Analysis of the Causes of Vine Death in Cucurbits and Control Methods
Analysis and Control of Vine Death in Cucurbits
(Agricultural Wealth Network) There are mainly three diseases that cause vine death. The most common is Fusarium wilt caused by Fusarium fungi, followed by gummy stem blight caused by another fungus, and then root-knot nematode disease. All three diseases can cause leaves to wilt rapidly and the entire plant to die. To carefully distinguish among these three diseases, examine the stem. In Fusarium wilt, the surface of the diseased stem appears normal or only develops longitudinal cracking at the base in later stages; cutting diagonally with a knife reveals browning of the vascular bundles. Root-knot nematode disease symptoms occur in the root system: nematodes stimulate the plant roots to form knobby galls, initially milky white and later turning light brown, small ones like millet grains and large ones like mung beans or bigger; peeling open a root gall reveals semi-transparent nematodes under a microscope. Neither of the above two diseases harms the leaves, whereas gummy stem blight can damage both leaves and stems simultaneously. After leaves are affected, circular yellow-brown lesions appear, and in later stages many small black dots can develop on them, with the lesions easily breaking apart. Lesions on the vines are elliptical to spindle-shaped, white, and in humid weather the diseased areas exude a gummy substance; in later stages they dry and shrink with longitudinal cracking, becoming tangled like hemp. Gummy stem blight often causes only partial leaf wilting or death.
It should be particularly noted that both Fusarium wilt and root-knot nematode disease are relatively difficult to control, and the pathogens can survive in the soil for many years. Continuous cultivation of cucurbits will lead to a constant increase in pathogens, and the disease and damage will continuously worsen. Therefore, crop rotation and planting resistant or tolerant varieties are the preferred control measures. Using grafted seedlings with black-seed pumpkin (Cucurbita ficifolia) as rootstock is currently the main measure for controlling cucumber Fusarium wilt. Removing diseased plant residues and uprooting diseased plants are also very important disease prevention measures.
To control the above three diseases, applying chemicals is essential, but an accurate diagnosis must be made and different agents used for different diseases. For nematode disease, soil can be treated with ethoprophos (Yishubao), isazofos, fosthiazate (10% Fuqiduo), abamectin, Junxianke, and other agents, or these agents can be used as root drenches in the early stages of disease; for Fusarium wilt, soil treatment or root drenching with hymexazol (Tujunxiao), benomyl, carbendazim, thiophanate-methyl, and others is used; for gummy stem blight, the main approach is foliar spraying for protection, with available agents including chlorothalonil, flusilazole (Fuxing), and others.
It should be particularly noted that both Fusarium wilt and root-knot nematode disease are relatively difficult to control, and the pathogens can survive in the soil for many years. Continuous cultivation of cucurbits will lead to a constant increase in pathogens, and the disease and damage will continuously worsen. Therefore, crop rotation and planting resistant or tolerant varieties are the preferred control measures. Using grafted seedlings with black-seed pumpkin (Cucurbita ficifolia) as rootstock is currently the main measure for controlling cucumber Fusarium wilt. Removing diseased plant residues and uprooting diseased plants are also very important disease prevention measures.
To control the above three diseases, applying chemicals is essential, but an accurate diagnosis must be made and different agents used for different diseases. For nematode disease, soil can be treated with ethoprophos (Yishubao), isazofos, fosthiazate (10% Fuqiduo), abamectin, Junxianke, and other agents, or these agents can be used as root drenches in the early stages of disease; for Fusarium wilt, soil treatment or root drenching with hymexazol (Tujunxiao), benomyl, carbendazim, thiophanate-methyl, and others is used; for gummy stem blight, the main approach is foliar spraying for protection, with available agents including chlorothalonil, flusilazole (Fuxing), and others.