Vegetable Garden: 8 Diseases Of The Zucchini.
Even though zucchinis are among the easiest vegetables to grow in the vegetable garden for beginner gardeners, they are susceptible to many fungal diseases. We suggest discovering 8 zucchini diseases and how to remedy them.
1- Zucchini mildew
The vine and tomatoes are not the only plants to be attacked by mildew. Zucchinis can also develop this fungal disease when the weather is very humid.
Zucchini mildew is caused by a pseudo fungus called Pseudoperonospora cubensis. The disease manifests itself as yellow spots that grow and gradually form a mosaic on the leaves. The leaves eventually fall off and the fruits have difficulty growing.
Bordeaux mixture is an effective treatment for this fungal disease. To prevent its appearance, it is also necessary to avoid wetting the foliage during watering.
2- Powdery mildew
Another well-known disease among gardeners, powdery mildew or white mold, can affect cucurbits such as zucchinis. This is another of the 8 diseases of zucchini, also caused by fungi, notably Golovinomyces cichoracearum and Podosphaera xanthii.
This disease is recognized by the white and powdery spots it causes on the stems and foliage. The fungus develops on both sides of the leaves and leads to their rapid drying out and falling off.
To prevent its appearance, only water at the base of the zucchinis and never on the foliage! This fungal disease is favored by excess moisture on the leaves and too dry soil. You can also use Bordeaux mixture as a preventive and treatment for powdery mildew in cucurbits.
3- White rot or sclerotinia
Among the 8 diseases of zucchini, one should not confuse powdery mildew with white rot caused by the fungus Sclerotinia sclerotorium.
The symptoms of these two diseases are quite similar since sclerotiniosis is manifested by a white and cottony mold. But it is accompanied by small black circles on the leaves and a wet and dark rot on the fruits.
This disease develops when the soil is too rich in nitrogen and the atmosphere is warm and humid (with a temperature between 20 and 25°C).
The best remedy against this fungal disease is to spray a suspension of another fungus called Trichoderma asperellum. This product acts as a natural fungicide because this fungus is an opponent of sclerotiniosis.
4- Gray mold or Botrytis
A humid weather and temperatures between 18 and 20°C can favor another form of rot: gray mold or Botrytis. Among the 8 diseases of the zucchini, this one is related to an airborne fungus called Botrytis cinerea.
It manifests itself through round spots on the leaves sometimes accompanied by a clear halo on the edges. The stems are also affected by a wet canker, which is a form of necrosis, and a wet and dark rot appears at the end of the zucchinis.
If you notice some of these symptoms, you can fight gray mold by spraying nettle, horsetail or comfrey purin every 15 days or Bordeaux mixture from the beginning of the disease.
5- Soft Rot
If you notice yellowing and wilting of leaves accompanied by liquefaction of your zucchinis, it is probably another one of the 8 diseases of zucchini called soft rot.
This disease is caused by a bacteria named Pectobacterium carotovorum and has excess moisture and wounds on the zucchinis as contributing factors.
Therefore, to prevent this disease, you must avoid fruits touching the ground by installing mulch at the base of your plants. You must also ensure to clean your gardening tools properly to limit the spread of this type of bacteria.
6- Gray night or Cladosporiosis.
Lesser-known than mildew or powdery mildew, cladosporiosis or gray mold is nonetheless a formidable fungal disease, favored by a mild and very humid climate.
This disease caused by the fungus Cladosporium cucumerinum attacks zucchinis and causes small spots on the leaves and fruits.
At first whitish, these spots turn dark brown. At the same time, elongated and sometimes viscous lesions appear on the stems.
To combat this disease, you can take several preventive or curative measures:
• practice crop rotation
• maximize ventilation of your plants
• treat your zucchini plants with horsetail or Bordeaux mixture.
7- Red night or anthracnose
Red blotch or anthracnose is another of the 8 diseases of zucchini, caused by the fungus Glomeosporium orbiculare. When the soil is too rich in nitrogen and the atmospheric conditions are very humid, the disease can appear and manifest itself with the following symptoms:
• beige to brown circles with black edges on stems and leaves
• brown circles that eventually rot on fruits.
To prevent this disease, you must absolutely avoid wetting the leaves during watering. You can also spray diluted horsetail manure at 10%, Bordeaux mixture, or a maceration of garlic with fungicidal properties on your zucchini plants.
8- Sooty mold.
The last of the 8 diseases of the zucchini is one of the easiest to identify. Fumagine, whose name derives from the word "smoke", is easily recognized by its color as black as soot.
When zucchinis are attacked by this fungus called Fumago salicina, the surface of the leaves is covered with a black and sticky substance.
But gardeners should not wait until it reaches this stage to react. This disease being favored by the excrement of aphids and scale insects, the problem must be treated at its source and fight against parasitic insects as soon as they appear.
