''Phyllophaga'' is a very large
genus (more than 900 species) of
New World scarab beetles
The family Scarabaeidae, as currently defined, consists of over 30,000 species of beetles worldwide; they are often called scarabs or scarab beetles. The classification of this family has undergone significant change in recent years. Several sub ...
in the subfamily
Melolonthinae. Common names for this genus and many other related genera in the subfamily Melolonthinae are May beetles, June bugs, and July beetles.
They range in size from
and are blackish or reddish-brown in colour, without prominent markings, and often rather hairy ventrally. These beetles are nocturnal, coming to lights in great numbers.
The generic name is derived from the Greek words ''phyllon'' (φυλλον), which means "leaf", and ' (φαγος), which means "eater", with a plural ending.
Lifecycle
The lifecycle takes about one year. Females lay 60 to 75 eggs over a period of about two weeks in midsummer. The white egg at first is elliptical (1.5 mm by 2.1 mm) but becomes more spherical as the larva inside develops. These hatch into
white grub
The family Scarabaeidae, as currently defined, consists of over 30,000 species of beetles worldwide; they are often called scarabs or scarab beetles. The classification of this family has undergone significant change in recent years. Several sub ...
s about 18 days after laying. The newly hatched
larvae are 8 mm long and grow to a length around 40 mm. Whitish with a brownish-black head, the grubs have conspicuous brown spiracles along the sides of their bodies. They molt twice before winter. The third larval stage lasts nearly nine months, after which they
pupate. They hibernate overwinter as grubs that may become active on warm winter days. They increase their activity in the spring.
Diet
The adults are
chafers, feeding on foliage of trees and shrubs. They may cause significant damage when emerging in large numbers. The larvae (called
white grub
The family Scarabaeidae, as currently defined, consists of over 30,000 species of beetles worldwide; they are often called scarabs or scarab beetles. The classification of this family has undergone significant change in recent years. Several sub ...
s) feed on the roots of grasses and other plants.
Adult chafers eat the leaves and flowers of many
deciduous trees, shrubs, and other plants. However, white grubs (reaching 40–45 mm long when full grown) live in the
soil and feed on plant roots, especially those of grasses and cereals, and are occasional pests in pastures, nurseries, gardens, and golf courses. An obvious indication of infestation is the presence of birds, such as crows, peeling back the grass to get to the grubs. The injury consists of poorly growing patches that quickly turn brown in dry weather. The grubs can be found immediately below the surface, usually lying in a characteristic comma-like position.
The grubs sometimes attack vegetables and other garden plants, e.g.
lettuce
Lettuce (''Lactuca sativa'') is an annual plant of the family Asteraceae. It is most often grown as a leaf vegetable, but sometimes for its stem and seeds. Lettuce is most often used for salads, although it is also seen in other kinds of food, ...
,
raspberries
The raspberry is the edible fruit of a multitude of plant species in the genus ''Rubus'' of the rose family, most of which are in the subgenus '' Idaeobatus''. The name also applies to these plants themselves. Raspberries are perennial with w ...
,
strawberries,
potatoes, and young
ornamental trees. Injury to the roots and rootstock causes small saplings and tender tap-rooted plants like lettuce to wilt suddenly or to show stunted growth and a tendency to shed leaves prematurely. Plants growing in rows are usually attacked in succession as the grubs move along from one plant to the next. Chafer grubs feed below ground for 3–4 years before changing into adult beetles.
Predators
Some
Pyrgotidae flies pursue the beetles in flight to lay an egg on the beetle's back under the
elytra
An elytron (; ; , ) is a modified, hardened forewing of beetles (Coleoptera), though a few of the true bugs (Hemiptera) such as the family Schizopteridae are extremely similar; in true bugs, the forewings are called hemelytra (sometimes alterna ...
where the beetle cannot reach it. The egg hatches and the fly larva enters the body cavity of the beetle, feeding on and eventually killing the host before
pupating. A species of bee fly, ''
Exoprosopa fasciata'', is also a parasite of this genus. The larvae feed on the ground and pupate in the grub cell where they stay over the winter.
Wasps in numerous families, including
Pelecinidae,
Scoliidae, and
Tiphiidae, are
parasitoids of ''Phyllophaga'' grubs. A variety of amphibians, some small mammals, including
skunks and
moles, feed on the grubs.
See also
*
List of ''Phyllophaga'' species
References
Further reading
* Dillon, Elizabeth S., and Dillon, Lawrence (1961). ''A Manual of Common Beetles of Eastern North America''. Evanston, Illinois: Row, Peterson, and Company.
* Evans, Arthur W
Generic Guide to New World Scarabs��subfamily Melolonthinae
* Haarstad, John A
* Smith, A. B. T. (2003). Checklist of the Scarabaeoidea of the Nearctic Realm. Version 3. Electronically published, Lincoln, Nebraska. 74 pp, availabl
* White, Richard E. (1998). ''Beetles: A Field Guide to the Beetles of North America''. Boston: Houghton Mifflin. .
External links
on the
UF /
IFAS Featured Creatures Web site
{{Taxonbar, from=Q2716763
Agricultural pest insects
Folivores
Melolonthinae
Scarabaeidae genera
Insect pests of millets