HERBICIDE EFFECTS ON Ganoderma boninense INFECTION IN OIL PALM SEEDLINGS

Abstract

The use of herbicides for weed management is a common practice in oil palm plantation. However, previous studies have shown that herbicide can reduce plant susceptibility and could also cause physiological injury to plant parts such as roots which will ultimately provide entry points for pathogens. This study aimed to investigate the effect of commonly used herbicides in the oil palm plantation as a predisposing factor to Ganoderma disease development. In vitro study on eleven commercial herbicides with four different dosages have shown that the highest percentage inhibition of radial growth (PIRG) of Ganoderma boninense was recorded by paraquat dichloride treatment (100%) followed by diuron (87%) and monosodium methyl arsenate (MSMA) (79%) at concentration of 100 µg ml-1. Based on nursery trial, oil palm seedlings inoculated with G. boninense and treated with diuron showed the highest Ganoderma disease progression at 92.73% followed by seedlings treated with metsulfuron-methyl and glyphosate monoammonium (83.27%) and by glyphosate glyphosate isopropylammonium with (73.81%). These findings will help the oil palm industry in Malaysia to choose the best herbicides in order to mitigate the development of Ganoderma disease incidence.