Ok, i see why you're not getting any residue. where did you get this application rate? I don't think they offered the dilution rate for foliar application.
Did you read the label? that's where i got it. Actually they say "mix 14-28 ounces of product per 100 gallons of water". Which is only 4-7 grams per gallon. But like i said, I double that and use 14g per gallon of water.
here you go, it's under
DIRECTIONS FOR USE
GREENHOUSES (AND OTHER COVER):
http://www.everwoodfarm.com/pdf/PFR-97_label.pdf
well thats way more than they recommend, seems like a waste of money to me. PFR-97 is not cheap at almost $250 for 5lbs , = about $3 per ounce. but he claims it was effective treatment so perhaps there is no risk of overdosing. that stuff seems to be pretty harmless to plants.btw, epic recommended 6 ounce per 5 gal of water.
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EDIT: i also found this useful information on the product label just now:
"Frequent application may be required under dry
conditions, during periods of increased pest buildup
or reproduction, or rapid host plant growth.
More frequent application at low rate (e.g. 14-16
oz/100 gal every 3 to 5 days) is more likely to
improve results than using higher rates at low
frequency (e.g. 28 oz/100 gal every 10 days)."