Imagine cooking without onions is simply impossible. This useful ingredient is used in almost all dishes: first, second, baking, in canning, even red onion marmalade is prepared.
Yellowing onions due to pests
It would seem that there is nothing easier than growing onions - these are not naughty tomatoes or tender overseas eggplants. So why does the onion turn yellow in the garden, and what to do about it? Let's figure it out.
Onion fly
Onion Fly Larvae dangerous for all types of onions (shnit, shallot, leek). In May, the fly lays its eggs, and a week later, the voracious caterpillars begin to eat the bulbs. The plant first turns yellow and, if you do not take measures, the onion will die.
As a preventive measure, it is advisable to plant the onion as early as possible so that it can get stronger before the invasion of the larvae. Choose carrots for the onions in the neighbors: flies do not like its smell.
How to save a bow from an onion fly, if it has already appeared on the garden beds. In May, when the fly starts laying eggs, powder the plants with a mixture: wood ash 200 g, tobacco dust and ground pepper 1 tsp. (per square meter). Suitable for dealing with maggots drug "Kreotsid PRO", the solution must be sprayed plants.
Another way to get rid of the insect used by the people: 200 g of salt, 10 l of water, a few ml of ammonia. Saline solution is watered during the development of the feather (feather length about 8 cm). It is advisable not to fall on the feathers, pour under the onion.
Onion Keeper
What is dangerous covertly: he eats leaves, and his larvae gnaw whole trenches in the leaves. Onion loses its presentation, turns yellow and dies.
For prevention, it is recommended after harvesting to carefully clean the soil in the beds, do not leave bulbs for the winter - this is a convenient wintering place for the beetle.
When a beetle appears, doing loosening and weeding the beds, powder the soil with wood ash or pepper, dry mustard. If there are too many pests, treat Karbofos plants (60 g per 10 liters of water).
Important! Immediately after treatment with parasites chemical preparations feathers in any case, do not eat. It should take some time.
Onion thrips
it microscopic (1mm) insect lays a colony of eggs right in the leaf tissue, sucking all the sap from the plant along with its offspring.
To protect against them, as a prevention you need observe crop rotation, clean the soil after harvesting and process onions before planting (keep seed in water up to + 45 ° C). When a pest appears, spray it with Confidor (1 ml per 10 liters of water) and Spark (1 tablet per 10 liters of water).
Onion mite
Onion mite his life destroys the bulb completely. Ticks overwinter in bulbs not harvested in the beds or spread during storage. Most of all, these parasites breed at temperatures over 13 ° C and high humidity, over 60%.
Adult insects and their larvae begin to eat onions from the bottom, it is impossible to notice them.
Therefore, effective prevention of parasite: complete destruction of residues after harvest, do not plant in one area for more than 4 years, warming the planting material, observing all storage conditions of the crop, obligatory deep digging of the soil. Planting material can be poured with chalk to protect against insects.
Nematode stem
Nematode dangerous because it is impossible to notice, it settles in the ground for many years. You can fight it by preventing its occurrence.
As prophylaxis follow the rules of crop rotation, disinfect the planting material (hot water or saline). Sow calendula or marigold in between rows of onion. Infusion of marigolds can be watered bulbs to scare the parasite.
Why onions turn yellow, treatment of diseases
In addition to the defeat of the bulbs by insects - parasites, the plant can destroy the disease. Why yellows and dries or rotting onions, what diseases harm it, and how to deal with them, we will look further.
Downy mildew
The causative agent of infection is the onion, wintering among other bulbs. Infected onions do not differ externally from healthy ones, so it is difficult to detect the disease immediately.
After planting, diseased plants develop and grow for about a month without problems, but then the leaves turn yellow and wither. On the surface of the sheet plates can be seen scurry, seeming to dirt.
Infection is transmitted to healthy specimens through the air and during precipitation. Since moisture and heat are favorable conditions for the development of a fungus, when storing onions, monitor the temperature and ventilate the room.
Preventive measures: maintaining crop rotation, early sowing, elimination of manure during fertilizer, the use of dressings with nitrogen and superphosphate; before planting, treatment of seedlings by heating for up to 8 hours at 40 ° C.
You can fight the fungus by spraying "Fitosporin" or "Phyto-plus." This is the best option: after processing onions can be eaten in 2 days.
Onion anthracnose
Anthracnose on leaves It is shown by dark green spots and circles. The leaves change color, deform and dry. How to process onions so that they do not turn yellow or spoil? Plants can be sprayed with the following compounds: copper sulphate, Bordeaux mixture or copper chlorine.
The fungus settles in shaded areas and in thickened plantings. Thin out seedlings, plant in open sunny beds and remove them after harvest. Infection spreads from plant residues or their seeds.
Attention! After processing the copper-containing solutions can not be eaten onions for 3 weeks.
Cercosporosis
If brown leaves with yellow edging appeared on the leaves - this is chalcosporosis. This infection overwinters in uncleared plants and their seeds. In the spring, with new plantings, the fungus is transmitted to the seedlings by air or by raindrops. Do not forget to clean the soil well after harvesting. To fight the fungus will help drugs: "Fitosporin" or "Fito-plus."
Neck rot
Common disease accompanying onions - neck rot. It is impossible to fight it, because when it falls into the open onion neck, the onion rots. This disease is manifested during storage of the crop. It is necessary to take into account that in a rainy summer, onions should be well dried before harvesting to a storage place.
Did you know? The first written mention of onions is found in the Bible. In describing all the lives of Israelis in slavery, it is mentioned that they ate onions. The ancient Greeks valued onions for healing properties, but considered food to the poor.
Donets rot
Quite often, the tips of the onions turn yellow, why this happens - we consider further.
Common disease for all types of onions - Donets rot. It infects the bulb during development, while onions suffer from onion feathers, turn yellow and dry. The bad thing is that this disease can only be prevented.
Carefully choose a place for landing: there should be no stagnant moisture. If you find an infection, plant onions on this site no earlier than after 5 years.
Before planting, disinfect seedlings, and the best precursors for onions are cereals. Properly store the crop, do not neglect the observance of temperature, humidity and ventilation.
Improper care of onions - one of the reasons for yellowing
Many diseases in plants appear as a result of non-observance of the norms of caring for them, inattention during harvesting and neglect of the methods of disinfecting premises for storing garden crops.
Insufficient or improper watering
First of all, you need to know what and how often water the onions so that it does not turn yellow. Water the onion when it takes root, you need every 3 days, abundantly, warm water with a temperature of +18 - +25 degrees.
It is best to do watering in the morning. If you used mulch, water a little less. Hard water should be softened. Further irrigation is reduced to once a week, in July - once a week and a half. The main condition is not to overflow and not to dry, there must be a middle ground.
Lack of feeding
Not less important question: how to feed the onions so as not to turn yellow. Feed must be combined with watering.
Fertilizers are dissolved in water for irrigation: 10 g of water 50 g of ammonium nitrate, 20 g of superphosphate and potassium salt.
The first feeding is carried out when the feather has shown 3 cm of green. Next - in a week. A few days before harvesting, feeding is stopped.
Interesting! Over 2000 years BC. er along the Great Silk Road, caravans with various goods, including onions, already went. The author of the book "Gourmets from the Silk Road" Laura Kelly risked cooking "Mesopotamian game pie", one of the ingredients of which was onions. Judging by the reviews of Mrs. Kelly, the Babylonian dish came to her taste.
The implementation of these recommendations: how to store onions; what to feed so as not to hurt; if onions turn yellow, than water and other valuable tips, nature can override. Too dry season or too wet with heavy rainfall, will lead to yellowing, fading, whatever you do. For onion beds to enjoy a healthy harvest, it is best if they are covered with a greenhouse.
