plants used in Manipur by different tribes. It is also often used together as a traditional fumigant by burning and smoking by hanging in traditional granaries to reduce the insect pest infestation. This study scientifically validates the use of these two plants in different proportions to manage storage pests. The suppressive effect of plant powders on population increase through the inhibition of off spring was assessed. The study and evaluation focused on defined combined ratios of 50:50, 60:40, 70:30, and 80:20 of Goniothalamus and Isodon. The lowest GI₅₀ of 2.92 mg/g was observed in G. sesquipedalis treated rice grains and exhibited the best suppression of the population growth of rice weevil among all the treatments evaluated. The subsequent best treatment was I. ternifolius with a GI₅₀ of 3.00 mg/g and very similar to G. sesquipedalis in growth inhibition capability. Among treatment combinations, Isodon and Goniothalamus combined in a ratio of 60:40 displayed good grain protection from rice weevil damage with a low GI₅₀ of 5.42 mg/g. The highest GI₅₀ of 13.60 mg/g was shown by the combination of Isodon and Goniothalamus in the ratio of 70:30. The statistical tests of treatment means were highly significant at 1% level of significance, as the p-values in all cases are less than 0.01 except for one (80:20) where it was non-significant. The viability of seeds treated with G. sesquipedalis and I. ternifolius were found to be both enhanced. However, the seeds treated with a combination of G. sesquipedalis and I. ternifolius failed to germinate ultimately.