The adults and larvae feed on asparagus spears and can defoliate ferns if populations are extensive. Larvae consume leaves and tender buds near the tips, which leaves scars that eventually turn brown. Damage caused by larvae interferes with the plant’s ability to photosynthesize (manufacture food); thus, depleting food reserves for next year’s crop.
The plant protection strategies that can be implemented to reduce problems with common asparagus beetle populations include: applying insecticides; handpicking eggs, adults, and larvae and placing into a container with soapy water; and/or removing any plant debris after the growing season to eliminate overwintering sites for adults. Insecticides should be applied as soon as common asparagus beetles are present, and again in late summer through early fall to kill adults before they overwinter. Thorough coverage of all plant parts is important in suppressing populations. (Raymond Cloyd)