Diatomaceous Earth--wet foliage first?

b54red · July 18, 2016

I have used over a cup of DE to the gallon but found myself having to sometimes open up my spray valve and clear it with a larger stream and found that a finer mist was not practical because of how often it started to clog. I also found that I got a heavy buildup of DE in the hose from the sprayer to the wand that took quite a while to wash out. I found that mixing the DE and some of the water in a separate jug, shaking it well then straining it into the sprayer tank helped keep clogging to a minimum.

If the mites are really bad like they were the last time I sprayed I will go slightly above the 2/3rds cup to the gallon and the coverage is better but it may take a bit longer to apply. I use an SP2 4 gallon backpack sprayer that builds up a lot of spray pressure and ordinarily will spray a super fine mist at a high volume; but when using a heavy concentration of DE I need to use a heavier mist in order not to start clogging the nozzle. The food grade DE mixes quite well in water and holds in suspension longer than you would think but it will eventually sink. I think the soap helps hold it in suspension longer but I try to shake my spray tank as much as possible when working to keep it suspended better. I have no idea how much can actually be used and still spray but I get good coverage with between 1/2 to 3/4 cup of DE to the gallon so why invite sprayer problems.

I have found the mix to be very effective at killing almost any insects including caterpillars which have also disappeared. My stinkbugs and leaf footed bugs are also gone but with so much season left they may reappear before the season is over along with the dreaded spider mite. I may do a follow up spray soon of just DE and water on the new growth just to assure myself that new spider mites don't attack that part of the plant that is unprotected by DE.

Bill

July 18, 2016	#1
b54red Tomatovillian™ Join Date: Sep 2009 Location: Alabama Posts: 7,068	I have used over a cup of DE to the gallon but found myself having to sometimes open up my spray valve and clear it with a larger stream and found that a finer mist was not practical because of how often it started to clog. I also found that I got a heavy buildup of DE in the hose from the sprayer to the wand that took quite a while to wash out. I found that mixing the DE and some of the water in a separate jug, shaking it well then straining it into the sprayer tank helped keep clogging to a minimum. If the mites are really bad like they were the last time I sprayed I will go slightly above the 2/3rds cup to the gallon and the coverage is better but it may take a bit longer to apply. I use an SP2 4 gallon backpack sprayer that builds up a lot of spray pressure and ordinarily will spray a super fine mist at a high volume; but when using a heavy concentration of DE I need to use a heavier mist in order not to start clogging the nozzle. The food grade DE mixes quite well in water and holds in suspension longer than you would think but it will eventually sink. I think the soap helps hold it in suspension longer but I try to shake my spray tank as much as possible when working to keep it suspended better. I have no idea how much can actually be used and still spray but I get good coverage with between 1/2 to 3/4 cup of DE to the gallon so why invite sprayer problems. I have found the mix to be very effective at killing almost any insects including caterpillars which have also disappeared. My stinkbugs and leaf footed bugs are also gone but with so much season left they may reappear before the season is over along with the dreaded spider mite. I may do a follow up spray soon of just DE and water on the new growth just to assure myself that new spider mites don't attack that part of the plant that is unprotected by DE. Bill