"Sue Su, you come to help me see, the eggplant seedlings in my greenhouse are dying if I don't know what happened?" On May 22, Su Guangming, deputy director of the Agricultural Bureau of Nanjiang County, Sichuan Province, and a senior agronomist When entering the Yushu Village of Dongpu Town, Li Yinquan, a large vegetable grower, was pulled into the greenhouse. Su Guangming pulled out a dead eggplant seedling and said that this is called eggplant plague, which is the main disease of eggplant. Eggplant can be harmed during each growth period. The general loss is 20%-30%, and the loss can be more than 50% when the disease occurs.

Observing symptoms

Seedling stage: The base of the embryo stem is water-stained and develops rapidly, often stumbling, causing the seedling to die.

Adult stage: Generally, the disease occurs first on the fruit close to the ground. At the beginning of the disease, a round brown spot is produced, which gradually enlarges, and the tip is sunken, and the inside of the fruit is black and rot. When the weather is wet, the disease minister has dense white wool. The incidence of the leaves starts from the edge of the leaf tip or the leaf. The lesion is dark green at first, and then turns brown, which is irregular. When wet, the diseased part is also sparsely white. The shoots develop, and they become water-stained, and then become brown and contracted to break, and the upper branches and leaves are wilting.

Pathogen discovery

The pathogens of eggplant plague are Phytophthora parasitica, Phytophthora capsici, and Phytophthora sojae, all of which belong to the subfamily fungus. Mycelium is filamentous and has no membrane. The cyst is simple, silky, colorless, and has a length of 35-500 microns. The sporangia are terminal, single-celled, ovoid, with papillary protrusions at the top, and the size (28-59) micron x (24.8-43.5) micrometers. The sporangia sprouted with double-flagellate zoospores. Thick-walled spores are spherical, unitary, and pale yellow. The oospores are spherical in shape and have a diameter of about 30 microns.

Master the law

The pathogens overwinter in the soil with oospores and diseased tissues. In the second year, the oospores are splashed on the eggplant fruit by rain, and the germination grows out of the bud tube. The bud tube contacts the surface of the eggplant to produce an applicator. The invading silk is produced from the bottom of the bud, penetrates the epidermis of the host, and then produces sporangia on the lesion. After the germination, zoospores are formed, which are spread by wind and rain to form reinfection. After the fall, oospore formation in the diseased tissue overwinter. Eggplant plague often occurs in the hot and rainy season from August to September. High temperature and rain during the fruiting period are also beneficial. The rainy season is early and the rainfall is heavy, especially the rainy weather and the sultry weather. The incidence is early and heavy. Low terrain, soil viscosity, easy accumulation of water in the field after rain, excessive dense planting, poor ventilation, easy to cause disease.

Control method

In agricultural control:

First, the selection of resistant varieties;

Second, the crops should be rotated for more than 3 years with crops other than Solanaceae vegetables and melons;

The third is to choose the land that is easy to drain, and at the same time, deep-turn the land in winter, apply more organic fertilizer and phosphorus and potassium fertilizer, and adopt high ridge cultivation, east-west direction, easy to discharge and easy to fill;

Fourth, it is reasonably densely planted, and the foot and leaves are promptly removed to ventilate the field, and the rotten fruit and diseased leaves in the field should be cleaned up and burned or buried deeply;

The fifth is to apply enough base fertilizer, timely topdressing, increase the application of phosphorus and potassium fertilizer, to avoid partial application of nitrogen fertilizer.

Physical control:

It can be soaked in warm water of 55 ° C for 15 minutes or warm water of 50 ° C for 30 minutes.

Chemical control:

1 soaking with 300 times of formalin solution for 15 minutes, washing with water and sowing;

2 In the seedling stage, 75% chlorothalonil wettable powder 600 times solution, or 40% ethyl phosphorus aluminum wettable powder 200 times solution, or 65% sensible zinc wettable powder 500 times solution. Spray once every 7 days for 2-3 consecutive times;

3 When planting tomato seedlings, use 70% thiophanate-methyl WP, or 75% dikesone wettable powder 1:100 to form a medicinal soil, apply 1100-1500 kg of soil per acre or ditch;

4 Before the onset, use 25% metalaxyl WP 500 times solution or 80% aluminum triethyl citrate 600 times solution to fill the roots, 150 ml per litter filling solution, once every 10 days;

5 spray protection in the early stage of the disease, commonly used pesticides have 80% spray wettable powder 600 times liquid, or 72% can expose wettable powder 800 times liquid, or 69% Anke manganese zinc wettable powder 900 times liquid, or 40 B Phosphorus aluminum wettable powder 200 times liquid, or 58% metalaxyl manganese zinc 400-500 times liquid. In order to prevent and form drug resistance, different kinds of drugs should be used for each medication.