Just received my Imidan order from E&R, and want to double check my ratio of 4 Tbls/Gal. This would be for apples, peaches, pears on the East Coast. Thanx in advance for your insight.
That sounds like it might be heavy. I assume you purchased 70WP? Here is a discussion about this from the forum archives I saved in "My Favorites". My plan was 1 tablespoon per gallon... I am NOT an expert. Read the post link below.
Here is a link that might be useful: Imidan Use Discussion
1 TBS per gallon if it's 70 WP. Measure outside w/ protection when winds are calm.
Yup, 1 TBS per gallon.
Honestly, for most pesticides, "more isn't better" -- you're just wasting it. The only real exceptions that I can think of to this rule is that sometimes, 1) it's helpful to paint trunks/stubs of trees and shrubs you want to kill, kill for sure, and kill quickly with either a very strong solution of an herbicide, or even the straight concentrate right out of the bottle; or 2) if I HAVE to spray, but rain, especially heavy rain, is forecast within 24 hours, I will do 1 1/2 times the normal rate, hoping that it will help ensure some remains. Even that is wrong, really, certainly NOT an approved method, but there are times due to weather and life circumstances that I have no other options.
Your right about the rain. I have read the amount removed by a given amount of rain for a given pesticide. I think an inch of rain removes about half the Imidan but does not meaningfully affect protection. 1 TBS is already more than needed in dry conditions. Maybe someone can post the chart- Opea has it, I think.
Newer insecticides stick better but can afford to lose less potency after application so it pretty much evens out, as I recall, except that Imidan has kick-back.
I am not the best with math, but when I calculated out rate
per acre by gallon basis, I got 2.5 tsp/gallon. I used this rate on the first batch of Imidan 70 I bought with great success. The last 4 pounds I bought came written with a note to use 1-TB per gallon. Since it is faster to measure a tablespoon than 2.5 tsp, I switched to the higher rate.
I think 4 Tb/gallon rate seems very high.
Spar, how did you come up with the rate by acre calculation? When I do this it generally comes to an acre being covered by 250 gallons so you divide the quantity needed for an acre by 2.5 to get to 100 gallons and take it from there. I originally had to weigh the Imidan to figure out what I'd need in a 25 gallon tank back in the days I used to cut open bags. Took a cup and a half for max rate.
I think the ease in which home growers may accept applying pesticides at 4X the legal rate speaks a lot about why Imidan is restricted in some states. If nothing else, it quadruples your exposure (and the environments) for no better control.
Below is John Wise (MSU) rain fastness chart for various insecticides.
Although he doesn't mention it in the article below, I also recall his research indicated although Imidan does wash off, it has a high toxicity to target pests, so that a small amount of residue will protect fruit.
The article also shows his decision chart. He shows Imidan need not be reapplied after an inch of rain unless the rain occurs 7 days after the application.
Here is a link that might be useful: MSU crop advisory alert
I used the application ratio provided 1lb/100gal. Can I apply Immunox back to back with the Imidan? I haven't been able to spray as all my blossoms have yet to fall.