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The occurrence of pests and diseases has always been the most concerned issue for all growers. So, what are the top ten pests and diseases that are most likely to occur in the near future?
April is a warm, humid, rainy month, what kinds of pests and diseases should be prevented? Zhi Nongjun will conclude with a predictor of predisposed diseases in April.
<h1 class="pgc-h-arrow-right" > the top ten high-incidence pests in the past two weeks</h1>
10th place: Citrus resin disease
Ninth place: Magnesium deficiency
Eighth place: Citrus anthrax, now only beginning to appear, there may be a major outbreak once the Qingming Pass.
Citrus anthrax leaves
Seventh place: Boron deficiency
Sixth place: Citrus brown spot disease
Brown spot disease, which is most severe from late April to mid-June, is also common from late March to early April, and is a common fungal disease in this season. Citrus with a wide skin, such as limes, are the most susceptible to infection. It will invade the new shoots, causing the new shoots to curl up, turn black and brown, and gradually die.
In addition to new shoots and young fruits, the most easily distinguished part of brown spot disease is the leaf. Brown spot disease can produce toxins, and toxins spread along the leaf veins, so leaves with brown spots have a very obvious symptom - the leaf veins are dark brown around the leaf veins. This is a special symptom of brown spot disease and can help us distinguish brown spot disease.
Citrus brown spot disease
Brown spot disease, similar to anthrax, often has fruit grower friends who are not clear, because of confusion, the use of the wrong treatment method, resulting in missing the best treatment period.
The biggest difference between the two is that brown spot disease is a dead parasite, suffering from brown spot disease, causing large leaves of fruit trees to fall. Many farmers do not pay attention to the leaves that fall on the ground, resulting in the spread of germs. Anthrax is a weak parasite, when the leaves are inverted V-shaped spots, the leaf veins have obvious symptoms of infection is brown spot disease.
Medication recommendations: Pyrazole ether esters, plurazole, or diphenoxymethicazole are commonly used.
Fifth place: Gray mold
Diseases that occur with a high frequency in March and April, if not prevented in advance, are likely to appear flower peel fruits, resulting in a great reduction in fruit. Gray mold first occurs from the petals, the petals appear hairy mold layer, in the flowering time, the petals fall on the young fruit, resulting in the young fruit infected with gray mold disease, and then the appearance of the peel fruit.
Prevention and control methods:
1. Shake the flowers
Gray mold infection is strong, the speed of infection is fast, must be prevented in advance, when it is serious, most of the peel fruits have already appeared. The lowest cost control method is to shake the flowers and do not let the germs on the petals contaminate the young fruit.
2. Pharmacy
Now in the rainy season, we should pay attention to the weather forecast, avoid rain after the drug, you can choose: pyrimidine, pyrimethamine, multiples in 1000 times or 1500 times.
Fourth place: Thrips
Both thrips and gray mold can lead to the appearance of peel fruit. Thrips prefer young shoots, young leaves, young flowers and young fruits, and when the thrips file suction mouthpiece rubs on the young peel, the flower peel fruit quietly appears.
The biggest difference between the scar caused by the thrips and the gray mold is that it is a circular scar. Some fruit grower friends are curious: why is it a circle shape?
This is because when the fruit is just finished, the flowers have not yet fallen, and the thrips can only bite along this circle. To judge whether the medicine to beat the thrips is good or not, it depends on whether there are circle-like scars, and if there are large scars, it means that the agent has little effect.
Thrips symptoms
Recommended Agents:
1. The most common formula, high efficiency cypermethrin + thiamethoxam, this formula can not only be used for thrips control, but also for aphids, weevils, whiteflies is also excellent effect.
2. But there is a difficulty in the prevention and control of thrips, that is, thrips will recur. Now an emerging agent, pyriproyl ether, belongs to the regulator and has a long-term effect. Methyl vitamin salt is a short-acting agent, for the recurrence of thrips, long-acting agent + short-acting agent, is undoubtedly a good choice.
Third place: Red Spider
Red spiders are already a common pest that everyone knows about. Although the red spider is called a spider, it is a small mite, because the insect is small, so it is not found, so some fruit grower friends can not distinguish. Zhi Nongjun tells you a little trick, you can see dense red dots on the leaves, mostly red spiders.
Citrus red spider harmful symptoms
Prevention and control methods: Red spiders are the most serious in Sichuan, and when they are sprayed, they are beaten as if it is raining. In addition to Sichuan, all major citrus-producing areas in the country are prone to red spiders.
1. Avermectin, the most commonly used control agent, is used to kill adult mites, but it is not enough to kill adult mites.
2. Biphenylhydrazine ester, ectozole, kill juvenile mites.
There are not many agents that kill young mites and have remarkable effects, and it is necessary to pay attention to the rational use of these two agents, so that young mites can be double-controlled and controlled, which can play a real effect.
Second place: Root damage
It is a recent common phenomenon, the mouth of root crop plants, used to absorb nutrients, there is damage, that problem is very large. Excessive watering, waterlogging, fertilizer damage and other reasons may cause root damage. As a comprehensive symptom, it is not treatable by drugs.
Occurs for:
1. Excessive watering, waterlogging and waterlogging after rain, resulting in root damage, are the causes of root damage.
2. Improper fertilization leads to root burning, and the most common reason for root burning in recent times is the use of organic fertilizer that is not decomposed.
3. Circumcision. Circumcision is too deep, resulting in nutrients not functioning properly, which is also one of the causes of root damage.
Root damage, not an overnight thing, usually pay attention to the management measures of the orchard, once the symptoms are found, we must find the cause, the right medicine!
1st place: Iron deficiency
Iron deficiency ranks first, and it is concentrated in several citrus regions in Guilin, Guangxi, Ganzhou, Jiangxi, and Chenzhou, Hunan, which is unexpected! Zhi Nongjun speculated that after fruit picking, the nutrient consumption of the tree was large, and the nutrients of the tree were not replenished in time, resulting in iron deficiency in the fruit tree.
Iron deficiency has a special identification method: the leaves are white.
It is mainly manifested in young leaves, the veins of young leaves are green, but the leaves have become pale green or white, and the old leaves are still bright green. In general, there is no large whitening of the leaves due to pests and diseases, and 99% of this symptom is iron deficiency.
Whitish iron-deficient leaves
In autumn, pay attention to the supplement of slow-release fertilizers, such as farm manure. If there is iron deficiency in the spring, quickly supplement the compound fertilizer containing the trace element of iron, or spray foliar fertilizer to play a slow release role.
Iron-deficient blades
After introducing the recent top ten high-incidence pests, the three most likely diseases that may occur in April, did you guess it? Zhi Nongjun speculated that the most likely to occur:
The three major diseases are: gray mold disease, brown spot disease, and scab disease.
The three major pests are: aphids, whiteflies and snails. Snails, in particular, prefer rainy and wet weather.
The most important thing to pay attention to is to prevent them in advance! Pests and diseases have occurred and then started to use drugs, and there has been a loss! Therefore, the majority of fruit farmers and friends, pay attention to strengthening the management of orchards!