SCIENCE FOR THE GOLF COURSE

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Research described in this article was supported in part by a grant from the USGA.

The black turfgrass ataenius (BTA), a small white grub, is a sporadic but sometimes severe pest of golf courses throughout the cool-season turfgrass zones and in California. Superintendents who normally don't expect grub problems until late summer may be caught off guard to find BTA grubs damaging fairways, tees, collars and putting greens in June. Timely diagnosis and control actions in spring can help to prevent BTA damage later on.

BTA differs from other turf-infesting grubs in that there are two generations per year throughout most of its range (see the life-cycle diagram). The damage appears about mid-June and late August to early September in the latitude of southern Ohio, Kentucky, West Virginia and Nebraska, coinciding with the first and second broods of grubs. There may be only one generation in the northern extremes of the BTA's range, including Minnesota, northern New England and southern Ontario, with damage appearing in July and August. In Kentucky and southern Ohio, where two generations occur, the first (June) brood of BTA grubs tends to be more synchronized and destructive than the late-summer generation.

BTA grubs thrive in the moist, short-cut turf of golf courses, especially bent

grasses, annual and Kentucky bluegrass and perennial ryegrass, where they feed on living grass roots and decaying organic matter. The first symptoms of an infestation are patches of thin or wilted turf that resemble localized dry spots, except that the grass does not recover with watering. As feeding continues, these patches coalesce into larger, dead areas. As is typical with grub injury, BTA-damaged turf will pull up like loose carpet.

BTA grubs are small, but they often occur at high densities, with 250 or more grubs per square foot in damaged areas. Birds, skunks or other predators may dig in the grub-infested turf, and birds also pull up tufts of grass when foraging for the adult beetles on putting greens. Superintendents sometimes mistake this as a sign of cutworm activity.

Adult BTA are shiny black beetles, ^3/16 to ^1/4 inch long, with distinct longitudinal grooves on the wing covers. Adults overwinter under soil or leaf litter along the edges of golf courses. They become active in late March and April and begin flying back to turf for egg-laying. In southern Ohio and northern Kentucky, the beetles begin emerging about when

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