Control of small green leafhopper with false eyes in tea plant

False-eyed small green leafhopper, commonly known as floating dust, is one of the main pests on tea trees in various tea areas of our province. Due to its harm, the light bud leaves are damaged, the yield is reduced, and the heavy bud leaves are destroyed, resulting in loss of harvest.

1. Morphological characteristics

False-eyed small green leafhopper belongs to Homoptera, Cicadellidae. The whole life goes through three stages of egg → nymph → adult.

1. The egg is crescent-shaped, about 0.8 mm long and 0.15 mm wide, initially milky white, gradually turning light green, and a pair of red eye spots can be seen through the front end before hatching.

2. The nymph is 5 years old. It was milky white at first and gradually changed from yellowish to green with the increase of age. The wing buds began to appear at the 3rd instar and reached the fifth ventral segment at the 5th instar.

3. Adult head to wing tip 3.1-3.8 mm, light green to yellowish green. There are mostly two green spots in the middle domain of the crown, and there is a pair of green circles on the front edge of the head, also known as false monocular eyes, compound eyes grayish brown. The small shield plate of the middle chest has white stripes and is engraved horizontally. The front wing is yellowish green, the base of the leading edge is green, and the wing tip is transparent or smoky brown. The foot is the same color as the body, but the ends of tibia and tarsus of each foot are green.

II. Ways of doing harm

Nymphs and adults were used to suck the sap of tender shoots and leaves, and the female adults laid eggs in the tender shoots, resulting in damage to the transport tissue, loss of nutrients and insufficient water supply. After the damage, the bud leaves withered, the leaf veins turned red, the leaf tip leaf edge turned red and even scorched, the internodes shortened and the texture became brittle, especially the second round tea suffered the most in the whole year.

III. Occurrence characteristics

The false-eyed small green leafhopper has tenderness, only harms the tender shoots and leaves, is afraid of light and humidity, is not very active when the frost is not dry in the morning, and gradually shifts to the canopy when the sun comes out. Its adults gradually lay eggs, and the eggs are laid day by day. 1-2 eggs per day, so it is determined that its occurrence algebra is irregular, summed up in its occurrence has the following characteristics.

The main results are as follows: 1. the annual occurrence algebra can occur for 13 generations a year in Guangdong, overwintering with adults in the north of Guangdong, and there is no obvious overwintering phenomenon in other places.

2. Adults and nymphs can be seen at the same time in overlapping generations and messy tea gardens. However, there are two peak periods in the whole year, the first from May to June and the second from September to October.

3. Climatic factors affecting air temperature, precipitation and rain days are the main climatic factors affecting the population growth and decline of false-eyed small green leafhopper. It is suitable to occur under the condition of average temperature 17-28 ℃, sometimes sunny and sometimes rainy.

4. There are more than 60 kinds of natural enemies, the most important of which are egg parasitoids, tasseled wasps, spiders, insect molds and so on.

In addition, its occurrence and development is closely related to cultivation management and varieties. A single clump of white leaves suffers a lot.

IV. Prevention and control methods

There are two different directions for the control of false-eyed small green leafhopper, one is to adopt the method of ecological regulation, the other is to rely on the method of chemical pesticide control.

1. Ecological regulation and control the so-called ecological regulation is to make use of agricultural cultivation and management measures, such as pruning and picking, to fully protect natural enemies, play the role of natural enemies, and control the occurrence of small green leafhoppers. For example, seagull farms and warrior farms on the Leizhou Peninsula in our province adopt the method of ecological regulation and do not apply pesticides in more than 7000 mu of tea gardens. For more than a decade, the small green leafhoppers have been controlled below the level of economic losses for a long time. The damage rate of bud and leaf is low, the population density is low, the species and number of spiders are many, and the parasitism rate of tassel wasp is high, which completely controls the small green leafhopper. This method is convenient, effective and low cost, and will not cause pesticide residue pollution in tea. Using the method of ecological control, there will be a certain risk in the initial stage of implementation, that is, the insect population will increase to a certain extent at the initial stage of stopping pesticide application, but there is no need to be afraid, when the population of natural enemies such as parasitic wasps and spiders increases, it can play a control role.

2. The method of chemical pesticide control, which is widely used in tea gardens all over our province, has some effects, but it also has some disadvantages. After taking the medicine, it killed the natural enemy. According to our investigation, it is difficult to find tasseled wasps in tea gardens where pesticides have been used, and the number of spiders decreases rapidly, making it difficult to play the role of natural enemies. While the small green leafhopper is irregular and the eggs are laid in the tender shoots, one injection of medicine often cannot solve the problem, but should be given frequently, which creates a vicious circle, and the more you take the medicine, the more you have to rely on it. For example, in some tea farms in our province, the medicine is given once after picking tea, and many times a year, there are still many bugs, but the cost has increased, and the pesticide residues have also increased. We believe that all localities should overcome the idea of blindly relying on chemical pesticides, use fewer pesticides as much as possible, and choose the right pesticides even if pesticides are to be used, so as to reduce agricultural residues and reduce costs.

At present, Uranus, kung fu, endosulfan, badan and imidacloprid are the most effective pesticides to control false-eyed small green leafhopper. The specific usage is as follows: 10% imidacloprid 15-20 grams diluted into 4000-5000 times liquid, 35% endosulfan 50-75 ml diluted into 1000 times liquid, 98% Batan 40-50 grams diluted into 1000-2000 times liquid, 2.5% Uranus diluted into 1500-2000 times liquid with 25-40 ml water per mu, 2.5% kungfu with 25-35 ml per mu, diluted into 2000 times liquid spray. You can choose one of the above drugs and apply them before the nymph peak of the false-eye small green leafhopper.