Pest Control of Cymbidium (1)

Insect pests that harm the orchid include scale insects, aphids, leaf mites, thrips, whiteflies, leaf miners, snails and slugs, nematodes, caterpillars, cockroaches, ants, etc.

1. scale insects

Scale insects are one of the most common pests that harm orchids. It has a wide variety of species, mainly parasitic on the stems and leaves of orchids, but also on the membranous sheaths at the base of petioles and pseudobulbs, white powder, and they suck plant juice for food with piercing mouthparts. When the harm is light, the organ turns yellow and ages, affecting the growth of the orchid plant, and when it is heavy, it covers the leaves in pieces, which consumes nutrients and affects the photosynthesis of the orchid plant, so that the growth and development are hindered, and the normal flowering and fruiting cannot occur, and even dead leaves and leaves appear until the whole plant dies. At the same time, the wound after scale insect invasion is easily infected with virus, and the secretion of scale insect is easy to cause the occurrence of black mold. Scale insects have strong reproductive ability and can reproduce for many generations in a year. Its adults have waxy shell, general pesticides are difficult to enter, control is more difficult, once it occurs, it is not easy to clean up.

Control methods:

(1) Prevention is primary. When purchasing orchids, it is necessary to ensure that seedlings are free of scale insects. Secondly, scale insects occur when the water is too wet and the ventilation is poor. Therefore, daily management should pay special attention to environmental ventilation to avoid excessive humidity.

(2) When there are a small number of scale insects, the soft brush can be used to gently remove the insects manually, and then rinse them with water.

(3) When using medicine to control, when the nymph hatches soon and has not formed waxy shell, the pesticide used can be 40% dimethoate or omethoate EC 1000 times, or 50% trichlorfon EC 250 times, or 80% dichlorvos EC 1000 - 1500 times, or 2.5% cymethrin EC 2000 - 2500 times. Generally, continuous spraying 1~3 times, each time interval 7~10 days, the effect is better. In addition, special attention should be paid to the fact that scale insects are easy to produce resistance to drugs, so it is necessary to master the concentration of pesticides and alternate use of pesticides.

2. aphids

They often parasitize orchid plants, lay eggs after mating, overwinter in leaf axils and crevices, but parthenogenesis can be carried out all year round in greenhouse. Adult aphids and nymph damage young organs such as leaves, buds and buds of orchids, absorb a large amount of sap nutrients, resulting in malnutrition of orchids; their excretions are honeydew, which will lead to mold breeding, black rot and infectious orchid viruses. Aphids reproduce rapidly and can produce several to dozens of generations a year.

Control methods:

(1) Control must be timely, can be in March to April when eggs hatch with 40% omethoate EC, acephate 1000 times solution, or 50% fenitrothion EC 1000 times solution, or 20% fenvalerate EC 2000~3000 times solution spray, spray once every 7~10 days, continuous 3~4 times can be.

(2) When aphids occur sporadically in family orchids, they can be brushed off with a brush dipped in water, and the aphids brushed down in time are concentrated and eliminated to prevent spread.

3. spider mite

There are many kinds of spider mites that harm orchids, among which red spider is more common, its body is small, reddish brown or orange. With sharp needles, absorb nutrients from middle leaves, and cause metabolic imbalance of plant water, affecting the normal growth and development of plants. Red spider and so on in the high temperature and the dry environment, the insect body reproduction is rapid, harms seriously.

Control methods:

(1) Keep the environment ventilated, keep the humidity above 40%, and spray water on the back of leaves frequently to control the propagation of spider mites.

(2) When pesticides are used, because pesticides are difficult to kill eggs, they are generally carried out in the adult and nymph stages after egg hatching. 20% dicofol emulsifiable concentrate 1000 times, or 40% omethoate emulsifiable concentrate 1000 times, or 20% tetramethrin emulsifiable concentrate 4000 times, once every 5~7 days, for 2~3 consecutive times. Alternate use of drugs is better. Can also be used 600 times the liquid of Derris essence plus about 1% of the washing powder solution spray kill.

4. thrips

Thrips is a Thysanoptera pest. Because of its small size and hidden activities, it is not easy to find it in the early stage of damage. Inflorescences and flowers and leaves of mainly endangered orchids. When damaging the leaves, it sucks the juice of orchids with needle-like mouthparts, resulting in many small white spots or gray spots on the surface of orchids, affecting the growth of orchids and reducing their ornamental value. Inflorescences are damaged when they grow malformed, difficult to flower normally or flowers are dull in color.

Control methods:

(1) Because thrips are particularly harmful to orchids and flowers and are not easy to find, they should be controlled before inflorescence.

(2) Spraying pesticides on the whole plant 1~2 times a year can kill thrips everywhere in the orchid plant.

(3) Before flowering, spray 50% phoxim emulsion 1200~1500 times or 40% omethoate emulsion 1000~1500 times, usually once a week, repeat 3~5 times.