White Grub (Coleoptera: Scarabaeidae) Population Density in Relation to Root Damage to Fraser Fir Seedlings in Transplant Beds

A field experiment was conducted in 2002 to evaluate the effect of five grub densities of second instar Phyllophaga anxia (LeCont) Glasgow larvae on feeding damage to roots of young seedlings of Fraser fir, Abies fraseri (Pursh) Poir., Christmas trees in a transplant bed. Larval densities were equivalent to approximately 0, 31, 62, 93, and 124 larvae per m2 (≈ 0, 3, 6, 9, and 12 larvae per ft2). Larval survival and variations in larval and seedling weight were also evaluated. Regardless of the larval density, when P. anxia grubs were present, all Fraser fir seedlings experienced significant root damage as well as subsequent plant injury (i.e., decline or mortality). Larval density as low as one grub per 0.11 m2 (≈ 3 larvae per ft2) caused heavy to severe root damage to young, two-year-old, P2-0 Fraser fir seedlings. An inverse relationship was observed between plant weight and root damage.

ACARI ASSOCIATED WITH PHYLLOPHAGA ANXIA (LECONTE) (COLEOPTERA: SCARABAEIDAE) IN SOUTHERN QUEBEC AND EASTERN ONTARIO

In the course of a systematic survey from 1979 to 1982 in southern Quebec and eastern Ontario, 11 genera of mites, representing five families and 15 species, were found associated with Phyllophaga anxia (LeConte). The rate of infestation in each growth stage of the host ranged from 0 (eggs and prepupae) to 54.6% (third-instar grubs). Although it was not possible to determine with certainty the ecological roles of the mite taxa, and thus to assess the real impact of the species involved, it is likely that the Macrochelidae, Parasitidae, and possibly Eviphididae were partially regulating local P. anxia populations. The Acaridae and Histiostomidae (Anoetidae) probably had a harmless phoretic or saprotrophic relation with their hosts. Most of the mite species reported here were found associated with Phyllophaga Harris in Canada for the first time.

Flight Patterns and White Grub Population Densities of Three Beetle Species (Coleoptera: Scarabaeidae) in the Mountains of Northwestern North Carolina

Light-trap and soil-sampling studies were conducted at higher elevations in the Appalachian Mountains of northwestern North Carolina to determine adult flight patterns and white grub population densities and instar ratios of three scarab species: Phyllophaga anxia (LeConte) Glasgow, P. fusca (Froelich) Glasgow, and Polyphylla comes Casey. Flights of the two Phyllophaga species overlapped (May–June), preceding Polyphlla flights (July–August). Multiple flights of Phyllophaga anxia and P. fusca occurred over periods of 10 and 12 weeks, respectively. Multiple flights of Polyphylla comes lasted for 6 weeks. For all three species, peak flight densities occurred 3 to 4 weeks after initial flights. Phyllophaga males and females were captured in large numbers, but very few female Polyphylla were caught. Most Phyllophaga were caught before midnight, most Polyphylla between midnight and 0400 h. White grubs were found in the root zone from early May to late September. The mean (±SEM) and maximum grub densities observed were 14.6 ± 1.7 and 34.0 grubs per m2, respectively.

A NOTE ON PELECINUS POLYTURATOR (HYMENOPTERA: PELECINIDAE), A PARASITE OF PHYLLOPHAGA ANXIA (COLEOPTERA: SCARABAEIDAE)

The common June beetle, Phyllophaga anxia (LeConte), is an indigenous pest of agricultural crops in North America (Hammond 1948; Ritcher 1949). A bionomic study and survey for natural enemies of P. anxia was conducted in southern Quebec from 1975 to 1977. Pasture soils were searched for immature stages of P. anxia, and any natural enemies found in situ were collected. A prepupa and pupae of Pelecinus polyturator (Drury) were found in the pasture on several occasions. Previously, P. polyturator had been reported as a parasite of grubs of Phyllophaga spp. (Davis 1919; Petch and Hammond 1925, 1926; Brues 1928; Hammond 1944), and its distribution ranges from Canada to Argentina (Masner 1979).

A MONITORING PROGRAM FOR THE COMMON JUNE BEETLE, PHYLLOPHAGA ANXIA (COLEOPTERA: SCARABAEIDAE), IN SOUTHERN QUEBEC

Blacklight traps were used for monitoring flight activity of Phyllophaga anxia (LeConte) in southern Quebec. Adults began flying during the last 3 weeks of May and flight terminated about the end of June, depending on the season and the locality. The adults required approximately 176 degree-days accumulated above a base of 5 °C for flying to commence. Peak flight occurred late in May or in early June. Both sexes were attracted to blacklight traps.