Comparison of five wax apples (Syzygium samarangense) from Dong Thap Province, Vietnam based on morphological and molecular data

Abstract

A study was conducted on the influence of biological insecticides (NeemAzal and Pyrethrum, applied alone and in combinations with organic products) to Bruchus pisorum L. (Coleoptera: Chrysomelidae) population density and rate of damaged seeds. The change of chemical composition in damaged by pea weevil and Cydia nigricana Fabr. (Lepidoptera: Tortricidae) seeds was found. The treatments were performed in budding and budding and flowering stages. The toxic effect of biological insecticides Pyrethrum and NeemAzal after treatment in budding and flowering stages was considerably higher in comparison to the single use. The weevil density was decreased at the greatest rate after treatment with Pyrethrum + Biofa (37.5%) among biological treatments. The biological and synthetic products use had positively influence on the crude protein, crude fiber and phosphorus content. The treatment in budding and flowering stages led to a stronger increase in the crude protein and phosphorus content to a single treatment.