GRUBS
Grubs are the larval stage of various beetles. Most are C-shaped and feed
on the roots of various plants. Grub heads are brown; their hind end is
a dark gray color and covered with hairs (used for identification).
Lawn grubs are usually one of three types -- annual white (from June
beetles), true, and aetenius. The annual white types typically cause the
most problems.
Annual white grubs emerge as adults in late June, depending on weather
conditions. Eggs are laid in moist soil, near sidewalks or driveways or
under night lights around the fourth of July. Eggs hatch during the first
week or so in August. Grubs feed on grass roots.
Large, dead patches in late summer may be an indication of grubs. Only
inspection under the dead turf can indicate grub presence. Control may
be necessary if twelve to fourteen grubs per square foot are found in an
actively growing lawn. If the lawn is dormant or less than active or dormant,
fewer grubs may be needed to cause noticeable injury to the turf.
Dead grass killed by grubs comes up "like carpet" if pulled.
Chemical controls must be watered in to place the chemical in the area
that grubs are located. Usually one-half (1/2) inch of water is sufficient.
Check the current University of Illinois Urban Pest Management Handbook
for recommendations. Make sure to physically locate grubs in the turf before
applying chemicals.
Grubs frequent the best looking lawns, which tend to be more suitable
for egg laying.
See: Sod Webworms
Cucumber Beatles
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