I have powdery mildew on most of my grapes this year. This is my first time using a fungicide. Are either of these preferable? Or should I avoid them both for some organic approach like sodium bio carbonate or Basic copper chloride?
I was waiting taht someone to answer you, but since I see that you do not get an answer, I will help you.
I am from Villarrobledo ( Castilla La Mancha region in Spain)
, which is one of the towns with the largest vineyard area in the world, so I know something about the vineyard.
I explain a little.
For when there are still no symptoms of the disease in the vine stocks, copper oxychloride is used as a preventive.
When there is already appearance of the powdery mildew disease in the vineyard, the heavy artillery must be used.
The use of fungicides is necessary but with preventive, curative and eradicating action.
Of the fungicides that you mention, Benomyl is not appropriate, and Methyl Thiophanate has a preventive and curative action ( not eradicating ) against powdery mildew, for which I recommend using these fungicides (they are active principles and are marketed under various trademarks).
- Tetraconazole: preventive, curative and eradicating activity against grape powdery mildew
- Cyproconazole: preventive, curative and eradicating activity against grape powdery mildew
- Meptildinocap: preventive, curative and eradicating activity against grape powdery mildew
Only with preventive and curative action there are many more, but the three that I quote you are the best against to grape powdery mildew .
That’s extremely helpful Jose-Albacete! Just the information I was looking for. I’ll search locally for these.
Horticultural oil (especially JMS stylet oil) is a strong eradicant which works by smothering the spores. Potassium bicarbonate has some eradicating properties. Both should be easy to find but are easy to misuse. Oils don’t mix with sulfurs and can be temperature sensitive. Too strong of a potassium bicarbonate mix can injure leaves due to raising the pH too high.
Neither the synthetics nor the organics-ish will really cure the infected grapes but will stave off the spread.
TheNiceGuy, I’m going to add another suitable fungicide (I had to check if it was authorized in the European Union).
- Tebuconazole: preventive, curative and eradicating activity against grape powdery mildew
Tebuconazole 25% is very easy to find under different commercial brands, since it is a widely used fungicide in many crops.
All the ones I have mentioned are very good and will solve the problem for you, but there is one especially good one, it is:
Meptildinocap 35%, and is marketed under the trademark:
- Karathane Star
DCinFLX, the ecological ones as preventives are really good, now precisely in my region everyone is applying sulfur to avoid problems with mildew (not to be confused with powdery mildew), but this is done as a preventive treatment to avoid the appearance of the disease.
If there is presence of the fungus in the plot and there are strains affected, it is necessary to use fungicides with eradicating action to avoid problems the next season and the following year only use preventives.
Obviously the bunches affected by the disease will be damaged and have no remedy, but what must be avoided at all costs is the spread of the disease and to get its eradication.
I myself prefer the use of ecological products as preventives, but if any serious problem appears, my pulse does not tremble to use chemicals "in their proper measure ".
Yeah I don’t disagree with anything you’ve said, but TheNiceGuy likely has 5-10 vines not 5-10 hectares and some of those synthetics may only come in 2.5 gallon containers for a couple hundred bucks. Your emphasis on knowing the way the fungicide works–preventative vs anti sporulant vs eradicant-- is spot on.
DCinFLX, I have assumed (without thinking), that in all continents the phytosanitary products, are sold as in Europe.
Here the same product is available in two types of formats:
Large formats, intended for professionals (from bottles of 250 milliliters onwards), and for the purchase of these formats it is necessary to present the phytosanitary product applicator card
Small formats (between 10 and 20 milliliters) intended for gardening and hobbyists, which can be purchased without the need for the phytosanitary product applicator card
Look at some examples
For the fungicide Tebuconazole 25%, I buy the commercial brand Song in liter bottles because my orchard is very large.
Song fungicide (available for professionals from 1 liter bottles to 120 liter jugs)
Exactly the same product, but in a 15 milliliter format for fans of gardening or fruit trees
For tetraconazole 12.5% the same
1 liter bottles
10 milliliter bottle
And the same for all products