How to prevent grafted cucumbers from producing adventitious roots

Because greenhouse cucumbers are planted year after year, Fusarium wilt occurs rather severely, seriously affecting the growth and yield of cucumbers. To solve this problem, grafting with figleaf gourd (Cucurbita ficifolia) as the rootstock is commonly used in production to control the occurrence of Fusarium wilt in cucumbers. At present, many greenhouse cucumbers are in the seedling recovery stage after transplanting, and the earlier ones have already entered the early fruiting stage. According to the author's on-site investigation, at this stage cucumbers very easily grow adventitious roots on the vines above the graft union; if these are not removed in time, Fusarium wilt easily occurs, affecting cucumber yield.

I. Causes of adventitious root formation in cucumbers

First, the graft union is too low, or the planting is too deep, so that the graft union is buried directly in the soil, and the cucumber plant produces adventitious roots. Second, the vines are tilted, and the cucumber vines come into contact with the surface soil, producing adventitious roots. Third, the soil surface humidity is too high; although the cucumber vines above the graft union do not touch the ground surface, the environmental conditions are suitable, so the base of the cucumber also easily produces adventitious roots.

II. Harm caused by adventitious roots in cucumbers

If the adventitious roots of cucumbers are not removed in time, the cucumber uses its own root system, or both the figleaf gourd roots and the cucumber roots, and then grafting cannot play its role, making the plant susceptible to Fusarium wilt; in the early stage it causes poor plant growth, and in the middle and late stages it causes plant death, seriously affecting yield. If the adventitious roots are removed too late, the nutrients produced by the plant will be supplied nearby to the development of the cucumber root system. The figleaf gourd root system does not get sufficient nutrients and thus develops poorly; even if the roots are removed later, there is still a certain effect on the growth and development of the cucumber.

III. Methods for removing and preventing adventitious roots in cucumbers

First, do it before the cucumber adventitious roots enter the soil, cutting them off from the base with a clean blade. Second, do it in clear, warm weather to help the wounds heal. Third, for seedlings planted too deep, after cutting off the roots, scrape away the soil at the base to expose the graft union. Fourth, for tilted vines, after cutting the roots, the vines should be hung upright. Fifth, water reasonably, avoid flood irrigation, and prevent the soil surface from becoming too wet. Sixth, keep the graft union above the plastic mulch film, seal the film tightly, and strictly prevent the formation of adventitious roots.

Ningjin County Agriculture and Forestry Bureau, Shandong Province Liu Zhongqiang