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, weeding can not be done only with weeding, top dressing and watering. The cucumber also has its enemies. If you know them “in person”, then the problem can be dealt with even at the initial stage of development, and if you prepare for the meeting in advance, then many troubles can be completely avoided.
- Cucumber Disease
- Pests of cucumbers
- Other reasons for the modification of fruits or leaves of cucumber
- Prevention of diseases and pests of cucumbers
Cucumbers have the same diseases as all melons. Basically, this is Fusarium wilt, anthracnose, powdery and downy mildew, bacteriosis, cucumber mosaic, gray and white rot. Most often, the lesion is observed in prolonged wet periods of summer, when planting plants without observing crop rotation and frequent watering with cold water.
Withering and dying of lashes of a cucumber indicates a fungal disease - fusarium. It is dangerous because the spores of the Fusarium oxysporum fungus can be stored in the soil for up to 15 years and affect plants under adverse weather conditions. During prolonged rains, prolonged cooling (below 10 ° C), a brown color appears at the neck of the cucumber stem, over which a pinkish or white coating forms over time.
As a result, one or several lashes fade, the whole plant dies behind them. Most often, these symptoms are observed during the flowering period, however, the disease is sometimes found on seedlings.
In order to prevent fusarium wilting of cucumbers, it is necessary to observe the alternation of crops, select seeds sown with fungicides for planting (or pickle them yourself), be sure to remove the remains of affected plants from the beds, and irrigate with warm water.
In the initial stage of the spread of the disease, the vegetative part of the cucumbers can be treated with Fundazol or Fitosporin-M. If you start the disease - to help the cucumbers is no longer possible.
Blurry rounded yellow-brown spots with small cracks on the leaves of the cucumber indicate that 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, and fruits. On the latter, they can be observed in the form of sores, which often cause a non-marketable appearance of cucumbers, rotting, breaking stems and dying off lashes.
Mushrooms causing anthracnose (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 weed the beds from weeds in time.
If planting damage develops rapidly and there is no improvement in growing conditions (for example, it rains heavily), use the Bordeaux mixture, Burgundy liquid or any other fungicides recommended for use against anthracnose.
White powdery spots on the upper surface of the leaves of the cucumber indicate that the plant is affected powdery mildew. Usually, this disease “attacks” cucumber beds by the end of summer and, if left untreated, gradually switches to the stems of the plant and its fruits. The danger of powdery mildew is that it gradually completely kills the cucumber bush.
The following conditions are favorable for the disease: sharp changes in day and night temperatures, watering with cold water, poor ventilation of plants (caused by thickening of plantings), cold drafts, and excessive feeding with nitrogen. In the later stages of the development of the disease, it is almost impossible to help the affected plant, therefore, in August, when picking the fruit, it is necessary to examine its whips for damage to the disease, and at the first signs to proceed with treatment.
The first thing to do is to tear and destroy damaged leaves. The second is to fertilize with potassium fertilizer. Third - try to spray the plants with mullein infusion or dust them with sulfur powder. If all else fails, you need to use one of the fungicides recommended for fungi Erysiphe cichoracearum and Sphaerotheca fuliginea, for example, Bayleton or Copper Chloride.
Downy mildew, or peronosporosis
Leaves of cucumbers covered with many small yellow spots - this downy mildew or peronosporosis (its causative agent is Pseudoperonospora cubensis Rostowz). After a few weeks, small spots will increase, a gray-violet tint will appear on the bottom of the leaf (a sign of sporulation of the fungus), the leaves will turn brown and begin to dry out and crumble.
This disease affects cucumber plants at different stages. A provocation to its spread can be increased humidity and watering with cold water. To help cucumbers survive as soon as the first signs of downy mildew are detected, you need to immediately stop feeding and watering, and treat the beds with a solution of Bordeaux liquid. If the first steps to improving the cucumber beds have not been successful, you can try to process the cucumbers with "Ridomil".
Angular holes on the leaves and brown sores on the fruits of the cucumber - a sign that the plants "attacked" bacteriosis. This bacterial disease (pathogen - bacteria Pseudornonas, Erwinia) spreads through contact: through insects, the touch of diseased parts of plants, with drops of water. As in all previous cases, the favorable moment for its outbreak is the temperature differences and high humidity of the soil and air.
In order to defeat bacteriosis, it is necessary to sow cucumbers with pickled seeds, observe crop rotation (without returning the crop to its former place for at least 4 years), and in time remove the affected greens from cucumbers. For prevention, in places of mass spread of the disease, it is recommended to process cucumber beds with 1% Bordeaux liquid, 0.4% copper chloride or Phytosporin-M.
Green speckled mosaic of cucumber and white mosaic of cucumber
If the young leaves of the cucumbers became covered with yellow-green spots, and then became wrinkled, the growth of the plants slowed down, the formation of flowers decreased, and the fruits became variegated and warty - this manifested itself green speckled mosaic of cucumbercaused by the Cucumber green mottle mosaic tobamovirus virus.
If the spots on the leaves of the cucumbers resemble the shape of stars, have a white or yellow color, fill most of the leaf (leaving mostly only streaks of green and a part of the tissue close to them), and no wrinkling of leaf blades is observed, and the color of the fruit includes white and yellow stripes - this is white cucumber mosaiccaused by the Cucumis virus 2A virus.
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 decontaminated before planting, garden tools must be etched before the new season, plants should be strengthened with top dressing, and their affected parts should be treated with a 10% skim milk solution.
The leaves of cucumbers fade in the heat, the root neck acquires a brown color, the roots of dead plants become rotten brick-red color - this root rotcaused by facultative parasites that prefer to settle on weakened plants. Most often, it is found in greenhouses and is one of the most dangerous plant diseases. The cause of its outbreak may be watering with cold water, prolonged heat or excess soil moisture.
It is difficult to deal with root rot. First of all, it is necessary to try to get the plants to give additional lateral roots: to spud the stems or pin them to the ground and dig in the whips. In addition, start to water the cucumbers with exclusively warm water (at least 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. Effective chemicals, except for "Previkur", to date, the recommendation does not exist.
The gray rot on the fruits of the cucumber indicates the defeat of plants with a fungal disease with the same name - gray rot (causative agent - Botrytis cinerea F.). It occurs during sudden changes in temperature and high humidity of air and soil. It can develop not only on the fruits, but also on the leaves of plants, eventually moving to their lower part. Gradually affected foliage turns completely yellow and dries.
The spread of gray rot occurs through the contact of plants with insects and humans, as well as by air. Favorable conditions for this are sharp fluctuations in temperature and planted thickened or clogged with weeds.
Gray rot control measures are more associated with prevention than with treatment. In order to prevent the spread of the disease, it is necessary to pick off and destroy the affected leaves and fruits, remove plant debris from the garden in the fall, and do not plant pumpkin crops nearby. Of the drugs, you can try to use "Euparen Multi" or "Rovral."
White rot, or sclerotinia
A white coating appeared on the cucumbers - this started a disease called white rot, or sclerotiniacaused by the fungus - Sclerotinia sclerotiorum. Under its influence, the decomposition of plant tissues occurs, as a result of which they become soft, slimy and begin to decay.
In order to prevent sclerotinia, it is necessary to constantly weed the beds and make sure that the cucumbers have adequate ventilation - mushrooms love moist air and therefore, with proper agricultural technology, are less likely to spread. If nevertheless white rot has appeared, it is necessary to temporarily suspend irrigation and top dressing of plants (for about a week), and then, with an interval of 7 days, spray the plantings with Topaz.
Pests of cucumbers
Love cucumbers and pests. The most harmful of these are slugs, melons and gourds, greenhouse whiteflies, and spider mites.
Slugs or snails
If at night someone eats young leaves of your seedlings - this is most likely slugs or snails. They love to act under cover of night and absorb the young tissues of plants. It’s hard enough to fight them, but you can still.
Firstly, this type of pest must be collected manually. To do this, go out to the beds at night and use a flashlight to look for mollusks and remove them from the beds.
Secondly, you can arrange on the trap site. It can be pieces of plywood, roofing felt or any other materials that do not allow light to pass and retain moisture underneath.
Thirdly, the beds need to be kept clean, observing weeding and loosening, in order to complicate the life of small "enemies". And, in extreme cases, you can resort to the help of chemicals, for example scatter granules of Thunderstorm on the ground.
The leaves of the cucumbers curled, the flowers fall, a sticky coating appeared in some parts of the plant - this works aphid. Usually its mass distribution is observed at the height of summer. Insects suck juice from plants, thereby inhibiting their development and helping to reduce yield.
But the worst thing is that in addition to direct negative impact, 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 the infusion of garlic, onion husks, wormwood, celandine, ash and laundry soap, as well as dusting of plants with dry ash.
- The second is to apply foliar dressing on the underside of the sheet with a solution of potassium chloride and superphosphate (10 g x 20 g x 10 l of water, twice, with a break per week), or nitroammophos (10 l of water 3 tbsp once every 7 days )
- The third is to feed plants with phosphorus-potash fertilizers.
- And, finally, treat the plants with biological preparations “Fitoverm”, “Arrow” or insecticides “Arrivo”, “Intavir”, “Tanrek”.
If tiny white insects appeared on cucumbers in huge numbers - this whitefly. Usually it settles in greenhouses, but in hot, humid summers it destroys open landings as well. It is quite difficult to protect against 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 carried out independently by painting a piece of plywood or thick cardboard with yellow color and coating it with any slowly drying adhesive.
- The second is to try to distract pests by planting several copies of tobacco near the cucumbers.
- Third, simply flush pests regularly with water.
- And the fourth - to conduct regular spraying with the preparations “Bud”, “Karbofos” or “Spark”.
A spider web appeared on the underside of the leaves of the cucumber - it settled spider mite. This pest is massively distributed in hot, dry weather. Its goal is the cellular sap of plants. That is why, where it appeared, the leaves of cucumbers acquire a marble color, gradually turn brown and dry.
In order to minimize the risk of settling this harmful insect on the beds, it is necessary to spray them with water in the heat, thereby maintaining optimal air humidity, and carry out regular weeding. In case of mass damage with a spider mite of cucumbers, it is recommended to use the drug Fitoverm.
Other reasons for the modification of fruits or leaves of cucumber
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 deficiency in the soil of one or another element.
Pear shaped fruits - a consequence of a lack of potassium. To change the situation - it is necessary to feed cucumber plantings with ash or potassium sulfate.
Pitcher-shaped cucumbers or an inverted pear is a lack of nitrogen. Here, nettle infusion, ammonia or potassium nitrate are suitable as a saving fertilizer.
Unnaturally light foliage of the upper part of the lashes of cucumbers, drooping lower leaves, slow plant growth and small fruits are also a manifestation of the need for nitrogen fertilizing. In addition to the measures listed above, mullein, bird droppings or ammophos can help here.
Leaves of cucumber plants look like scorched, acquired brittleness and pale green or yellowish color, but at the same time retained the green color of the veins is a lack of magnesium. However, the result of fading and changing the color of the plant to light may be an excess of moisture. Often this effect is observed in prolonged bad weather, with excessive rainfall.
Unnaturally dark fragile leaves cucumbers, on the contrary, talk about a lack of moisture. In this case, you need to take care of regular watering.
Color drop, small leaves, bluish-violet tide - manifestations of a lack of phosphorus. Here we need urgent dressing complex fertilizer with the content of this element. However, the falling of flowers can be observed with insufficient pollination of plants. Attraction of bees (with the help of aromatic solutions and planting of flowering plants) or artificial pollination should come to the rescue here.
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, it is necessary to observe a number of preventive measures:
- Apply crop rotation;
- Choose seeds of varieties and hybrids that are resistant to a number of major diseases;
- Before sowing, seed seed must be etched;
- Follow the rules of watering;
- Qualitatively feed the plants;
- Timely respond to the first signs of damage to the culture of diseases and pests;
- Remove from the beds affected parts of plants;
- Fight weeds;
- After the growing season, carefully remove plant residues from the garden (greenhouses).
If you, dear readers, have your own secrets for preventing or combating the diseases of cucumbers and their pests, we will be happy to read them in the comments to the article.