How to treat eggplant leaf diseases? A detailed guide to prevention and control methods
Eggplant is a vegetable we often eat in our daily life. It originated in tropical Asia and is now distributed all over the world, with the most cultivation in Asia, accounting for about 74% of total world production; Europe is next, accounting for about 14%. It is cultivated throughout China and is one of the main summer vegetables. So during the growing process of eggplant, how do you treat leaf diseases?
I. Main diseases of eggplant leaves and their control
The diseases that harm eggplant leaves mainly include gray mold, Phytophthora blight, brown spot (Phomopsis rot), brown patch, powdery mildew, leaf mold, bacterial wilt, and so on. To control these diseases, the type of disease must be determined according to the specific symptoms, and the right remedy should be applied.
Eggplant gray mold occurs mainly on overwintering greenhouse eggplants and early spring plantings, and is frequent in the cool autumn and winter areas of southern China. Gray mold mainly damages young fruit and leaves, and in severe cases it also infects the stems. Infected leaves show typical V-shaped lesions, and severe cases form large coalesced patches that cause the entire leaf to dry up. The main measures include properly regulating the temperature and humidity in the greenhouse or room, promptly removing diseased fruit and leaves, carrying them outside the greenhouse and burying them deeply. For spraying, you can choose 50% Procymidone wettable powder at 2000 times dilution; 38% oxadixyl, pyrimethanil and copper octanoate 800 times dilution; 41% polyoxine-pyrimethanil 600 times dilution, and other chemical treatments.
Eggplant Phytophthora blight, also called late blight, is one of the three major diseases harming eggplant. It mainly infects leaves, stems, flowers and fruit, and when severe it often causes large amounts of fruit to rot, directly affecting yield. The main control measures are selecting disease-resistant varieties, disinfecting seeds, practicing crop rotation, and carefully choosing the site. There is currently no chemical treatment method.
Eggplant brown spot (Phomopsis rot) is a disease unique to eggplant. On leaves it mainly appears as round to irregular spots on the leaf surface, with small black dots arranged in rings on the spot surface, and in severe cases the stem bark peels off, causing branches or the whole plant to die. The main control measures are clearing weeds in the field and around it, burning them in a centralized manner or composting them, rotating with non-grass-family crops, selecting disease-resistant varieties, and raising seedlings for transplanting. For disease occurring at the seedling stage, spray 75% chlorothalonil wettable powder at 1000 times dilution, 50% captan wettable powder at 500 times dilution, 65% zineb wettable powder at 500 times dilution, 40% flusilazole emulsifiable concentrate at 8000 times dilution, etc. For disease occurring at the fruit-setting stage, spray: 75% chlorothalonil wettable powder at 600 times dilution, 70% zineb wettable powder at 400-500 times dilution, 65% ziram wettable powder at 500 times dilution, or 1:1:200 Bordeaux mixture.
Brown patch often occurs at the seedling stage and in the middle and late growth stages of eggplant, mainly harming leaves. Infected leaves have light brown lesions, with a light grayish-brown patch area in the middle of the lesion; when mature plants are infected, the leaves initially show small water-soaked brown spots with halos. The main control methods are practicing crop rotation for more than 2 years, rational irrigation, and mulching with plastic film. Chemical measures are to begin spraying at the early stage of disease with 75% chlorothalonil wettable powder at 600-700 times dilution or 70% mancozeb wettable powder at 500 times dilution, 64% oxadixyl-plus wettable powder at 500 times dilution, or 58% metalaxyl-mancozeb wettable powder at 500 times dilution. Stop using chlorothalonil 7 days before harvest, and stop using the others 3 days before harvest.
Eggplant powdery mildew is one of the common diseases of eggplant. At the early stage of disease, irregular chlorotic yellow small spots appear on the leaf surface, and corresponding white small mold spots appear on the underside of the leaf. Later, the number of lesions increases and the white powdery material becomes increasingly obvious, appearing as white powdery spots. Chemical control measures are to promptly spray at the early stage of disease with 15% triadimefon (Tridimefon) wettable powder at 1000-1500 times dilution, or 20% triadimefon emulsifiable concentrate at 2000 times dilution, 40% sulfur-multi suspension concentrate or 36% thiophanate-methyl suspension concentrate at 500-600 times dilution, or 50% sulfur suspension concentrate at 300 times dilution.
Leaf mold mainly harms the leaves and fruit of eggplant. When leaves are infected, chlorotic spots with indistinct edges first appear, and on the back of the lesion grows olive-green downy mold, namely the pathogen's conidiophores and conidia, causing the diseased leaves to fall off early. Chemical measures are to begin spraying at the early stage of disease with 50% thiophanate-methyl or sulfur suspension concentrate at 800 times dilution, or Aitefu emulsifiable concentrate at 800-1200 times dilution, or 10% difenoconazole at 2000 times dilution, or 47% kasugamycin-copper wettable powder at 800-1000 times dilution.
The symptoms of eggplant bacterial wilt are that at first the leaves of individual branches, or part of a single leaf, wilt, and then it gradually spreads to the entire branch. At the early stage of disease, use 72% agricultural streptomycin sulfate soluble powder at 4000 times dilution, or 50% copper bis(dodecylbenzenesulfonate) wettable powder at 500 times dilution, pouring 0.3-0.5 liters of solution per plant, once every 10 days, for a total of 3-4 pourings.
The above are the main diseases harming eggplant leaves. When abnormal symptoms appear on eggplant leaves, the cause should be determined promptly so that the correct cause can be identified and timely targeted treatment can be given.