Cucumber black star disease, also called scab disease, leaf mildew disease, is a kind of fungus disease seed disease. It is a destructive disease in greenhouse. It is listed as quarantine object, which seriously affects the yield and quality of cucumber and can completely lose its edible value. It is an effective way to control cucumber black star disease, reduce the use of chemical pesticides and reduce environmental pollution by developing high-efficiency inducers from natural bioactive substances. Chitosan oligosaccharides can be used as plant growth regulators to enhance plant defense against pests and diseases. In this paper, the resistance of cucumber to black star disease induced by chitosan oligosaccharides was studied.
Cucumber at seedling stage was induced by 6 mg/ml chitosan oligosaccharide solution, and the activity of main defense enzymes in cucumber leaves was measured. The results showed that chitosan oligosaccharide induced 65.85% and 46.10% of cucumber melanosis at 10 d and 17 d, respectively, and the activity of the main defense enzymes in cucumber leaves could be significantly improved as an inducer.
Chitosan oligosaccharide, as a new type of plant resistance inducer, can effectively induce cucumber and other plants to produce disease resistance response, promote plant growth, improve plant immunity, and has the characteristics of high efficiency, natural, non-toxic and so on. It can be popularized as a green and efficient pesticide, and has a very open application range and market prospect.