permaculture

[Paul Cross <charybda@newmex.com>]

You want the parasitic wasp Encarsia formosa to control your greenhouse 
whiteflies. Get the wasps now before the summer flare up. Much easier to 
control the whiteflies during cool temperatures, when they take as long 
4 months to complete a life cycle, versus 2.5 weeks when it's hot. 
That's why you see big population explosions in summer. EF comes on 
little cards that you hang on your plants. They hatch and fly around 
looking for whitefly larvae to parasitize. The wasps are so small you'll 
likely never see them. This solution takes no spraying and is more 
effective.

I get my Ef here:

http://www.hydro-gardens.com/whitefly.htm

Scott, for mealybugs have you tried a douse or swab of alcohol directly 
onto the critters? Cryptolaemus is the main biological control but I've 
never tried them and they are expensive.

Paul