How many ladybugs to buy?
I have about 20 fruit trees, a couple of which have been hit by aphids. I am thinking about buying some live ladybugs, but don't have any idea how many to buy. I know they only stay around if there's things for them to eat. The fruit trees are in my back yard; there is also vegetable beds and flowers. In the front yard are roses, which sometimes get aphids and a few fruit trees, none of which have the aphids at this point. I can buy 750, 2000 or more. Is there a way to get a ballpark figure on how many would be helpful? I should mention our friends across the street also have 50 or more fruit trees and they're beginning to see aphids as well.