Sensitivity of selected Alliaceae seedlings to crude extracts of Cucumis myriocarpus fruits

Abstract

Crude extracts of wild cucumber (Cucumis myriocarpus) fruits have been successfully used as postemergent bio-nematicide in suppression of the southern root-knot nematode (Meloidogyne incognita). Compatibility of this bio-nematicide with plant growth when used as a pre-emergent bionematicide was tested on onion (Allium cepa), leek (Allium ampeloprasum) and chive (Allium schoenoprasum) under greenhouse conditions. In each trial, 10 levels of crude extracts of C. myriocarpus fruits were arranged in a randomised complete block design, with five replicates. At harvest, 18 days after planting, seedling height, radicle length, coleoptile length and coleoptile diameter each were each subjected to the Curve-Fitting Allelochemical Response Data (CARD) model, which demonstrated that at both low and high levels, the bio-nematicide had stimulatory and inhibitory effects on growth of test plants, respectively. The total sum of transformations (�k), expresses the sensitivity of the test plant to the bio-nematicide, �k being inversely proportional to the degree of sensitivity. Overall, onion was the most sensitive to the bio-nematicide, followed by chive and leek. In conclusion, since the material had 100% inhibition of plant growth where it suppresses nematodes, the material is not suitable for use as a pre-emergent bio-nematicide.