Which kinds of diseases and pests should be prevented when cucumbers are grown in the greenhouse

In recent years, the variety of cucumber diseases in greenhouses has been increasing, causing significant damage to production. To help growers manage these issues effectively, we have compiled some common diseases, their symptoms, and practical prevention and control methods based on our field experience. Bacterial leaf spot typically appears in the early stages as water-soaked spots that turn light brown over time. The lesions are usually restricted by leaf veins, appearing as polygonal, grayish-brown or yellow-brown areas. When humidity is high, a milky, watery bacterial exudate may appear on the leaves. After drying, white marks remain, and the affected tissue becomes brittle and prone to tearing. Lesions on stems, petioles, and fruits start as water-soaked, round spots, with a white mucus when wet and a white residue after drying. For control, seeds can be treated with 70°C dry heat for 72 hours (with moisture content below 10%) or soaked in 50–52°C warm water for 20 minutes, followed by soaking in water for 3 hours before sowing. In the early stages of the disease, spraying 1000 times diluted agricultural streptomycin powder, 500 times diluted 30% DT sterilizer, or 1000 times diluted 5% chlorothalonil dust is highly effective. Fusarium wilt is a serious disease that can persist in the soil for up to 5–6 years. It thrives in high temperature and humidity conditions, especially when the soil temperature is between 25°C and 30°C, and air temperature ranges from 24°C to 27°C. Excessive nitrogen fertilizer and acidic soils (pH 4.6–6) increase the severity of the disease. Fields with high nematode populations or those prone to flooding are more likely to suffer from it. To manage Fusarium wilt, planting resistant varieties and rotating crops with non-cucurbit vegetables like onions for more than three years can reduce pathogen buildup. Early treatment with 50% carbendazim wettable powder at 500 times dilution or 70% thiophanate-methyl at 800 times is recommended. Root irrigation with 70% dexamethasone WP at 1000 times or 50% fipronil dry powder at 800 times, applying 250 ml per plant every 7 days for three applications, is also effective. Grafting is currently one of the most effective methods, using black pumpkin as rootstock and cucumber as scion, which can provide over 95% disease control. Downy mildew initially shows as irregular, water-soaked yellow spots on the underside of leaves. As the disease progresses, the lesions expand and become polygonal due to vein restriction. In severe cases, small lesions merge into larger ones. Under moist conditions, a layer of gray or black mold develops on the back of the leaves. The disease spreads upward, eventually causing complete wilting of the plant. Prevention involves proper fertilization, increased phosphorus and potassium application, strong seedling cultivation, controlled irrigation, and improved ventilation to reduce humidity. Chemical control options include 25% Rhizoctonia WP at 800–1000 times, 90% Epimedium WP at 500–600 times, 75% chlorothalonil WP at 500–600 times, 72% Kexin wettable powder at 600–800 times, or 72% Pu Liqin liquid at 600–1000 times. Alternatively, 20–30 grams of chlorothalonil smoke agent per acre can be used. Apply every 7–10 days for 3–5 consecutive treatments. Root-knot nematodes cause visible galls on the roots, especially in severe infections. Affected plants show stunted growth, poor fruiting, and midday wilting. Pulling up the roots reveals swollen, necrotic nodules, often resembling beads. Inside these nodules, small white nematodes can be seen. To manage root-knot nematodes, deep plowing, fallow irrigation, and increased organic matter application are recommended. During the growing season, 50% phoxim EC at 1500 times or 30% Jiasheng microcapsule suspension at 500 times can be applied, using 0.25–0.5 kg of solution per plant. One application is usually sufficient for effective control.

Plant Extract

Product Name: Chamomile extract

English Name: Chamomile extract

Plant part used: Flowers

Active ingredient: apigenin

character; Brownish yellow powder

Specification: 10:1

CAS No.: 520-36-5

Efficacy: calm the mind, help digestion, improve skin and resist oxidation.

Function:

(1) Calming effect

The cooling effect of chamomile can treat fever. Its calming and soothing effect can resist allergy, relieve nervous tension, improve insomnia, soothe mental trauma, and improve allergic constitution;

(2) Antispasmodic and analgesic effects

Chamomile has anti spasm and analgesic effects (stomach pain, physiological pain, headache, muscle pain and toothache);

(3) Role of Gynecology

Chamomile can nourish uterus and ovary and improve pelvic inflammation;

(4) Role of digestion

Chamomile can improve digestion, regulate intestines and stomach, and eliminate flatulence;

(5) Role of skin

Chamomile Essential Oil can improve sensitive, dry and peeling skin and increase skin elasticity. It can also treat skin inflammation such as eczema, abscess and acne, promote wound healing, and has excellent effect on regulating sunburned and scalded skin.

Purslane Seed Extract, Chamomile Extract Powder, Morinda Root Extract

Xi'an Tian Guangyuan Biotech Co., Ltd. , https://www.tgybiotech.com