In the soybean planting process, in addition to the emergence of common pests such as pod borers and aphids, the silver moth is also an important pest that cannot be ignored, and they will use the young leaves, flower utensils or young bean pods of soybeans for large-scale destruction, causing normally growing soybean plants to stop growing or withering and dying, ultimately affecting the yield and quality of soybeans. So today Xiaobian will introduce the soybean silver-streaked nocturnal moth to you through the following points, that is:
· What are the occurrence rules and living habits of the soybean silver-streaked nocturnal moth?
· What are the harmful characteristics of the soybean silver-streaked nocturnal moth?
· How to identify soybean silver-streaked nocturnal moths in the field?
· Why do soybean silver-streaked nocturnal moths occur seriously year by year?
· How to reduce the harm of soybean silver moth to soybeans?
<h1 class= "pgc-h-arrow-right" >, the occurrence law and life habits of soybean silver-streaked nocturnal moth</h1>
Occurrence rules: although the life of the soybean silver moth is short, but they need to go through 4 kinds of insect states, namely eggs, larvae, pupae and adult insects, after the temperature decreases after winter, the soybean silver moth will be in the form of pupae in the field plants, field weeds, soil cracks and other hidden places to resist the cold winter, to the next year the temperature rises and then break the cocoon feathers out of the adults, adults in mating to lay eggs, eggs hatch to hatch larvae, this is a multi-cycle process, due to the relationship between geographical environment and climate, It can occur 6-7 generations a year in South China, so there is sometimes a significant overlap of times.
Life habits: soybean silver moth likes to stay in a warm, humidity suitable environment, while adult insects are used to come out at night, there is a clear tendency to black light; newly hatched larvae like to cluster together to eat, they like to eat soybeans, they also like to eat rape, cabbage, cabbage, etc., eating, while liking to come out in the morning and evening, is the best time to spray medicine.
<h1 class="pgc-h-arrow-right" > second, the hazard characteristics of soybean silver moth</h1>
After feathering, the adults of the soybean silver moth will quickly mate under the conditions of the external environment, and then lay the eggs on the back of the soybean leaves, and the eggs hatch after a period of development, these young larvae will cluster on the back of the leaves or the dark side of the two leaves to feed, using the mouthparts to nibble on the flesh of the young leaves leaving only a transparent epidermis.
With the development of larvae, their food intake is getting larger and larger, they are no longer only eating leaf flesh tissue, but the entire young leaf is eaten, in the case of severe outbreaks, even flower utensils, young pods are eaten, and finally let the leaves appear missing or porous phenomenon, in addition, they eat enough excrement will also pollute soybean plants, seriously affecting the growth of plants.
<h1 class= "pgc-h-arrow-right" > three, how to identify soybean silver moths in the field? </h1>
For the control of soybean insect pests, only in the field diagnosis to identify specific pests can be correctly prescribed, and the same is true for soybean silver moths, it is necessary to know what they look like, so that they can be controlled in time in the field. However, the eggs of the soybean silver moth are relatively small, and very hidden, it is difficult to distinguish with the naked eye, and the pupa is the same, so if you see adults and larvae that grow like this in the field, then you can conclude that it is a soybean silver moth, that is:
The adults of the soybean silver-striped nocturnal moth are 12–15 mm long, with a grey-brown body color and yellow-brown wings. A closer look reveals a bluish-purple flash on the forewings, followed by a silvery-white, triangular-shaped stripe in the center of the wing and a "U" sub-shaped silver-sided brown stripe, both close but not connected, which is the most typical identifying feature. The hindwings have dark brown markings similar to metallic luster.
The newly hatched larvae of the soybean silver moth are blue-green, with a body length of about 20 mm, and then develop to 30 mm, and the body color becomes pale green; the head of the body is relatively small, the posterior end is relatively large, and the back of the body has 6 white fine longitudinal stripes, and the back of the body is arched when crawling.
<h1 class = "pgc-h-arrow-right" > fourth, the cause of serious occurrence of soybean silver moth year by year</h1>
First of all, the soybean silver nocturnal moth will be wound in a pupae in a pupae in a more secret place such as the back of the leaf, the stem or the soil crack, etc. If the soybean is not cleared in time after harvest, such as cleaning, burning dead branches and leaves, ploughing the soil, etc., it will aggravate the number of insect populations in the next year.
Secondly, if the field is planted with soybeans for many years, that is, continuous cropping, there is no stubble rotation, because the relationship between feeding materials makes the soybean silver-streaked nocturnal moth not transfer the harm, resulting in more and more pupae and eggs accumulating, aggravating the occurrence and harm.
Finally, if farm manure is used frequently, but it is not fully decomposed, it may be possible that the uncorried farm manure carrying the eggs of the soybean silver moth into the field, aggravating the occurrence of the soybean silver moth.
Of course, the outside conditions are suitable, that is, the warmth and humidity of the field are conducive to the activity and reproduction of soybean silver moths, or farmers miss the best control period, etc. These conditions will also aggravate the occurrence of soybean silver moths.
<h1 class= "pgc-h-arrow-right" >5, how to reduce the harm of soybean silver moth to soybeans? </h1>
1. Basic agricultural prevention and control measures
Stubble rotation and strengthen field management: after planting a season of soybeans, you can consider planting other crops such as peanuts, rice, etc., the best water and drought rotation, but it should be noted that you can not plant crops that can be harmed by the silver moth, such as rapeseed, kale, etc.; secondly, pay attention to field management, apply sufficient base fertilizer, use completed decomposition of farm manure, and at the same time carry out precision fertilization, watering, weeding and other agricultural operations during the critical period of soybean growth, cultivate robust plants, and enhance stress resistance.
After picking, do a good job of clearing the field: after the soybean harvest, the diseased branches and leaves and other debris in the field should be uniformly taken to the outside of the field to be burned, and then the soil will be deeply turned over many times and sunburned, and the lime powder can be used for sprinkling conditionally, which can effectively kill the eggs of soil insects overwintering, and can also improve the soil.
2. Physical science prevention and control measures
The adults of the soybean silver moth like to come out after dark, and have obvious tendencies to black lights, can use this feature of adult worms, in the period of frequent activity and mating of adults, hang multiple black lights in the field to trap them, with a good control effect, can reduce the difficulty of control in the later stage.
3. Biological auxiliary control measures
In the early hatching stage of soybean silver moth larvae, it can be diluted 1000-1500 times with water with biological pesticides such as Thuringiensis wettable powder or its nuclear polykeratovirus for foliar spray control, which has a slower onset of action, and has excellent effect in the case of a small population base of soybean silver moth larvae, but if the insect mouth base is too large, then it is necessary to rely on chemical agents for control.
4. Chemical agent prevention and control measures
For the control of soybean silver moth, if the larval population base is large or has been seriously occurred, the use of chemical agents is the most efficient means of control. At the same time, it is necessary to grasp the control period, that is, the early stage of larval hatching, so that it can be easily controlled, because the larvae hatched by the soybean silver moth are very sensitive to chemical agents, low resistance, and the use of a small dose can have a good killing effect on the larvae, and at the same time, the egg killing component should be added, so as to effectively reduce the hatching rate of the larvae and enhance the effectiveness of the control.
Period of administration: the initial stage of larval hatching
Dosing period: 9-10 a.m. or 5-6 p.m
Recommended agents: 240 g/ liter insect mite nitrile suspension 20 g, 10% methyl vitamin salt indinale suspension 15 g and 20% chloranthrine benzamide suspension 10 g and other agents, with 5% lice mite urea suspension agent 20 g foliar spray, can effectively kill larvae and egg blocks, but need to pay attention to the rotation of the agent.
The above is the basic introduction of the soybean silver moth, including the occurrence law, living habits, hazard characteristics and how to effectively control it, hoping to help the majority of farmers.