Symptom Identification and Control Methods of Cucumber Gummy Stem Blight

Cucumber is one of the common vegetables in daily life, and it is a good choice whether eaten raw or cooked. During cucumber cultivation, pests and diseases often attack, and a common one is cucumber gummy stem blight. Once this disease occurs, it damages the marketability of cucumbers. So what are its symptoms? How can it be controlled?

I. What are the symptoms of cucumber gummy stem blight?

The stems, leaves and young fruits of cucumber can all be damaged. On affected stems, the lesions are oil-soaked in appearance and yellow-brown; in severe cases, the stem nodes turn dark brown, rot and break easily. The lesions often crack, are red-brown, and the vascular bundles do not change color. After leaves are damaged, the disease mostly spreads inward from the leaf edges to form large triangular spots that are yellow-brown and crack easily, with dense small black dots on the lesions. When fruits are damaged, water-soaked areas mostly appear at the top of the fruit, with white sticky gum.

Cucumber gummy stem blight is a disease caused by fungi and can infect many plants of the Cucurbitaceae family and cause disease. The pathogen overwinters in the soil or on seeds and trellis poles. In the following spring, it spreads through wind, rain and irrigation water, and invades plants through stomata, water pores or wounds. Seed-borne bacteria cause infection of the cotyledons. Disease is likely to occur on cloudy and rainy days and when there is heavy dew at night. In continuous cropping fields, flat-bed cultivation, poor drainage, excessive density or insufficient fertilizer, the disease occurrence is greater.

The pathogen overwinters as pycnidia or perithecia with diseased residues in the soil, or attached to seeds, trellis poles, greenhouses and greenhouse frames. The following year it spreads through wind, rain and irrigation water, and invades through stomata, water pores or wounds. The pathogen prefers warm, high-humidity environmental conditions. At a temperature of 20-25°C, with a maximum of 35°C and a minimum of 5°C, and a relative humidity above 85%, the disease is more severe.

II. How can cucumber gummy stem blight be controlled?

1. Chemical control

Commonly used agents: Sike 1 plus Adjuvant 1, difenoconazole plus zinc thiazole zhongshengmycin or kasugamycin, etc.

Treatment formula: Sike 1 at 150 times plus Adjuvant 1 at 750 times plus benzyl propiconazole at 750 times plus zinc thiazole zhongshengmycin at 750 times, sprayed, and at the same time Sike 1 at 5 times can be used to smear the stems.

2. Strengthen management

Carry out a 2-3 year crop rotation; apply sufficient base fertilizer and topdress in a timely manner to prevent premature aging of plants; drain promptly after rain. In protected cultivation, pay attention to ventilation and dehumidification; after harvest, thoroughly remove diseased residues from the field, then deep plow; plant on high beds, cover with plastic film, and water under the film; in the early stage of disease, carefully and thoroughly remove diseased leaves and diseased vines; pay attention to scientific ventilation.

3. Fertilization

Adopt a formula fertilization technique and apply sufficient fully decomposed organic fertilizer. After harvest, promptly and thoroughly remove diseased residues, burn them or bury them deeply. In protected cultivation, the center should be reducing humidity, using ridge cultivation, full-film mulching, and dark irrigation under the film; where conditions permit, drip irrigation can be used; maintain reasonable close planting, strengthen ventilation and light transmission, and reduce humidity and dripping in the greenhouse. During cucumber growth, remove diseased leaves in time; in open-field cultivation, avoid flood irrigation, strengthen waterlogging prevention in the rainy season, reduce soil moisture content, and appropriately control watering after disease occurs.

4. Seed treatment

Before sowing, soak the seeds in warm water at 55°C for 15 minutes while stirring constantly, then soak them in warm water for 3-4 hours, and then germinate and sow. Alternatively, soak the seeds in a 100-fold solution of 40% formalin for 30 minutes, rinse with clean water, and then germinate and sow.