Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Abstract

Fungal pathogen of Rottboellia cochinchinensis and its potential as bioherbicide.

Abstract

The possibility of using an indigenous plant pathogen to control itchgrass (Rottboellia cochinchinensis) was investigated. A fungal pathogen of itchgrass, Exserohilum longirostratum, was determined in the laboratory and greenhouse as a potential bioherbicide. The disease symptoms on inoculated plants appeared 24 h post-inoculation as discrete spots with watery dark border, eventually expand and cause extensive necrosis on the leaves, resulted in burnt-like symptom. When applied as a post-emergence foliar spray, the fungus inflicted high percentage of mortality to young itch grass seedlings. It did not kill older plants but was capable of reducing biomass by approximately 56% when the plants were inoculated with 3.5×105 conidia/ml. Media containing carbon:nitrogen ratio of 10:1 as in V8 juice agar and PDA produced more conidia compared to medium (CMA) containing carbon:nitrogen ratio of 40:1. Light and temperature had major influence on fungal sporulation, exposing the fungus to longer duration (12 h) of light significantly increases conidia production. The optimum temperature for growth and sporulation of the fungus ranged from 25 to 30°C.