Aphids

For the past couple of years, the leaves on our plum trees have curled up and died.  I have not paid much attention because the weather has been so cold for two years that we've had very little fruit in our orchard anyway.  This spring, in contrast, the weather has been very mild and we are likely to have a good fruit crop.  In order to help the fruit along, I have been conscientious about spraying "Bonide" every two weeks.  The spray contains a mix of Captan, Malathion, and Carbaryl, and is supposed to control most insect pests.  Despite this attention, however, the plum leaves have been curling again.  My father-in-law asked me if we had aphids.  That was my first clue.  My second clue came when I examined the plum trees and found them covered with ladybugs.  (In the picture above there may be both a lady- and a gentleman-bug.)  Because ladybugs are known to feast on aphids, I thought I should look to see what they were eating.  Sure enough.  The curled leaves were playing host to those tiny, fat, transparent, ugly, white, green pests—aphids.  The Bonide says that it controls aphids, but I'm not sure what to do now.  I don't want to harm the ladybugs, and the aphids are not bothering any of the other fruit trees, so I may just let them be.  The plums can be my trap trees, I guess.