Sumac Flea Beetle

The Blepharida genus includes 73 different species, half of which are from tropical Africa, and the other half are from the New World tropics. The Blepharida rhois is a species of outlying distribution found widespread in North America. It is most commonly spotted in states of the more northerly regions of the continent. This species distribution extends from Virgian to Alberta in the east and Montana in the west. This is atypical as all other members of the Blepharida species inhabit Mexico and Central America.

This beetle can be considered a pest for the sumac tree. Because larvae cause most of the primary damage to plants during their intense feeding phase, integrated pest management programs advise for leaves to be monitored for larvae in mid to late May. To inhibit B. rhois as a pest, the soil may be broken up by farmers during July when the beetle is pupating in the soil. Insecticides may be applied to branches and leaves of plants shortly after egg hatching to control larvae feeding. While pesticides are only needed in more extreme cases where monitoring is ineffective, the pesticides used may include Bacillus thuringiensis var. tenebrionis, carbamade, lead arsenate, and pyrethroid. This is primarily to ensure Rhus plants maintain overall health because larvae feeding can lead to plant death if unmonitored.

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Adults and larvae are considered dietary specialists that exclusively feed on the sumac genus, Rhus. This species of beetle typically feeds on smooth sumac, R. glabra, exclusively. Most New World species feed on Bursera instead, so this beetle is one of the few New World species that feeds on Rhus. This beetle’s herbivory pattern is extremely patchy. Some regions of plants become defoliated while nearby regions are untouched, indicating that this variation may be due to secondary chemistry among the plants. Host versus non-host plants have been found to differ in the amount of chemicals that B. rhois larvae can incorporate into their defense, specifically the presence of tannic acid conjugates and of phytol. B. rhois typically feed on the external surface of leaves. Larvae, after emerging from the fecula after 10 to 14 days, will crawl up the stems of the Rhus plant and feed on the youngest leaf tissue or flower bud. Larvae will feed alone on young leaflets, but when feeding on an older leaf, they may line up in groups. Larvae, unable to fly and lacking a hard protective cuticle, face exposure and vulnerability to predators. The fecal shield provides a source of chemical defense, so the larvae deter predators that want to take advantage of its vulnerability while feeding.