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Cucumbers are grown on a huge scale in open fields, but in recent years, high plastic tunnels have gained favor. It’s served raw in a salad with onion and tomato. Vitamins B and C are found in the fruit. A variety of diseases have been found to harm cucumber crops both in the field and in the greenhouse. Under ideal environmental conditions, cucumber downy mildew causes significant losses. The disease is the greatest limiting factor for cucumber output in many regions and tunnels with high humidity. The fungicides against cucumber downy mildew disease. Pale green dots on the dorsal sides of the leaves give them a mottled appearance, indicating the disease. The dots get larger, yellow, and consolidate to cover huge portions of the leaves. Then, from the center, they begin to turn necrotic brown. Light purple mycelium covers the ventral side of the leaves, bearing big lemon-shaped sporangia.

Chlorothalonil @ 2.4 lbs. ha1 was used to control downy mildew infections in cucumbers and onions. In another study, Ridomil was found to be the most efficient when used at 0.1 percent. There are a number of fungicides that can be used to treat downy mildew on cucumbers and other plants.

Contents

Fungicides

There are preparations designated for cucurbit downy mildew that contain components from 11 different fungicide chemical groups that have targeted activity and are thus in danger of developing resistance. There are other protectant fungicides (mancozeb and chlorothalonil) that should be used alone to avoid downy mildew and tank-mixed with the targeted fungicides to manage resistance when downy mildew is present. The most effective fungicides include Orondis (the newest fungicide), Omega, Ranman, and Zing, according to the results of the seedling bioassay done over the past four seasons. Curzate (and thus Tanos) and Previcur Flex were both successful. With Forum and Presidio, effective control was gained in just one year. Quadris and Revus were ineffective on a consistent basis. In other states where the bioassay was performed, similar results were observed.

It has been working hard to guarantee that pickle growers continue to have access to the most effective fungicides on the market. The previously effective techniques will last or if new items and strategies will be required based on our findings. We evaluated new and unregistered fungicides for efficacy at low and high rates when used alone or in a rotational programme with existing downy mildew fungicides. The method of action of the active ingredient on the pathogen is determined using FRAC codes. Fungicide field experiments were planted at the Research Center after a natural downy mildew infection was discovered. The trials were set up in a four-replicate randomized full block design. Sprays were started after the first true leaf appeared, and fungicides were applied to the foliage by broadcast foliar sprays.

Geeken Chemical fungicides against cucumber downy mildew
Spraying Geeken Chemical Fungicides against cucumber downy mildew

Pseudoperonospora cubensis into four groups

Bains divided symptom expression presented by leaves of diverse cucurbitaceous crops in response to downy mildew infections caused by Pseudoperonospora cubensis into four groups. The following are the four categories:

  • Category-I:Isolated faded green to light yellow lesions with no sporulation or necrosis.
  • Category-II: Visible spots of limited size with water-soaked corky lesions on the bottom.
  • Category-III: Visible lesions due to colour, i.e. yellow to tan yellow, enlarging patches that frequently coalesce and become necrotic.
  • Category IV: Necrotic lesions without sporulation are classified as .
  • Downy mildew disease was examined on various cucurbitaceous crops who observed symptoms confined only to leaves with yellow watersoaked uneven regions on the upper surface. These lesions became covered on the lower side by violet grey to brownish proliferation of sporangiophores and sporangia as time went on. These spots subsequently became larger, consolidated, and became necrotic.
fungicides against cucumber downy mildew in geeken chemical
Cucumber Downy Mildew

Cucumber downy mildew was controlled with the following eleven different fungicides:

At these sowing dates, the relative rate of disease progression and the area under the disease progress curve were also measured. Cucumber downy mildew was controlled with the following eleven different fungicides. In comparison to other fungicides and the untreated control, fruit yield was significantly higher in plots treated with Ridomil MZ and Ridomil Gold.To know more about the best Fungicide available in India and worldwide clink on the link:Geeken Chemical Product

Metalaxyl + mancozeb (9.59%)metalaxyl M + mancozeb (11.02%)azoxystrobin (13.37%)Curzate M-8 (cymoxanil + mancozeb) (18.99%)
dimethomorph) (20.66%)mancozeb (24.85%)fluopicolide + propamocarb (24.88%)Mandipropamid (26.21 (29.86 percent )

Resistant varieties

Cucumbers relied heavily on resistance until a new strain of the pathogen emerged. The resistant varieties, which include most hybrids, have produced some suppression of the new disease strains. But not nearly as effective as the great suppression achieved against strains. These resistant varieties, however, are still regarded as an important part of an integrated program. Thankfully, new sources of resistance have been discovered. And cucumber cultivars containing these novel resistance genes are beginning to become available.

DRM 401 had the highest level of resistance in a cucumber variety study. Bristol and Citadel (fresh market pickling types) were fairly resistant but not considerably less badly affected than SV3462CS, SV4719CS, and Diamondback. Marketmore 76 had limited resistance, but Speedway was not much less affected than the sensitive check variety, Straight Eight. The most yielding types were DMR 401, Bristol, and Citadel. Cornell plant breeders produced DMR 401. Resistance was good in NY264, DMR 401 (both sold at Common Wealth Seeds), and Bristol, with NY264 and Bristol responding best under strong disease pressure.

Guidelines on Managing Cucurbit Downy Mildew

  • Cucurbit plants are susceptible to downy mildew from the moment they emerge.The forecasting program keeps track of where the disease appears and forecasts where the pathogen is most likely to spread successfully.
  • There is no evidence that the disease persists between growing seasons when cucurbit crops are killed by freezing temperatures. Both mating types, however, have recently been detected on several cucurbit crop kinds, showing that the disease may produce oospores that allow it to persist.
  • The forecast system’s success is dependent on knowing where downy mildew outbreaks are occurring, thus growers must report outbreaks as soon as possible.
  • Cucurbit Crops are classified according to their scientific names. The pathogen specialisation of downy mildew is based on the Latin name of the cucurbit. This is crucial to know when deciding if a certain crop type is susceptible to downy mildew.
  • Scouting for early signs on a regular basis is necessary to ensure that targeted fungicides are sprayed as soon as disease symptoms appear.
  • While the forecast programme has correctly predicted many outbreaks. A predicted risk of infection may not occur if conditions are not as favourable as predicted, and the forecast method can miss anticipating a risk in particular when downy mildew is not reported.
  • Apply targeted fungicides weekly with protectant fungicides. Alternating between available chemistries to manage resistance development and control failure if resistance develops.
  • When there is a risk of downy mildew for the individual crop based on the forecasting programme.And start with protectant fungicides alone. When new fungicides become available, add them to the programme.If the two products are in the same group, use the new one instead of the old one.

Results and Observation

The effectiveness of fungicides in the treatment of downy mildew. The results demonstrated that all of the test fungicides significantly suppressed the illness as compared to the control. Ridomil MZ application resulted in the lowest disease severity (9.59 percent). Followed by Ridomil Gold, Amistar 25 SC , Curzate M-8 (18.99 percent), Acrobat , Indofil M-45, Infinito , Mandipropamid , Antracol , Polyram .

Ridomil MZ had the highest fruit yield, followed by Ridomil Gold , Amistar 25 SC , Curzate, M-8 , Acrobat , Indofil M-45, Infinito , Mandipropamid (10.26 kg/plot). All of whom found Ridomil MZ to be highly efficient against cucumber downy mildew. Indofil M-45 at 0.3 percent and Ridomil MZ at 0.25 percent, according to Apaydin3, were effective in controlling the condition.

Conclusion

A variety of diseases have been found to harm cucumber crops both in the field and in the greenhouse. Under ideal environmental conditions, cucumber downy mildew (Pseudoperenospora cubensis) causes significant losses. Disease is the greatest limiting factor for cucumber production in various countries and tunnels with high humidity24 and Keinath10.On cucumber leaves, downy mildew shows as small, slightly chlorotic to bright yellow spots on the upper surface of the leaves, which later turn necrotic and brown. Lesions have an angular shape and are bordered by leaf veins. In Punjab, Rostow has become a major issue in the successful production of cucumbers cultivated in low-plastic tunnels.

Sporangiophores emerge on the lower leaf surface and produce brown or colorless zoosporangia through the stomata. Resulting in necrosis of larger leaf regions and, eventually, the loss of the entire leaf. While studying the symptom expression on various cucurbits such as cucumber (Cucumis sativus), muskmelon (Cucumis melo), ridge gourd (Luffa acutangula), and spongegourd (Luffa aegyptiaca). We observed the development of pale green areas, separated by islands of darker green, progressively these spots turn yellow. And become well-defined angular in shape, often. With regard to lesion color, form, size, coalescing, necrosis, and amount of sporulation.

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