Grain legumes are an important source of proteins in vegetarian diet besides their role in biological nitrogen fixation. They are prone to heavy pest infestation both on and off the field. Pest associated losses are an important contributing factor towards declining per capita availability of grain legumes. Synthetic chemical pesticides have played an important role in crop preservation however; their incessant use has posed several environmental and human health concerns. Methyl bromide and phosphine are commonly used for the post harvest preservation of grain legumes. However, the former has to be phased out by 2015 as per the Montreal protocol whereas; the latter is showing development of resistance to it by the insects. In the light of this, alternative, safer and sustainable strategies are needed for crop protection. Plants can serve as a rich source of bioactive chemicals for this purpose. Both primary as well as secondary metabolites can be evaluated against the target pests.The paper reviews the status of research in the area of use of plant metabolites in post harvest pest management of grain legumes.

The growth inhibitory activity of the leaf extract of plants (Viola odorata, Gardenia gummiferra, and Anthocephalus cadamba) belonging to family Rubiaceae and Violaceae was studied against H. armigera, an economically important pest of cotton and legumes in India. The EC20 and EC50 values were found to be in the range of 100 to 600 ppm and 400 to 600 ppm, respectively. The extracts at EC50 with natural diet did not affect the relative consumption rate(RCR), approximate digestibility (AD) and efficiency of conversion of ingested food (ECI) but the relative growth rate (RGR) and efficiency of conversion of digested food (ECD) were found to be affected, indicating chronic toxicity rather than antifeedent activity. The retardation in growth in larvae was marked and visible with Viola odorata. Biochemically, the lipase, superoxide dismutase (SOD) and catalase activities, as well as lipid peroxidation, were found to be affected as a function of treatment with the extracts. HPLC chromatograms of the partially purified extract yielded sharp and symmetrical peaks at 17.5, 11.5 and 7.4 min for V. odorata, G. gumiferra and A. cadamba, respectively, indicating the presence of circular proteins in the plant extracts.

A few indigenous members of family Rubiaceae and Violaceae were screened for the presence of bioactive circular proteins.......