Detailed Explanation of the Symptoms, Causes, and Control Methods of Wax Gourd Charcoal Rot

Wax gourd is one of the vegetables we commonly eat; it tastes crisp and mild, and is a green, healthy vegetable. During the cultivation of wax gourd, it can be attacked by pests and diseases for various reasons, and wax gourd charcoal rot is very common. Once it occurs, it causes great harm to the fruit of the wax gourd. Below, let us take a look at the introduction to the symptoms, causes, and control measures of wax gourd charcoal rot.

I. Symptoms of wax gourd charcoal rot

Wax gourd anthracnose and charcoal rot are widely distributed and occur fairly commonly; they can occur both in protected cultivation and in open fields. They usually occur sporadically, and in severe cases can reach more than 10%. They mainly harm the root and stem base of wax gourd plants, and can also harm the fruit; in severe cases they also harm the leaves and stems and vines. During the adult plant stage of wax gourd, when the root and stem base above the soil surface is affected, the epidermis initially becomes water-soaked, then the cortex develops slight cracks, and the diseased area mostly forms dark brown tumors, with dark brown juice flowing out; later, the parts above the diseased area wither and die. On the root and stem base of dead plants, large numbers of black dot-like bodies can be produced, namely the pathogen's pycnidia and microsclerotia. When leaves are infected, they mostly form brown, nearly circular lesions, and later black granular dots are produced on the lesions, eventually causing the leaves to wither and die. When fruit is affected, water-soaked, nearly circular spots initially form, then it softens and rots, with obvious sunken areas, and on the lesions charcoal-black granular matter gradually appears, namely the pathogen's pycnidia. Later it develops into large charcoal-black lesions, and the diseased melon completely loses its edible value.

II. Causes of wax gourd charcoal rot

The pathogen overwinters in the soil as mycelium or sclerotia with diseased plant residues. The following spring, conidia are released from the pycnidia and spread by wind and rain, invading through wounds and continuously causing secondary infections in the field. The disease is likely to occur under conditions of high temperature and high humidity or when the plants have wounds.

III. Control measures for wax gourd charcoal rot

1. Select disease-resistant and disease-tolerant varieties. Before sowing, soak the seeds with Xin Gao Zhi Mo (New High Lipid Film); after soaking, remove them and let them dry before sowing. It can preserve warmth, retain moisture, and promote imbibition, improve the seed germination rate, and make the seedlings robust. It repels underground pests and isolates viral infection. It can also be mixed with seed coating agents. 2. Controlling diseases such as late blight, anthracnose, and powdery mildew well can basically also control this disease, so there is no need to control it separately. Targeted fungicides can be sprayed in advance together with a 500-fold dilution of Xin Gao Zhi Mo for control, inhibiting pathogen replication, reducing its drug resistance and the amount of pesticide used, and improving pesticide effectiveness.

2. During storage, do a good job of cleaning and disinfecting the cellar or warehouse before storage, and pay attention to regulating temperature and humidity, which can reduce the occurrence of this disease during storage.

In addition, wax gourd anthracnose is also fairly common, mainly harming leaves and fruit, and can also harm seedlings and vines. When seedlings are affected, the stem base near the ground turns dark brown and constricts, and the seedlings wither and die; when leaves are affected, water-soaked, circular, light brown spots initially appear, quickly becoming black or purple-black round spots, and some show concentric rings; when stems and vines are affected, the lesions are round or spindle-shaped, black, and slightly sunken, and after the lesions encircle the stem and vine, the upper leaves and vines wither and die; when fruit is affected, slightly raised spots initially appear on the fruit surface, then turn brown to purple-brown, round or oval lesions, obviously sunken, with many small black dots borne on them in a ring arrangement, and cracking often appears at the lesions.