Biological Control Potential of <i>Colletotrichum gloeosporioides</i> for Coffee Senna (<i>Cassia occidentalis</i>)

Abstract

A fungal pathogen, Colletotrichum gloeosporioides was isolated from a greenhouse-grown seedling of coffee senna (Cassia occidentalis) and evaluated as a mycoherbicide for that weed. Host range tests revealed that coffee senna, wild senna (C. marilandica), and sicklepod (C. obtusifolia) were also affected by this pathogen, but 35 other crop and weed species, representing 8 botanical families were not affected. The fungus sporulated prolifically on solid and liquid media with maximum spore germination and growth occurring at 20˚C -30˚C. Optimal environmental conditions included at least 12 h of free moisture (dew) at 20˚C -30˚C. Spray mixtures containing approximately 1.0 × 10 5 or more conidia·ml -1 gave maximum control when coffee senna seedlings were sprayed until runoff occurred. Coffee senna seedlings that were in the cotyledon to first-leaf growth stage were most susceptible to this pathogen. Weed control efficacy studies under field conditions demonstrated that control of coffee senna was directly proportional to the inoculum concentration applied. Results of these tests suggest that this fungus has potential as a mycoherbicide to control coffee senna, a serious weed in the southeastern U.S.

Bio-herbicides: An eco-friendly approach for integrated weed management

“…It was the first mycoherbicide commercially available for controlling annual wild plants in crops with over 90 percent efficacy. Named in 1982 (Boyette et al, 2012) [26] . [29] .…”

Role of biocontrol agents in weed management – recent developments and trends

“…It was also mycoherbicide first available on commercial bases for annual wild plants in crops with > 90 percent regulatory competence. It was named in 1982 [Boyette et al 2012].…”