Prevention and control of blight of carnation

Symptomatic stem and root disease. It was infected at the seedling stage, causing root rot and death. After planting, the main stem and branches were infected, and the injured part was flooded, gray when dry, and the stems and leaves above the injured part withered.

The pathogen PhytophthoranicotianaeBreda is called Phytophthora tobaccoides, which belongs to the subphylum flagellate fungi. The cyst stem protrudes from the stomata, 10-744 microns long, sporangia solitary, long oval or ovate, 28.8-67.5 × 12.5-30 microns in size, obvious papillae at the top of the cyst, oospores spherical, yellowish or golden yellow, 20-22 in diameter. 5 micron. Chlamydospores are yellowish spherical and 20-40 microns in diameter. The developmental temperature limit of the pathogen was 12-36 ℃ and 25-32 ℃ was the best. The mycelium of 50 ℃ was killed in 5 minutes.

The transmission route and disease conditions were overwintered by oospores on the disease remains in the soil. When the conditions are suitable in the following year, sporangia and zoospores are produced, and the disease occurs after infecting the host. When the humidity is high, the sporangium is produced by the disease minister, which spreads by wind and rain and carries on repeated infection.

Prevention and cure method

1. Build high beds to prevent rain and drainage.

2. Chemical control should be applied before the rate of diseased plants does not exceed 1%.

1) spray: commonly used sprays include 25% metalaxyl wettable powder 600 times, 40% carbendazim 250 times, 64% poisonous alum wettable powder 500 times or 77.2% Pulic water 800 times, 72% Kelu or cyanohydrin 800 times. In areas where there is resistance to the above fungicides, 69% Anke manganese-zinc wettable powder or 1000 times water dispersible granule can be selected, about once every 10 days, for 2-3 times.

2) smoke: aerosol is used in the shed, 45% chlorothalonil aerosol can be used, 250 grams per mu each time.

3) Dust: dust application technology uses 5% chlorothalonil compound powder, 1 kg per mu each time.

4) Root irrigation: use 50% nail cream copper wettable powder 600 times solution. Or 60% ethyl phosphate aluminum wettable agent 400 times liquid irrigation root, each plant irrigation solution 300 grams.