I have been comparing the labels of Daconil and Monterey Fruit, Vegetable and Ornamental Fungicide (MFVO) with Echo 720. There seems to be a considerable difference in the label rates, based on %A.I.. Daconil and Echo calculate out very close to the same while MFVO is quite different. Any suggestions would be appreciated.

Following are my calculations -

Daconil and MFVO are both 29.6% chlorothalonil, Echo is 54%

Daconil's label rate for BFR is 2 1/4 tsp/gal with no mention of area covered.

MFVO's label rate is 3 3/4 tsp/4 gal and states, "Apply this product in sufficient water to obtain uniform coverage of tree canopy, including the undersides of leaves, to the point of spray runoff. Mix the indicated rate of FRUIT TREE, VEGETABLE & ORNAMENTAL FUNGICIDE into each 4 gallons of water to be used for each application, generally sufficient to treat 200 square feet."

Echo's label rate is 3 1/8 - 4 1/8 pints in 20 to 300(full dilute rate) gal..
Given 1 pint = 96 tsp..
(4 1/8 pt. x 96 tsp) / 300 gal = 1.3 tsp/gal at the high end full dilute rate
(3 1/8 x 96) / 300 gal = 1.0 tsp/gal at the low end full dilute rate

Accounting for %A.I. in all 3 products in units of A.I. in a mix, by product (comparing apples to apples)-
Monterey = 0.278
Daconil = 0.67
Echo high end full dilute = 0.70
Echo low end full dilute = 0.54

In words, the MFVO rate is less than 1/2 of the Echo and Daconil rates and the Daconil and Echo rates agree with one another. I am wide open to corrections and comments and am very aware that it is possible I'm missing something here. That is why I am coming to you.

Humbly yours,

Michael

Michael

"Chlorothalonil, also known as tetrachloroisophthalonitrile, is a broad spectrum, non-systemic fungicide. Chlorothalonil-containing products are sold under the names Bravo, Echo, and Daconil. It was first registered for use in the US in 1966. In 1997, the most recent year for which data is available, it was the third most used fungicide in the US, behind only sulfur and copper, with some 12 million lbs used in agricultural alone that year.[1] Including non-agricultural uses, the EPA estimates that on average almost 15 million lbs were used annually from 1990-1996."

One thing I found is that some "combination" fruit tree sprays contain 29% chlorothalonil and have label directions to use as a cover spray all season. But the Daconil label says to not spray it after petal fall. Your MFVO says to spray it on the leaves, so sounds like they think it's OK for a cover spray, too, but I'm not sure that's right. Cheaper combination sprays have captan (plus malathion and sevin), Monterey Fungus Fighter has propicanazole (Orbit), which is the most common fungicide cover spray used by commercial peach orchards.

The way I do is paint the trunk with Dursban (I guess I'll have to buy Lorsban when I run out) with a paint brush to kill borers. Chlorothalonil when the buds swell, up to petal drop. Captan and Malathion after that, every two weeks or after a rain washes it off. Stop when fruit gets near to ripening.

I am planning to get some Orbit (MFF) and a less stinky insecticide, but the above works good. I'm sure others here have different suggestions, as in several earlier stone fruit spray program threads.

The good news is, my disease pressure has been very light as there are no other peach trees and only one almost dead plum tree for miles around, apparently there are no other alternate hosts either.

Michael

The best thing about using Orbit (MFF) or Indar is that it allows you to take some chances to find out what the minimum fungicided input is. If brown rot shows up you can rescue the uninfected fruit and notch up the earlier sprays the following season.

As I have said many times here, I have sites where all stone fruit used to rot but I've gotten control with a single ap. of Indar in mid-July. Just cleaning things up one time can sometimes do the trick. I almost never spray stonefruit closer than a month before harvest- try that with Captan!

Maybe I'll learn the hard way and kick myself in the butt, maybe the blooms will all get frozen off this year like they very nearly did last year and I won't have to worry about BFR for another year.

Michael

Here, I don't need to control fungus on stonefruit until mid-July.

Haven't seen anything that explains why not to use it that way, only what the Daconil label says.

It's titled Pest Management Guidelines for Commercial Tree-Fruit Production.

We usually have heat in the mid 90s with about 50% RH by June and little too no rain from June on. So far, lucky me, never sprayed the peach past shuck split.

Michael

"2.2] The shuck split application is an important spray. Chlorothalonil (Bravo, Echo) provides a longer period of protection than either captan or sulfur, but do not use Chlorothalonil after shuck split."

Hman, thanks for the link. I've heard you quote Cornell's spray guide, but until recently I didn't know it was online.

Thanks for the headsup on tomatoe application. I was planning on using it on my tomatoes for the first time next year- I'm so sick of early blight just decimating my crop. My vegie garden is usually all organic.

Strangely, the old heirloom Brandywine is much more tolerant to chlorothalonil than the newer hybrids. Maybe it has something to do with the leaves being so different.