Cucumber treatments, most common diseases and pests of this vegetable

cucumber cucumis sativus treatments common diseases pests vegetable

cucumber cucumis sativus treatments common diseases pests vegetable

The cucumber (Cucumis sativus) is a vegetable plant of the Cucurbitaceae family, which also includes zucchinis, pumpkins, melons, etc. It is grown on a large scale and it originates from India, being grown in tropical and temperate regions. It is grown in many varieties due to the variety of fruits. The cucumber has been cultivated for at least 3000 years in western Asia; in Europe, it came during the Roman Empire, and there are 19th century French chronicles recalling the cultivation of the cucumber as well. It is believed to be a native plant of the territory of India today. The cucumber is mentioned in the legend of Gilgamesh, among the products of the old town of Ur, being consumed by its inhabitants. Some sources say it was widely produced in Thrace; its belonging to the Bulgarian and Turkish cuisine come to reinforce this theory. From India, the cucumber arrived in Greece (where it is called “vilwos”) and in the Italian peninsula, where the population is very fond of this vegetable. The cucumber fruit is also mentioned in the Old Testament as a plant widespread in Egypt, even to the Israelite slaves.

Main diseases

Viruses:

The cucumber mosaic virus (CMV) has a large spread, being known for affecting zucchini, pumpkin, tomato, eggplant, and other spontaneous plant species. It manifests on the leaves of the plant through the appearance of symptoms of a weak mosaic, which evolves in parallel burns on tissues, and subsequently leads to their wilting. Attacked plants produce small, deformed fruits, showing mosaic stains themselves. The virus is transmitted from plant to plant through the species of Cuscuta (a parasitic plant), infected seeds and aphids.cucumber cucumis sativus mosaic virus

Prevention and control measures:

  • crop hygiene;
  • destruction of weeds in the crop;
  • applying insecticides to control the aphids’ population;
  • the use of healthy seed;
  • the use of resistant varieties.

Bacteriosis:

Angular leaf spot of cucumber is produced by the bacterium Pseudomonas syringae pv. lachrymans. The attack is manifested on all aerial organs of plants (cotyledons, leaves, flowers and fruits). Small, damp, brown spots and irregular circular shapes appear from the beginning of the vegetation. Subsequently, these spots are browning, and the tissues die and fall apart. On the fruit, the attack produces small, circular spots, deep in the tissue, with a wet look and with a whitish central area. Instead of these spots, the tissue is filled with bacterial fluid in wet weather and cracks in dry weather. The disease is favoured by high humidity (over 90%) and temperatures between 18-28°C. The disease is transmitted through infected seeds by vectors such as wind, irrigation, rain, people or agricultural tools.

cucumber cucumis sativus angular leaf spot

Prevention and control measures:

  • seed treatment before sowing;
  • cultural hygiene;
  • avoid sprinkler irrigation;
  • chemical treatments with Funguran OH 50 WP, Dithane M45, Champ 77 WG, Zeama Bordeleza, Melody Compact 49 WG.

 

The bacterial wilt of cucurbits is produced by Erwinia tracheiphila bacteria. In attacked plants, the leaves wither and fall down as an umbrella. Later, the stem and the plant dry as well. This wilt symptom is due to the fact that the bacterium blocks the plant’s vascular tissue. Following the separation of the roots and stems, a white-grey bacterial fluid flows out of the vascular tissue. The bacterium does not resist more than a few weeks on the plant debris, but it is transmitted by the striped cucumber beetle (Acalymma vittata) and the spotted cucumber beetle (Diabrotica undecimpunctata). The bacterium lasts for a long time in the intestines of these insect species.

cucumber cucumis sativus bacterial wilt

Prevention and control measures:

  • cultural hygiene;
  • insecticide treatments for destroying insects that contribute to the spread of the disease; Product examples: Decis Mega 50 EW, Calypso 480 SC, Kaiso Sorbie 5 WG, Faster 10 CE.

Mycosis:

Powdery mildew on cucurbits is produced by the fungus Sphaerotheca fuliginea. It is a ubiquitous disease in cultures of cucumbers, melons, courgettes and other cucurbits, and it appears in greenhouses and solariums causing significant damage to the crops. The disease is manifested through the appearance of large, white pastels on the leaves of the plants. The white pastels eventually become crisp once the formation of the fungus fructifications appear. The leaves that are completely covered by the fungus become brown, dry up and fall. The appearance of the fungus is favoured by temperatures above 24°C and dry weather.cucumber cucumis sativus powdery mildew

Prevention and control measures:

  • cultural hygiene;
  • chemical treatments with Topas 100 EC, Kumulus DF, Ortiva 250 SC, Thiovit Jet 80 WG, Systhane Plus 24 E.

 

Downy mildew on cucurbits produced by the fungus Pseudoperonospora cubensis. It is the most important disease of cucurbits, causing significant damage both in field crops and those from protected areas. The disease manifests itself through the appearance of yellow-greenish spots on the upper part of the leaves, which later become yellow and finally brown. On the underside of the leaves, near the spots, a purple-grey fluff appears, caused by fungus fructification. After the attack, the leaves dry and fall, and the fruit remains small. The occurrence of infection is favoured by the presence of drops of water on the leaves and temperatures between 10°-30°C.cucumber cucumis sativus downy mildew

Prevention and control measures:

  • cultural hygiene;
  • avoid sprinkler irrigation;
  • cultivation of resistant varieties;
  • chemical treatments with Aliette 80 WG, Verita, Ridomil Gold MZ 68 WG, Antracol 70 WP.

Fusarium wilt of cucumber is produced by the fungus Fusarium oxysporum. It is a vascular disease, the first sign of its presence being the yellowing of the leaves and their wilting, after which the disease gradually progresses to the top of the plant. On the stem, browning of the vascular tissue can be observed, as this fungus develops. Temperatures between 28 ºC -32ºC, soil pH between 5-5.6, high humidity and low potassium levels are all factors that favour the occurrence and development of this disease. If the temperatures are below 20°C and above 34°C, the disease does not occur.

cucumber cucumis sativus fusarium wilt

Prevention and control measures:

  • cultural hygiene;
  • disinfecting the seed substrate and treating seeds before sowing. For more information on methods;
  • soil disinfection and seed treatment click here;
  • rational fertilization;
  • chemical treatments during the growing season with Topsin 500 SC or Topsin 70 WDG. Prepare a solution of 0.05 – 0.1% (5 or 10 g per 10 litres of water) and spray each plant with 0.5 l (of the solution).

The grey mold on cucumber is produced by the Botrytis cinerea fungus. The attack occurs in greenhouses, solariums and in years with abundant rainfall in the field. The most common symptom is sudden wilting of succulent tissues (strains, fruits). On the fruit, the attack is manifested by the appearance of deep, damp, brown spots of irregular shapes and sizes. The attack is favoured by high humidity (over 95% for several days in a row), lack of ventilation, persistent nebulosity, fertilisation and excessive watering.cucumber cucumis sativus grey mold

Prevention and control measures:

  • cultural hygiene;
  • rational fertilization;
  • chemical treatments during vegetation with Rovral 500 SC, Folpan 80 WDG, Teldor 500 SC, Switch 62.5 WG.

Anthracnose of the bark is produced by Colletotrichum lagenarium. The disease is manifested on all airborne organs, under high atmospheric humidity conditions and temperatures of 25°C. On the leaves and stems of the plant appear oily, brown stains appear. The affected tissues sink in. Large, circular, brown spots appear on the fruit, and over time, stains get covered by a pink mold. Other pathogens can be applied to these lesions, worsening the health of the plant.

cucumber cucumis sativus bark anthracnose

Prevention and control measures:

  • use of treated and disinfected seeds. For more information about seed treatment methods click here;
  • harvesting and destruction of plant remains after harvesting;
  • chemical treatments during the vegetation period with Dithane M45, Merpan 50 WP, Captan 80 WDG, Melody Compact 48 WG, Champ 77WG.

The damping off and falling of seedlings, produced by Pythium debaryanum. It is a very important disease of the seedlings, as it gravely affects the plant from an early stage. It manifests from the stage of germination and rising, up to the stage of 2-3 true leaves. In the event of an attack, the strain tissues at the soil level become black, watery and decompose. The occurrence of the disease is favoured by temperatures between 18°C -30°C and humidity above 90%.

cucumber cucumis sativus damping off

Prevention and control measures:

  • affected plant elimination from the crop and soil disinfection in the respective region;
  • substrate disinfection and seed treatment before sowing. For information on seed and soil disinfection click here;
  • avoiding excessive watering;
  • vegetation treatments with Previcur Energy, Merpan 50 WP, Captan 80 WDG, Folpan 80 WDG.

Verticillium wilt produced by the Verticilium dahliae fungus. This disease causes a slow withering, accompanied by yellowing and burning of the leaves. Eventually, the entire plant is destroyed. Depending on the degree of the attack on the plant, small, brown leaves gradually dry out. The conductive vessels are blocked by the fungus mycelium. The fungus lives in the soil, and when environmental conditions allow, it grows and attacks the plants.cucumber cucumis sativus verticillium wilt

Prevention and control measures:

  • correct rotation of the crops;
  • disinfection of soil and seeds. For information on the methods of soil and seed disinfection click here;
  • chemical treatments during the growing season with Topsin 500 SC or Topsin 70 WDG. Prepare a solution of 0.05 – 0.1% (5 or 10 g per 10 litres of water) and spray each plant with 0.5 l (of the solution);

Scab of cucurbits produced by Cladosporium cucumerinum. The disease can be present beginning with the appearance of the cotyledons. The attack is seen as angular, green, then grey spots on the leaves. The spots are bordered by a yellow ring. The attacked tissues then become brown, dry and detach from the plant. On the fruit grey spots appear, which then sink. The occurrence of the disease is favoured by high humidity and low temperatures (18-25°C).cucumber cucumis sativus scab of cucurbits

Prevention and control measures:

  • cultural hygiene;
  • disinfecting the seed substrate and treating seeds before sowing. For more information on soil disinfection methods and seed treatment click here.
  • rational fertilization;
  • cultivation of resistant varieties;
  • chemical treatments with Bravo 500 SC, Dithane M45, Topsin 500 SC.

Alternaria leaf blight of cucurbits produced by Alternaria cucumerina. It is a disease commonly found on plants of the Cucurbitaceae family (cucumbers, pumpkins, melons, etc.). On the infected leaves, small spots of decolouring appear, which can then unite. Stains are surrounded by a yellow border, and on the surface of the spots concentric areas appear, which represent the fructification of the fungus. The fungus withstands on vegetal debris on the surface of the soil and on spontaneous cucurbits.cucumber cucumis sativus alternaria leaf blight

Prevention and control measures:

  • correct rotation of crops;
  • harvesting and destruction of plant remains after harvesting;
  • weed control;
  • seed treatment before sowing. For more information about seed disinfection methods click here;
  • chemical treatments with: Dithane M45, Score 250 EC, Bravo 500 SC, Antracol 70 WP

Main pests

The rootworm is a polyphagous species. The larvae attack the plant root system and causehypertrophy of tissues. Fighting it is very difficult, but it can be done by sterilising the soil through hot vapours or through chemical measures and very rigorous hygiene measures of the crop.

The two-spotted spider mite (Tetranychus urticae). It can reach 6-10 generations per year and it winters in the adult stage, especially as a female (males are generally bigger in size), under the scuffed bark of trees, under the fallen leaves, on dry weeds or in the superficial soil layer,etc. The attacked leaves dry off and fall, defoliation occurs, which can sometimes reach 80-100% of the leaf count. As a result of the attack, there is a stoppage in the growth of the sprouts and a premature ripening of the fruits.

cucumber cucumis sativus two-spotted spider mite

Control measures:

  • treatments with Vertimec (1 l / ha), Nissorun 10 WP (5 g / 12 l water), Envidor 240 SC, Millbeknock EC;

 

 

Aphids are polyphagous species that migrate from one plant to another or from one species to another. They grow on any kind of plant or tree, and then move on and attack crops. They appear in the form of a colony on the lower part of the leaves, on flowers or inflorescences and on young sprouts. Insects prick and suck the cell juice, causing a stress on the plant. In the event of a severe attack, it causes even the death of the plant.

cucumber cucumis sativus aphids

Control measures:

  • treatments with Decis Mega 50 EC (0.2 l / ha), Confidor Energy (0.6 l / ha), Mospilan 20 SG (1.5 g / 12 l water), Actara 25 WG;
  • the use of attractant traps.

 

Greenhouse whitefly (Trialeurodes vaporariorum). The pest develops best in greenhouseconditions, throughout the year, and in the field only during the summer. In the greenhouse, it can develop 3-6 generations when conditions are favourable. Adults and larvae colonize the leaves, often the sprouts, and after the attack, the leaves are etiolating, dry off and fall.

cucumber cucumis sativus greenhouse whitefly

Control measures:

  • destruction of vegetal remains after the dissolution of the crop;
  • the disinfection of greenhouses and solariums before the establishment of a new crop;
  • treatments with Decis Mega 50 EC (0.25 l / ha), Actara 25 WG (0.2 kg / ha), Confidor Energy (1.3 l / ha), Mospilan 20 SG (1.5 g / 6 l water);
  • the use of attractant traps.

Trips are small insects, hard to see with the naked eye, attacking a very large number of cropplants. They colonize the tops, flowers and leaves, causing flower abortions and plant dwarfism. They transmit a series of viruses.

cucumber cucumis sativus thrips

Control measures:

  • treatments with Actara 25 WG, Mavrik 2 F, Karate Zeon 50 CS, Decis Mega 50 EW;
  • the use of attractant traps.

 

Got a question?

    1. Gnld Super Gro is a fertiliser that can be used for cucumber crops. It does not affect the pests or diseases of the cucumber. If you treat the crop against a certain pest or disease, you can use the fertiliser as it will help the plant to recover, but it will not do anything against phytosanitary problems.

      Nexles Post author-
      Answer
    1. There are various reasons (diseases, pests, high or low temperatures). Please, give us more information.

      Nexles -
      Answer
  1. My squash (cucuzza plant) will stop growing and will develop a weird growth at the end of the vine like a lot of bloom in same spot.

    Cleo James -
    Answer
    1. If you have not seen any pests, the lack of growth and deformed new growings may be caused by physiological stress.
      In order to improve soil quality, it is recommended to administer a special fertilizer, which increases microbial activity and intensifies the absorption processes at the roots such as Organic Soil Activator. Apply it by watering to the root in a dose of 10 ml / 1 l of water.
      In order to help the plant overcome the stress period, it is recommended to apply a foliar fertilizer such as Terra-Sorb Foliar, applied by spraying in a dose of 25 ml / 10 l water. Two treatments can be done at least 14 days apart

      Nexles -
      Answer
  2. What can I do or use, to kill Pythium Diseases on cucumbers in my garden. Doe you need any pictures

    Jerry Nolan -
    Answer
    1. In order to get rid of the rot that is damaging your cucumbers, you can apply a fungicide like Switch 62.5 WG.

      In the future, if you will have Pythium you can use Previcur Energy to get rid of it. Please read the product specifications before use.

      Nexles -
      Answer

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