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Downy Mildew of Cucurbits
2025/1/22 11:21:57


Downy Mildew of Cucurbits


General

Pseudoperonospora cubensis is a plant pathogen causing downy mildew on cucurbit crops like cucumber, cantaloupe, pumpkin, watermelon and squash.


Life cycle and appearance of Downy mildew

Pathogens causing downy mildew are not fungi but Oomycetes and related to Pythium and Phytophthora. They survive as oospores. From these oospores or surviving mycelium sporangia are formed, structures in which zoospores are produced. However, in downy mildews, sporangia often germinate directly and the germ tubes infect the plants either through the stomata or directly by penetrating the cuticula. For germination free water is required. For most downy mildews, the optimum temperature is around 15oC and the closer the temperature is to this, the shorter the leaf wetness period that is required.

Inside the plant, the pathogens produce haustoria, small organs with which the pathogen can take up nutrients from the living plant cells. The pathogens continue to grow inside the leaves and after a while new spore-bearing structures are protruding from the stomata. Because there are more stomata on the underside of the leaf, this is where most fluffy symptoms are found.


Damage symptoms

Downy mildew pathogens infect mostly the leaves but occasionally also stems and fruits. They cause lesions on the upper leaf surface, bordered by the veins, which are first yellow and then turn brown. On the underside of the leave fluffy growth appears which is first white and later turns grey-brown. This is actually the sporulation of the pathogens extruding from the stomata.



How to prevent Downy mildew

Choose resistant cultivars

Use a wide crop rotation with non-host crops

Prevent a humid microclimate. Achieve this by lowering crop density, good aeration during propagation and maintaining a warm and dry climate in greenhouses.

Use hygiene measures. Start clean, remove crop residues and prevent splashing water.

Prevent plant diseases by optimizing plant potential and crop resilience.

(Source: Koppert)


King's Sonata.pngKing's Sonata-1.png

King's Sonata is a new generation of fungicide developed by King Qunenson for excellent control of downy mildew and blights in cucurbits. It is a compound formulation of Famoxadone and Cymoxanil with protective and curative action. As protective agent, it is combined with the plant epidermis closely to inhibit spore germination and mycelium growth.


Feature of King's Sonata:

Contact, systemic and translaminar product

Protective and curative action

Long-lasting protection

Excellent control for downy mildew and blights


King's Sonata rapidly penetrates into plant tissues with long lasting protection, and it is rainfast within 1 hour after application. King's Sonata is an excellent resistance management strategies product. With the help of King's Sonata, growers will get more higher quality and safer production from agriculture and horticulture.

 

You can also watch the video for King's Sonata:https://www.youtube.com/watch?v=sJRuoQ6X9_Q


Since 2003, King Quenson has been thriving to introduce the latest technologies to agricultural industries and farmers to achieve mutual development and prosperity. With years of dedication and rich experience, King Quenson devotes more than 20 years to crop protection and offers solutions.

 

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