Yellowmargined Leaf Beetle
Yellowmargined leaf beetle larva.
(Order: Coleoptera, Family: Chrysomelidae, Microtheca ochroloma)
Adult: The adult is small (5 mm long) and dark bronze or black in color. The outer edges of the elytra have a yellow or brownish margin and the elytra has four rows of deep punctures lengthwise.
Immature stages: Eggs are bright orange, elongate and can be found on the plant foliage. The larvae are dark yellowish brown with a dark brown-black head capsule.
Yellowmargined leaf beetle damaged mustard.
Life cycle: Little is known about the life cycle of this pest, possibly because of its sporadic occurrence. The insect can complete development in less than a month under favorable conditions, but multiple generations have not been reported.
Seasonal distribution: In Florida and southern Georgia this pest has been encountered in mustard greens in the spring or early summer and possibly aestivates in the mid summer.
Damage to Crop: Damage generally occurs in the spring leafy green crop, but it has only been observed very sporadically. Even though the gregarious nature of this beetle results in complete defoliation of the crop (see photos), the damage appears highly clumped, notably on the margins of the field. Thus, the economic importance of this pest is minimal.
Damage to mustard greens occurs in clumps.
Management: Since the occurrence of this pest is sporadic and highly clumped, and multiple generations are not known, a single treatment of an effective contact insecticide to the affected area at the first sign of damage should be all that is needed. In general, this pest, although dramatic in damage when present, rarely if ever needs to be controlled commercially.
Prepared by Dr. Alton “Stormy” Sparks, Jr. and Dr. David G. Riley - University of Georgia