To judge the root cause of the disease by the characteristics of orchid leaves.

To judge the root cause of the disease by the characteristics of orchid leaves.

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1. The orchid leaves are yellowed and grow normally: the light is too strong.

two。 The orchid leaves turn yellow and the new buds are smaller: excessive light, lack of nitrogen fertilizer and necessary humidity.

3. Yellowing and shedding of old leaves: caused by normal aging or turning the basin.

4. Old leaves yellowing and falling off quickly: too much watering, too often, improper pot turning and planting.

5. New leaf tip scorched: excessive fertilization, planting materials are not clean.

6. The focal tips of new leaves and old plants are black: excessive dampness and heat in the basin and rotten roots in the root system.

7. After the new bud is unearthed, it stops growing again: there are rotten roots or unclean things next to the new bud, open the breeding material around the new bud, remove the unclean matter and resume growth.

8. There are scorched spots on the leaves of orchids, and there are no yellow around them: scorching spots in the hot sun.

9. There is a dipping and scalding head at the end of the leaf: the water temperature of watering is too high; the temperature is too high when watering; showers are caught in high temperatures in summer.

10. New bud rotten heart: after watering into the bud core, the water can not be evaporated and absorbed, and the unclean breeding material in the basin produces leaf rot and so on.

11. There are water immersion on the periphery of orchid leaves: excessive humidity, basin humidity and air humidity produce asphyxiation, accompanied by leaf rot pathogen. Poor ventilation and ventilation.

12. There are chloasma on the leaves: caused by heat at the roots.

13. Orchid leaves have irregular maculae, mesophyll tissue necrosis and depression: virus disease, also known as Balas.

14. There are small yellow spots on the leaves: caused by beetles.

15. Orchid leaves appear purple-black, the back of the leaves are still green: caused by low temperature frost. Lack of phosphate fertilizer can also occur.

16. Leaf dehydration, false corm crepe: caused by long-term over-drying and dehydration in the basin.

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Orchid is an ornamental plant of Orchidaceae. The common diseases are anthracnose and leaf spot.

1, orchid anthracnose: mainly harmful leaves, black-brown disease spots appear on the leaves at the beginning of the disease, and there is a faded green halo around. After enlargement, the lesion is oval or strip-shaped. The edge is dark brown, the interior is yellow brown, and the disease spot is slightly raised. In the later stage, black particles appeared on the disease spot, and the black particles extruded pink colloids under wet conditions, that is, the conidia disk and conidia pile of pathogens. Anthrax occurred for a long time, especially from July to August.

Prevention and treatment: ① pay attention to ventilation and light transmission. ② fertilized reasonably, improved disease resistance, controlled the application of nitrogen fertilizer during the growing period, and applied more phosphorus and potassium fertilizer appropriately. At the initial stage of ③, 50% carbendazim or 70% topiramine wettable powder was sprayed 500-800 times.

2. Orchid leaf spot: it is a fungal disease harmful to leaves, which can occur in the whole growing period. Leaf spot disease is easy to occur in high temperature and humidity, shell insects and poor ventilation.

The initial stage of leaf spot is brown spot, after enlargement, the spot is long oval to striped, the edge is reddish brown, and the inside is grayish brown. In the later stage, black grains are scattered on the plaque.

Control: ① improves ventilation conditions and eliminates pests. At the initial stage of the onset of ②, 50% methamphetamine 1000-fold solution or 65% Dysen zinc 800-fold solution were sprayed for prevention and treatment.