#谷丰计划 #
<h1>preface</h1>
In recent years, with the increase in the planting types and varieties of fruit trees and the expansion of the planting area and the geographical expansion of the planting area, coupled with the unreasonable, irregular and excessive use of chemical pesticides for disease and pest control branches, as well as the extensive management methods of some fruit farmers, there is a pest - pear small heartworm in some fruit tree production areas The trend of harm is also increasing year by year, and has become an important pest on fruit trees such as peaches, large cherries, pears, apples, etc., which seriously affects the yield and quality of fruits. In the article about peach pests, it is mentioned that there are fruit farmers who call to talk about it in detail, can you make a detailed picture introduction to the small pear situation alone, this article focuses on this issue.
Large cherry sprouts are subject to small harmful symptoms of pears
Small pears endanger the condition of peach trees
<h1>First, first understand the basic situation of the pear small</h1>
The host plant of pear small heartworm has a wide range of generations, its adult flight ability is strong, and the larval borer fruit is harmful, and it is difficult for general insecticides to reach the insect body. All these have brought certain difficulties to the prevention and control work. Therefore, how to better prevent it has always been a headache for growers.
If you want to do a good job in prevention and control, you must first understand it together.
Pear heartworm belongs to the order Lepidoptera, a small leaf curler, which is also known as the pear small borer fruit moth, the oriental fruit beetle moth and the pear heartworm. It is sometimes referred to simply as Pear Small. Because of its harmful symptoms on the fruit and on the branches, some local growers also call it black plaster and peach folding worm.
Pear small heartworms are common in peach, pear and apple producing areas in Northeast China, North China, East China and Northwest China. This is especially true in orchards where peach, pear and apple are mixed. In addition to the pests of peaches, pears and apples, the pear small heartworm also hosts plum, apricot, jujube, begonia, cherry, bayberry, hawthorn and other fruit trees.
The damage of small pears on pear trees leads to rotten fruit situations
Pear heartworms belong to the fully metamorphic developmental type of insects. That is to say, at different stages of its development, we see different forms of insect bodies.
<h1>Second, what does the pear look like in each period</h1>?
1. Look at the eggs first
Its eggs are oblate oval in shape and are about 0.8 mm in diameter. The newly laid eggs are milky white and gradually turn yellowish white or white and translucent as the eggs develop. Turns blackish brown before hatching. The egg stage of pear small heartworms is 3-6 days. Pay attention to the peach orchard for small pear eggs.
2. What do the larvae look like
The incubating larvae of the pear small heartworm , its body is white , and the dorsal plate of the head and forebreast is black brown. The body length is less than 1 mm.
Not only are the mature larvae more than a dozen times larger than when they first hatched, but they also change color. By this time, its body length had reached 10-13 mm. The head became yellowish brown, the dorsal plate of the front chest became light yellowish white or yellowish brown, and the body became light pink. The larval stage of pear small heartworms is generally 10-15 days, and the overwintering generation can reach 180 days.
3. Small pupa of pears
6–7 mm long, spindle-shaped, yellow-brown, compound eyes black. There are 2 rows of spikes on the back of the 3rd to 7th ventral segments, one row of larger spikes on each of the 8th to 10th ventral segments, and 8 barbs at the end of the abdomen. Pupal period 7-14 days. The last generation of larvae overwinter in white silk cocoons.
4. Adults
The body length is between 4.6-6 mm and the wingspan is 10.6-15 mm. All grayish brown, dull. The head has gray scales, the antennae are filamentous, and the lower lip must be gray-brown upwards.
The hindwings of adults are dark brown with a pale base and yellowish brown margins.
Male adults and female adults who do not look closely at pear heartworms look basically the same, but if you look at their abdomen, you will find that the tail of the male is pointed, while the tail of the female is round.
Its lifespan is generally 4-15 days, up to 18 days.
The pear heartworm completes a cycle of its life by hatching from an egg into a larva, then becoming a pupa, and finally feathering into an adult.
3. Pear small harm symptoms
Next, let's take a look at what kind of harm the small pear heartworm can cause to the peach tree.
Pear heartworms mainly harm the young shoots and fruits of peach trees.
To harm the young shoots, the larvae moth in from the base of 2-4 leaves at the upper end of the young shoots. After moth in, the larvae feed from top to bottom in the marrow of the new shoots, and gradually wilt and droop after the new shoots are affected, and finally die, this phenomenon is commonly known as "folding the tips". Some people also call it a folding worm.
When the larvae feed on the new shoots, they will excrete feces outside the borer holes, so the accumulated feces can be seen at the borer holes of the new shoots. In the later stages of the victimization, in addition to the insect feces, there will be a small amount of glue in the borer hole. Usually, when the victim shoots turn black, the larvae have often left the affected shoots. This is when the treetops have turned black, and many fruit growers still think it is caused by diseases?
To harm the fruit, the larvae feed on the flesh after entering the fruit, and discharge the worm dung outside the borer hole. As the larval borers go deeper, it will leave the worm droppings in the moth tunnel. In the late stage of the borer fruit, the borer fruit is easy to fall off.
The larvae emerge from the fruit after ripening, leaving a relatively large round hole. Under high humidity conditions, the area around the borer hole is easily infected by pathogenic bacteria and becomes black and rotten. This is the reason why the pear small heartworm is called a black plaster, and it is also the main cause of the occurrence of peach tree brown rot.
Fourth, what is the law of peach tree pear occurrence
Due to the difference in climate, orchard nutrition conditions, agricultural operations, etc. in various parts of China, there are also certain differences in the occurrence time, calendar period and generation number of pear small heartworms.
Two generations occur in one year in northeast China, 3-4 generations occur in most parts of north China in one year, and 6-7 generations occur in provinces south of the Yangtze River in one year.
In Fei County, Shandong Province, the overwintering old mature larvae begin to pupate in early April, with the peak of feathering in mid-to-late April; the first generation of larvae occurs from late April to mid-June, and late May is the peak of occurrence; the second generation of larvae occurs from early June to late June; the third generation of larvae occurs from early July to early August; and the fourth generation of larvae occurs from early August to early September.
Due to the wide range of host plants of pear small heartworms, not only harm peach trees, but also harm apples, pear trees, etc., there are many generations per year, the flight ability of adult insects is stronger, and larvae moths or borers are harmful, and it is difficult for general insecticides to contact insect bodies. Therefore, it has brought certain difficulties to the prevention and treatment of drugs. Therefore, it is crucial to grasp the key prevention and control period and adopt comprehensive prevention and control measures to achieve scientific, efficient and economic prevention and control.
Fifth, how to fight the combined fist of comprehensive prevention and control
The principle of integrated control is based on agricultural and physical control, and scientifically uses chemical control techniques in accordance with the law of insect occurrence and control indicators.
1. Agricultural physical control measures
(1) Do not mix plant orchards
For new orchards, mixed planting should be avoided, especially in peach orchards, and other fruit trees should not be mixed. At this point, we must remember that some fruit farmers mix apples, pears, peaches, large cherries, etc. when they build gardens, resulting in small and large pears.
This is because small pear heartworms are able to transfer between different hosts. Peach tree germination is early, the larvae that occur after overwintering are mainly the new shoots of the stone fruit trees such as the peach tree, and the larvae that occur later can also provide rich food for the larvae in addition to the peach fruit, but also for the young shoots of the kernel fruit trees such as the pear tree. Therefore, the occurrence of small pear heartworms is more serious.
(2) Tree trunks tied to newspaper weeds booby traps
After the peaches are harvested, the grass or newspaper tied to the trunk of the peach tree can lure the larvae into the cocoon for overwintering. The straw handles can be straw or field weeds, tied to the trunk. Before the beginning of spring of the following year, the grass handles are plucked from the trees and burned in a concentrated manner.
(3) Clear the garden in time after pruning
In winter, combined with peach tree pruning, careful inspection, found that the branches with worm holes should be pruned in time, and the length of the pruning should be to cut off the dry and dead branches and expose the fresh tissue, so that the overwintering larvae in the branches can be removed.
After pruning, the orchard should be thoroughly cleaned, and the cut branches should be taken out of the field and destroyed, and must not be stacked in the orchard or near the orchard.
(4) Dry with stone sulfur compound
Because after the pear larvae mature, some of them will overwinter in the branches and other places, so for this habit of the small heartworm of pears, the residue of stone sulfur compound can be used to coat the branches, which can also kill some of the wintering larvae. Of course, combined with winter whitening, the use of whitening agent is also good.
(5) Timely treatment of insect fruits
For orchards without bagging, if you find that the larvae of the pear heartworm have been mothed, you must not think that it is useless to control it at this time. Although the effect of re-spraying in this period is not good, it can also be picked off in time and taken out of the field for destruction, which can reduce the occurrence of the next generation of pear small heartworms.
2. Sweet and sour solution booby trap
The use of sweet and sour liquid to trap and kill small pear heartworms is not only low cost, but also saves labor and time without pollution and residues.
Sweet and sour traps are set up when adults emerge from the local overwintering generation. Since the generations of pear heartworms overlap more severely, it is best to hang them before harvesting.
The booby trap solution is prepared with brown sugar, vinegar, white wine and water in accordance with the ratio of 1:4:1:16, in order to increase the insecticidal effect, 90% of the dichlorocyte crystals can also be added to the mixed booby trap. The amount added is 0.2% of the amount of liquid medicine.
The sweet and sour trap is suspended in the upper part of the canopy perimeter without shelter, and the height is about 1.5 meters. Hang 5-6 such traps per acre. During use, change the sweet and sour solution every 10 days. And remove the insect corpses and debris in the booby trap in time. If it rains, in order to ensure the insecticidal effect, it is also necessary to replace the sweet and sour liquid in time after the rain.
3. Sexual seduction booby traps
Sex traps take advantage of the sexual pheromone tendency of male adults. The female and male adult worms of the pear small heartworm basically only mate once in their lives, so by booby-trapping 1 male, the female insect has one less mating object. So this approach is both efficient and economical. In addition, sexual trapping also has the advantages of not harming natural enemies, not easy to produce resistance, not polluting the environment, and easy to operate.
The trap is composed of four parts: a bracket, a stickworm board, a lure net, and a lure core.
The trap should be hung 1.5 meters from the ground outside the canopy, and a trap should be hung every 30 meters or so, so that the male adults of the pear small heartworm will fly into the trap under the lure of the decoy smell, and due to the small space of the trap, the male adults who fly in will be stuck by the armyworm board below if they are not careful.
During the use of the trap, check the number of male adult insects trapped on the armyworm plate every day, and if the armyworm plate is full of worms, replace the new armyworm plate in time.
Another thing to note during the use of traps is that the core should be replaced every 10-15 days to ensure the booby trap effect on male adults.
Of course, now there is a technology of mesmerizing silk, and the effect is also good, that is, the application of lost silk on the trunk of the orchard, convenient operation.
In addition to the methods introduced above, biological control methods can also be taken for pear heartworms.
4. Biological control
The natural enemies of the pear small heartworm either parasitize on eggs or on larvae. The main parasitizing eggs are pine caterpillar red-eyed bees; the main parasitizing larvae are heart-eating flat-stranded wasps, pear small heart-eating white cocoon bees, heart-eating longitudinal cocoon bees, tooth-legged skinny bees, blunt-lipped wasps, white zombies, etc.
The most commonly used in production is the pine caterpillar red-eyed wasp. It has a parasitic rate of up to 50% on small pear heartworm eggs.
The time to release the pine caterpillar red-eyed bee can be judged by the number of adults trapped in the sex trap, and when the number of adult insects in the trap suddenly increases, 100,000 pine caterpillar red-eyed bees are artificially released per acre.
5. Chemical drug prevention and control
Since the pear small heartworm larvae moth into the young shoots or fruits, the effect of drug application and control becomes worse. Therefore, it is very critical to accurately grasp the peak period of adult feathering and the peak period of egg hatching, and timely application of medicine and prevention is very critical.
(1) Forecast forecast
In order to accurately judge the peak period of adult feathering and the peak period of egg hatching of pear small heartworms, it is necessary to do a good job in predicting and forecasting insect conditions.
Using the sex trap described earlier, you can make accurate predictions about the occurrence of small pear heartworms.
The method is to check the trap every day, pick out the insects on the armyworm board for identification and recording, and then make a curve based on the date as the abscissa and the total number of male adults induced as the ordinate coordinate.
Male adults of pear small heartworms generally mature earlier than female adults, and when the number of male adults trapped increases significantly, it indicates that it has entered the peak period of adult feathering. Since the egg incubation period of pear small heartworm is only 3-6 days, it is necessary to seize the time to spray control.
(2) Spray control
The drugs selected are urea, methyl vitamin salt, high-efficiency cypermethrin, cypermethrin, etc., which should be prepared in accordance with the requirements of the instructions for use, and pay attention to rotation to prevent the resistance of pear small heartworms.
Since the adult worms of pear small heartworms can be migrated and transferred, in order to ensure the control effect, it is best to spray drugs at the same time in the nearby orchards to achieve joint prevention and treatment, which can better consolidate the control effect.
Xu Mingju Introduction:
Fruit tree master, graduated from Huazhong Agricultural University in 1996, majoring in fruit trees, is good at promoting advanced fruit tree technology on the Internet, and founded a representative column: Lao Xu takes you to visit the orchard. Welcome to today's headlines: Fruit Tree Master Xu Mingju