Pest control of cold orchid

1. Scale insects: scale insects are also called scale insects. The scale insect is mainly parasitic on the leaves of orchids, the back of the leaves is more than the leaves, and it is also found on the petiole and on the membranous sheath of the pseudobulb. It feeds on sucking orchid juice. The adult is covered with white or other colored secretions, namely the shell, and stays in a fixed position, constantly sucking nutrients from the orchid. Light affects the growth of orchids. In serious cases, it covers the leaves, depletes the nutrients of orchids, and affects photosynthesis, causing orchids to grow weak, fail to blossom normally, even wither, defoliate and die.

The prevention and control of shell insects mainly improve the environment, especially pay attention to ventilation to avoid excessive moisture. The method of prevention and control can be used to remove the worms on the leaves with a toothbrush, mainly by spraying 3Mel 4 times when the nymphs hatch. Each time at an interval of 5 cents for 7 days, the drug was used:

1000 times dimethoate or omethoate (EC).

Once 10% imidacloprid wettable powder 1500 times liquid.

Aktai 25% water dispersible granule (Shanghai factory) 1000 times liquid.

There are also good spray results with 1000 times liquid wind oil essence after brushing off the worm body.

2. Mites: mites are small, similar to red spiders, and are not easy to find. The mites that harm orchids are mainly Tetranychidae. With sharp needles, the mites pierce the leaf tissue through the leaf surface and sponge tissue layer, absorb the chloroplasts of palisade cells and absorb cell inclusions, causing the damaged cells to dry up and the remaining inclusions to condense into lumps. In severe cases, this layer of cells collapse, epidermal cell necrosis, and cause orchid plant water parallel imbalance, transpiration accelerated, photosynthesis weakened, affecting the normal development of orchids.

The control of mites is generally sprayed with drugs at the adult and nymph stage:

20% dicofol (EC) 1000 times liquid.

40% omethoate oil slick 1000 times liquid.

75% propargite (EC) 1000-1500 times liquid.

3. Aphids: aphids are also common pests that harm orchids. It is harmful to tender leaves, buds, buds and other young organs, piercing orchid tissue with piercing and sucking mouthparts, absorbing a large amount of juice nutrients, resulting in orchid malnutrition, destroying the balance of growth and development, leaf spots, leaf shrinkage, leaf curling, galls and so on, causing deformities. In addition, aphid excreta is honeydew, which will cover the surface of orchid leaves, affect photosynthesis, cause mold breeding, induce black mildew, infect harmful viruses and so on. Aphids reproduce quickly and can produce several to dozens of generations a year, so it is necessary to control them in time to prevent the harm of fulminant development. The commonly used drugs are:

40% omethoate (oil slick) 1000 times liquid.

20% permethrin (EC) 1000-1500 times.

50% fenitrothion (EC) 1000 times liquid.

4. Nematodes: nematodes parasitic in leaves, causing yellow or brown patches on leaves, causing necrosis, withering, and even defoliation. As a result, the orchids grow slowly and underdevelop. Parasitic on the flower bud, make the flower bud dry; parasitic on the root, make the root appear beaded nodule and so on.

In order to control nematodes, the source of the disease was removed first, the diseased roots or leaves were cut off in mild cases, and the whole plant was removed and burned in severe cases. The plant material was watered 1000 times with omethoate. It was found that the diseased plant could be treated with 10% gram phosphorus granule 1.5-2g/m2 or aldicarb granule 1.2-5.6g/m2 2 weeks before transplanting, but human and animal poisoning should be prevented.

In addition to the above four kinds of insect pests, there are thrips, leaf miner, whitefly, ants, snails, earthworms and other insects can also harm cold orchid. It is worth mentioning here that weeds around the Orchid Garden should also be medicated regularly to prevent summer afternoon showers from driving away the insects, and the Orchid Garden has become a habitat for weeds to spread a large number of diseases. For this purpose, poison bait or drug spray can be used; the bait can be mixed with dichlorvos, arsenic and other drugs; it can also be sprayed with 40% omethoate 100 times, pyrethrin 500 times, and 50% phoxim and 80% dichlorvos 1000-1500 times. (Yang Jixin, Orchid Association of Wuyishan City, Fujian Province)