I spent two weeks away from my marijuana plants, but when I finally got a look at them, I found large colonies of 1/16-inch pale, green insects scurrying on all the stems. Their heads were thing and bodies wide in a sort pear shape. What are these bugs and can they damage the plant? If I need them gone, what should I do?
Your marijuana plants have incurred an aphid infestation. These bugs come in many colors like white, brown, black, and many different greenish hues. They’ve got proboscises (straw-like mouths) that they use to prick the stem and suck up its juice. Aphid reproduction happens rapidly because females generally don’t need males to reproduce. Ants herd aphids for the honeydew they produce. It doesn’t take that long for aphids to ruin a marijuana plant and this problem requires swift action. Although some populations are immune to pyrethrum, it should be attempted early on. Aphid sprays like Botanigard and Cinnamite are effective just like fatty-acid-based (soap-based) insecticides. You can wash the aphids off the plant with water if that’s feasible. Water won’t exterminate them, but it can prevent a great deal of the damage. You can also control aphids with other predatory insects.