Today we summarize 20 common diseases of crops and recommended drugs, I hope it will be helpful to everyone.
1. Damping-off
Damping-off is one of the important diseases of crops in the seedling stage. It is mostly caused by inappropriate temperature and humidity and extensive management in the seedling stage. When the disease is serious, it often causes seedlings to fall and die in large areas. In addition to peppers and Solanaceae vegetables, the disease can also harm vegetable seedlings such as melons, lettuce, celery, cabbage, kale, radish, and onions.
Recommended drugs: meconium sulfoxide, cymoxanil, oxadiazine, metalaxyl, mancozeb, and polyoxin.
2. Root rot
Root rot mainly harms seedlings and can also occur in adult plants. The symptoms of this disease are similar to root rot. It is a fungal disease that causes root rot, and the function of absorbing water and nutrients gradually weakens, and finally the whole plant dies. The main manifestations in the early stage of the disease are yellowing and wilting of the leaves of the whole plant.
Recommended drugs: meconazole, thiram, carbendazim, thiophanate-methyl, propiconazole, Ningnanmycin.
3. Damping-off
Damping-off often occurs in the middle and late stages of the seedling stage, mainly harming the base of the plant stem or the underground roots. Initially, it is an oval or irregular dark brown lesion. The crop wilts during the day and recovers at night. When the lesion expands around the stem, it dries up and dies, but does not fall over. The disease range is wide. In addition to Solanaceae and melon vegetables, some legumes and cruciferous vegetables can also be affected.
Recommended drugs: meconazole, mancozeb, ethoxypropane, polyoxin, Ningnanmycin.
4. Sclerotinia
Sclerotinia is a soil-borne fungal disease that mainly harms stems, leaves and fruits. The mycelium is not resistant to dryness and can only grow when the relative humidity is above 85%. It is a disease suitable for low temperature and high humidity conditions. In addition to cruciferous plants, common ones include lettuce, beets, sunflowers, citrus, mulberry, legumes, etc.
Recommended drugs: prochloraz, tebuconazole, difenoconazole, thiophanate-methyl, procymidone, and isoprodinil.
5. Downy mildew
Downy mildew can occur at all stages from seedlings to harvest, and mature plants are more seriously affected. It mainly harms leaves, developing from the base to the upper leaves. Common crops that are affected include cucumbers, lettuce, tobacco leaves, grapes, sugarcane, and soybeans.
Recommended drugs: copper hydroxide, thiram, thiophanate-methyl, cymoxanil, myclobutanil, azoxystrobin, dimethomorph, mancozeb, ethoxyconazole, fosetyl-aluminum, polyoxin, triadimenol, triadimefon, epoxiconazole, myclobutanil, propiconazole, tebuconazole, hexaconazole, and diniconazole.
6. Powdery mildew
Powdery mildew can occur on various vegetables such as peppers, tomatoes, cucumbers, and zucchini. The pathogen is spread by air flow and conveyors during agricultural operations. Pests such as thrips, aphids, and whiteflies can also spread it. Especially when it is hot and rainy, and the weather is hot and humid, powdery mildew is very likely to spread.
Recommended drugs: difenoconazole, hexaconazole, flusilazole, myclobutanil, azoxystrobin, prochloraz, thiophanate-methyl, procymidone, and ningnanmycin.
7. Leaf spot/leaf blight
Leaf spot: infects leaves, petioles, and stems. The lesions on the leaves are round, and then expand into irregular large lesions, and produce ring patterns. The lesions change from reddish brown to black brown, with gray-brown in the center. The lesions on the stems and petioles are brown and long.
Leaf blight: Leaf blight usually infects the leaf margin and leaf tip. The lesions are irregular from small to large, reddish brown to grayish brown, and the lesions are connected into large dead spots. The dry area reaches 1/3-1/2 of the leaf. There is a darker band on the edge of the lesion than the lesion; the boundary between the diseased and healthy is obvious.
Recommended drugs: azoxystrobin, fenpropimorph, mancozeb, propiconazole, tebuconazole, triadimenol, myclobutanil, chlorothalonil, thiram, methyl thiophanate, ethionine, and zhongshengmycin.
8. Gray mold
Gray mold is a common and difficult to control fungal disease of open-field and protected crops. It is a low-temperature and high-humidity disease that can affect flowers, fruits, leaves, and stems.
Recommended drugs: prochloraz, pyrimethanil, isoprodinil, procymidone, ethionine, and polyoxin.
9. Blight
Blight is divided into two categories: bacterial and fungal. Among fungal diseases, there are higher fungi represented by early blight and lower fungi represented by late blight. There is a saying that "early blight is high and late blight is low".
Recommended drugs: difenoconazole, azoxystrobin, mancozeb, propineb, isoprodinil, chlorothalonil, cuprous oxide, polyoxin, fosetyl aluminum, and ethionine.
10. Wilt
Blight is a plant disease caused by fungi or bacteria. It occurs suddenly, and symptoms include severe spots, wilting or death of leaves, flowers, fruits, stems or the whole plant. The root system of the plant is poorly developed, which will aggravate the disease.
Recommended drugs: azoxystrobin, mefenamic acid, prochloraz, methyl thiophanate, sinocycline, kasugamycin, nucleotides, ethionine, polyoxin, and Bacillus licheniformis.
11. Anthracnose
Anthracnose mainly harms mature fruits. The diseased part initially develops small transparent spots in the shape of water stains. After expansion, it becomes black, slightly sunken, with concentric ring patterns, densely covered with small black spots, and secretes light red sticky substances.
Recommended drugs: prochloraz, azoxystrobin, diniconazole, mancozeb, chlorothalonil, carbendazim, procymidone, methyl thiophanate, copper rosinate.
12. Scab
Scab mainly harms young leaves, twigs, and young fruits. The affected parts begin to show oil-soaked spots, which then turn waxy yellow. The lesions expand and bulge to one side to form conical nodules. It is spread by wind, rain, and insects. The disease is prone to occur when the temperature is 16-24℃, and the prone period is from March to May.
Recommended drugs: mancozeb, chlorothalonil, sulfur, and cyprodinil.
13. Sheath blight
Sheath blight is a common fungal disease in rice cultivation. It is prone to occur under high temperature and high humidity conditions. When the field temperature in the planting area is greater than 25 ℃ and the relative humidity is greater than 90%, the disease spreads faster and faster.
Recommended drugs: difenoconazole, tebuconazole, triadimefon, propiconazole, diniconazole, hexaconazole, cuprous oxide, thiophanate-methyl, fosetyl-aluminum, carbendazim, and jinggangmycin.
14. Rice blast
Rice blast is one of the important diseases of rice. It occurs in various places. According to the period and location of the damage, it can be divided into seedling blast, leaf blast, node blast, ear neck blast, and grain blast. After the occurrence, it can cause different degrees of yield reduction, especially ear neck blast or node blast occurs early and severely, which can cause white ears and even no yield.
Recommended drugs: tricyclazole, rice blast, prochloraz, ethozone, thiram, fosetyl-aluminum, thiophanate-methyl, carbendazim, methyl thiophanate, and kasugamycin.
15. Smut
Smut is transmitted through seeds and soil, mainly through soil. Generally, the whole ear is affected, but the ear shape is normal, but the grain becomes a small oblong gray bag, which bursts after maturity and releases the black powder inside. Once the plant is harmed by smut, the yield loss is serious.
Recommended drugs: tebuconazole, diniconazole, difenoconazole, triadimefon.
16. Ring rot
Ring rot mainly harms the branches and fruits of fruit trees, and sometimes also leaves. After infection by the pathogen, small dark brown spots with water stains appear at the beginning, mostly centered on the lenticels, and then turn brown and expand, showing concentric ring-shaped spots of different shades, causing fruit rot. The rotten fruit has a sour smell and sometimes oozes brown mucus.
Recommended drugs: mancozeb, thiophanate-methyl, carbendazim, tebuconazole, and cyproconazole.
17. Black spot
Black spot is a fungal disease that invades directly from the epidermis of plant leaves, fruits, and stems, and can also invade from stomata and wounds. The disease requires low temperature and high humidity conditions, high planting density, low light, poor ventilation, large irrigation in protected areas, repeated cropping, and low fertilizer management. Improper management will cause severe disease.
Recommended drugs: azoxystrobin, flusilazole, difenoconazole, mancozeb, tebuconazole, diniconazole, procymidone, and myclobutanil.
18. Soft rot
Soft rot mainly harms the juicy and thick organs of plants, such as tubers, rhizomes, fruits, and stem bases, and can cause the tissues or organs of plants to rot. It also occurs during transportation and storage. It harms many types of crops, including cruciferous crops, tomatoes, potatoes, melons, sweet potatoes, etc.
Recommended drugs: chlorothiazolin, isoprodinil, cyproconazole, and kasugamycin.
19. Bacterial angular leaf spot
Bacterial angular leaf spot is a bacterial disease that mainly harms leaves and fruits. It is generally more serious in greenhouses and sheds with low temperature, high humidity, and repeated cropping. It often harms cucumbers, watermelons, beans, cotton, sweet persimmons, etc.
Recommended drugs: copper hydroxide, copper rosinate, ethoxypropane, and cyprodinil.
20. Viral disease
Viral disease is a disease caused by plant virus parasitism. High temperature, drought, severe aphid damage, weak plant growth, repeated cropping, etc. are prone to cause the disease. It can be transmitted through contact during field operations, and can also be transmitted by aphids and machinery.
Recommended drugs: Ningnanmycin, guanidine hydrochloride, tridecaneguanidine, copper rosinate, amino oligosaccharides, triacontanol, sodium phosphate, oxytetracycline, and tetracycline.
