Table of contents:
- Diseases of cucumbers
- Cucumber pests
- Other Causes of Cucumber Fruit or Leaves Modification
- Prevention of diseases and pests of cucumbers
Video: Pests And Diseases Of Cucumbers
In order for vegetables to develop well and give full-fledged fruits, careful care of them and knowledge of measures to combat diseases and pests are necessary. Unfortunately, only weeding, dressing and watering is indispensable in the summer season. The cucumber also has its enemies. If you know them "by sight", then you can cope with the problem at the initial stage of development, and if you prepare for a meeting in advance, then many troubles can be avoided.
- Diseases of cucumbers
- Cucumber pests
- Other Causes of Cucumber Fruit or Leaves Modification
- Prevention of diseases and pests of cucumbers
Diseases of cucumbers
Cucumbers have the same diseases as all melons. Basically, these are fusarium wilting, anthracnose, powdery and downy mildew, bacteriosis, cucumber mosaic, gray and white rot. Most often, damage is observed during prolonged wet periods of summer, when planting plants without observing crop rotation and frequent watering with cold water.
Withering and dying off of cucumber lashes indicates a fungal disease - fusarium. It is dangerous because the spores of the fungus Fusarium oxysporum can be stored in the soil for up to 15 years and infect plants in adverse weather conditions. During prolonged rains, prolonged cold snap (below 10 ° C), a brown color appears at the neck of the cucumber stem, which over time forms a pinkish or white bloom.
As a result, one or more lashes wither, behind them the whole plant dies. These symptoms are most often observed during the flowering period, however, the disease sometimes occurs on seedlings.
To prevent fusarium wilting of cucumbers, it is necessary to observe the alternation of crops, choose seeds treated with fungicides for sowing (or pickle them yourself), be sure to remove the remnants of affected plants from the beds, and irrigate with warm water.
At the initial stage of the spread of the disease, the vegetative part of cucumbers can be treated with "Fundazol" or "Fitosporin-M". If you start the disease, it is no longer possible to help the cucumbers.
Blurry, round, yellow-brown spots with small cracks on the leaves of the cucumber indicate that the plants have developed a disease called anthracnose. Usually it occurs at high humidity in combination with high temperature and affects not only foliage, but also the stem, petioles, fruits. On the latter, they can be observed in the form of ulcers, which often become the cause of unmarketable cucumbers, decay, breakage of the stems and the death of lashes.
Anthracnose-causing fungi (Gloeosporium, Kabatiella, Colletotrichum) are afraid of dry air and open sunlight. Therefore, when growing cucumbers, it is necessary to monitor their thickening, as well as to weed the beds from weeds in time.
If the damage to the plantings develops rapidly, and there is no improvement in the growing conditions (for example, there are prolonged rains), you should apply Bordeaux mixture, Burgundy liquid or any other fungicides recommended for use against anthracnose.
White powdery spots on the top surface of cucumber leaves indicate that the plant is affected by powdery mildew. Usually this disease "attacks" the cucumber beds by the end of summer and, if left untreated, gradually spreads to the stems of the plant and its fruits. The danger of powdery mildew is that it gradually kills the cucumber bush completely.
The following contributes to the disease: sudden changes in day and night temperatures, watering with cold water, poor ventilation of plants (caused by thickening of plantings), cold drafts, excessive nitrogen feeding. In the later stages of the development of the disease, it is almost impossible to help the affected plant, therefore, in August, when collecting fruits, it is necessary to examine its whips for damage by the disease, and at the first signs to start treatment.
The first thing to do is tear off and destroy the damaged leaves. The second is to fertilize with potassium fertilizer. Third, try sprinkling the plants with mullein infusion or dusting with sulfur powder. If all else fails, you need to apply one of the fungicides recommended against Erysiphe cichoracearum and Sphaerotheca fuliginea, for example, Bayleton or Copper Ochloride.
Downy mildew, or downy mildew
The leaves of the cucumbers are covered with many small yellow spots - this is downy mildew or peronosporosis (its causative agent is Pseudoperonospora cubensis Rostowz). After a few weeks, small spots will increase, a gray-purple tint will appear on the bottom of the leaf (a sign of sporulation of the fungus), the leaves will change color to brown and begin to dry out and crumble.
This disease affects cucumber plants at different stages. Increased humidity and watering with cold water can provoke its spread. To help the cucumbers survive, as soon as the first signs of downy mildew are found, it is necessary to immediately stop feeding and watering, and treat the beds with a solution of Bordeaux liquid. If the first steps towards improving the cucumber garden did not bring success, you can try to process cucumbers with Ridomil.
Angular holes on the leaves and brown sores on the fruit of the cucumber are a sign that the plants were "attacked" by bacteriosis. This bacterial disease (the causative agent is the bacteria Pseudornonas, Erwinia) spreads through contact: through insects, touching diseased plant parts, with water drops. As in all previous cases, temperature drops and high humidity of the soil and air are a favorable moment for its outbreak.
To defeat bacteriosis, it is necessary to sow cucumbers with pickled seeds, observe crop rotation (without returning the culture to its original place for at least 4 years), remove affected greens from cucumbers in time. For prophylaxis, in places of mass spread of the disease, it is recommended to process cucumber beds with 1% Bordeaux liquid, 0.4% copper oxychloride or Fitosporin-M.
Green mottled cucumber mosaic and white cucumber mosaic
If the young leaves of cucumbers became covered with yellow-green spots and then became wrinkled, plant growth slowed down, the formation of flowers decreased and the fruits acquired variegated color and wartiness - this was a green speckled mosaic of cucumber caused by the Cucumber green mottle mosaic tobamovirus virus.
If the spots on the leaves of cucumbers resemble the shape of stars, have a white or yellow color, fill most of the leaf (leaving mostly green only the veins and the part of the tissue close to them) and at the same time no wrinkling of the leaf blades is observed, and the color of the fruits includes white and yellow stripes is a white mosaic of cucumber caused by the Cucumis virus 2A.
Basically, these are diseases of greenhouses, but they are also found in open ground, especially in areas with a temperate warm climate. In order to avoid their spread, the seeds of cucumbers must be disinfected before planting, garden tools must be etched before the new season, the plants must be strengthened with dressings, and their affected parts must be treated with a 10% solution of skim milk.
Cucumber leaves fade in the heat, the root collar becomes brown, the roots of dead plants become rotten, brick-red in color - this is root rot caused by facultative parasites that prefer to settle on weakened plants. It is most often found in greenhouses and is one of the most dangerous plant diseases. Its outbreak can be caused by watering with cold water, prolonged heat or excess soil moisture.
Fighting root rot is difficult. First of all, it is necessary to try to force the plants to give additional lateral roots: to huddle the stems or pin them to the ground and dig in the whips. In addition, start watering the cucumbers with extremely warm water (not lower than 22 ° C). And finally, stop pouring water directly under the root, and try to do it at some distance.
From biological remedies, you can try "Trichodermin". To date, there are no effective chemicals other than Previkur.
Gray rot on cucumber fruits indicates the defeat of plants by a fungal disease with the same name - gray rot (causative agent - Botrytis cinerea F.). It occurs with sudden changes in temperature and high humidity in the air and soil. It can develop not only on fruits, but also on plant leaves, eventually moving to their lower part. Gradually, the affected foliage turns completely yellow and dries up.
The spread of gray rot occurs through contact of plants with insects and humans, as well as by air. Favorable conditions for this are sharp temperature fluctuations and thickened or weed-infested plantings.
Gray mold control measures are more about prevention than treatment. To prevent the spread of the disease, it is necessary to cut off and destroy the affected leaves and fruits, remove plant debris from the garden in the fall, do not plant pumpkin crops nearby. Of the drugs, you can try to apply "Euparen Multi" or "Rovral".
White rot, or sclerotinia
A white bloom appeared on the cucumbers - this began a disease called white rot, or sclerotinia, caused by the fungus - Sclerotinia sclerotiorum. Under its influence, plant tissues decompose, as a result of which they become soft, slimy and begin to rot.
To prevent sclerotinia, it is necessary to constantly weed the beds and make sure that the cucumbers have sufficient ventilation - mushrooms love moist air and therefore, with proper agricultural technology, have less chance of spreading. If, nevertheless, white rot appears, it is necessary to temporarily suspend watering and feeding the plants (for about a week), and then, with an interval of 7 days, spray the plantings with Topaz.
They love cucumbers and pests. The most harmful of them are slugs, melon aphids, greenhouse whitefly, spider mites.
Slugs or snails
If at night someone eats the young leaves of your seedlings, these are most likely slugs or snails. They like to act under the cover of night and absorb young plant tissues. It's hard enough to fight them, but you can still.
First, this type of pest must be collected by hand. To do this, you need to go out to the beds at night and use a flashlight to find shellfish and remove them from the beds.
Secondly, you can arrange traps on the site. These can be pieces of plywood, roofing roofing or any other materials that do not transmit light and retain moisture under them.
Thirdly, the beds must be kept in a clean condition, observing weeding and loosening, in order to complicate the life of the little "enemies". And, as a last resort, you can resort to using chemicals, for example, scattering "Thunderstorm" granules on the ground.
The leaves of the cucumbers are twisted, the flowers are falling off, a sticky bloom has appeared in some parts of the plant - this is what aphids work. Usually its mass distribution is observed at the height of summer. Insects suck sap from plants, thereby inhibiting their development and contributing to a decrease in yield.
But the worst thing is that in addition to direct negative effects, they often become carriers of diseases, so it is imperative to fight aphids!
- The first thing you can try to apply is folk remedies. These include infusion of garlic, onion husks, wormwood, celandine, ash and laundry soap, as well as dusting the plantings with dry ash.
- The second is to carry out foliar feeding on the underside of the leaf with a solution of potassium chloride and superphosphate (10 g x 20 g x 10 l of water, twice, with a break a week), or nitroammophos (for 10 l of water, 3 tablespoons once every 7 days).
- The third is to feed the plants with phosphorus-potassium fertilizers.
- And, finally, treat plants with Fitoverm, Strela biological products or Arrivo, Intavir, Tanrek insecticides.
If tiny white insects have appeared on cucumbers in large numbers, this is the whitefly. She usually settles in greenhouses, but in the hot, humid summer, she also destroys open plantings. It is quite difficult to protect yourself from it, since this pest is carried by the wind. However, control measures are still worth applying.
- The first thing you can use is glue traps. They are performed independently by painting a piece of plywood or thick cardboard with yellow color and coated with any slowly drying adhesive.
- The second is to try to distract pests by planting several copies of tobacco next to the cucumbers.
- The third is simply to regularly wash off pests with water.
- And fourth - to carry out regular spraying with the preparations "Buton", "Karbofos" or "Iskra".
A cobweb appeared on the underside of the leaves of the cucumber - this was the spider mite. This pest spreads en masse in hot dry weather. Its purpose is plant cell sap. That is why, where it appeared, the leaves of cucumbers acquire a marble color, gradually turn brown and dry.
To minimize the risk of this harmful insect settling in the beds, in the heat they must be sprayed with water, thereby maintaining optimal air humidity, and regular weeding. In case of mass infestation of cucumbers by spider mites, it is recommended to use Fitoverm.
Other Causes of Cucumber Fruit or Leaves Modification
Strange manifestations on the fruits and leaves of a cucumber are not always a sign of disease or pest damage. Often, external changes that appear on one or another part of the plants indicate a lack of this or that element in the soil.
Pear - shaped fruits are a consequence of a lack of potassium. To change the situation, it is necessary to feed the cucumber plantings with ash or potassium sulfate.
Cucumbers in the form of a jug or inverted pear are a nitrogen deficiency. Here, nettle infusion, ammonium or potassium nitrate are suitable as a saving fertilizer.
The unnaturally light foliage of the upper part of the cucumber lashes, drooping lower leaves, slow plant growth and small fruits are also a manifestation of the need for nitrogen fertilization. In addition to the measures listed above, mullein, bird droppings or ammophoska can help here.
The leaves of cucumber plants began to look like scorched ones, acquired fragility and a pale green or yellowish color, but at the same time retained the green color of the veins, this is a lack of magnesium. However, excess moisture can also be the result of fading and a change in plant color to light. Often this effect is observed in prolonged bad weather, with excessive precipitation.
Unnaturally dark fragile cucumber leaves, on the contrary, indicate a lack of moisture. In this case, you need to take care of regular watering.
Falling color, small leaves, bluish-purple tint are manifestations of a lack of phosphorus. Here urgent fertilizing is needed with a complex fertilizer containing this element. However, the fall of flowers can also be observed with insufficient pollination of plants. Here, the attraction of bees (with the help of aromatic solutions and planting of flowering plants) or artificial pollination should come to the rescue.
Prevention of diseases and pests of cucumbers
As practice shows, in order to reduce the risk of morbidity and damage to cucumbers by diseases and pests, and to maintain plants in a healthy state, a number of preventive measures must be followed:
- Apply crop rotation;
- Choose seeds of varieties and hybrids that are resistant to a number of major diseases;
- Before sowing, it is imperative to dress the seed;
- Observe the rules of watering;
- Feed the plants efficiently;
- Timely respond to the first signs of damage to the crop by diseases and pests;
- Remove affected plant parts from the beds;
- Fight weeds;
- After the end of the growing season, carefully remove plant residues from the garden (greenhouse).
If you, dear readers, have your own secrets of prevention or control of diseases of cucumbers and their pests, we will be glad to read them in the comments to the article.