Soil Feeders - Black Turfgrass Ataenius (BTA)

BLACK TURFORASS ATAENIUS (BTA)
aka: Black Fairway Beetle
scientific name: Ataenius spretulus
Similar species: Aphodius Beetle

FIELD KEYS
Hosts: bentgrass, annual bluegrass, ryegrass,
Site symptoms: Wilted turf in late spring to early summer that turns brown in small to large patches despite sufficient water. Wilted and brown leaves and crowns pull up easily from soil because of extensive root damage. Many small grubs may be visible on soil below removed turf.
Plant symptoms: Extensively damaged root structure at the plants' crown/root interface.
Site keys: A serious problem on golf tees, greens, and fairways and other sports turf sites and occasionally a problem on residential sites.

SPECIMEN ID
Immatures are very small to small white grubs with full grown 3rd instars reaching 1/3 inch. Adults are small bullet shaped, red-dish brown to black, shiny beetles that reach 1/4 inch.

SCOUTING TIPS
At many locations BTA is a two generation pest, so in-season adults and all three instar stages can frequently be found together. Over-wintering adults fly to site and can be seen swarming over turf at dusk on a warm evening before they burrow into soil to lay eggs. Adults can be captured with either a sweep net or black-light traps. Third instar grub is the most damaging and can be found in great numbers peaking in late June and again in August. Grubs can be sampled with a cup cutter or similar plug removal device (down to 2 inch depth).

CONTROL STRATEGIES
Cultural: At sites where BTA has been a problem monitor for swarming adults on warm evenings in spring. Natural predators do not seem to adequately control BTA, and immature concentrations that exceed 30 grubs per square foot should get additional attention. Since over-wintering sites can be as much as a mile away and are often wooded areas, cleaning the local site of debris or leaf litter may not prove helpful.
Chemical: Grub concentration thresholds that start to show damage can vary widely from 30 to 100 per square foot. Managers should correlate populations with the appearance of damage to develop site specific treatment thresholds.
Growth stages: egg - grub (three instars)* - pupa - adult*
* - treatable stages

Life cycle:1 year life cycle (multiple generations)
Sequence: grub - pupa - adult - egg - grub