Control Of Cucumber Fusarium Wilt With Chlorine Dioxide And Manure

Cucumber Fusarium wilt is one of the main soilborne diseases of cucumber, which is restricting cucumber production seriously. The control effect of pesticide is not only unsuccessful but also produces pollution of environment and agricultural products, threatening the security of foods and environment seriously. So seeking an integrative control technique that is highly efficient, broad-spectrum, nontoxic and nonpolluting is of great importance for current research. Chlorine disxide, which is known as one Al standard safe disinfectant, and manure, which has the biological control function, were studied as antiseptic materials in this paper, and lab experiments, pot experiments and field experiments were taken to study their effects on cucumber Fusarium wilt control and major factors affecting their effects. The suppressive mechanisms of them on Cucumber Fusarium wilt pathogen were also explored. The key results are as following:1. ClO2 could control cucumber Fusarium wilt effectively. Its suppressive effects increased with the increase in ClO2 concentration. The control effects in all treatments with ClO2 concentration over 200mg/L were higher than 50%, and the best control effect of 96.4% appeared in ClO2 500mg/L concentration.2. The sterilization effect of ClO2 to soil and manure was strong and it increased with the concentration of ClO2, But its effect on different microbial species varied and its effects to the three main groups of microorganisms decreased in the order of fungi, bacteria and actinomycetes. The sterilization function of ClO2 on Fusarium oxysporum was very effective and lIO2 with concentration of 10mg/L could kill all the microorganisms in solution after ten minutes.3. Germination of cucumber seed was affected by ClO2 signifcantly. Soaking seed directly with concentration less than 40mg/L, ClO2 had no significant negative effect on seed germination percentage, radicle length, bud weight and seed vigor index, and positive stimulative effects were noticed in some treatments. Significant suppressive effects appeared when the ClO2 concentration was higher than 40mg/L. Soaking seed after pregermination, ClO2 had no significant negative effects on germination when concentration was less than 10mg/L, a much lower concentration than 40mg/L, and significant suppresseive effects appeared after the concentration was higher than 10mg/L.ClO2 could improve cucumber growth when applied to soil one week before seeding and with the increase in ClO2 treating concentration, cucumber growth increased first and then declined. The treatment with best cucumber appearance was that with ClO2 concentration of 200mg/L and cucumber height and weight were increased by 50% and 108% compared with control.4. Manure could control cucumber Fusarium wilt effectively, and the control effect varied according to fertilization style, manure dosage and other factors. For different fertilization style, base manuring combied with foliar spray got the best disease control effect and next was base manuring solely and foliar spray solely. The disease control effect also increased with the manuring intensity. Sterilization treatment to manure could affect its disease control effect at the beginning, but it general control effect was not significantely affected.5. The suppressive effect of manure on Fusarium oxysporum was significant and the suppressive effects of solid manure were more significant than that of manure extract solution. Suppressive zone appeared around manure in culture dish with Fusarium oxysporum being inoculated. The diameter of suppresive zone around solid manure increased with culture time and the maximal diameter reached 7.9cm and 6.2cm for cattle feces and microbial manure respectively. The suppresive zone of manure extract solution also increased first and then declined with time increase, and the maximum suppresive zone reached 2.7cm and 2.5cm in diameter for cattle feces and microbial manure respectively.6. Soil microorganism increased significantly after manuring, but bacteria, fungi and actinomycetes had different changing regularity. In base manuring treatment, bacteria increased first and then declined with time, fungi decreased gradually and the actinomycetes vavied with manure kinds, increasing in cattle feces but decreasing in microbial manure treatment. The bacteria, fungi and actinomycetes were also noticed to increase in the foliar spray treatment.Manuring style also affected soil microorganism status. The base manuring combied with foliar spray with manure extract solution had the most microorganism increase and the foliar spray solely with manure extract solution got the least increase. Sterilization treatment to both manure and soil could affect soil microorganism status at the beginning of the experiment but its later effects was not significant.7. Manure could improve cucumber growth significantly. The growth stimulating potential of microbial manure was better than that of cattle feces. Manuring style also affected plant growth and their effects decreased in the following order:base manuring combined with foliar spray＞base manuring＞foliar spray. The optimal dosage for base manuring was 5% for cattle feces and 3% for microbial manure. The best foliar spray concentration was 100 times.8. ClO2 treatment combined with manuring obtained perfect effects on cucumber Fusarium wilt control. Its control effect was more significant than other treatments and the disease incidence was less than 10%.