When the temperature rises, Pleurotus ostreatus should pay attention to mite control.

In recent years, many of the raw materials used by mushroom farmers to grow Pleurotus ostreatus in spring and early summer are left over from last year, often with mites. Mites feed on the hyphae and fruiting bodies of Pleurotus ostreatus, resulting in a reduction in the yield of Pleurotus ostreatus, and in serious cases, the harvest is lost. At present, the temperature is gradually rising, which is very suitable for the growth and development of mites and the acceleration of reproduction. Mushroom farmers should pay attention to prevention and control.

First, the main harmful mites

1. Acaroid mites with thick feet

Distribution and damage: this mite is a worldwide widespread species. In the production of edible fungi, acaroid mites often occur in the environment polluted by miscellaneous bacteria. Because of their activities, the miscellaneous bacteria are enlarged and the healthy fruiting bodies rot. Acaroid mites can also directly feed on the mycelium of Pleurotus ostreatus, resulting in yield reduction or even loss of harvest.

Morphological characteristics: the adult length of male mite is 240 rain 320 microns, and the adult length of female mite is 350 rain 650 microns, the body is colorless, the legs and feet are yellowish to reddish brown, and the back end is obtusely round. The foot is thicker and is divided into 6 sections.

Habits: coarse-footed mites often enter the mushroom room with culture materials that are not fermented at high temperature or not thoroughly sterilized or brought to the mushroom bed through insect-borne, wind-borne, labor tools, etc. After inoculation of edible fungi, if there is miscellaneous bacteria pollution, they will quickly gather in places with more mold. Under suitable temperature and high humidity, it can reproduce rapidly. Under the condition of temperature 23 ℃ and humidity 87%, it only takes 11 days to complete a generation. When the occurrence is large, a large number of peeling and excreta are left on the culture material or mycelium, giving off a moldy smell. The cold resistance of acaroid mite is very strong, but its dry tolerance is very poor, the eggs can hardly hatch under the condition of 60% relative humidity, and a dormant body can be formed between the first and second instar in dry environment. The transmission of the mite in the mushroom house or mushroom bed, in addition to its own crawling, mainly depends on other pests and mites.

2. Tetranychus tyrophagus

Distribution and damage: this mite is a worldwide harmful mite, which is widely distributed in China. It is often mixed with acaroid mites and harms fungal substances. The victimized storage often has a foul smell. In addition, substances with saprophytic mites can cause rash after human consumption, and dermatitis sometimes occurs after human skin comes into contact with the mite.

Morphological characteristics: the adult male mite is 280ft 350 μ m long, the epidermis is smooth and shiny; the female mite is 320ft 415 μ m long, and the shape, setae length and arrangement of the female mite are similar to those of the male mite; the young mite is milky white with 3 pairs of feet; the nymph is milky white with 4 pairs of feet, which can be divided into the first nymph and the second nymph.

Habits: as long as the environmental conditions are suitable, it can grow, develop and reproduce all the year round. In China, during the plum rain season, the mites move quickly, like to move in the dark, often cluster on the surface, and like to be wet and afraid of dryness; eggs need more than 70% relative humidity to hatch.

Second, occurrence regularity

1. The reason for the occurrence of harmful mites is that the mushroom of cultivated Pleurotus ostreatus is close to the warehouse, feed room, chicken house and storage of crude bran, cottonseed shell, rapeseed cake, etc., or brought to the mushroom bed by insects; the mites and their eggs latent in the cracks are not killed during disinfection in the empty room; the bacteria with harmful mites are not killed; the culture materials with harmful mites are not thoroughly treated; the soil covered with soil is not disinfected, and there are harmful mites in the soil.

2. For the bacteria with harmful mites, the hyphae at the mouth of the bottle are not dense enough, atrophied and degraded, and even the hyphae can not be seen in the medium. When Pleurotus ostreatus is damaged by harmful mites, the white clumps turn black and emit an unpleasant mildew smell. When the young mushroom or mature fruiting body is damaged, brown or yellow spots appear on the cap or stalk, with different shapes; the initial spots are sunken or porous, the edge is dark brown, the middle is slightly light or hollow, but the fruiting body does not rot.

III. Prevention and control methods

The main results are as follows: 1. The culture room, mushroom room and culture material disinfection mushroom room should install screen doors and screen windows with fine mesh, and the vents should also be fitted with screen screen, and the gaps around the room should be tightly sealed with mud to prevent insects from flying into the room to bring mites to the bacterial bed. The strain culture room should be built far away from livestock houses, poultry houses and warehouses, and it is strictly forbidden to pile up sawdust, cotton shells and other culture materials and sundries indoors; disinfect the culture rooms and mushroom rooms frequently, and spray chemicals around the house, the ground and the cultivation bed frame to eliminate mites and pests. The culture material should be fermented twice or sterilized at high temperature to kill the harmful mites. Do a good job in environmental hygiene and reduce the pollution of miscellaneous bacteria so as to reduce the infection harm of mites.

2. Ensure that the bacteria are absolutely free of mites. Carefully examine the strains and find that there are mites in the bottle, which should be eliminated, or the strains suspected to have mites should be sown in separate rooms.

3. When harmful mites are found on the mite-killing mushroom bed, the drug can be sprayed with stone-sulfur mixture of 2000 times of propargite solution and Baume 0.5m / 1.0 degree. It can also be trapped and killed: lay the fresh tobacco leaves on the culture material surface harmed by bacteria and mites, and gently remove the tobacco leaves and burn them with fire when there are more bacteria and mites on the tobacco leaves; if there are still mites, you can continue according to the previous method until there are no mites. Or, take 10 ml of boiling water, 100 ml of vinegar, 10 grams of sugar, mix well, stir until dissolved, after cooling, drop a drop of dichlorvos and mix well into sugar and vinegar. Soak the gauze in the prepared sugar and vinegar solution and soak it thoroughly, then lay it on the culture material or mushroom bed harmful to the mites, lure the mites to the gauze, remove the gauze and burn the mites to death with boiling water, repeat many times until the mites are basically killed.