Cucurbit scabis a disease caused by the fungus Cladosporium cucumerinum. Mainly cucumbers, pumpkins, melons, squashes and courgettes are attacked, and the characteristicsymptoms of cucurbits scabare brown spots with gelatinous spills. In this article you will learn exactly how to recognize this disease, as well as how tocontrol squash scabin home and allotment gardens. We recommend the best sprays for cucurbit scab !.
Pumpkin scab
Fig. Rasbak, CC BY-SA 3.0, Wikimedia Commons
Pumpkin scab - symptoms
Symptoms of cucurbit scabcan be seen on fruits, leaves and stems.
On leaves infected with Cladosporium cucumerinumirregular brown spots surrounded by a yellow borderThey can be round or angular and appear to be saturated with water. With time, the tissue dries up and crumbles in the place of the stains, as a result of whichholes are formed in the leavesStains may also appear on the stems. The internodes are also shortened, which gives the impression of a viral infection.
The most painful thing for the gardener is the infestation of the fruit.Water spots appear on young fruits , which become concave as the fruit ripens. Sick, young fruits stop growing, they have bent ends and wither.
The spots on older fruits arehollow, brown, with clear outlines. The surface of these spots may be corky, which is reminiscent of apple scab.At high air humidity, initially white, then olive, mycelium appears on the spots.
Within the spots and corks, drops of a brown resinous substance may leak from the skin of the fruit, which is quite a characteristic symptom of cucurbits scab infection. Fruits with scab symptoms cannot be eaten.
Leaf with cucurbit scab symptoms
Fig. depositphotos.com
How do cucurbits get scab infection?
The fungus Cladosporium cucumerinum, which causes cucurbits scab , may hibernate on plant debris left over in vegetable beds. The source of infection may also be weeds growing nearby.
The rapid development of infection and the infestation of subsequent plants occurs in conditionsrainy and windy weather, with air temperature from 21 to 24 ° COutside with raindrops and gusts of wind, mycelium spores can also be transferred by ourselves, on the surface of garden tools, during maintenance work in the vegetable garden.
Pumpkin scab attacks vegetablesboth grown in the ground and in greenhouse.
Pumpkin scab - combating
Combating cucurbit scabconsists primarily in selecting cucumber vegetable varieties resistant or tolerant to this disease for cultivation. Among thevarieties of cucumbers resistant to scabit is worth mentioning such cucumbers as: Aladyn F1, Borus F1, Oedipus F1, Julian F1, Krak F1, Lider F1, Octopus F1, Partner F1, Racibor F1, Zefir F1.
It is also extremely importantto remove crop residues and residuesso that the fungus does not overwinter on these residues until the next year. In addition to cleaning the beds, remember to regularly remove weeds, which can also be outbreaks of disease.
The rules of vegetable crop rotation are also helpful in preventing the occurrence of pumpkin scab . If the disease has appeared in our garden, you should take at least a 4-year break in the cultivation of pumpkin vegetables, and if you really want to enjoy their taste, at least do not grow them on the same beds where they grew earlier.
The methods of naturalprotection of cucumbers and other cucumber vegetables against scab described hereare important because in amateur crops we do not have a wide range of means for spraying against this disease.
Pumpkin scab - spraying
Amateur gardeners have practically no ecological and natural preparations that could beeffectively combating pumpkin scabon cucumbers, pumpkins, squash or melons. You can only use preparations that strengthen plants in general, such as Biosept Active, or ecological extracts intended forprotection of cucurbits against other diseasesPrepared nettle manure can be helpful here ready-made preparations of nettles, as well as macerates based on horsetail. In gardening stores, a preparation based on horsetail, Evasiol, is available, which can be used in the cultivation of cucumbers against powdery mildew of cucurbits, but due to the overall strengthening effect of horsetail, it is also worth using it against other diseases of cucumbers.
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It is worth noting here that the effect of the natural preparations mentioned above has little strength. They can be used preventively in order tostrengthen cucurbits and make them resistant to diseasesHowever, they do not have the power to directly combat cucurbit scab, especially when the symptoms of the disease are already present on the plants.
Among the chemical pesticides, the only amateurregistered for use against cucurbits scabis Scorpion 325 SC. In the past, I would recommend Topsin M 500 SC, but at the time of writing this article, this agent is being withdrawn from sale and cannot be bought anymore.
Scorpion 325 SC can be used in the cultivation of cucumbers, pumpkins, melons and watermelons both outdoors and under cover.Spraying against cucurbits scabScorpion 325 SC can be applied preventively or immediately after noticing the first symptoms of the disease until the fruit ripening stage, but remember to observe the 3-day waiting period (the last spraying cannot be performed later as 3 days before harvest). Scorpion 235 SC is used in the amount of 10 ml per 5-15 liters of water, which is enough to spray up to 100 m² of crops. The intervals between successive sprayings should be at least 10 days and we must remember that the agent can be used up to 2 times during the growing season. In practice, therefore, you can not perform more than 2 such sprays, and additionally use the above-mentioned natural preparations.
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