Control techniques of mites in garlic

The basic morphological characteristics, biological characteristics and harmful symptoms of 3 mite pests damaging garlic were preliminarily identified, and effective control methods were put forward.

(1)Root mites: widely distributed, fast-breeding, harmful, garlic field and storage period is a dangerous pest. Adult mites are 0.58~0.81 mm long, broadly ovoid, pear-like, white, smooth and shiny, with 4 pairs of short and thick oval feet, 0.2 mm long, milky white, relatively transparent. Adult mites and nymph mites overwinter in garlic plants or soil, and eggs overwinter in garlic bulbs. Adult mites lay eggs in the depression at the base of garlic bulb, mostly single or several eggs, each female mite lays about 600 eggs. It usually takes 20 to 30 days to reproduce. The optimum temperature for development is 20~25℃. It occurs easily in acidic sandy soils rich in organic matter. Adult mites and if mites eat garlic bulbs, so that the injured bulbs rot and stink, the ground withered and died. Storage garlic can also rot and stink or dry into empty shells when it is killed.

(2)Caseophile rot mite: a worldwide pest, widely distributed, fast-breeding, serious harm. It is mainly harmful to stored garlic, and it has also occurred in garlic fields in recent years. Adult mites are ovoid, 0.51 - 0.61 mm long and 0.50 mm wide. 27 to 0.29 mm. The skin is smooth, milky white, translucent, with. 4 pairs of short, thick feet. The egg is oblong, 0.09 - 0.12 mm long, 0.05 - 0.08 mm wide, milky white. Overwintering in garlic as eggs, nymph or adult mites. Adult mites lay eggs in the gaps at the base of garlic cloves on the stem disk of garlic bulbs, or in the holes of the injured parts. Most of them lay eggs in piles, and a few are single. Each female mite lays 85 - 100 eggs. The optimum temperature for reproduction is 20~24℃, and the optimum air relative humidity is 80%~90%. Caseophile mites are gregarious and like to live in damp and moldy environments. Adult mites and if mites harm garlic, the initial borer: garlic cloves surface, and then gradually borer garlic cloves inside, forming a lot of irregular holes. Injured garlic rotted under wet conditions and withered under dry conditions. In the field; damage to the bulb base causes rot and odor, resulting in plant death.

(3)gall mite: also known as tulip mite, widely distributed, for the world pest. In addition to harm onions and garlic vegetables, but also harm wheat, corn and trees. Adult mites are small in size and carrot-shaped, milk-yellow Demodex. Female mites lay eggs on the surface of garlic cloves, most of them are single, and a few lay eggs in piles. Ovoid subglobose, milky white, slightly transparent. The newly hatched nymph mites are multicolored, translucent, and gradually turn milky white after peeling. With the increase of mite age, the body color is slightly deepened. The optimum temperature for reproduction is 15~20℃ and the optimum relative humidity is 70%~95%. When the temperature is lower than 3℃ and the relative humidity of the air is lower than 60%, fertility stops. Adult and nymph mites damage stored garlic, and sometimes garlic in the field can also be damaged. Most of them invade from the edge gap of garlic stem disk, prick and suck juice at the base of garlic clove, and then gradually transfer to the tip of garlic clove, causing garlic clove to gradually wither, brown and dry, and garlic head becomes empty shell. Under high humidity conditions, the wound of the garlic will also be infected with many bacteria, making the garlic rot and stink. The gall mite is also a vector of virus disease, with large amount of virus, fast transmission, long period of virus, serious damage, and the transmission rate of virus to garlic is 100%. After sowing, the seedlings of garlic damaged by gall mites showed various virus disease symptoms, grew slowly, did not sprout, did not form garlic heads, or formed single garlic heads.

Mite pest control methods: According to the garlic mite pests can occur during the storage period, but also in the field during the characteristics of growth, control work can be carried out from the following aspects:

First, garlic storage period such as mites found when harm, sulfur powder fumigation available. Every cubic meter of space with sulfur powder 100 grams, add a small amount of sawdust, mix well and put in a container, put in the garlic storage room, after lighting the doors and windows closed, fumigation for 24 hours, killing mites effect up to 100%, but ineffective on eggs, can wait for eggs to hatch after fumigation once.

Second, do not plant with scallion, onion and leek continuously, and do not plant adjacent to each other. Implement rotation for 3~4 years.

Third, strictly select seeds before sowing, eliminate the garlic cloves with diseases and insects, and then soak the selected seeds in 80% dichlorvos emulsion 1000 times solution for 24 hours, and the acaricidal effect can reach 100%. After breaking garlic, the remaining garlic skin, garlic root, garlic stem residue and stem plate should be burned together to reduce the infection source.

Fourth, when sowing, evenly sprinkle phosphorus granules in the sowing ditch, 3~4 kg per 667 square meters. Fifthly, garlic roots were irrigated with 80% dichlorvos emulsion 300~400 times during field growth.

Sixth, timely removal of the field killed plants, burned or buried deep to reduce mite sources.