In addition, aphids may introduce fungus, bacteria and viruses. Eggs hatch in spring as female nymphs. They mature in one to two weeks and themselves bear live females, as many as 10 per day. They produce many asexual generations, allowing populations to grow quickly. Toward the end of the season, males are born and mate with females to produce eggs for the following year.
Aphids expel sticky, sugary honeydew, which supports growth of a sooty-colored mold on leaves.
The larvae feed on tender roots and then larger ones through the summer and fall. Larvae feed in early spring as temperatures rise, pupate and emerge as adults by early summer. They feed for about a month and by late June or early July lay tiny white eggs in the soil. The eggs hatch some 10 to 14 days later. Surface-feeding cutworms cause the most damage.