Critters, Pests & Diseases
|
North Carolina State University College of Agriculture & Life Sciences North Carolina Cooperative
Extension Service |
|
Extension Agent Agriculture-Consumer Horticulture |
| Swarming Ants/Termites | White Grubs in Turf |
Mosquitoes and
West Nile |
Carpenter Bees |
| Fire Ants |
Bagworms |
Japanese Beetles |
Fireblight |
The Plant Disease and Insect Clinic has gone electronic. Send
in digital pictures + a complete description of the nature of the
problem in the body of the e.mail to digital_clinic@ncsu.edu.
Go to: http://www.ces.ncsu.edu/depts/ent/clinic/Submit/submit.htm
for forms and additional information.
You may also submit live samples to the Plant Disease and
Insect Clinic for Weed/Insect ID and disease analysis that cannot be
determined from photos alone. Contact jcmastergardener@yahoo.com
for additional information.
White grubs are the larval stage of scarab beetles and may damage lawns by feeding on roots.
Check for grubs in April and August. To check if you've got a grub problem cut a 1 square foot flap of soil, 3-4 inches deep, and roll it back. They have creamy, blunted bodies with yellow to brownish heads, brownish hind parts and six legs. They can be ¼ to 1½ inches long and are usually curled up into a C shape. Billbug larvae may also be present but can be distinguished by the absence of legs. Repeat the 'flap test' in 3 locations. If you've got an average of 5 or more grubs per flap, pesticide treatment is recommended.
Timing of pesticide application is critical. April -
May & August - October are when pesticides should be applied
because the grubs are small, close to the lawn's surface and most
vulnerable to pesticides. Pesticides applied any other time will
be ineffective.
*Sevin (carbaryl) 50WP - 6 oz./1000 sq.ft. - Apply to the soil
surface but do NOT water in.
*Mach 2 (halofenozide) 2SC and 1.5G - read label for rate of
application and water in
*Advanced Lawn Grub Control (imidacloprid) - read label for rate of
application and water in.
An interesting note is that recent studies have indicated that traps
for Japanese beetle adults have no real impact on the subsequent
population of grubs in the soil.
White Grubs Publication - http://www.turffiles.ncsu.edu/pubs/insects/ag366.html
Officials have found West Nile Virus infected birds, mosquitoes,
humans and horses in 46 states. This includes every state except
for Oregon, Washington, Alaska and Hawaii. North Carolina alone
reported 24 human cases of West Nile Virus in 2003. To learn
more: http://www.cdc.gov/ncidod/dvbid/westnile/index.htm
For FAQ on WNV go to the webpage: http://www.ces.ncsu.edu/depts/ent/notes/Urban/westnile.htm#, click on 'Brochures (PDF format)' and then go down to third item on pop-up menu
MOSQUITO CONTROL IN A
HURRY
Dr. Mike Waldvogel, Entomologist, NCSU and Al Cooke, Extension Agent,
Chatham County
There is not one bright silver bullet that will control mosquitoes. Often a combination of tactics is most effective. In this case it means clean-up and chemical control. Learn about mosquito ID, eliminating breeding sites and control methods (a good write-up on what works and what doesn't) at: http://www.ces.ncsu.edu/depts/ent/notes/Urban/mosquito.htm
* Rain gutters - If you're going expend the time and effort to climb a ladder to put insecticide in your gutters, then why not simply clean the gutters so they don't trap water. Then you won't have to climb back up again in three weeks to re-apply the insecticide since there should be no more standing water in the now clean gutters.
* Birdbaths - Be a good sport to the birds and flush the birdbath out at least twice weekly to give them fresh water. Then you don't need any chemical because you've flushed out the mosquito larvae. Same thing applies to pet water bowls outdoors.
* Rain barrels - Great idea for conserving water for your garden. Keep them screened, which helps keep out the junk and the mosquitoes as well.
* Pre-Strike is an insect growth regulator. It kills mosquito larvae, but has no effect on the adults. The best way to eliminate adults is to make your outdoor area unattractive to them - ie. this means no standing water for breeding.
WHY ARE THEY A PROBLEM? They excavate tunnels in wood with their strong jaws. Typically, carpenter bees do not cause serious structural damage to wood unless large numbers of bees are allowed to drill many tunnels over successive years. Woodpeckers also may damage infested wood in search of bee larvae in the tunnels. In the case of thin wood, such as siding, this damage can be severe. Holes on exposed surfaces may lead to damage by wood-decaying fungi or attack by other insects, such as carpenter ants.
WHEN ARE THEY A PROBLEM? Usually April/May
HOW CAN YOU TELL IF YOU'VE GOT THEM (ID)? Carpenter bees are large, black and yellow bees often seen hovering around the eaves of a house, wooden fences, or the underside of a deck in late spring. They are often mistaken for bumble bees, but differ in that they have a black shiny tail section. The males have a white spot in the middle of their "foreheads" and you can actually spot it if the bees hover around you.
They create round half-inch diameter entrance holes that are usually found on the underside of a board. A tell-tale trace of coarse sawdust is often found on the surface beneath the hole. Wooden decks, overhangs and other exposed wood on houses are prime targets. Painted (especially white glossy) and treated woods are less preferred, but they are not immune to attack. Unpainted or stained cedar, cypress and redwood shingles and siding are also attacked despite their pest-resistant reputations.
The bees often eliminate their wastes before entering the tunnel. Yellowish-brown staining from voided fecal matter may be visible on the wood beneath the hole.
WHEN IS IT NECESSARY TO CONTROL? When you see the damage.
TIMING OF CONTROL? At night. When the bees are in their nests.
HOW TO CONTROL? Preventive sprays applied to wood surfaces are effective only for a short period, meaning that you would have to repeat the application about every 2-3 weeks. Since virtually any exposed wood on the house is subject to attack, it is difficult (and usually not practical or safe) to try to protect all of the possible sites where the bees might tunnel.
Nesting activity may be substantially reduced by treating the entrance holes with an insecticidal spray or dust and then covering up the holes. Products containing carbaryl (Sevin), cyfluthrin or resmethrin are suitable.
Wait about 24 hours before sealing up the holes with wood putty or wooden dowlels to make sure you get bees entering the treated openings.
Always stand upwind from the surfaces you're treating.
Be sure to chemically treat the bees before you plug them up. Plugging untreated tunnels with wire mesh or similar material might trap bees inside, but more resourceful bees will simply chew another exit hole.
For additional info:
http://insects.ncsu.edu/Urban/carp-bee.htm
http://www.uky.edu/Agriculture/Entomology/entfacts/struct/ef611.htm
http://hgic.clemson.edu/factsheets/HGIC2451.htm
Check out our fire
ant publication. It covers ID, control options and when and
how to apply treatments.
A comprehensive treatment of fire ants
from Texas A&M University - identification, control, FAQ - can be
found here. http://fireant.tamu.edu/
**Chemical recommendations from Texas do not necessarily apply in North
Carolina.
In home lawns, we recommend Amdro, Affirm, Over-n-Out, Firestar or Orthene.
Amdro, Affirm,
Over-n-Out and Firestar = Baits. Do not disturb mound and apply
around the mound, not directly on top of it.
Orthene = Dust. Distribute uniformly on top of
mound. Don't get wet for 24 hrs.
There are different recommendations for mounds located in gardens, pastures, and commercial turf.
To learn about regulations regarding fire
ants in nursery crops: http://www.ncagr.com/plantind/plant/entomol/IFA.htm
Bagworms are insects that feed on a
variety of plants but can do significant damage and defoliation to
junipers, arborvitae, and Leyland cypress. Defoliation of
these plants can result in their death.
By late spring the eggs start to hatch.
The young bagworm exits the cocoon left by Mama and descends from a
fine silken thread until it finds a suitable place to grow up. A
suitable place requires vegetation suitable for feeding. It will
also use some of the vegetation to construct its own cocoon that it
disguises by attaching some of the plant material. Inspect
your susceptible plants now for these tiny worms.
If you had these guys last year, you
should stop reading and go out to look for them now. :) If you
haven't had them (yet) you can finish reading
first. The bagworms at this time will be about ½ to 1 inch long
(in the cocoon). The cocoon is widest in the middle and tapers to both
ends. One end is attached to the plant. The other end is free to
move about as junior searches for delectable foliage. If the plant is
tall like a Leyland cypress, you may require binoculars or a ladder to
inspect it.
If you find bagworms, hand removal is the strategy of choice. If you get tired before you finish, or if your ladder is too short, then you may fall back on insecticides. Later in the summer, the worms will be protected from pesticides inside their bags, which must then be removed by hand.
Bagworms are relatively easy to control with insecticides at this time of year, when they are small and vulnerable. The organic Bacillus thurengiensis (B.t.) marketed as Dipel, Biotrol, or Bactospeine will be effective if used early. Apply Bt when rain is not in the forecast, as the bagworms must feed on it before rain washes it off. As the bagworms get larger, they eat less and it takes more stuff to kill them. If you wait you'll have to fall even further back on insecticides such as Orthene, Sevin, Malathion, or Conserve (also organic).
By late summer, very few insecticides
will help. In fact by that time about all you'll find in the cocoon is
eggs and the remains of Mama (RIP). And you'll then have until next
spring to get those cocoons off to prevent next year's damage. If
there's any plant left to save, you may actually need pruners to remove
the bags.
Winter is a good time of the year to check conifers for bagworms. Look for sacks made of white silky thread which are covered with bits of the host plant on the outside. These bags are currently full of eggs waiting for spring when they will hatch out and devour your plant.
For more information on bagworms, visit http://www.ces.ncsu.edu/depts/ent/notes/O&T/trees/ort081e/ort081e.htm
For control information on Japanese beetles see: http://www.ces.ncsu.edu/depts/ent/notes/O&T/flowers/note44/note44.html and http://www.ces.ncsu.edu/depts/ent/notes/O&T/lawn/note67/note67.html
Fireblight is a bacterial disease that can affect any plant in the rose family. This includes pears, apples, crabapples, peaches, cherries and plums. Other plants to watch include Cotoneaster, Crataegus (Hawthorn), and pyracantha. Plants outside the rose family are not affected.
The dominant symptoms are black foliage that remain on the tree and affected tissue that may ooze thick milky material.
Other symptoms include an initial wilting at the stem tip, often described as resembling a shepherd's crook. Before turning black, foliage may appear water soaked, wilted, or shriveled. Fruits may appear water soaked and will then shrivel, dry up, and remain on the branch as a source of reinfection.
Control of fireblight begins with selecting resistant plant varieties. For example, pear varieties such as Moonglow, Seckel and Keiffer are relatively resistant.
Control by pruning and careful sanitation.
When pruning infected material, cuts should be made at least 12 inches below the lowest sign of damage. Care should be taken to avoid spreading the infection on hands and pruning tools. Tools should be sanitized with a 1:9 dilution of bleach between cuts. Watch for and remove signs of further infection. Be sure to throw out any affected material, do not compost it.
Since rapidly growing tissue is most susceptible, remove water
sprouts and root suckers and avoid excess fertility.
The azalea lace bug is among the most frequently reported insect pest in the landscape. Lace bugs are active starting in June in the Raleigh area.
Lace bugs cause the leaves to become completely bleached and have a bronzed appearance on the upper leaf surface. They also leave shiny, black excrement on the lower leaf surface. Azalea lace bugs are relatively difficult to completely eliminate. Fortunately, they rarely kill plants.
Insecticidal soap can control small populations, or Orthene may be used for control is pressure is high. Be sure to treat the undersides of the leaves. Imidacloprid can be used as a soil drench in specimen or small, valuable plantings. Azaleas planted in full sun will have more lace bug problems than those planted in partial sun or shade.
http://www.ces.ncsu.edu/depts/ent/notes/O&T/shrubs/ort039e/ort039e.htm contains additional information on the azalea and other lace bugs.
Gardenias that are in need of iron have yellow leaves with green veins. Iron can become scarce in the soil in cases of excessive watering or long periods of rainfall and soil saturation, but the most common cause of iron deficiency is from the soil pH.
Applying iron chelate will help to restore the amount of iron needed
by the gardenias. Also run a soil test (we have kits here for
free) to make sure your soil pH is correct.
You may have seen this in a pile on your sidewalk or near your lawn, said "YICK" and then wondered what it was. Well, it was a mass of darkwinged fungus gnat maggots - probably in search of food. The maggots stick together and slither along in a ribbon, sometimes as much as an inch wide and a yard long - resembling a silvery snake. This is a startling sight, but perfectly harmless.
The fungus gnats are native insects that are normally not
noticed. They feed on decaying organic matter and are usually not
particularly abundant in the landscape.
Spider mites love hot weather and dry, dusty leaves. A weekly
blast of water directed upward from beneath the plants can dislodge
them from the undersides of the leaves. If you do a thorough
blasting of the foliage, it is usually enough to keep mites in control
without the need for pesticide sprays. For additional information
go to: http://www.ces.ncsu.edu/depts/ent/notes/O&T/flowers/note25/note25.html
Fall webworms usually cause little
long term health damage to the trees they defoliate. The
populations of fall webworms wax and wane so that they are conspicuous
and damaging for a year or two and then the populations seem to
disappear.
Fall webworms feed on over 600 kinds of trees, shrubs and other
plants.
Destroy as many webs as you
reasonably can, monitor the health of the affected tree and then let
Mother Nature run her course and the tree will recover.
If the webs are within reach and you're feeling ambitious, fall webworms can be destroyed by pulling down the webs, or simply puncturing the webs and letting birds, fungus and weather take its toll. If the webs are within reach of a hose-end sprayer, several insecticides can be sprayed for control. Insecticides work best when the caterpillars are young, so it is best to treat as soon as the webs are first noticed. A product containing Bacillus thuringiensis works well.
Tomatoes are the most popular of all the garden vegetables. We
love our vine-ripened tomatoes, but getting to that point is not always
so easy. Below are 2 of the most common problems (and remedies)
of what ails our tomatoes.
MILLIPEDES ON THE MARCH
by Dr. Mike Waldvogel, Entomologist, NCSU
The good news: they do not bite, sting, transmit disease, damage wood, nor infest fabrics.
Millipedes are gaining momentum and people's attention. In past years, millipede invasions were triggered primarily by very dry conditions. This year, the critters are trying to keep their thousand legs somewhat drier so they're hiking to higher ground. (NOTE: millipedes don't actually have 1000 legs; it's closer to that more scientifically accurate determination of "right many legs"; 2 per body segment)
Millipedes are prolific climbers and often make their way up to the second floor and even the roof of a house.
You will commonly find millipedes (alive or dead) along the walls indoors. Millipedes do not survive very long indoors, but typically long enough to raise your frustration level. You'll find that they prefer areas where moisture accumulates like crawlspaces, basements and garages. Refer to http://insects.ncsu.edu/Urban/millipedes.htm for more information about their life cycle and management practices. Pesticides are typically a short-term solution, and long-term management should focus on changing favorable conditions and access points.
Outdoor Control: Pesticides usually do not stop millipede invasions, however they will slow them down. Granular insecticides (such as those made by Bayer Advanced, Ortho or Spectracide). Avoid applying granulars if the grass is wet from rain or dew because the chemical is likely to get stuck up on the foliage and not reach the soil where it belongs.
Indoor Control:
That's somewhat of a losing battle if you try a conventional baseboard
sprays. You'll see dead millipedes, but there is a good chance that
they would have died regardless of any chemical simply because it's too
dry indoors. Vacuuming up dead millipedes is the best approach.
YELLOWJACKETS
by Stephen B. Bambara and Christine A. Casey
Extension Entomologists
North Carolina State University
Summer is when unsuspecting lawn-mowing homeowners suddenly come across a yellowjacket nest in their yard. These nests react defensively when disturbed.
Yellowjackets are house fly-sized wasps with distinct yellow and black-colored markings. Their nests are found in the ground 99% of the time. Occasionally, yellowjackets will nest in attics or walls voids of houses or storage buildings.
Yellowjackets may also be pests around picnics, trash cans, ripened fruit and hummingbird feeders as they scavenge for food or moisture. To help manage this interaction, keep food and trash covered and promptly clean up food spills. Yellowjackets are especially adept at flying into open cans of soda.
If the location of the nest is known, do not pour gasoline down the hole to destroy it. Use an aerosol hornet and wasp killer sprayed directly into the hole at night. A second treatment is sometimes necessary.
Do not forget that yellowjackets can be helpful too, because they
prey on other insects. One additional note is that I have not
seen data to make me believe that yellowjacket traps catch many adults
or lower populations in this part of the country.
You can find information about yellowjackets on the Internet at:
http://www.ces.ncsu.edu/depts/ent/notes/Urban/horn-yj.htm
Methods of reducing the probability of stings can be located at:
http://www.ces.ncsu.edu/depts/ent/notes/Beekeeping/bee15.html
Everyone notices the damage in the early spring - the oozing peach tree. But late August - early September is the time to treat for the critters that do that damage - the peach tree borer. Once you notice the damage in the spring they are already under the bark of the tree and it's impossible to control them effectively.
Borers are serious pests of fruit trees in the Prunus genus. Cherry, plum, peach, apricot, nectarine, and cherry-laurels, including ornamental varieties, are all vulnerable to borers. Watch for little piles of sawdust on the trunk or around the ground, or small entry holes in the trunk.
Peach Tree Borers can attack young or old trees, but they normally
are more attracted to diseased or stressed trees. Prevention
is the best way to avoid infestations. Apply Thiodan to tree
trunk until it drips from the trunk. Best control results when
applied the week of September 1.
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