Biocontrol of Parthenium Hysterophorus using Zygogramma Bicolorata: Implications for Maize Grain Yield

Abstract

Biological control is a cost-effective and sustainable method many countries use to control invasive alien plant species. This study was conducted to establish the effectiveness of Z. bicolorata in controlling the noxious weed crop Parthenium hysterophorus and the associated benefits in enhancing maize yield performance under screen house conditions. The R-studio software was used to analyse data on plant height at flowering, number of leaves, leaf length, plant height at maturity, number of plants harvested, ear length, ear diameter, number of kernels per ear, number of kernels per row, plant biomass and grain yield. Maize yields were considerably higher (1800 g) in plots without parthenium than those with parthenium and no beetles (322 g). In plots with parthenium and the biocontrol agent maize yields were 1617 g, evidence that the agent effectively reduces the competitive ability of parthenium weed under these conditions.   In addition, maize plants in plots with no parthenium weed and those with parthenium weed and Z. bicolorata were significantly taller, had longer leaves, had more kernel rows and kernels per ear and had higher plant biomass compared to those maize plants growing together with parthenium in the absence of the biocontrol agent. Furthermore, the study found that defoliation of parthenium weed by Z. bicolorata contributed to a significant decrease in plant height, root length, number of flowers per plant and plant biomass of this invasive plant. Zygogramma bicolorata can significantly suppress the growth of parthenium weed in maize cultivation plots and thus enhance the growth and yield of maize.