Red spider, we fruit farmers are more familiar with a pest mite, in recent years the harm to apple trees more and more serious, we for the prevention and control of this pest mite, there are many times the effect is not good, resulting in a large-scale outbreak, causing serious losses.
An important reason why we do not have a good control effect on red spiders is that we do not distinguish which kind of red spider it is. Although the red spiders on the apple tree are similar on the surface, but in fact there is a difference, the control focus of different types of red spiders is also different, many fruit farmers and friends treat all the red spiders as one, without distinction, the measures taken are unreasonable or miss the best time to control, it is easy to have a bad control effect.
In this year's survey of wintering pests in our orchards in the southern part of Zhaoyuan, I also found some overwintering red spiders, and I will take my investigation as an example to discuss some problems in the control of red spiders in apple trees with my fruit grower friends.
The red spider that appears on the apple tree is very small and difficult to distinguish
< h1 class="pgc-h-arrow-right" > let's take a look at the wintering red spiders we found in the far south</h1>
The picture below is my photo taken in our orchard on February 4 this year, that is, the day of Lichun, we fruit grower friends should be able to see at a glance that this is a red spider, if you look closely, although this pest is relatively small, we can still see that it is a worm rather than an egg, and from the morphology of an adult worm rather than a nymph.
In the upper left corner of the picture, we can see a piece of silk mesh, which was scratched when I unveiled the old warp, but the position did not change much, and it can be seen that it is with these red spiders. In this way, we have found two characteristics of this red spider: one is overwintering with adults, and the other is that it will spit out silk and knotted webs.
I found that these red spiders are not all orchards, mainly concentrated in the orchards that were heavily harmed by red spiders last year, and there are more old warped skins on the trunk and branches of fruit trees, and more rot and dry rot spots appear more, mainly concentrated under the old warped skin of fruit trees.
On February 4 this year, we photographed wintering red spiders in the south of Zhaoyuan, and we can see adult worms with webs
<h1 class= "pgc-h-arrow-right" > the species and characteristics of red spiders that harm apple trees</h1>
Now let's take a look at what kinds of red spiders harm apple trees and what their characteristics are, so as to find out which kind of red spiders we have in the picture above.
The main harm to apple tree red spiders are hawthorn leaf mites, apple full claw mites and fruit mites three kinds, these three kinds of hawthorn leaf mites and apple full claw mites are more common in our place, fruit mites now occur less, in the control method and full claw mites are basically similar, here is not much to say, the following focus on the other two more common.
Here to explain, the size of the red spider is very small, from the appearance of basically the same, the above picture is enlarged after the shooting, we fruit farmer friends basically did not take a magnifying glass to observe the pests, so here the specific morphological characteristics, such as back hair, feet, etc. are not introduced much, only by the naked eye we can not see, mainly introduce some of the characteristics of their harm, we identify from these aspects.
1. Comparison of hawthorn leaf mites and apple full-clawed mites overwintering and hatching
Hawthorn leaf mites, to fertilized female adult overwintering, overwintering is mainly in the main trunk and branches of the apple tree under the old skin, the soil cracks around the root neck, spring fruit tree buds out of the sting, they will first go to the bud body of the fruit tree after the sting, wait until the young leaves grow out to begin to harm the young leaves, the flowers grow out to harm the flower vessel.
Apple full claw mite, with eggs in the short fruit branches, fruit table and some small branches overwintering, inflorescence separation period overwintering eggs began to hatch, hatching peak period is basically in the full flowering period of apples, hatching began to harm the young leaves and flowers of apples, one week after flowering most of the wintering eggs hatched.
Zoom in to see the female adult hawthorn leaf mites overwintering, also photographed in the southern part of Zhaoyuan
2. Comparison of hawthorn leaf mites and apple full-claw mites from the first generation to before overwintering
Hawthorn leaf mites, which lay eggs after stinging, basically begin to lay eggs during the expansion of the buds, and the first generation hatches the most neatly, which basically hatches in our place about 7 days after flowering, that is, around mid-May. After the first generation hatches, it continues to breed hazards, generations overlap, breeding is particularly fast before and after the wheat harvest, the degree of harm reaches the peak of the whole year, in our place basically in early to mid-June, can last until July, to August, the number of occurrences with the increase of rainfall and decrease, around the middle of October began to enter the wintering state.
Apple full claw mites, in addition to the first generation of wintering eggs hatched more neatly, the future are overlapping generations, the front can not be prevented, the later stage of the harm will be particularly heavy, generally in July to reach the peak of the harm, in mid-to-late August began to appear overwintering eggs.
3. Comparison of hawthorn leaf mites and apple whole claw mites and harmful symptoms
Hawthorn leaf mites, there is a habit of spitting wire knots, when the damage to the leaves is serious, the leaves are like being burned by fire, and rust color appears on the back of the leaves, which can cause the leaves to fall off in advance.
Apple full claw mites, there is no habit of spitting silk knots, when the damage to the leaves is serious, the leaves are gray, hard, but generally do not fall leaves.
After hawthorn leaf mites harm the leaves, rust color appears on the back of the leaves
<h1 class= "pgc-h-arrow-right" > the correct control of apple tree red spiders</h1>
I believe that you can see the fruit grower friends here, should have their own answer to which kind of wintering red spider we found in the first picture, according to the characteristics of spitting silk webs, adult overwintering and overwintering under the old warp skin, we can determine that this is hawthorn leaf mite, according to the characteristics of hawthorn leaf mites to control, if the red spider's wintering eggs are found on the branches, then it is necessary to focus on the prevention and control of apple full claw mites.
Now determine which kind of red spider is wintering in their orchard, this is very important, which is related to the prevention and control effect of this year, it is recommended that fruit grower friends do this work when they clear the garden now.
Then when it comes to our current Qingyuan, the old problem of scraping tree bark is no longer verbose. In terms of medication, the most effective spring Qingyuan is the stone sulfur compound, using 3 to 5 baumei degrees, thoroughly penetrated, it is not recommended to use other acaricides alone.
Now that many of us fruit growers are scraping the bark of the trees in the garden, it is necessary to carefully check the occurrence of red spiders on the trees at this time
1. The same key prevention and control period
We can see from the above comparison that the control of hawthorn leaf mites and apple full claw mites has two common time periods, the first is in the spring when the garden is cleared, that is, the work we have to do now, and then it is about a week after the flower, but this time is more inclined to the prevention and control of apple full claw mites.
2. Differences in the control of hawthorn leaf mite and apple full claw mite
The most critical thing in the prevention and control of apple full claw mites is to check the orchard in time after flowering to before bagging, if the medicine is not stopped, then the second time the medicine is changed to a mite, or take the method of compounding to enhance the effect, and strive to control it before bagging, and then take measures according to the occurrence of insect pests in the orchard.
Hawthorn leaf mites throughout the year focus on the wheat harvest before and after, this time basically finished bagging, now found on the fruit tree hawthorn leaf mites, it is recommended not to directly hit Bordeaux liquid after bagging, first hit a clear water medicine, plus acaricide, this time the hawthorn leaf mite breeding speed is very fast, do not take it lightly.
Hawthorn leaf mites can trap overwintering female mites by strapped weeds to the trunk in the autumn, around mid-October, while apple full-claw mites are not feasible with this method.
After bagging, before and after wheat harvest is a critical period for hawthorn leaf mite control, and it is necessary to pay attention to prevention and control when there is hawthorn leaf mite
Red spiders are now becoming more and more resistant, and it is recommended to choose a reasonable rotation according to the specific situation:
43% biphenylhydrazine ester 3000 times liquid, this performance is better, but the price is slightly higher;
15% pyridoxine 2000 times liquid, the resistance is relatively large, it is recommended to use after flowering, but the fruit tree can not be used when it is also a two-spotted leaf mite;
1.8% avermectin 3000 times liquid, avermectin is now also used with great resistance, can be used in combination with other agents;
240g/L spironoate 3000 times liquid, this effect is very good, mites at all growth stages can basically kill;
20% triazoltin 1000 times liquid, triazoltin feel warm, the efficacy is relatively long, when using, pay attention to improper use is prone to drug damage.
There are some other acaricides, here will not be enumerated, we control mites for the choice of agents according to the time of control and the characteristics of mites to choose drugs, the effect is not good can be used with two kinds of agents to enhance the effect, such as avermectin + triazoltin, etc., but it should be noted that mite pests on the drug resistance to enhance particularly fast, to avoid repeated use of the same drug.
<h1 class="pgc-h-arrow-right" > summarize the problems that need attention</h1>
We for the control of red spiders, the difference between species is very important, such as apple full claw mite as hawthorn leaf mite control, wait until the wheat harvest time focus on prevention, it is likely to have been particularly serious, in the autumn tied grass to lure the overwintering adult insects will not have a little effect, and the hawthorn leaf mite as an apple full claw mite in the flower after the key prevention, to the wheat harvest neglect prevention and control is also likely to cause serious harm to hawthorn leaf mites.
In the management of apple trees throughout the year, if there is a problem of red spider harm, we can judge which kind of red spider it is based on specific performance, such as the color of the harmful leaves, whether there is a knotted web, etc., and take targeted measures according to its occurrence characteristics. Many of our fruit growers here are now in Qingyuan, and at this time, checking the occurrence of red spiders in the orchard at the same time in Qingyuan can play a good guiding role in the prevention and control of red spiders throughout the year.
I am the seventh brother of the farmer, the above is just a little personal experience and opinion, the level is limited and inevitable deficiencies, welcome to leave a message to correct!