DAMAGE DESCRIPTION:
Gradual turf thinning in enlarging patches that turn brown; roots pruned to 1 inch or less below soil surface; sod easily lifted or rolled back; C-shaped grub larvae found by lifting sod; adults do not feed on turf and are active at night; beetles are about ½ inch long and tan-brown; adults strongly attracted to light; larvae grub from 3 /16 to 1 inch through 3 instars-have irregular pattern of bristles on the raster.
HOST GRASSES:
Northern: mainly Kentucky bluegrass and Tall fescue and cool season turfgrasses; found from Connecticut to Alabama and west to California
Southern: mainly turfgrasses throughout Southwest and in Texas, Oklahoma, Illinois and Iowa
LIFE CYCLE:
Adult beetles emerge from soil in June or July; adults lay eggs that hatch into tiny grubs in about 3 weeks; grubs begin to feed on roots of plants and organic debris in the soil almost immediately after hatching; they work their way to the surface as they continue to feed on roots; at the approach of cold weather, the grubs descend into the soil where they overwinter at a depth of 14 to 16 inches.
FACTORS THAT MAY PROMOTE INSECT DAMAGE:
Inadequate irrigation and drought stress may compound damage, if eggs are already hatched; signs of grubs may be skunks, moles raccoons, birds feeding in the turf infested areas; severe drought, though, may dessicate most eggs causing minimal grub populations; moist areas favor grub success.
CULTURAL CONTROL:
Adequate water balance to turfgrass; frequent monitoring below turf for grubs; identifying symptoms of grub damage from Spring to Fall.
CHEMICAL CONTROL:
Pre-irrigation suggested prior to chemical treatments; after application of insecticide, drench into soil root zone with water; timing varies by product; repeat irrigation to keep moving insecticide down; control any thatch, which could impede movement of insecticide; threshold level is 8 to 10 per sq. ft.; adult and larvae insecticides may be different.
| Specific Insecticide Recommendations | ||||
|
Insecticide (chemical name) |
Efficacy |
Application Interval |
Time of Year To Apply |
Example of Products (trade names |
| Bendiocarb (larvae) | Good to Excellent | As needed | Spring to Fall | Turcam |
| Imidacloprid (larvae) | Good to Excellent | As needed | Spring to Fall | Merit |
| Trichlorfon (larvae) | Good to Excellent | As needed | Spring to Fall | Dylox, Pronto, Proxol |
| Ethoprop (adult and larvae) | Good to Excellent | As needed | Spring to Fall | Mocap ( not on bentgrass) |
| Bifenthrin (adult) | Good to Excellent | As needed | Spring to Fall | Talstar |
REFERENCES:
Beard, J. B. 2002. Turfgrass Management for Golf Courses. Second Edition. Ann Harbor Press. Chelsea, Michigan..
Decker, H. F., Decker, J. M. 1988. Lawn Care-A Handbook for Professionals. Prentice Hall. Englewood Cliffs, New Jersey.
Liskey, E., “Turfgrass Insecticides”, Grounds Maintenance, Volume 37, Number 2, February 2002, pp. 8-10.
Turgeon, A. J. 2002. Turfgrass Management. Sixth Edition. Prentice Hall. Upper Saddle River, New Jersey.
Taylor, G. R. - Editor. 2000. Turfgrass Pesticide Recommendations 1999-2000. Extension Publication SCS-1991-01. Texas A&M University. College Station, Texas.
Duble, R. L. 2001. Turfgrasses-Their Management and Use in the Southern Zone. Second Edition. Texas A&M University. College Station, Texas.
Emmons, R. D. 2000. Turfgrass Science and Management. Third Edition. Delmar Thomson Learning. Albany, New York.