Harm and control of thrips to orchid

In recent years, orchid friends often talk about: after the budding of orchids, the buds are black, shrunken, shrunken, and fall off; when the orchids are open, they look like colorful flowers from afar, and there are brown spots at the base of the petals and tongue; when the new leaves are semi-mature, not far from the base, there is a section about one centimeter long, with rusty spots on a brownish-yellow surface, suspected to be Balas disease. In fact, it's not a disease, it's a pest. The chief culprit is a thrips.

Thrips learn the name onion thrips, aliases tobacco thrips, cotton thrips. It has miscellaneous food habits and a wide range of hosts, and more than 350 kinds of hosts are known. It mainly harms onions, onions, garlic, cucurbitaceae, Solanaceae and other plants, as well as orchids, which is more severe in recent years.

Thrips are very small insects, smaller than small ants, adults 1.2 to 1.4 mm long, yellowish to dark brown. Six legs, a pair of antennae and two pairs of feathered wings are active and good at flying. When you squeeze them with your fingers, they disappear without a trace.

The adults and nymphs of thrips feed on the host juice by sucking mouthparts. Mostly in the heart leaves, buds and buds, cluster damage. When harming onions, leeks and garlic, many fine, long, gray-white spots will be formed on onion tubes and leek garlic seedlings. When endangering orchids, the above symptoms appear. After growing flowers for several years and watching flowers for a while, the harm of thrips to flowers often makes orchid friends lose their confidence in raising orchids, which shows how serious the harm is.

The egg of thrips is 0.2 mm long and the nymph is second instar. The first instar nymph is 0.37 mm long, white and transparent. The second instar nymph is 0.9 mm long and its body color is light yellow to orange. The prepupa is like a second instar nymph, has grown wing buds, can move, but does not feed, and has a body length of 1.2 to 1.4 mm. Pupa, with large wing buds and antennae attached to the back of the chest. Thrips occur for 8 or 10 generations a year in Jianghuai region. Adults or nymphs overwinter in onion and garlic leaf sheaths or host litters, peas, cabbages, grasses, orchid leaf axils and soil seams. Activities begin in March every year, and the harm is the most serious in May, until late autumn. Adults are afraid of light, hidden during the day and active at night. Parthenogenesis in summer, bisexual reproduction in autumn and winter. Each female lays more than 50 eggs each time, and the highest is more than 180 eggs. Low temperature, high temperature and high temperature are disadvantageous to its growth. 20 ~ 25 degrees, the relative temperature is below 60%, and the dry climate is the most harmful. In addition, close to the village, there are many insect sources in the vegetable field and the harm is serious.

Thrips are small and easy to be killed by drugs. Insecticidal drugs, such as dimethoate, dichlorvos, pyrethroids, parathion and so on, have good killing effect on thrips. The dual-use medicine of orchid disease and insect is also very effective in killing thrips. However, thrips live in flower buds and leaf axils, which are often the dead corners of spraying, so pay attention to these dead corners when spraying. When choosing pesticides, it is best to choose drugs with internal inhalation and steaming effect, the effect is better. Spraying time, choose early March thrips to start activities, May to June bud growth period and flower bud stage, spray twice, the interval between a week. Winter spraying should also pay attention to soil seams to kill overwintering thrips.

When spraying acid insecticides, it can also be mixed with acid fungicides and foliar fertilizers such as potassium dihydrogen phosphate and urea, so that insecticidal, sterilization and topdressing are carried out at the same time, which is killing three birds with one stone.

Address: Zhejiang Huangyan Marine Fisheries Co., Ltd.

Tel: 0576muri 42772581 139576O9879

Wang Deren