NGHIÊN CỨU ẢNH HƯỞNG CỦA CHẾ PHẨM CHITOSAN ĐẾN SINH TRƯỞNG, PHÁT TRIỂN, KHẢ NĂNG HẠN CHẾ BỆNH HẠI TRÊN CÂY CÀ CHUA TẠI HUYỆN HOẰNG HÓA, TỈNH THANH HÓA

The paper will introduce research findings on potentiality of Chitosan as plant growth stimulation and fungicide on tomato in 2013. It was indicated that when applying with the dilution of 1/500; 1/300 and 1/100 by (1). drenching into the root, (2). foliar spraying and (3). foliar spraying + drenching, Chitosan extration did not bring clear effect on plant growth, ecept the increase of flower, but could make positive effect on disease control. Chitosan provided clear advantage to control major diseases on tomato, especially to soil born ones such as damming off and bacterial wilt. The bio-efficacy was depended on treating method and product concentration. In all treating methods, the bio-efficacy was increased with the higher dosage. The highest bio-efficacy of Chitosan was recorded when combining of drenching product into the soil just after planting and spraying every 15 days at 1/100 concentration. Thank to good control diseases as well as the stimulation of flower and fruit quantity, the crop yiled was significantly higher compared to untreated check and farmer practice. At the same dosage, the crop yield was highest when combining drenching and spraying, followed by spraying and next to drenching singly. Chitosan could also prolong the storage of tomato from 4 - 6 days to 12 -15 days after harvest.