Melon diseases mainly include melon damping-off, melon stem rot, melon bacterial wilt, melon soft rot, melon downy mildew, melon powdery mildew and melon Fusarium wilt, among which melon damping-off mostly occurs in low-temperature and humid environment, mainly at the seedling stage of melon, and when the disease is serious, the seedlings will wither and die. Its pathogen can survive in the soil for a long time and will spread through irrigation water and other media.

First, melon diseases

1, melon damping-off disease

(1) Melon damping-off mostly occurs at the seedling stage of melon. After emergence, the part of the stem contacting with the ground will be flooded, and then it will turn into a yellow-brown linear shape, which will cause the seedlings to collapse, lack water, and then wither and die.

(2) Melon damping-off disease is easy to occur in low temperature and humid environment, and its pathogen can survive in soil for a long time, and it will spread with wind and rain, irrigation water and other media in spring.

2. Melon stem rot

(1) Melon stem rot mainly harms the stems and roots of melon. In the mature stage, water stains will appear on the root epidermis near the ground, and then gradually crack and ooze brown juice, which will lead to melon withering and death in severe cases.

(2) When melon is exposed to high temperature and high humidity for a long time and has a wound, germs will enter from the wound, thus causing diseases.

3. Bacterial wilt of melon

(1) Bacterial wilt of melon mainly harms the stems and vines of melon. After illness, the stems and vines began to thin, waterlogging appeared, and the top vines began to wither. If there is not enough nutrition in the later stage, the whole plant will easily wither and die.

(2) The main pathogen of melon bacterial wilt is Bacillus europaeus, which overwinters in leaf-eating insects and disease residues and begins to infect through wounds on insects and plants in spring.

4. Melon soft rot

(1) Melon soft rot occasionally damages vines, but mainly fruits. At the beginning of the disease, there will be water stains. With the expansion of water stains, there will be depressions and the affected area will be slightly soft. In the late stage of illness, it will rot and stink.

(2) The subspecies of European Bacillus soft rot is the main pathogen of melon soft rot, which overwinters in diseased residues and soil and then spreads through insects, wounds and wind and rain.

5, melon downy mildew

(1) Melon downy mildew mainly harms leaves. At the beginning of the disease, there are small yellow spots on the leaves. With the aggravation of the disease, the lesion will be limited by the veins of the leaves, and it will be yellow-brown but irregular polygon.

(2) If the environment is humid, there will be a layer of black mold on the lesion on the back of the leaf, which will spread upward from the base of the plant. In severe cases, the diseased spots will be connected together, resulting in dry and atrophy of the whole leaf.

6. Melon powdery mildew

(1) Melon powdery mildew mainly harms leaves, develops from bottom to top, and seriously harms petioles and stems and vines.

(2) At the early stage of the disease, small white speckles will appear on the front of the leaves, which will expand into white round speckles in the future, and multiple diseased spots will be connected with each other. With the aggravation of the disease, the white and pink lesions will gradually turn gray, and finally the diseased leaves will wither and die.

7. Melon Fusarium wilt

(1) Melon stem blight mainly harms main and lateral vines. At the beginning of the disease, there will be a slightly sunken yellowish oil-soaked spot near the nodule, then the affected area will crack and secrete yellowish-brown colloid, and a reddish-brown or black lump will appear after drying.

(2) Melon Fusarium wilt is one of the common diseases in melon production in solar greenhouse. In a serious solar greenhouse, it usually leads to the death of the whole plant, which leads to serious yield reduction.

8. Melon Fusarium wilt

(1) Melon blight mainly harms leaves, stems and fruits. In the early stage of infection, dark green spots will appear in the leaves, which will rot in boiling water when the humidity is high.

(2) Phytophthora melongena can infect not only melons, but also beets, potatoes, tomatoes and other crops. The optimum temperature for the growth and development of this pathogen is 28-32℃.

Second, the prevention and control methods of melon diseases

1, melon damping-off disease

(1) Before sowing, the seeds need to be disinfected and can be dressed with chemicals. When fertilizing seedling soil, we should also apply fully decomposed farmyard manure.

(2) After the onset of the disease, agents such as cuprammonium mixture can be used to prevent and control melon damping-off.

2. Melon stem rot

(1) Continuous cropping is not allowed, with rotation for at least three years. If there is water in the field, drain it in time.

(2) When harvesting cantaloupe, it is necessary to thoroughly remove diseases and residues, and to reasonably control planting density and fertilization at ordinary times.

3. Bacterial wilt of melon

(1) The main control method of melon bacterial wilt is to avoid continuous cropping and clean up the diseased body in the garden in time.

(2) After the onset, agricultural streptomycin can be sprayed for control.

4. Melon soft rot

(1) Pay attention to rotation and drainage at ordinary times, and remove the sick and disabled in time.

(2) Pesticides such as phytochemicals can be sprayed to control melon soft rot.

5, melon downy mildew

(1) Chemicals such as mancozeb, chlorothalonil, propineb, dimethomorph cymoxanil and flupirimicarb can be used to control melon downy mildew.

(2) You can choose varieties resistant to downy mildew, such as yellow river honeydew melon, which should be properly fertilized and pruned in time at ordinary times to keep ventilation and light transmission, and should not be adjacent to or continuous cropping or flooded with melon crops.

6. Melon powdery mildew

(1) Methylthio, myclobutanil, diethyl ether phenol and kresoxim-methyl can be used to control melon powdery mildew.

(2) Selecting varieties with strong resistance to melon powdery mildew is an effective way to prevent the disease, such as farmer Lan Xiang. It is necessary to do a good job in field cleaning, reduce the spread probability of germs, and strengthen plastic pruning, humidity management, ventilation management and fertilizer and water management.

7. Melon Fusarium wilt

(1) Generally, fungicides such as methylthio, chlorothalonil, bensulfuron-methyl and zineb can be used to control the stem blight of melons.

(2) Disease-resistant varieties such as Elizabeth and Xinmiza can be selected to rotate with non-melon crops for 2-3 years, and litter and plant residues should be removed in time at ordinary times.

8. Melon Fusarium wilt

(1) Mancozeb, fenpropathrin, cyazofamid and flupyrazole can be used to control melon wilt.

(2) Disease-resistant varieties such as honeydew melon 1 can be selected, and water and fertilizer management should be strengthened, more phosphorus and potassium fertilizers should be applied, and nitrogen fertilizer should be properly controlled.