Evaluation of the pathogenicity of microorganisms isolated from Egyptian broomrape (Orobanche aegyptiaca) in Israel

Abstract

Diseased Egyptian broomrape (Orobanche aegyptiaca) inflorescences were collected from a heavily broomrape‐infested tomato (Lycopersicon esculentum) field in Israel. The microorganisms that were isolated from the diseased inflorescences were passed through Koch's postulates on Egyptian broomrape‐parasitizing tomato roots in a polyethylene bag system and pots under greenhouse conditions. The fungi, Alternaria alternata, Macrophomina phaseolina, Rhizoctonia solani, and Fusarium solani, and the bacterium, Bacillus sp., were newly isolated from the diseased inflorescences of Egyptian broomrape and were found to be pathogenic to the parasite. Fusarium solani damaged all of the developmental stages of broomrape and prevented the damage that Egyptian broomrape causes to tomato plants. The level of pathogenicity and the damage of M. phaseolina, A. alternata, and Bacillus sp. to Egyptian broomrape in greenhouse experiments were relatively low. All the tested microorganisms are known as pathogens of tomato, yet none caused disease symptoms on the tomato plants grown in the inoculated polyethylene bags or in the pots. Fusarium solani demonstrated the highest potential for further development as a mycoherbicide for Egyptian broomrape control in tomato.