Sharp-eyed mosquito, a major pest of orchids

[editor's note: in this paper, the prevention and control of one of the orchid pests is very detailed and scientific. The harm of eye-losing mosquitoes to orchids is rarely reported in various orchid books and orchid journals. ]

In orchid cultivation, the main common pests are red spiders, shell insects, aphids, thrips, ants, earthworms, slugs and snails, which are generally introduced in orchid books. However, there is a kind of pest which is common in orchid planting and does serious harm to orchids, but from the orchid materials seen by the author, there is no report that the insect harms orchids. The pest was identified as Insecta-Diptera-Coleoptera-Mushroom mosquitoes (Bradysia minpleuroti yang et zhang). The occurrence, morphological characteristics, occurrence characteristics and control methods of acuminate mosquitoes in orchids are introduced as follows.

1. Occurrence of harm

The insect has a wide range of hosts and mixed food habits. According to the investigation of 105 orchid farmers in Dali City for many years, no matter in courtyard, greenhouse or balcony, in orchid cultivation places, different places and different cultivation methods, but the incidence of pests in orchid farmers is 100%. The investigation results showed that the insect did harm to orchids in three aspects: first, the larvae gnawed the orchid roots in the basin, causing the orchid roots to die; second, the insect was mainly saprophytic, accelerating the decomposition of organic matter in the basin soil; third, the adult flies around in the orchid cultivation place, stays on the orchid leaves and produces feces, pollutes the orchid leaves and spreads orchid diseases. The results show that it affects the growth and development, overall beauty and economic value of orchids. Therefore, orchid farmers should pay attention to the prevention and control of the pest.

2. Morphological characteristics

Adult: the biggest characteristic of the worm is that the body of the worm is small, the length of the male is 2.7mi 3.2 mm, dark brown, dark head color, compound eyes, dark brown chest, light gray wings, 1.8 mi 2.2 mm long. The female is larger, 3.4 Mel 3.6 mm in length, 2.8 mm in length and 1 mm in width, and the abdomen is larger.

Eggs: oblong, milky white at the initial stage.

Larvae: the length of the initial hatching body is about 0.6 mm, and the length of mature larvae is 0.8 mm.

Pupa: pupate in a thin cocoon, 3 Mel 3.5 mm long, milky white at the initial stage, black after three days.

3. Occurrence characteristics

The insect mainly occurs in the basin soil with a lot of humus and organic matter, and on potted orchids in Dali City, the main occurrence period is from February to November every year. The average temperature is 15-20 ℃ from March to May, with an average of more than 50 heads per pot. The life cycle of each generation of pests is 30-35 days, and a pair of adults lay more than 300 eggs on average. 810 generations a year, the reproduction speed is quite fast, if no attention is paid to control. It is easy to cause outbreaks and harmful situations. In indoor, the number and time of insect pests are related to watering and soaking. Generally, the number of adults increases significantly 5 days after watering and soaking.

4. Prevention and control methods

4.l it is strictly forbidden to bring an orchid with a cymbidium.

For newly purchased orchids, especially those with cultivation, should be carefully checked, do not have worm basin soil with Languo; Languo vents, such as doors, doors and windows, it is best to install 60 mesh screen to prevent adults from flying.

4.2 strengthen cultivation management

When changing the soil of orchids, it is best not to use the potted soil with insects. If it is reused, the potted soil must be treated at a high temperature of more than 50 ℃. In view of the moist characteristics of the insect, prevention and control should be carried out in time after each watering.

4.3 rational use of pesticides

As most of the potted orchids are indoors, the use of chemical pesticides should pay special attention to the safety of the human body, establish the idea of safety first, do not misuse pesticides, and choose safe, efficient and low-toxic agents. The results showed that 1500 times of permethrin EC had a certain control effect on the adults and larvae of the insect, but the spray caused great indoor pollution and affected human health. After years of research, the author has successfully studied a kind of granule with no pollution and good control effect. The diameter of the basin mouth is 22-25 cm. As long as 5 grams are evenly sprinkled on the surface of the basin and a little water is poured, the efficacy period is more than 2 months. In general, you only need to apply the medicine twice a year in March and May.

Author: plant Protection and Plant Inspection Station, Dali Prefecture, Yunnan Province

Address: 219 Xiaguan Jiandong Road, Dali City

Telegram: 0872 mi 2123713, 2175070 13099848056