Morphological characteristics, occurrence regularity and key control techniques of mountain plum longicorn beetles

Morphological characteristics, occurrence regularity and key control techniques of mountain plum longicorn beetles

1 morphological characteristics

1.1 Adult has a long cylindrical body, the front end of the body expands into a round shape, like a head, the head is flexible, and the back is slightly flat, with a pair of long antennae, which are born on the protuberance of the forehead, with a length of more than 1 plump of the body; claws are usually single-toothed, a few are tooth-attached; mouthparts are suitable for chewing; various body colors, mostly brown, sometimes miscellaneous and bright colors, or similar to tree trunks, have the function of concealment and protection The middle chest dorsal plate often has a sound generator, which can make a "squeak" sound due to the friction between the front chest and the middle chest.

1.2 the egg shape varies from species to species, generally long ovate, sometimes wide and cylindrical, oval or oval, fusiform or oblate, white in color and with a length of 0.5 ~ 5.0 mm [Jishan Huayao].

1.3 the larvae are yellowish or white in color, thick and fat, long tube-shaped, a few slender bodies, yellow or brown head, tightened into the forechest, antennae small, only 2 or 3 nodes, large jaws, stripes on both sides and center of the forechest dorsal plate. Some of the chest feet are well developed and some are even degenerated according to different species.

1.4 the naked pupa has obvious segments of each part of the body, the shape proportion is similar to that of the adult, the antennae curl around the body, and the pupa color is milky white or yellow, usually located in the pupa chamber.

2 harmful symptoms

Longicorn beetles can harm from larva to adult stage, and the larval stage is the most serious. The larvae first eat under the bark and do harm to the second year. After the worms grow up, they eat into the xylem for damage. After Shanhua plum was damaged by longicorn beetles, wormholes and scars appeared on the trunk and branch surface of fruit trees. With the continuous growth of larvae, the wormholes gradually deepened to the center of the branches, and there were reddish-brown sawdust or sawdust-like dung and sawdust outside the wormholes. Sometimes there is a phenomenon of sap outflow. After the longicorn beetle is harmful to the mountain plum fruit trees, it will cause voids in the trees, hinder the sap flow and weaken the trees. This will lead to the decrease of Shanhua plum yield, smaller fruit and lower nutritional value, which will greatly damage the economic value of Shanhua plum.

3 occurrence regularity

3.1 Adults of life habits generally appear in May-July of each year, and males are earlier than females. It begins to spawn from July to August, and there is a certain demand for light and temperature when spawning, preferably in areas with high light intensity, and the temperature is about 21 ℃. The adult first bites a scar on the trunk and branch of Shanhua plum tree, and then lays eggs into it. After about 2 weeks, the egg can hatch into a larva. When the larva is born, it moves under the bark and gets nutrition by eroding the fruit tree. When the larva goes deep into the fruit tree, it will build a wide pit in the fruit tree, which will be used as a pupa chamber. The two ends are closed by sawdust, where the pupal period is 10 ~ 30 days long. After Eclosion, the adults will climb out of the Eclosion hole, feed and mate during the day, lay eggs in the evening, and their life span is generally 10 ~ 30 days. Longicorn beetles mainly feed on tender bark, twigs, leaves, branches, sap and fruits of Shanhua plum trees. Wang Jian et al. [8] conducted a test on pine brown longicorn beetles on healthy and disease-free Pinus massoniana. It was found that the number of larvae per female longicorn beetle was 3.0 ~ 28.0, with an average of 12.3, and the destruction rate of subcutaneous tissue was 3.0 ~ 85.0%, with an average of 25.6%. These data show that longicorn beetles replenish their own nutrition and reproduce by feeding trees, which will cause serious damage to forest planting.

3.2 the occurrence generation of longicorn beetles varies according to the region. One or two generations of longicorn beetles are completed in one year, and another generation is completed in 2 ~ 5 years. It is reported that longicorn beetles occur one generation in 2 years or one generation in 3 years in Zhejiang, Jiangxi and other provinces and regions. The same variety varies greatly according to different regions. it generally occurs one generation a year in Guangdong, and the damage period is as long as 6 months. Xu Jielian et al found that the pupa stage of longicorn beetles in Guangdong is generally from April to May, the adult stage is from May to July, the egg stage is from July to August, and the larval stage is from August to April of the following year. The larval period can be up to 8 months, and the damage period can be as long as five or six months. Longicorn beetles are usually young.

Insects or adults that emerged in autumn overwintered, and a small amount overwintered as pupae.

3.3 there are many kinds of longicorn beetles in the way of spawning, and there are also various ways of spawning. However, almost all longicorn beetles produce secretions before and after spawning to build egg chambers to protect their eggs. Generally speaking, longicorn beetles mainly lay eggs in two ways, one is the habit of grooving and spawning, the female first bites the bark with her upper jaw before delivery, and then inserts it with the spawning tube, producing one grain per hole, and some produce more than one grain. After laying eggs, the female secretes a transparent gel-like mucus to cover the spawning hole, which can well protect the eggs from the external environment. Another way to lay eggs is not to bite the hole, but to lay eggs directly in the gap in the bark with a spawning tube. In a few cases, it will also be produced in the smooth part of the stem. Longicorn beetles that use this way of spawning usually excrete secretions twice before and after spawning, and the color is generally grass green, which may be related to the concealment of the eggs.

3.4 damage situation

3.4.1 investigation of occurrence

3.4.1.1 the time and place of the investigation was conducted in the Huali Orchard of Niuguling, Taowei Town, Jianghua County from 2013 to 2016.

3.4.1.2 the age of the investigated tree is 7 ~ 20 years, and the variety is Shanhua plum.

3.4.1.3 investigation methods the whole orchard was sampled and investigated according to the method of interlacing and interplanting. The species and number of longicorn beetles on each Shanhua plum fruit tree and the number of overwintering longicorn beetles were investigated respectively, and the parasitism of longicorn beetles in fruit trees was judged by observing the ways, grooves and eggs of longicorn beetles, and finally the damage rate and hatching rate of longicorn beetles were calculated.

4 Analysis of the causes of disaster

4.1 Life concealment of longicorn beetle larvae due to the living habits of longicorn beetles, longicorn beetle larvae have a high concealment, and the larval period is very long, so that the growers of Shanhua plum do not know the longicorn beetle larvae very well and can not distinguish them immediately when they see the larval feces. And take correct control measures.

4.2 the number of professionals who are less engaged in the agriculture and animal husbandry industry is scarce, and they are mainly scientific research institutes, university scholars, etc., due to the limitations of their own energy and working environment, although they have mastered advanced technology and cutting-edge knowledge, it is still unable to teach experience and technology to front-line fruit growers in time, which is lagging behind. When insect pests occur, fruit growers are unable to identify due to lack of relevant professional knowledge, while professionals with relevant knowledge cannot accurately judge the situation because they can not grasp the situation of insect pests in time, so the occurrence of insect pests can not be controlled in time.

4.3 knowledge aging is fragmented at present, most of the longicorn beetle knowledge mastered by fruit farmers comes from the family.

Technical books and personal experience are relatively old and fragmented, unable to form a systematic knowledge system.

Therefore, it is difficult to respond in time when new situations arise, and can not adapt to the current work.

Need. Therefore, when insect pests occur, fruit growers who lack a systematic knowledge system can not

Make a correct judgment, resulting in the further expansion of insect pests, resulting in irreparable

The economic loss.

5 key prevention and control techniques

5.1 Biological control longicorn beetle pheromones including sex pheromones, host pheromones,

Heterogeneous pheromones, repellent pheromones and oviposition interferon, due to the activity of longicorn beetles

Because of the characteristics of concealment and dispersion of hazards, it is more important to adopt conventional prevention and control methods.

Limitations, while the use of pheromones for control has the advantages of strong specificity, less pollution and

Not easy to produce drug resistance and other advantages [13]. No nutrition and long distance for adults.

Longicorn beetles that are free from sex pheromones can concentrate on releasing sex pheromones to entice longicorn beetles. Yes

Adults in the reproductive stage can use spawning pheromones to seduce the sky.

Cow. For adult longicorn beetles that need supplementary nutrition, feeding luring information can be used.

Used to seduce longicorn beetles. In order to improve the efficiency of pheromone luring, compound can also be used.

And pheromones. It has been reported that the combination of attractant and longicorn beetle pathogenic microorganisms

It can improve the control effect.

5.2 Agricultural Prevention and Control method through field investigation and indoor artificial feeding experiment, it was found that longicorn beetle adults preferred neem tree and silver sugar maple [1415]. Therefore, in the actual planting process, these two kinds of trees can be used as bait trees to attract longicorn beetles, and neem trees can have a seductive effect on longicorn beetles at a distance of 200 m. In general, bait trees can be planted along ventilated and sunny forest roads, at a certain distance from Shanhua plum. In addition, longicorn beetles are not only partial to some trees, but also obnoxious to another kind of trees. It is found that longicorn beetles have a strong aversion to the ketones produced by camphor trees, and this natural substance produced by camphor trees can avoid, fumigate and contact longicorn beetles, so camphor trees can also be planted at a certain distance in Shanhua plum planting forest. With the combination of the two, camphor trees are planted in Shanhua plum forest to drive insects, and bitter neem trees or silver sugar maples are planted at a certain distance outside the forest to trap longicorn beetles, which can achieve better control effect. In this way, it is simple and economical, will not cause biological pollution, and the effect is remarkable.

5.3 physical control method is the most direct way to control the pest of longicorn beetles in Shanhua, which is to capture adults, kill larvae and remove eggs. The peak period of adult emergence is from May to July every year, and it can be caught manually according to the living habits of adults. For the larvae, the tree trunk can be inspected during the day, and when the larval feces are found, the larvae can be killed with thin wire and other tools in time, or the cotton soaked with dichlorvos can be selected to block the moth passage, or the diluted dichlorvos can be directly injected into the wormway with a syringe, and finally seal the insect mouth with mud. For those eggs with low spawning sites, you can manually knock on the oviposition scar to kill the eggs and larvae, but not too hard to prevent damage to the fruit trees; you can also use lime, sulfur powder and water to whiten the tree trunk with a mixture of lime, sulfur powder and water at the ratio of 10 ∶ 1 ∶ 40. The advantage of direct prevention and control method is that the effect is quick and the time is short, but it requires more manpower.

5.4 the traditional chemical control method is not very effective for the pest of longicorn beetles in Shanhua, so a new type of longicorn beetle poison label can be adopted. Poison label is a new type of insect track fumigant made by mixing metal phosphide and oxidizer and other chemicals. When in use, the poison label is inserted into fresh wormholes, and the death rate of pests can reach more than 90%. This method is simple to operate and easy to use, but the price of the poison label is high, and it is not easy to save, so it is suitable for short-term temporary use.

Shanhua plum, also known as Sanhua plum, belongs to Rosaceae and belongs to the genus Prunus in China. Shanhua plum is known as "the king of plums" and "the top ten best fruits in Lingnan" because it was first planted in Sanhua Town, Wengyuan County, Guangdong Province. Because of its delicious juice, fragrant smell, crisp meat, moderate sweet and sour taste and rich taste, it contains 11.9% carbohydrate, 0.6% ~ 2.0% fruit acid, 0.7% protein and rich vitamin E, so it has high nutritional value and is loved by customers. it has high economic value.