Effect of the biocontrol Agent Trichoderma harzianum and the Fungicide Carbendazim White Rot Disease Sclerotium cepivorum of Onion Crop

Abstract

To evaluate the efficiency of the biocontrol fungus Trichoderma harzianum and the fungicide Carbendazim in inhibiting the growth of the pathogenic fungus Sclerotinia cepivorum, which causes white rot disease of onion crop in the greenhouse, this study was conducted at the Biodiversity Laboratory of the General Biotechnology Authority, Damascus, Syria, where the fungal isolate SCL1 (causing 89.2% of infection severity) was used. The study included protective spraying with two fungicides, separately, for treating onions infected with the white rot fungus. The disease severity at 4, 8, 12, and 16 days after infection was measured. In addition, some growth indicators and chlorophyl concentration (A, B, and total) were estimated 60 days after inoculation. The results obtained showed that the disease severity 4 days after inoculation in the healthy control, the carbendazim and Trichoderma pesticide treatments reached 0.0, 1.1, and 1.6%, respectively, with a significant difference with the fungus-infected control (72.5%). Significant differences continued between treatments and the infected non-treated control. Pesticides treatment caused a significant reduction in the severity of the pathogenic fungus infection in the greenhouse, with the superiority of the bio-pesticide compared to the chemical fungicide. On the other hand, the plants treated with Trichoderma outperformed the rest of the treatments in the wet and dry weight of the shoot and root growth. The same significant differences were obtained related to onion head weight and chlorophyl content. It can be concluded that the pesticide treatment; biological or chemical, reduced the damage caused by the pathogenic fungus by increasing plant growth and its chlorophyl content.

Keywords:

Onion, sclerotium, fungicide, biocide.