By Big Country Master Gardener Kathy Feagan
Blister Beetles differ in form and size within the 100 species found in Texas. Common blister beetles include Black Blister Beetles (Epicauta pennsylvanica and E occidentalis) in east, central and west Texas and Epicauta temexa in south Texas and Cysteodemus armatus mainly found in west Texas. Commonly, they mature to 3/8 to 1” long, are solid gray or black with spots or stripes of yellow to orange and pale margins at the wings. Females lay eggs in soil where grasshoppers lay their eggs, in early winter. The eggs hatch and begin their instars. These beetles have a specialized manner of metamorphosis in which the first instar is active, long legged and very mobile in order to hunt for food and hosts (such as grasshopper eggs or ground nesting bees) before going through the second instar to a grub form. The first instar sometimes climbs onto flowers and attaches itself to bees for transportation. Once it finds a proper host of egg casings, the larvae begin to develop. They then eat their way inside the egg casing, then feed and continue through instars 2 through 4 in grub form. In spring, they reach the final instar and the beetle larvae pupate then emerge as an adult. The male beetles produce a toxic blister toxin, ‘cantharidin’, for defense. The toxin is transferred to females while mating. The toxin can cause severe skin blisters on people and this toxin can be fatal to horses and other livestock if they consume hay or feed contaminated with dried, dead beetles. Some predators have developed immunity and feed on the beetles and also use blister beetles for their benefit. In Europe. Asia and Africa, Great Bustards (Otis tarda), huge ground dwelling birds, eat large quantities of blister beetles to exterminate their parasites, especially during mating seasons in spring. Blister beetles eat flowers and foliage like alfalfa, soybeans, potatoes, vegetables and other plants. Blister beetles are highly attracted to alfalfa (partly due to the available grasshopper eggs) but the danger to livestock can be limited by cutting alfalfa before the peak bloom. Due to the blister beetle’s ability to control grasshopper populations, they are considered beneficial insects but can be devastatingly harmful when handled.
1. Blister Beetle (Epicauta temexa) by Annika Linqvist, https://www.inaturalist.org/photos/231535180
2. Blister Beetle Cysteodemus armatus (by Dee Shea Hines, https://www.inaturalist.org/photos/262059465)
3. Black Blister Beetle (Epicauta pennsylvanica) Public domain by Alejandro Santillana, Univ. of Texas “Insects Unlocked” https://www.flickr.com/photos/131104726@N02/31007972486
Scarab Beetles, Scarabaeidae, include June Bugs, Southern Masked Chafer, Rainbow Scarabs and Green June Beetles. The hated June beetles (Phyllophaga) are a genus of over 300 species. June “bugs” grow ½ to 1” long, are a rusty brown and have shiny wings. They feed on flowers and vegetation during the nights of summer and can wreak plenty of damage. Their larvae (white grubs) are about 1” long and live in the soil. Every female lays between 50 to over 200 eggs. The larvae remain in the soil for up to 3 years, feasting on and severing the roots of crops (especially strawberries, potatoes, corn and grains) and also heavily damage lawns, gardens and pastures by feeding on and severing the roots of grasses and plants. Finally, the larvae pupate and emerges as an adult in summer. They overwinter by burying themselves. They return in spring and usually die within the year after mating and laying eggs. They do have an enemy predator, the Waved Light Fly (Pyrgota undata). The female fly lays an egg below the June beetle’s protective elytra (forewings), usually while the beetle is flying. When the fly’s egg hatches, it feeds on the beetle, killing it. Moles and skunks also hunt and eat June bugs’ larvae and some people use the larvae for fish bait! Gardeners can spray beneficial nematodes to help control grubs in early fall or spring. The nematodes aggressively hunt and kill grubs in the soil.
June Beetle Phyllpphaga drakii
(Nick Bédard Wikimedia Commons- https://www.inaturalist.org/photos/168516995 )
Green June Beetles (Cotinis nitidas) are active during the day. They grow to ½ to 1-” long and have metallic green wings, gold sides and bright shiny green heads, legs and undersides. They mate in early mornings when the female attracts a male by emitting a strongly scented fluid. After mating, the female burrows under soil or matted grass and lays 60 to 70 eggs over about 2 weeks. They lay their eggs in soil rich in decomposition, manure and other organic materials (gardens, yards, pastures and hayfields). The eggs hatch within 18 days to become small, white grubs. After two molts, the grubs grow to about 1-1/2 to 2” long and they evolve from pure white to yellow/white with brown heads and green to blue tails. They travel speedily underground thanks to the stiff bristles on their abdomen. They are much faster than any other Scarabaeidae in America. Larvae feed on mold and humus, decaying plants, roots and even manure. The larvae do lots of damage to plant and grass roots (mainly through creating surface soil mounds and tunneling). The mounds and holes they create weaken and kill grass and vegetation. The larvae pupate into an oval cocoon. Adults appear in June after pupating. They feed on many ripening thin-skinned fruits, fruit tree leaves, and especially rotting fruits and flowers. While feeding, they defecate a noxious smelling waste and they are known to defoliate fruit trees and bushes. They have natural predators like birds (especially brown thrashers, crows, grackles, robins and blue jays), flesh flies, digger wasps and moles. After a heavy rain, larvae often crawl to the surface where they are eaten by raccoons, chipmunks, gophers, skunks and possums. They rely on tall grass for protection and are most active in the spring when plants are actively growing.
Green June Beetle (Public domain by Alejandro Santillana. Univ. of Texas “Insects Unlocked” https://www.flickr.com/photos/131104726@N02/28985441224)
Southern Masked Chafer (Cyclocephala lurida) are very common in the southeastern U.S. and their destructive larvae are thought to be one of the hardest to control. It is the larvae (white grubs) of this species that do so much harm by eating turfgrass and other roots. They are also pests of many crops. They can attract racoons and skunks who dig for them in lawns, fields or gardens. These ¼ to ½” long, dull yellow to brown beetles have a black ‘mask’ across their face and eyes. Females emerge from overwintering in the ground in early summer. Females attract males by emitting a sexual pheromone. After mating, the female digs back into the soil and lays her eggs. The 1” gray/white larvae (with brown heads and six legs) then begin eating mainly grass roots, but also attack crops, vegetable and plant roots until the following spring, when they pupate to adult. Adults do not eat during their very short lifetimes which last a few weeks. They live only to mate and reproduce their very damaging larvae.
Southern Masked Chafer (Wikimedia Commons by Mila Turov, https://commons.wikimedia.org/w/index.php?curid=165490780)
If you have any gardening questions, call the Taylor County Extension Office at 325-672-6048 or email us at mgardeners@yahoo.com. We hope you visit bcmgtx.org for all Big Country Master Gardener information and events, like us on BCMGA Facebook, and check out training presentations on BCMGA YouTube. We are here to help you.
Until next week, Happy Gardening!