Phyllophaga crinita

Within the United States, Phyllophaga crinita has been reported in Texas, Louisiana, Mississippi, Alabama, Iowa, and Missouri. Within Mexico it has been found in Tamaulipas, Nuevo Leon, Coahuila, and Chihuahua. However, P. crinita is predominately reported in Texas and Tamaulipas (Dr. Luis Rodriquez, personal communication).

Phyllophaga crinita is primarily found in temperate grasslands, especially those containing Bermuda grass, St. Augustine grass, and tall fescue or crops of corn and sorghum. The larval form, or white grub, lives and develops in the soil found below these types of vegetation. The white grub prefers and has a better chance of survival in moist soil. (Drees and Jackman, 1998; Frankie and Gaylor, 1979)

The adult form of P. crinita ranges in size from 1.3 to 1.7 cm long. This heavy-bodied, reddish brown beetle has six wiry legs, and a double pair of wings. The anterior leathery pair, also known as elytra, serve as covers for the hindwings. The elytra are held out to the sides during flight although they do not participate in flight itself. The hindwings are the primary structures responsible for the mechanics of flight. Larvae of P. crinita are white grubs. The white grub is C-shaped with a brown to orange head and a white body. Dark-colored digested material can be seen in the transparent abdominal segment of the grub. The white grub's three pairs of true legs appear on each of the first three segments behind its head. (Crocker and Merchant, 1995; Cronholm, et al., 1998; Grzimek, 1972)

Phyllophaga crinita typically require one year to complete their life cycle. Adults begin to emerge from the soil in late spring or summer. After mating, the females tunnel 5.4-13.5 cm into the soil and deposit their eggs. Each female can lay about thirty to forty eggs. Within three to four weeks, the small white grubs hatch. These larvae develop through three stages, or instars. The first and second instars last about three weeks. The final larval instar remains in the soil throughout the fall and the winter feeding on grass root systems. In spring and early summer the pupal stage follows the third-instar. Inside the puparium, the white grub transforms into an adult beetle eight to sixteen centimeters below the ground. Adults then emerge from pupae three weeks later. (Crocker and Merchant, 1995; Drees and Jackman, 1998)

Once P. crinita emerges from the soil in late spring or summer it begins its mating flight. This flight usually begins at night after a significant rainfall or irrigation and may last up to three weeks. The process of mating begins with the male hanging onto the females back in a piggyback position using his mandibles. Eventually the male allows himself to fall over backward. The male is then pulled around on his back by the female for the duration of copulation, which may last for several hours. Once mating has taken place the female proceeds to lay her eggs in the soil while the male continues his flight. (Cronholm, et al., 1998; Drees and Jackman, 1998; Grzimek, 1972; Klots and Klots, 1959; Ueckert, 1979)

It is common to see large groups of male P. crinita flying clumsily about. They are strongly attracted to lights, causing them to bang and buzz against window screens, enter homes, and cover walkways and porches as they helplessly roll on their backs with their legs in the air. Their lack of ability to fly well results in P. crinita barely reaching eight kilometers per hour. They only produce forty-five to fifty wingbeats per second, while in comparison, the mosquito beats its wings 280-310 times per second. (Crocker and Merchant, 1995; Grzimek, 1972; Klots and Klots, 1959; Crocker and Merchant, 1995; Grzimek, 1972; Klots and Klots, 1959)

Phyllophaga crinita is a herbivorous night feeder that eats the foliage of broadleaf and coniferous trees, often causing extensive defoliation. Larvae feed on the roots of grasses often reducing the vegetation's chance of survival. The most common grasses fed upon are Bermuda grass, St. Augustine grass, and tall fescue. Larvae will also feed on the roots of weeds, vegetable transplants, and ornamental plants. Crops of corn, sorghum, and sugarcane can also be negatively affected by the feeding of white grubs. (Drees and Jackman, 1998; Ueckert, 1979)

Phyllophaga crinita benefits humans very little. Its most significant contribution would be that it serves as a good fish bait. Bass have been known to take them enthusiastically in place of the typical worm. (Klots and Klots, 1959)

The adult Phyllophaga crinita does not have a serious economic impact. Its buzzing, strong attraction to lights, and clumsy flight causes many humans to regard them as pests. The adult also feeds on foliage causing an eyesore for gardeners, although they cause very little damage to the health of the plant.

The larvae of P. crinita is a significant agricultural threat primarily to lawn owners and farmers. The white grub has been considered among the most destructive of soil-dwelling insects. The results of white grub eating habits can be deadly to lawns of Bermuda and St. Augustine grass causing them to turn yellow and literally be rolled up. The grub can also do damage to vegetables, and ornamental plants. Corn, sorghum, and sugarcane crops can also be adversely affected, causing great economic loss for farmers. (Drees and Jackman, 1998; Ueckert, 1979)

This species does not require any special status or protective measures. (Ueckert, 1979)