Thistle caterpillar: Injury and damage

Thistle caterpillar leaf injury: Leaf injury resulting from thistle caterpillar, Vanessa cardui, feeding.Thistle caterpillar leaf injury: Leaf injury resulting from thistle caterpillar, Vanessa cardui, feeding. These leaflets have 35 [left], 20 [center], and 35% [right] of tissue removed, respectively. (Photos Marlin E. Rice)

Thistle caterpillars cause the most injury during V3-V4 soybean stages (Pedigo 1994a). The larvae will web together the leaves of soybean and will consume about 37.5 in2 of tissue per larva. 97% of this tissue consumption occurs during the last two larval instars (Scott 1986).