The appearance value is the most intuitive embodiment of the commerciality of fresh grapes, but the grapes from hanging fruit to harvesting period is not short, but where a disease and insect patronage, mechanical damage, fruit surface medicine damage, this phase will also be broken, fruit farmers' income is also greatly discounted.
We are cultivated again to avoid the rain, and we are bagging the fruit, in the end, is it not for the grapes to have a good appearance? But friends, open guns are easy to hide, dark arrows are difficult to defend! Many people wondered, this disease and insect have also been controlled, and the medicine has also been paid attention to, but what is the rust, black spots, and white spots on this grape? Let's explain each one.
<h1>01 grape rust spots
</h1>
Rust
Rust spots are often called fruit rust, generally only on yellow-green grape varieties, belonging to the category of physiological diseases. Eurasian species are more prone to fruit rust than European and American hybrids; the same type of Eurasian species, thin-skinned and thicker-skinned, are prone to rust.
Main symptoms: the peel is rusty like a metal surface, and there are two forms of rust spots and rust spots, with different shapes.
Pathogenesis: one is due to the fruit surface stomata is blocked, free radicals can not be discharged, oxidation in it, and produce peel rust spots; there is also a kind of cell necrosis on the surface of the peel, the loss of intracellular substances caused by withering, and rust spots appear.
Causes of occurrence:
(1) Low sunlight, high humidity, and slow fruit development, creating a good environment for fruit rust to occur;
(2) Various drugs, fertilizers, regulators, auxiliaries, etc. destroy the normal opening and closing of stomatal defense cells, which will lead to the occurrence of fruit rust;
(3) Improper pruning, too much amount of vines, resulting in poor ventilation and light transmission, easy to produce rust;
(4) Excessive application of nitrogen fertilizer, the fruit is easy to produce fruit rust; insufficient calcium fertilizer, high incidence of fruit rust;
(5) Although the part that suffers from air or sunburn does not show obvious symptoms, it is also prone to fruit rust in the later stage.
Prevention and control methods:
(1) Reasonable fertilization Increase the amount of organic fertilizer and phosphorus and potassium fertilizer, reduce the amount of nitrogen fertilizer, and cooperate with the application of sea spirit biological stimulators to make the peel develop normally. Increasing the application of calcium fertilizer, if the period of spraying Gaishimei, can increase the thickness of the peel, promote fruit expansion, reduce the occurrence of rust.
(2) Scientific use of pesticides during the fruit period is prohibited from using organic sulfur or emulsion-type insecticides, Bordeaux liquid, stone sulfur compounds, zinc or copper preparations that are easy to form fruit surfaces; the correct use of pesticide concentrations generally starts from the lower limit concentration of pesticide use and gradually increases later; the sprinkler head is far away from the fruit spike to avoid causing mechanical injury.
(3) Fruit bagging Master the most suitable bagging time and method of the variety, and choose a paper bag with good permeability. For example, sunshine roses can use green or cyan fruit bags, which have a good inhibition effect on peel yellowing and fruit rust. In addition, when using colored bags in areas with low contrast, there is a tendency to slow down due to the rise in sugar content, and it can be harvested after the grape flavor has accumulated sufficiently.
(4) Timely harvest In general, the later the harvest period, the more rust occurs, and when there is already rust in the field, timely harvesting can control the rust to a certain extent.
<h1>02 grape dark spots
Dark spots
The black spots on the grapes are also called small black spot disease, which is different from the black powder after the nutrition beads are dried up, and the nutrient beads are gently shaken off, and the small black spot disease is difficult to clean even with water, which has a greater impact on the appearance quality of light color varieties.
Main symptoms: small black dots are only on the surface of the fruit, do not enter the pulp, can be peeled off with fingers or simple tools, will increase with the growth of grapes, some will be connected into a piece, no fixed shape, severe can cause the fruit to crack.
Pathogenesis: Some researchers believe that the harm of trace fertilizers is the result of the combination of the harm of Streptosporium, and some scholars believe that this disease is a symptom of the fruit manifestation of panicle axis brown blight, because the pathogen of the disease is also Streptosporium.
Causes: Uneven absorption of micro-fertilizers, grapes are infected by Streptomyces after excretion.
Prevention and control methods: rational use of fertilizer, mainly prevention, drug selection of triazole fungicides, and anti-anthrax.
<h1>03, grape white spots
day shift
Leukoplakia is actually a layer of white mold spots, the full name is fruit spillage mold spot disease, the disease was first found in 2005 on the summer black, usually when the fruit is close to maturity.
Main symptoms: the surface of the peel of the diseased fruit is covered with snowflake-like mold spots, although there is no further ulceration or graining after the onset of the fruit, but it has a serious impact on the fruit.
Pathogenesis: Pathogenic bacteria are mainly Cyperus tangerine, which are produced by colonization on the fruit surface.
Causes: Current studies have pointed out that the disease may be exogenous gibberellin treatment to promote changes in the permeability of the fruit epidermis, providing favorable conditions for the colonization of Ceratophyllus tangerine, and is prone to occur in large quantities under humid cultivation conditions.
Prevention and control methods: Due to the heavy incidence of grape fruit sugar herrhea mold spot disease and occurs at the ripening stage of the fruit, it is not appropriate to use chemical agents for remediation, so it can only be prevented by taking measures in advance.
(1) Do a good job in drainage and ventilation of the park to reduce the environmental humidity;
(2) Strengthen the winter clearance garden, reduce the base number of orange penicillium and the biological matrix that can be used by it;
(3) Control plant growth regulators, especially gibberellin, in the process of flower preservation and fruit preservation.
This article is written by the agricultural assistant team, please be sure to indicate the source of the agricultural assistant, and do not modify the content of the article, the modification must be investigated!