Although it is still in the high temperature and rainy August, but autumn has arrived, in half a month into September, the weather will begin to slowly become cooler, this moment is the opportunity for apple aphids to come back, but also the key moment of apple growth. In order to prevent the harm of cotton aphids to the yield and quality of apples, fruit growers need to do their precautionary homework in advance to avoid being busy and caught off guard when the second peak period of apple cotton aphids comes.
In order to help fruit growers reduce losses, the following will be analyzed through the introduction of apple cotton aphids, hazard characteristics, morphological characteristics, occurrence habits, prevention and control techniques, so that you can refer to it.
<h1>First, what is apple cotton aphid</h1>
Apple aphids, also commonly known as "aphids, blood aphids, aphids, and white caterpillars", belong to the family Aphids of the order Homoptera and play a great destructive role in the growth and development of apples. In addition to harming apples, plums, pears, hawthorn and other fruits, it will also affect plants such as begonias, bonuses, sand fruits, etc., which is a high incidence of insect pests in spring and autumn, mainly endangering Shandong, Liaoning, Tibet, Jiangsu, Yunnan and other places in China. Due to the strong reproductive capacity of apple aphids, 8 to 21 generations can occur in just 1 year, and if there is no strengthening of attention to timely prevention and control, it will seriously affect the yield and quality of apples and bring economic losses to fruit growers.
<h1>Second, the harmful characteristics of apple cotton aphids</h1>
Apple aphids are mainly group activities, whether it is nymphs or adults, they like to hide densely in the shade of the backlit trunk scars, trunk cracks, saw openings, new leaf axils, stems, calyxes, etc., but mainly harm the branches and roots of apple trees, and most of the victims will form small tumors that are easy to rupture. The surface of various insect forms of the cotton aphid will be covered with a layer of white cotton wool, and the tree body with insects looks like a layer of white cotton wool spread on the tree, and the reddish-brown insect body of the cotton aphid can be seen by breaking the white cotton wool. The white cotton of the apple cotton aphid is equivalent to its protective cover, which makes it difficult to control measures.
1. The harm of cotton aphids to branches, leaves and fruits:
Swarms of cotton aphids cling to the shade of apple branches and leaves like a cotton wool, sucking up the sap. Branches that are harmed by cotton aphids will form nodular protrusions, which will rupture into wounds at a later stage; petioles will become black-brown after being killed, because the function of photosynthesis is destroyed, and the leaves will easily fall; the endangered fruits will be stunted and easy to fall from the branches.
2. Harm to the roots:
The aphid absorbs the sap of the tree and secretes a digestive juice that stimulates the fruit, multiplies the affected area, and the root tumor is dense and begins to rot. As a result, the apple tree weakens, nutrients can not get the normal supply, the result is a small number, small fruit, poor peel coloring, affecting the quality and yield of the fruit, and in severe cases, it may also cause the whole garden to fall leaves, damage, and harvest.
<h1>Third, the morphological characteristics of apple cotton aphid</h1>
(1) Adult worms
1. Wingless female aphid: the shape is oval, the body length is about 1.7 to 2.2 mm, the color is yellow-brown or russet, the head has no frontal tumor, there are dark red compound eyes, the mouth pecks the russet end is black, there are a small number of short hairs on the body, there are 6 antennae, and the 3rd section is the longest. There are lateral tumors in the abdomen and 4 longitudinal columns of pores on the dorsal abdomen, which are able to secrete white waxy filaments. The abdomen is enlarged, the abdominal tube is ring-shaped, and only a semi-circular crack is left after degeneration, and it is commonly used to gather on the branches in a group way, as if hanging cotton wool.
2, winged fetal female aphid: the shape is oval, the size is slightly shorter than the wingless female aphid, the body size is relatively thin, the body color is dark, the head and chest are black, the wings are transparent, the abdomen is dark brown or olive green, there are red-black compound eyes, the mouth pecking black, the same 6 antennae, the 3rd section is the longest. The white cotton on the abdomen will be less common than the wingless female aphid, and the abdominal canal degenerates into a black annular hole.
(2) Sexual aphids
1. Sexual female aphid: the body length is 0.6 to 1 mm, the abdomen is russet, and other colors (head, antennae, feet) are light yellowish brown, with 5 antennae, and the mouthparts are degenerated.
2. Sexual male aphid: the body length is about 0.7 mm, the body color is light green or yellow-green, with 5 antennae, the antennae end is transparent color, the abdomen has obvious groove marks, and the central bulge of each segment is raised.
(3) Nymphs
Nymphs are also divided into two forms: winged nymphs and wingless nymphs. Juvenile nymphs are slightly cylindrical in shape, with less white cotton hairs on the dorsal ventral area, a russet body color, 5 antennae, and a mouth peck longer than the abdomen. The size of the 4th instar nymph is relatively similar to that of adults.
(4) Eggs
The shape of the egg is oval, about 0.5 mm long, the two ends are thicker and thinner, and the color gradually changes from orange-yellow to brown.
<h1>Fourth, the occurrence habit of apple cotton aphids</h1>
(1) Wintering methods
Apple aphid breeding and survival ability is very strong, in Our country can occur 8 to 21 generations a year, often the old aphid or eliminate the new aphid and began to be continuously multiplied, which is also a reason why the aphid is difficult to eliminate clean. The aphids are mainly 1 generation 2 generations of juvenile nymphs in the thick skin cracks of the branches, near the roots of the surface or under the nodules, around the wounds of decaying diseases and diseases, and more in the wounds of insect pests such as the transfiguration moth and the celestial bull, and some hide on the saw-cutting and indeterminate buds at the roots.
(2) Conditions of occurrence
Activity Timeline:
1, apple cotton aphid likes to survive in a refreshing and comfortable environment, high temperature and dry weather is not conducive to its activities. The aphids overwinter on their hosts, and when the temperature rises to about 9°C around April of the following year, the nymphs still come out to move. By May, as the temperature rises, aphids begin to spread at about 11 °C, harming the more delicate branches and leaves, axillary shoots, and breeding wingless females in large numbers in the form of parthenogenesis. If the aphids that overwinter successfully in early May grow into aphids, there are many hazards in situ.
2. From the end of May to the beginning of July every year, it is the peak period of the annual breeding of apple aphids, and flocks of aphids lie on the wounds and scars of the branches of fruit trees and the new branches, leaf axils, etc. to carry out hazards, and the juice of the victim site is collected, and then the secretions of the aphids cause swelling of the victims, shaped like tumors.
The temperature is relatively high from late July to early September, especially in August, which is not conducive to the breeding and activity of aphids. In addition to the high temperature, the large increase in the natural enemy solar bee has also reduced the number of cotton aphids and been controlled to a certain extent.
4, after entering the autumn, the weather will begin to slowly cool, in the second half of September, when the temperature drops to the appropriate temperature of the cotton aphids, the number of apple aphids will increase, at this time the apple will be affected by the second big attack of the cotton aphid infestation.
5, when the temperature gradually drops below 7 ° C, about in November of each year, apple aphids will look for a suitable location for wintering to overwinter, and then the next year will begin to repeat the hazard.
(3) Methods of dissemination
The transmission mode of apple cotton aphid is mainly divided into close transmission and long distance transmission. Close-range transmission: that is, in the field, there are three main ways, winged insects fly to spread, wingless insects spread by crawling, and can also be artificially spread through agricultural operations. Long-distance transmission, with insect seedlings or scions being carried from the area where the insect infestation occurs to the area where the insect infestation occurs is carried out in the area where the insect is free.
<h1>Fifth, the prevention and control technology of apple cotton aphid</h1>
(1) Agricultural prevention and control
1. Strengthen the quarantine of seedlings and scion
Strict quarantine should be carried out on the breeding base of cultivated seedlings and scion to ensure that the seedlings and scion leaving the garden are healthy and disease-free. It is strictly forbidden to transfer seedlings and scion with apple cotton aphid infestation, and quarantine must be carried out before and after transfer to prevent apple cotton aphids from entering non-epidemic areas. When insect infestation is found, it is necessary to use drugs for control in time, and can be soaked for 50% octylthion emulsion 1500 times liquid for 5 to 10 minutes, or placed in a confined space with bromomethane for 3 hours of fumigation.
2. Strengthen orchard management
Usually, it is necessary to strengthen the management of orchards, and in the dormancy period of fruit trees, the rough skin and scars that have been damaged by insect pests are scraped down with a scraper and packed into specially prepared bags, and at the same time, the branches and branches with serious pest damage are cut down with scissors, packed into bags together, and taken outside the garden for centralized destruction. The scraped position and the trimming position are applied with a sludge to prevent and control the infection of the wound, while speeding up the healing of the wound and not giving the insect infestation another chance to harm.
3. Rational use of natural enemies
No matter what the pest has its natural enemies, the apple aphid is the same. In July and August, the activity of cotton aphids decreased in high temperature weather, and its natural enemies aphid wasps, daylight bees, ladybirds, grasshoppers, etc. Fruit growers can use natural enemies to reduce the harm of apple aphids. Try not to use broad-spectrum insecticides to check for insecticides, and you can also plant diverse plants in pest-prone orchards to attract predators.
(2) Chemical prevention and control
1. Apply medicinal mud to the branches:
Apply 200x of chlorpyrifos emulsion or 15x of 40% oxidized lego emulsion to the location of scraping and the dense overwintering of insect pests.
2. Whole tree spraying:
Early prevention before the outbreak of aphids can have a multiplier effect, so spray the drug once in mid-April and early May, and then spray the drug again in early June for consolidation, and spray the drug evenly and spray thoroughly. Spray scars and cracks between branches.
The reference drugs that can be used are as follows: 48% chlorpyrifos emulsion 1200 to 1500 times liquid, or 5% acetamidine emulsion 1500 to 2000 times liquid, 10% imidacloprid wettable powder 2000 times liquid, or 22.4% spironium ethyl ester suspension 2000 times liquid, or 2.5% flutter aphid wettable powder 1000 times liquid, etc.
3. Root application
(1), in the orchard with many insect pests can be applied to the roots, in the nymph aphids in April to May, peel open the soil around the trunk, let the roots be exposed, and then sprinkle 5% octyl thion particles 60 grams per tree, after sprinkling the soil and then cover the soil, so as to prevent the roots of the cotton aphids from infestation.
(2) After rain or after watering, you can spray 48% chlorpyrifos emulsion 800 times liquid within one meter around the trunk.
(3) When the two peak periods of apple aphids come (May to June, September to October), a root irrigation treatment can be carried out separately, and 10% imidacloprid wettable powder can be used for irrigation.
Through the above analysis of the introduction, hazard characteristics, morphological characteristics, occurrence habits, and prevention and control techniques of apple aphids, I hope that fruit growers can bring help. The harm of apple aphid can not be ignored, now into the middle of August, is about to usher in the second peak period of the outbreak of apple aphid, fruit farmers need to strengthen the awareness of prevention, timely prevention and control measures, once found the signs of aphid activities, it is necessary to immediately take scientific control methods, the use of agricultural control and chemical control of the combination of methods, reduce the degree of harm of aphids, to avoid causing serious economic losses.
Text: Country grains of rice
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