JAPANESE BEETLE ALERT!!
WHO? - ANY HOME OWNER
WHAT? - JAPANSESE BEETLE DAMAGE
WHERE? - YOUR PLANTS AND TREES
WHEN? - STARTING IN MID JUNE (SEE BELOW)
HOW? - THROUGH GRUBS AND FLY THROUGH THE AIR (SEE BELOW)
WHY? - BECAUSE YOU DIDN'T USE PROPER PREVENTATIVE MEASURES TO MINIMIZE DAMAGE
BEETLES MAY ALSO STILL NEED TO BE TREATED - THEY CAN KILL YOUR PLANTS AND TREES! DO NOT MESS AROUND WITH BEETLES!
PROTECT YOUR PLANTS
The Japanese beetle was introduced accidentally into New Jersey from
Japan in 1916 and is now widespread over the eastern United States.
Adult Japanese beetles are 3/8 inch long metallic green beetles with
hard, copper-brown wing covers. Five small white tufts project from
under the wing covers on each side, and a sixth pair at the tip of the
abdomen. These white tufts help to distinguish them from similar
metallic green or coppery colored beetles.
Adults emerge from the ground in mid or late June. Individual
beetles live about 30 to 45 days with activity concentrated over a four
to six week period. Beetle numbers begin to decline in late July but
some can be found as late as September.
Japanese beetles can feed on about 300 species of plants,
ranging from roses to poison ivy. Odor and location in direct sun seem
to be very important factors in plant selection. The beetles usually
feed in groups, starting at the top of a plant and working downward.
While a single beetle doesn't eat much; group feeding by many causes
severe damage. Adults feed on the upper surface of foliage, chewing out
tissue between the veins. This gives the leaf a characteristic
skeletonized appearance.
Japanese beetles can fly as far as 5 miles but 1 to 2 miles is
more likely. Usually, they make only short flights as they move about to
feed. Local infestations spread as beetles move to favored food and
egg-laying sites. It is a weak flyer and drops several centimeters when
it hits a wall.
The adults can be controlled by spraying susceptible plants with
insecticides. Several systemic insecticides are also available for
extended control.
Several traps using a floral lure and sex attractant are available. These traps are
not recommended
for general use unless special conditions can be met. The traps have
been demonstrated to be effective in reducing damage and populations
only when landscapes are isolated from other Japanese beetle breeding
areas or when mass trapping (everyone in the neighborhood) is used. In
most urban areas, traps tend to attract more beetles into the area than
would normally be present. In this situation, adult feeding and
resultant grub populations are not reduced.
Females lay 1 to 5 eggs before returning to plants to feed and
mate. This cycle of feeding, mating and egg lying continues until the
female has laid 40 to 60 eggs. Most of the eggs are laid by mid-August.
The eggs hatch in 8 to 14 days and the first instar larvae dig to the
soil surface to feed on roots and organic material. The second instars
take 18 to 45 days to mature and molt again. Most of the grubs are in
the third instar by late September and by October they dig deeper into
the soil to overwinter. The grubs return to the surface in the spring as
the soil temperature warms, usually in mid-April.
The grubs are best controlled when they are small and actively
feeding near the soil surface, usually August. However, systemic
applications in June have sufficient residual activity to kill the new
grub populations as they come to the soil surface in late July through
August. Control of grubs in late-fall or early-spring is difficult, at
best, because the grubs are large and may not be feeding. The key to
good control is to make an even application and water thoroughly.
Control Strategies
Adult Control
Option 1: Cultural Control - Hand Picking
By noticing when the first adults arrive on a property, you can pick
off and destroy these scouts that attract additional pests. The adults
are less active in the early morning or late evening. They can be
destroyed by dropping into a container of soapy water.
Option 2: Cultural Control - Plant Non Attractive Plants
The adults do not like to feed on ageratum, arborvitae, ash, baby's
breath, garden balsam, begonia, bleeding heart, boxwood, buttercups,
caladium, carnations, Chinese lantern plant, cockscomb, columbine,
coralbells, coralberry, coreopsis, cornflower, daisies, dogwood
(flowering), dusty-miller, euonymus, false cypresses, firs,
forget-me-not, forsythia, foxglove, hemlock, hollies, hydrangeas,
junipers, kale (ornamental), lilacs, lilies, magnolias, maple (red or
silver only), mulberry, nasturtium, oaks (red and white only), pines,
poppies, snapdragon, snowberry, speedwell, sweet pea, sweet-William,
tuliptree, violets and pansy, or yews (taxus).
Option 3: Cultural Control - Trapping
Several traps using a floral lure and sex attractant are available.
These traps are not recommended for general use unless special
conditions can be met. The traps have been demonstrated to be effective
in reducing damage and populations only when landscapes are isolated
from other Japanese beetle breeding areas or when mass trapping
(everyone in the neighborhood) is used. In most urban areas, traps tend
to attract more beetles into the area than would normally be present. In
this situation, adult feeding and resultant grub populations are not
reduced.
Option 4: Chemical Control - Insecticide Spraying
The adults can be controlled by spraying susceptible plants with
insecticides. Over-the-counter pesticides available for this include:
acephate (Orthene), carbaryl (Sevin), and several pyrethroids -
bifenthrin, cyfluthrin, deltamethrin, lambda-cyhalothrin, permethrin,
and others. Applications of imidacloprid (=Bayer Advanced Tree &
Shrub Concentrate) generally need to be made 20 days before anticipated
Japanese beetle adult activity. During the heavy adult activity periods,
sprays may be needed every 5 to 10 days.
Grub Control
Option 1: Biological Control - Bacterial Milky Disease
The bacterial milky diseases,
Bacillus popilliae Dutky, has
been quite effective at controlling the grubs in certain areas of the
eastern United States. The spore count must build up for 2 to 3 years to
be very effective and during this time you should not use an
insecticide against the grubs that are needed to complete the bacterium
cycle. In Ohio and Kentucky, test trials have not produced satisfactory
results. Additional experiments are needed to determine the lack of
efficacy of milky disease in these soils.
Option 2: Biological Control - Entomopathogenic Nematodes
Insect parasitic nematodes have recently become commercially available. Products that contain strains of
Steinernema carpocapsae (Biosafe, Biovector, Exhibit, Scanmask) have been marginally effective against white grubs in turf. Preparations containing
Heterorhabditis spp. seem to be more effective. Apply the nematodes when the white grubs are small. Irrigate before
and after applying the nematodes.
Option 3: Chemical Controls - Insecticides
The grubs are best controlled when they are small and actively
feeding near the soil surface, usually late July to mid-August. However,
with the development of new grub control chemistry (e.g., imidacloprid
[Merit] and halofenozide [MACH2]), applications in June and July have
sufficient residual activity to kill the new grub populations as they
come to the soil surface in late July through August. Control of grubs
in late-fall or early-spring is difficult, at best, because the grubs
are large and may not be feeding. Only trichlorfon (Dylox) and carbaryl
(Sevin) formulations are available for such rescue treatments. The key
to good control is to make an even application and water thoroughly.
