The caterpillars of the painted lady butterfly rarely cause problems in soybeans unless an unusually large spring migration of the butterflies occurs from the U.S. desert Southwest or Mexico. The caterpillars are commonly found on thistles, but will also attack early vegetative soybeans. The larvae (up to 1.5 inches long) feed on the top leaves and web them together with silk. Their appearance is quite distinctive. The body is black with yellow spots and has numerous multi-pronged spines. Treatment is recommended if defoliation exceeds 50%.
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URL: http://www.soybeans.umn.edu/crop/insects/thistle_caterpillar.htm
Last Modified
8/3/06 11:33 AM
by Sarah Jameson-Jones - james039@umn.edu
External Images:
Thistle
Caterpillar Images - Iowa State University Entomology Image Gallery