Cucumber Diseases Pictures and Prevention

Cucumber is a vegetable crop grown in many areas. During the cucumber planting process, various diseases are prone to occur if the management is improper. Common diseases include downy mildew, wilt, powdery mildew, etc. Let’s take a look at the complete pictures and prevention of cucumber diseases below.

1. Downy Mildew

The disease is prone to occur when the temperature reaches 15-28℃ and the relative humidity is greater than 80%. Yellow lesions appear on the front of the leaves, and water-soaked, light green spots appear on the back. The lesions are irregular polygonal, and a gray-black mold layer appears on the back in a humid environment.

Prevention and control methods : Use enoyl aluminum phosphate, mancozeb, flumarin, propiconazole, enoyl cymoxanil, mancozeb, cyazolin, etc., choose one of the agents each time and use them alternately for 5-7 days, and apply 3 times in a row.

2. Fusarium wilt

The disease develops rapidly when the temperature is between 24-30℃. It is very easy to get sick under conditions such as heavy soil, poor drainage, excessive watering, many underground pests and many root wounds. The base of the main vine of the diseased plant is cracked longitudinally. If the diseased stem is cut longitudinally, you can see that the vascular bundle has turned brown, yellow-brown stripes appear at the base of the stem, and yellow gelatinous fluid flows out. When it is moist, a white to pink mold layer will form on the surface of the diseased part.

Prevention and control methods: In the early stage of the disease, you can use 500 times diluted 50% carbendazim, or 400 times diluted 50% thiophanate-methyl to irrigate the roots. Use 250 grams of solution for each plant, irrigate once every 10 days, and irrigate 2-3 times in a row.

3. Powdery mildew

The disease is prone to occur under conditions of closed field conditions and leggy plant growth. This disease mainly harms the leaves, with less damage to the fruits. In the early stage of the disease, small white, nearly circular, star-shaped spots appear on the front or back of the leaves. In severe cases, the spots cover the entire leaf. In the later stage of the disease, the white powder gradually turns grayish white and the leaves dry up.

Prevention and control methods: In the early stage of the disease, you can spray with Agro-antibiotic 120 or 2000 times diluted 40% DuPont Fuxing, spray once every 7-10 days, and spray 3-4 times in a row.

4. Angular spot disease

The disease is prone to occur when the field humidity is high, rainfall is heavy, and ventilation is poor. The diseased leaves develop needle-sized light green water-soaked spots, which gradually turn into yellow-brown, light brown, brown, grayish white, and white. Due to the limitations of leaf veins, the spots are polygonal. When moist, the lesions on the back of the leaves are covered with milky white pus. When dry, they appear as a white film, which is brittle and easily perforated.

Prevention and control methods: At the beginning of the disease, you can spray 500 times diluted DT fungicide or 600-800 times diluted 47% Carranon, once every 5-7 days, and spray 3-4 times in a row. Or spray 2000 times diluted 72% agricultural streptomycin sulfate soluble powder. Spray once every 5-6 days, and spray 2-3 times in a row.

5. Anthrax

The disease is more serious under conditions of high temperature, high humidity, dense planting, excessive nitrogen fertilizer, continuous cropping in protected areas, and poor ventilation. Small yellow-brown, round spots appear on the leaves, which gradually expand into nearly round reddish-brown spots with yellow halos on the edges. In severe cases, the cucumber leaves dry up and crack and become perforated in strips after drying.

Prevention and control methods: In the early stage of the disease, you can use 45% benomyl smoke agent, with a dosage of 3.75 kg per hectare each time, fumigate once every 10 days and spray once every 8-10 days.

6. Disease

The leaves are infected during the adult stage, initially appearing as dark green water-like spots, which then expand into large, nearly circular or irregular spots with unclear edges. When wet, the entire leaf quickly rots and droops.

Prevention and control methods: You can use chlorpyrifos·mandelin, copper oxychlorvate·metalaxyl, oxadiazine·metalaxyl, myclobutanil-methyl, azoxystrobin, and metalaxyl cyanamide.

7. Botrytis cinerea

In the early stage of the disease, water-soaked spots form on the edges of the leaves. As the disease worsens, the color gradually turns gray-brown and the diameter can reach 20-50mm. When leaves are infected, most of them will form "V"-shaped spots on the leaf edges, with gray mold growing on the surface and obvious edges.

Prevention and control methods: You can use pyrimethanil, flutolanil, boscalid, carbendazim, and fucymidone.

That’s it