The prevention and control of sunflowers mildew

The prevention and control of sunflowers mildew

Sunflower sunflower downy mildew is heilongjiang province of recurrent disease, general 10-20%, the incidence of severe incidence area of up to 40%, the disease make sunflower plant small, cannot bear plate of cafa, severe cases can cause plant death, bigger threat to the sunflower production.

Sunflower downy mildew genera flagellated bacteria and fungi, bacteria spores in soil with eggs or sick wintering in the body, the seeds can also be the carrier, the soil, the sick body wintering bacteria pathogen and seeds can become the next source of infection of the disease.

Sunflowers mildew is a kind of systematic infection of the disease, because of the different and environmental conditions of the infection, the symptoms are divided into four kinds:

Death of the seedling: after the germ of the seed is infected with the seedling, the seedling growth is severely impeded, and the severity of the disease is not found in the case of death or soon after it is unearthed;

(2) strain dwarf: strain growth is restrained, internodes short, internode shortened, thin stems, leaves small and shrinking, light green color, back covered with a layer of white mold (germs spore capsule terrier and sporangium);

The leaf spots and the flowers rot, the leaves of the leaves are affected by the leaves of the main vein, the main pulse of the leaves of the main vein of the leaves of a large scale, the back covering a layer of white mildew, the flowers victimized and decayed, and finally dried up. When the flower dish is affected by the yellow of the flower disc, the disease is still green, but the size of the flower disc is unchanged, but the yield is low and the seed is small and white.

(4) the hidden disease: murder seedlings hypha body exist, but the hyphae scaling up to 10 to 25 centimeters only no longer spread upward, strain appearance does not show obvious symptoms, environmental conditions when appropriate, also can form spores sporangium and eggs.

The occurrence and development of the sunflower downy mildew is highly affected by the bacteria source and climate condition, soil eggs inside the spore number, continuous cropping heavy disease, spring rain is big, easy to promote the downy mildew in soil moisture, if after seedling unearthed a persistent low temperature, rain, humidity climate environment is developing fast.

Method of prevention and cure:

Reasonable rotation: 3-5 years of rotation with gramineous crops.

Destroy the bacteria source: after the strain is found in the field, the strain should be completely removed, and the plant will be destroyed in the harvest after autumn harvest, so as to reduce the source of the bacteria.

Seed treatment: select seeds to remove the disease.

Chemical prevention in the field: at the beginning of the onset of the disease, 72% of the urea manganese zinc (kue) can be used as a wet powder for 2.5-2.7 kg. Or 722 g/liter of mildewy hydrochloride (prick), 0.9 to 1.5 litres; Or 68 per cent of the cream of the powder. Or 64 percent evil frost manganese zinc (antivirus) can be wet powder 2.5 to 3.0 kg; Or 687.5 g/l fluoride (silver Farley) suspends 0.9 to 1.125 litres; Or 69% enyl manganese zinc hydrate powders 1.8-3.0 litres of water spray, the interval between 7 to 10 days, the best rotation drug, the disease spray 2 to 3 times. Spraying, join canola lactone class plant growth regulator, can promote the growth of strain resumed as soon as possible, and 150 ml per hectare and 0.01% day FengSu 60 g 481 or 0.1% of masters abundant soluble powder or 0.003% increased 75 ml of the love, improve the control effect. At the same time, the dosage of the organic silicon auxiliary can be added to the organic silicon auxiliary, or the full 75 ml, which can improve the effectiveness of the treatment.