Beware of mite damage when planting Pleurotus ostreatus in spring

Pleurotus ostreatus is a kind of popular edible fungus, which has a wide consumer population, high biological efficiency and good economic benefits, so the planting area is larger, but the raw materials used in planting Pleurotus ostreatus in spring are generally left over last year, often with mites, with the temperature gradually rising, suitable for the growth and development of mites, rapid reproduction, which mainly feeds on Pleurotus ostreatus hyphae and fruiting bodies, resulting in reduced production of Pleurotus ostreatus, serious cases of loss of harvest.

1. Distribution, morphology and biological characteristics of acaroid mites and saprophytic mites.

1. Acaroid mite

(1) Distribution and harm: 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.

(2) morphological characteristics: the adult length of male mite is 320 ~ 240 μ m, the adult length of female mite is 350 ~ 650 μ m, the body is colorless, the limb and foot are yellowish to reddish brown, and the back end is obtusely round. The foot is thick, with 4 pairs of short feet, which is divided into 6 sections. The first pair of feet of male mites are thick and have a large thorn-like process on the leg. There are two suckers on the tarsus of the fourth pair of feet. There are anal hair and anal sucker on both sides of the anus. The first pair of feet of female mite is weaker than that of male, there is no spiny process on the leg segment, the fourth pair of foot tarsus has no sucker, and the reproductive foramen is located between the fourth pair of foot basal ganglia. The dormant body is about 200 μ m long, reddish brown, arch-concave and wide-ovate, with a front tip and a round back.

(3) Life history and habits: acaroid mites often enter the mushroom room with the culture material that is not fermented at high temperature or not thoroughly sterilized, or brought to the mushroom bed through insect, wind, labor tools, etc. After inoculation of edible fungi, if there is miscellaneous bacteria pollution, they will quickly gather in places with more mold. At suitable temperature and high humidity, it can reproduce rapidly, and under the condition of 23 ℃ humidity 87%, it only takes 9 to 11 days to complete a generation. When the occurrence is large, a large amount of peeling and excreta will be left on the culture material or mycelium, which will give 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.

two。 Tetranychus tyrophagus

The main results are as follows: (1) Distribution and harm: this mite is a worldwide harmful mite and is widely distributed in China. It is often mixed with acaroid mites, and the harm of fungal substances is also serious. 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.

(2) morphological characteristics: the adult length of the male mite is 280 ~ 350 μ m, the epidermis is smooth and shiny, there is a round sucker on each side of the anal foramen on the ventral side of the body, and the fourth pair of feet is planted in the middle of the tarsus. One pair of mating suckers. The length of female mite is 320 ~ 415 μ m, and its shape, setae length and arrangement are similar to those of male mites. The reproductive foramen is located between the third and fourth pairs of foot bases, and the anus almost extends to the end of the body, and there are 5 pairs of anal hairs around it. The egg is about 115 μ m long, the front end of the long oval is slightly pointed, milky white; the young mite is milky white, 3 pairs of feet; the nymph is milky white, 4 pairs of feet, which can be divided into the first nymph and the second nymph.

(3) Life history and habits: as long as the environmental conditions are suitable, they can grow, develop and reproduce all the year round. In China, the peak period of mites in a year is during the plum rain season. This mite acts quickly, likes to move in the dark, often clusters on the surface, and likes to be wet and afraid of dryness. Eggs need to be more than 70% relative humidity before they can hatch.

Second, occurrence regularity

1. Causes of harmful mites

The mushroom where Pleurotus ostreatus is cultivated is close to the warehouse, feed room, chicken house and storage of crude bran, cottonseed shell, rapeseed cake, etc., or taken to the mushroom bed by insects; the mites and their eggs lurking in the gap 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.

two。 Harmful symptoms

The main results are as follows: (1) for the bacteria with mite damage, the hyphae at the mouth of the bottle are not dense enough, and the hyphae are atrophied and degraded, even the hyphae can not be seen in the culture medium.

(2) when Pleurotus ostreatus is damaged by harmful mites, the white fungus becomes black and gives off an unpleasant mildew smell.

(3) Brown and yellow spots appear on the cap or stalk of young or mature fruiting body, and the initial spots are sunken or porous, with dark brown edge and slightly light or hollow in the middle, but the fruiting body does not rot.

III. Prevention and control methods

1. Mushroom room to install fine screen doors, screen windows, ventilation holes should also be installed with screen screen, around the room and cracks with tight mud seal to prevent insects from flying into the room to bring mites to the bacterial bed.

two。 The culture material should go through secondary fermentation or high temperature disinfection to kill the harmful mites in the material.

3. Do a good job in environmental hygiene and reduce the pollution of miscellaneous bacteria so as to reduce the infection harm of mites.

4. Absolutely ensure that there are no mites in the strain and culture room. Careful examination of bacteria, found that there are mites in the bottle, to be eliminated, or suspected mites should be sown in separate rooms. 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.

5. When harmful mites are found on the mushroom bed, drugs should be used to eliminate harmful mites as soon as possible. First, drug spraying: use 2000 times of Ketite liquid, 0.5cm 1.0 Baume degree of stone sulfur mixture; second, the use of trapping methods: (1) lay fresh tobacco leaves on the culture material surface harmful to bacteria and mites, wait for more bacteria and mites to gather on the tobacco leaves, gently remove the tobacco leaves and burn them with fire; if there are still mites, you can continue according to the previous method until there are no mites. (2) take boiling water 100mL, vinegar 100mL, sugar 10g, mix well, stir until dissolved, after cooling, drop a drop of dichlorvos and mix well to form sugar and vinegar solution. Soak the gauze in the prepared sugar and vinegar solution, then spread the soaked sweet and vinegar gauze on the culture material harmed by mites or on the mushroom bed, 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.