Cucumber is a common popular vegetable. In the process of planting cucumbers, various diseases will inevitably appear, which will affect cucumber fruits, stems, leaves, and seedlings. In order to ensure the production of cucumbers, it is necessary to make cucumbers well. What are the diseases of cucumber and their control methods? Let's take a look together!

1. Cucumber downy mildew

Both the seedling stage and the adult plant stage can be affected, mainly damaging the leaves.

Symptoms: After the leaves are damaged, water-soaked spots appear at the beginning, and the spots gradually expand, showing polygonal light brown spots. When the humidity is high, a gray-black mold layer grows on the back or surface of the leaves. When it is severe in the late stage, the lesions rupture or connect.

Chemical control:

Propamocarb hydrochloride , Mancozeb+Dimethomorph,  Azoxystrobin,  Metalaxyl-M+Propamocarb hydrochloride

2. Cucumber white powdery mildew

It can be infected from the seedling stage to the harvest stage, and the leaves are the most severely affected, followed by petioles and stems, and the fruits are less affected.

Symptoms: In the early stage of the disease, small white nearly round powder spots appear on both sides of the leaves, and there are more leaves. Later, it expands into unobvious edges and continuous white powder. In severe cases, the whole leaf is covered with white powder, and it turns gray in the later stage. The diseased leaves are withered and yellow, but generally do not fall. Symptoms on petioles and stems are similar to those on leaves.

Chemical control:

Pyraclostrobin , Chlorothalonil , Thiophanatemethyl ,Propineb

 

3. Cucumber red powdery mildew

Symptoms: Mainly damage the leaves of cucumber in the late growth period. Dark green to light brown lesions develop on leaves. When the humidity is high, the lesions are thin, the edges are water-soaked, and they are easy to break. The longer the high humidity lasts, the easier it is for light orange mold to grow on the lesions, which expands rapidly and causes the leaves to rot or dry up.

The colonies are initially white and then turn pink.

Preventive agents:

Iprodione , Azoxystrobin,Chlorothalonil

4. Cucumber blight

Cucumber vine blight mainly damages stems and leaves.

Leaf disease: In the early stage, there are nearly round or irregular light brown lesions, some of which form a "V" shape from the leaf edge inward. Later, the lesions are easily broken, the ring pattern is not obvious, and black dots grow on them.

Diseases of stems and tendrils: mostly at the base or nodes of stems, oval to fusiform, slightly sunken, oil-soaked lesions appear, sometimes overflowing with amber resin jelly, when the disease is severe, the stem nodes turn black, rot, Easy to break. It causes yellowing and necrosis of the leaves above the lesion spots, the vascular bundles of the diseased plants are normal and do not change color, and the roots are normal

Preventive agents:

Azoxystrobin,Difenoconazole

 

5. Cucumber anthracnose

Cucumbers can be damaged at both the seedling stage and the adult plant stage, mainly the leaves, but also the petioles, stems, and melon strips.

Incidence characteristics:

Seedling disease: Semicircular brown lesions appear on the edge of the cotyledon, with black dots or light red sticky matter on it, and the base of the stem turns light brown and shrinks, causing the melon seedlings to fall.

Incidence of adult plants: The leaves appear light yellow, water-soaked, and round lesions at the beginning, and then turn yellowish brown with yellow halos. When dry, the lesions crack and perforate; when wet, the lesions secrete pink sticky matter. Onset of melon strips: Water-soaked light green lesions are produced, which later turn into dark brown slightly sunken round or near-round lesions. In the later stage, the diseased fruits are bent and deformed, cracked, and pink sticky matter is produced when wet

Preventive agents:

Pyraclostrobin,metiram ,Mancozeb,Propineb