Late blight fungicide

[arnorrian]

Just wanted to share my experience with a late blight-specific fungicide called Orvego, made by BASF. I used it to treat my tomatoes two seasons ago after a heavy late blight, and it saved the plants. I used it last year preventively, with no late blight occurrence, which is a very common plant disease here. The good thing about it is its waiting time (don't know the exact term) on tomatoes of only one day after spraying, so it can be used even with ripening-fruit plants. BASF suggest using it in combination with another fungicide called Signum to cover other fungal diseases, like early blight or Fulvia. Apart from tomatoes (and potatoes), Orvego treats downy mildew, as well as Pseudoperonospora cubensis in cucumbers.

It's sold in a liquid form, and available in 100 ml bottles, so dosing for small gardens is not a problem.

The components are Initium (ametoctradin) which is a preventative, and Dimethomorph which is a local-systemic.

I don't know if it's available everywhere, but as the dreadful Phytophthora infestans is a nightmare of tomato growers, I thought I'll tell you about it.

[Mark_Thompson]

Are you sure that’s for vegetables? The Orvego label I can find is pretty specific about being for ornamentals only. I don’t even see a PHI (pre harvest interval) listed, which is a pretty good indicator.

Orvego_Label.pdf

[arnorrian]

It is here. There are variations from country to country for what it's intended for. I don't know why. In Germany it's listed for hops, in the Netherlands for potato, salad, and leek, in Hungary for potato and grapes, in some countries like Serbia, Poland, Greece for tomatoes, cucumber, and other things, in some countries for nothing under that name. Corporations are weird.

Both components are part of other fungicides too.

It looks like it has a diferent name in the US, Zampro.

https://www.basf.com/us/en/media/news-r ... 2-176.html

https://agriculture.basf.us/crop-protec ... ampro.html

[Mark_Thompson]

Good find. Knock on wood I’ve been pretty lucky with the leaf diseases, but always good to know what is out there.

[pepperhead212]

I wouldn't use anything systemic on food. And I don't see how something systemic can be safe to eat after a day.

Update - it does say systemic, on the first page. And another thing that caught my eye:
There are currently no registered residential uses for dimethomorph. And all of the toxicity categories are III or IV. Not super toxic, but still not something I want to be around.

https://www3.epa.gov/pesticides/chem_se ... Sep-98.pdf

[arnorrian]

I don't use it past the start of first fruits preparing to ripen. But if I get a late blight outbreak it would be a choice between losing all the plants and using it. And I would use it.

Both active ingredients are approved by the EU.
https://ec.europa.eu/food/plant/pestici ... tedID=1248
https://ec.europa.eu/food/plant/pestici ... tedID=2024

[brownrexx]

Late Blight appears in late summer here so I try to grow early ripening types and get all of my sauces and stewed tomatoes frozen ASAP. That way it Late Blight hits, I just give up on tomatoes for the rest of the season and I pull and dispose of the plants.

It mainly appears in August if we have cool air that is humid at night. This does not happen every year and I have been lucky for the last several years. Brandywine is a late maturing variety that we like but if Late Blight hits, then we don't get any Brandywine.