I'm finally resorting to a copper fungicide (copper oxychloride) to combat out-of-control iris leaf spot. Finding a spreader-sticker is a bit of a challenge as none of the nurseries here on the Sunshine Coast of BC sell any. I bought some concentrated Safer's insecticidal soap but at the mix rate suggested - 20ml/L - we'll be going through $100 worth of it before all the spraying is finished (client has 100s of affected irises). Does anyone have any suggestions/recommendations about a commercial sticker-sprayer easily available in BC? or if I can use a pure soap like Dr. Bronner's castille? or about controlling iris leaf spot in general?
Have been using "Ivory" liquid dish detergent as a sticker with no apparent problems. Haven't used copper fungicide though.
I've used copper oxychloride in a farming enviornment for many years and have never used a sticker. We put it on thru the chemigation system. It's a bit tough to get it to mix with water as it doesn't disolve easily and quickly goes out of solution once mixing stops. I mix it in a 20L pail using an industrial paint stirrer in an electric drill. The mixture must be continually agitated during use to ensure an even application. Works OK for an inexpensive product.
I agree about the safer's product being expensive, the dilution rate is amazingly high, or is it low...well, you know. I have used a product called Mega-Wet made for this purpose. It would be wholesaled thru Allie's in Langley, which supplies most of the hydroponic outlets. If you have a hydro store on the Sunshine Coast (gotta have, with all the indoor hobby gardeners in the area, wink) they should have this, or sometimes carry Agra II which is even better but less common. A little goes a long way, which is what you want to keep that cost on budget. These are surfactants, but not stickers. I mostly worry about getting the droplets to spread over the waxy leaves, so this is what I go for. I can see iris leaves being tough to get stuff to adhere! A sticker might be helpful too, not sure how to accomplish that while using a surfactant which would tend to break the sticker down (such as hort oil?). So I just try to spray in the evening when rain isn't on the way, and hope the product hangs around for the night at least...which should do the trick.
Well yes, we do have a hydro store here and I never thought to look at what products they might have available... I'll probably try the surfactant - it's all trial and error at this point. Thanks very much for the suggestion.
Yes, I'm finding the copper oxychloride hard to keep in solution but the soap seems to help a bit with this. I need to use a sticker-spreader in this case because the waxy leaves of the iris make the solution completely bead off and just pool around the rhizomes.
There has been a lot of debate about the use of dishwashing liquids as either an insecticidal soap or spreader-sticker. Some people see no ill effects from their use of it and I guess it all depends on the situation. Regardless of how carefully I spray the irises I get a lot of the solution pooling around the rhizomes and soaking into the soil. And I have to repeatedly spray this solution over the next 2 months, so I will end up with quite an amount of solution in the soil. This is apparently where using detergent as a spreader-sticker can get dangerous.
any time I have asked a product rep about the use of spreader/stickers they say that the products are designed to be used as packaged and according to the directions on the label, surfactants should not be necessary. that said, you can try a few drops of mineral oil (aka dormant oil) to help break the surface tension of the water. On another note, copper spray is referred to as a wettable powder which actually goes in to suspension rather than solution. Also remember to clean your spray equipment out, it may crystalize and plug the gear up. http://www.uap.ca/products/documents/CopperSpray4.pdf
Years ago my client tried this with oil and it only resulted in clogging up the sprayer. We're going to use soap until we can order a surfactant. Thanks for the suggestion, though.
This is a product I used to sell to a lot of hydroponic shops and a few garden centers: http://www.agriorganics.com/products/agri2.html
