Recently, due to the influence of high temperature and high humidity climate, some apple orchards have appeared obvious leaf diseases, mainly brown spot disease, spotted leaf litter, anthrax leaf blight and so on.
In the face of the occurrence of these leaf diseases, some fruit farmers do not think so, today I heard such a voice, in the chat with a fruit farmer he said don't care, now this is going to be autumn fruit trees fall a little leaves are fine, not to mention that spraying does not work, will often fall more severely.
Speaking of this, many people may wonder, why is the spraying of leaves more serious? In fact, it is caused by the wrong use of drugs, not to do the right medicine, did not effectively control its disease, just blindly sprayed Bordeaux liquid, ignoring the prevention and control effect of clear water medicine.
In the face of the outbreak of early defoliation disease in apple orchards now, we must spray effective fungicides reasonably according to the situation of our own orchards, and then spray Bordeaux liquid to protect them after the disease is effectively controlled, for the choice of clear water medicine, we can use pentanzole, diphenoxymethanazole, imidazole, pyrazole ether esters, oxime esters, daisen manganese zinc, agricultural resistance 120 and so on for reasonable compounding.
Recently, the high temperature and humidity have shown signs of leaf blight in the leaves of the Gala apple.
This is what I took in my orchard today, and it doesn't seem like a big problem. This is mainly due to two sprays in June, a fungicide compounded with dicyanone and pyrazole ether ester.
It is now a critical period to control anthrax leaf blight in August, although apple prices are now depressed, and everyone should not relax management. After all, in a few days, The apple will be on the market.
It is recommended that you add zinc manganese to the basis of dicyanoanthraquinone pyrazole ether ester and use it alternately with Bordeaux liquid. The interval should not exceed 7 days.
Is there still a good way to prevent anthrax leaf blight?
Fruit farmers should pay attention to the fact that apple brown spot disease and spotted leaf litter disease have appeared in some orchards, and they are afraid of a big outbreak if they are not well controlled.
In recent days, I have found that there are more leaves in several orchards, some of which are caused by the closure of orchards and poor ventilation and light transmission; some are because the orchards are not used rationally, and they have been infected with brown spot disease, causing leaf fall.
It is recommended that the fruit grower friends in the early stage of leaf fall, Bordeaux liquid for more than 30 days, immediately spray the whole park through the phenylmethicazole, benzene. Imidazole, propaconazole, pentazole fungicide, due to the frequent rainfall this year, poor control will really cause large-scale leaf fall, do not be careless.
Early maturing apple anthrax leaf blight, which enters a new peak in August, is likely to erupt in a short period of time in the event of rain.
First, the occurrence of the overview
Apple anthrax leaf blight mainly harms the leaves and fruits of apples such as Qinguan, Golden Crown, Gala, and Jonajin, and the disease occurs quickly, the harm is widespread, and the prevention and control is difficult.
2. Symptoms of harm.
The initial symptoms of apple leaf blight caused by anthrax bacteria are black necrotic spots, under high temperature and high humidity conditions, the spots expand rapidly, and can spread to the entire leaf within 1 to 2 days, making the whole leaf black and necrotic. The affected leaves are scorched and withered after dehydration, and then fall off. When the environmental conditions are not suitable, the spots stop expanding, forming dead spots of varying sizes on the leaves, and the healthy tissue around the spots then turns yellow, and the diseased leaves quickly fall off.
The main difference from the harmful symptoms of brown spot disease is that the leaves of anthrax leaf blight have scorched wilt plaques before they fall off, while the brown spots do not appear before they fall off. After anthrax leaf blight is infected with greening, the leaf surface is mildly watery, while the brown spot disease is more bright yellow after greening. Anthrax leaf blight infests the leaves from the lower main branch, and the peripheral and inner chamber diseases are not obvious. Brown spot disease mostly begins from the lower main branch and the old leaves of the inner chamber, and the incidence of new shoot leaves is mild.
Third, the occurrence characteristics:
1. Rapid infestation, short incubation period, large spore production, acute onset.
The spores infect the pathogens very quickly, and it takes only 2 hours of moisturizing time at 30 °C to complete the entire infection process. Generally from infestation to onset is only 3 to 4 days or less, under high temperature and high humidity conditions, the spots expand rapidly, and can spread to the entire leaf within 1 to 2 days, causing shedding.
2. The spores are mainly transmitted by wind and rain, and can also be transmitted by air currents at long distances. It is estimated that the annual extension distance is more than 200 kilometers.
3, different apple varieties between the disease resistance difference is very large, Gala, golden crown, etc. are easy to infect varieties, Fuji and other disease resistance, almost no disease. The in vivo leaves of inoculated Fuji apples produce only needle-tip-sized blight spots, indicating that Fuji is highly resistant to leaf blight anthrax bacteria.
4. The germs overwinter on the branches, and the germs are difficult to eradicate.
Fourth, prevention and control measures
Anthrax leaf blight is characterized by the rapid spread of pathogenic bacteria, strong harm, will cause a large number of apple leaves in the early stage, serious leaf fall orchards that year the formation of secondary flowers, the apple production is a great threat, should be through comprehensive prevention and control measures, control its harm.
1. Unified defense and rule
The prevention and treatment of the disease must first start from the basics, and there must be a set of prevention and control measures to achieve the purpose of mass prevention and treatment and reducing the incidence of disease.
2. Eradicate overwintering bacteria
In Orchards with a large number of fallen leaves in October, spray 100 to 200 times the copper sulfate solution once, and spray again before the apples sprout in March of the following year. The pre-bud eradication agent can be sterilized by spraying dry branches with 3 to 5 baumedo stone sulfur compounds.
3. Agricultural prevention and control measures
While doing a good job in winter pruning, strengthen summer pruning, with the premise of improving light and reasonable load, timely remove branches that hinder ventilation and light transmission, and worsen the conditions for the breeding of pathogens; increase the application of organic fertilizer, formula fertilization, enhance tree potential, and improve the resistance to diseases. Fruit bagging, changing the past early ripening apple bagging habit, to reduce fruit disease.
4. Pharmaceutical prevention and treatment during the growth period
Since mid-June, intermittently spraying of systemic and protective fungicides every 5 to 7 days ensures that the foliage and branches are under the protection of the agent before each continuous rain of more than 2 days. In consideration of the prevention and control of other diseases, the spraying of Daisen agents can be mixed with other systemic fungicides.
When spraying, we must pay attention to the quality of spraying, try not to use a spray gun in the young fruit stage, improve the degree of spraying, improve the quality of spraying, so that the branches and leaves are used evenly, and the stimulation of young fruits and young leaves is reduced.
5. Remedies
Apple anthrax leaf blight peak period is July to August, the orchard that has already occurred should be immediately applied to control the prevention and control, control its spread hazard, avoid secondary flowering, causing greater losses.
At the same time, the following prevention and control suggestions are proposed for reference and exploration.
Prevention and control measures
1. Select disease-resistant varieties: The new garden tries to choose fruit tree varieties that are not susceptible to disease.
2. Prevent the spread of pathogens: thoroughly clean up the orchard, clean up the dead branches and leaves, scrape the branches and destroy the pathogens. Strengthen the tree posture and improve the disease resistance of the tree.
3, agent: pyrazole ether bacteriolate (note: although the same methoxyacrylate fungicide, but in the early ripening apples such as Gala do not use azoxystrobin, will be harmful) long effective period, no rain up to 10 days, with a certain systemic therapy effect, is a more ideal prevention and treatment agent; Bordeaux liquid, Daisen zinc and Daisen manganese zinc have a better control effect on the disease. Other organic fungicides are effective when used as protective agents, but the duration is only 7 days, and bordeaux liquid can reach 20 days.
Due to the rapid infestation, large spore production and urgent onset of anthrax leaf blight, the interval between application should be shortened to 4 to 5 days, and the continuous administration should be used 2 to 3 times.
Be careful to rotate the use of the agent. When spraying, we must pay attention to improving the degree of atomization of the agent, improving the quality of spraying, so that the branches and leaves are used evenly, and the ground should also be applied.
What about winter dates (grapes, apples, pears) after the rain?
Sterilization with high-grade "Oxime, Zhuo Green" or middle block "Synergy, Dragon Shield, Bikang".
The insecticide high gear uses "Jiaku, Speed Teng, Kang Huan, Fidalar" or low gear "Speed, Strength, Flame Burst Armor Salt" remember "Din, No".
Red spiders must be treated with "Gao Xi Mites or Da B".
The puffed fruit can choose "Puff fruit enzyme, plant shell jian, big gui puff fruit excellent, full tree fruit". Early ripening dates can be removed from greening and reddishing, and you can choose "There is gold, starting point, fruit beauty or great power with Benfu".
Leaf fertilizer can choose "red and bright, ammonia sugar, twelve elements, lan yue golden ton or excellent rehydration solution".
【Source: Department of Agriculture and Rural Affairs of Shaanxi Province_Production Technology】
![Apple orchard high yield management 3 elements, old farmers prefer pruning, not only to slow down the trend[fig]](data:image/gif;base64,R0lGODlhAQABAIAAAP///wAAACwAAAAAAQABAAACAkQBADs=)