I just noticed that i have a lot of little white spots that have formed on the tops of a couple of my leaves on my 6 week old seedling. My seedling has a total of 12 leaves on it so far and the the largest 2 leaves have the spots. My plant is growing outdoors. I just noticed and killed an aphid (little green bug) that was on the plant. Is this the source of my problems, or is there more that needs to be done? i would post the pictures that I took, but my posting rules say that i am unable to post attachments. Any responses would be helpful, thanks.