Warning: High Numbers of Black Cutworms in Traps

June 28/11. We are reporting very high numbers of black cutworm moths in traps right now. These numbers are, in fact, higher than we have seen in many years.

What this means to you is that there is a possibility that these moths will lay eggs on your turf and the resulting caterpillars may damage your golf course.
We generally do not see black cutworms damage fairways although we know they are feeding there. On bentgrasses, however, damage can become quite severe if populations are high and feeding goes undetected.
We are not suggesting preventative treatments because of the spotty infestations of these insects, but we are suggesting that you be aware of the increased threat right now and monitor bentgrass tees and greens for the presence of the caterpillars.
Larvae are hairless caterpillars with unique markings on the head and body. The upper half of the body is a darker gray than the lower half.

They have black dots along both sides of their body.

Newly hatched cutworms are small but they may grow to a length of 2 inches.
A soap solution (1/2 ounce of liquid dish soap per 3 gallons of water) applied as a drench to the green during the day will flush the caterpillars from below the thatch to the surface where they can be easily seen. If three or more cutworms per square yard are found, a pesticide application may be needed.
If a decision to treat a green or tee is made, remember to also treat a 20-foot border to kill any cutworms that otherwise may crawl onto the green. Research from Wisconsin shows that daily mowing may remove more than 75% of the cutworm eggs before they hatch. However, eggs easily survive the mowing and may hatch where the grass clippings are deposited. It is therefore recommended that clippings be deposited at least 100 yards from susceptible tees or greens to prevent the cutworms from crawling back.

One female black cutworm moth can lay up to 2,000 eggs over a series of several days. The eggs hatch in three to 10 days (depending on temperature) and the young caterpillars begin to feed on the grass shoots. As the caterpillars increase in size, they burrow into the turf and move to and from these holes at night to feed on the grass.
Regular sampling for cutworms and damage, followed by insecticide treatment, if needed, will protect turf grass against significant damage by black cutworms. Chemical control should only be considered when the cutworms are confirmed in high numbers and damage begins to become apparent.
Insecticides recommended for cutworm control include any of the pyrethroids labeled for use in turf.

Tim Gibb, Turfgrass Entomologist

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Mound Making on Greens and Tees

In addition to earthworms, there are several insects that can create small mounds of soil above the surface of turfgrass. Usually such mounding is of minimal consequence and, in fact, is beneficial to turfgrass environments as it accomplishes the same thing as cultivation, aeration and top-dressing - only on a very small scale.

On occasion, however, the mounds can become a nuisance, especially on closely mown greens where they may interfere with putting and ball roll.

In such cases it is important to know the identity of the insect in question. Because mounds alone are difficult to identify, associated insects should be used for validation.

Look for insects directly associated with the damage in question. Sometimes these insects are difficult to find because they are nocturnal or because they live in tiny burrows beneath the mounds.

One suggestion is to use a small probe or trowel to dig beneath the mound to a dept of several inches. Quickly deposit the core into a glass jar and look closely for any insect that might be present. Be persistent. Groups of typical mounds seldom fail to produce at least one token specimen, by which an identification can be made.

Ants and ground nesting solitary bees can sometimes cause mounds to appear. Both of these insects are easily managed with the use of carbaryl, among other pesticides.

Some tiny beetles such as scarabs (Geotrupes) and ground beetles (carabids) also can tunnel and deposit soil in small mounds on the surface of the turfgrass.

The above photo was submitted, compaining of nuisance ‘mounding’ on a putting green. This was reportedly occurring on a daily basis on 6 greens during June. A subsequent sample of the soil below revealed two ground beetles that we commonly know as seed corn beetles.
Despite their name, corn seed are not the primary food source for seed corn beetles. Rather, they feed on other things that they find in the soil including other insects. We also know that they are highly attracted to and fly to lights at night. There are two generations per year, typically occurring in May/June and again in August.

Their appearance is more likely in cool, wet conditions, typical of this spring.

Management recommendations for these beetles usually include applying a surface insecticide as soon as mounds appear. Insecticides recommended for seed corn beetles control include any of the contact pesticides labeled for use in turf.

Tim Gibb, Turfgrass Entomologist

Doug Richmond, Turfgrass Entomologist

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The Case of the Dead Zoysia in Southern Indiana

Zoysia grass is a warm-season grass that is being more frequently used in warm, humid and transitional regions. As zoysia is becoming more frequent in our state we are learning more about the pests that attack it. The photograph below was taken of a stand of zoysia in the southern part of Indiana. It was clearly killed by something – but what? Damage was evident in the late fall and got even worse this spring. We went through the usual bank of questions; diseases, winter kill, billbugs, but came up with no certain cause of decline.
At last, a sample was run through a Berlese funnel that uses heat and light as a method to extract live insects. In addition to the myriad of mites that are found in nearly every soil sample, we extracted many small red insects with white stripes across their backs (photo below).

These were identified as newly hatched chinch bugs. Looking back at the weather conditions last fall, it became apparent that this zoysia lawn occurred right in the middle of the drought affected region of the state. Interestingly, chinch bugs are also known to occur most in times of drought.

Putting two and two together allowed us to make a tentative diagnosis of a difficult problem. Certainly, the drought must have played a part in the decline of the turfgrass, but finding the chinch bugs also allowed us to say with certainty that they also contributed, AND are continuing to contribute to this damage.

Chinch bugs have piercing-sucking mouth parts and suck juices from the crowns and stems of grasses. Adults are black and have shiny white wings that are held flat across the back. The newly hatched nymphs (1st and 2nd instars) are bright red in color and have a characteristic white strip across their back. As they grow they slowly change to a brown, and eventually black, color and the white stripe vanishes.

Natural controls often hold these pests in check, however, when conditions (including weather) are just right, populations can build up and damage may be manifest.

Chemical control should only be considered when the chinch bugs are confirmed in high numbers and damage begins to become apparent. Otherwise, insecticides often take out the very predatory insects that keep chinch bugs in check.

Insecticides recommended for chinch bug control include any of the pyrethroids labeled for use in turf.

Tim Gibb, Turfgrass Entomologist

Doug Richmond, Turfgrass Entomologist

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Sod webworms

Sod webworms may cause damage to closely mowed turfgrass early in the spring. Damage, similar to that depicted in the photos below, may be seen on golf tees and greens.

The overwintered caterpillars become active when the temperatures warm up in the spring and begin to tunnel and feed. They are mostly active at night, so they often elude inspection. The absence of an obvious insect makes the diagnosis difficult, - but look for patches of close-cropped turf as well as the tiny trails or tunnels in the thatch. Often the soil (and sand topdressing material) in these trails is bound together with silken material to create a cover or cap, hence the name “webworm”. Along with the damage, these tunnels help provide evidence of sod webworm activity. A soap flush is a sure method of verifying sod webworm presence.

To flush suspect areas, mix one full tablespoon of lemon scented Joy dishwashing liquid in two gallons of water and dispense the solution through a sprinkling can over 1 square meter of turf. It is best to mix the detergent into the proper amount of water by hand in order to minimize the formation of foam which can make it much more difficult to find emerging insects. Allow 10-15 minutes for the sod webworms to appear on the surface as it may take a while for the soapy water to penetrate the silk-lined tunnels these insects create.

Healthy and vigorously growing turfgrass will often ‘outgrow’ damage from sod webworms. However, if the damage is unsightly and controls are warranted, use a pesticide that is labeled for sod webworms and apply at the recommended rates. Mach 2 and Conserve are both labeled for sod webworms as well as a host of conventional insecticides. Do not irrigate after application so that the insecticide stays on the blades and in the thatch where the webworms reside and feed.
The following photo, taken two days after treatment shows the resulting dead larva.

Tim Gibb, Turfgrass Entomologist

Doug Richmond, Turfgrass Entomologist

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Small Moving Specks on the Windowsill?

No you are not imagining this. The specks are actually moving. That is because they are actually tiny mites called clover mites. Clover mites can become annoying household pests, especially in and around homes where new lawns have recently been established or where there’s a heavy growth of well-fertilized grass close to foundation walls. They enter a home from outside and often become most active near sunny areas – why you see them on windowsills.
These tiny mites feed on grasses, clovers and certain other plants in the lawn and around the home. They often crawl into cracks and crevices to molt and lay eggs. Typical “hiding places” are under the loose bark of trees, on foundations walls, beneath siding and around window frames.
Clover mites are most abundant in the fall and spring and are relatively inactive during the hot summer months and again during cold weather. They migrate into homes either when population pressure becomes too great or when feeding conditions become unfavorable, such as the onset of hot or cold weather.

Clover mites are very tiny as can be seen on this ruler.	Under magnification, however, they are reddish in color and have characteristically long front legs.

The mites are very tiny creatures (smaller than a pin head) and may occur in countless numbers. They usually appear first around windows, but later may overrun entire walls of a home. To most people they appear as tiny, moving, black specks. Under magnification, however, they are reddish in color and have characteristically long front legs. This character helps separate them from the hundreds of other different mites.

Clover mites can be prevented from entering a home or building by using perimeter treatments. These may be either physical or chemical. A physical barrier can be established by separating turfgrass (where the mites feed) from the perimeter wall of the building. A strip of clean cultivated soil or stone, free of grasses, that extends 18 – 24 inches out from the foundation is usually sufficient to deter these mites from crossing. Ornamental plants that are not clovers or grasses may be added to increase the attractiveness.

Chemical barrier treatments may be applied to the outside foundation perimeter (three feet high and three feet out). Soaps as well as pyrethroid insecticides have been shown to be effective IF applied during the times that the mites are on the move.

Use of chemicals inside the home is not recommended. Remember that these mites do not directly damage the building nor do they bite people. Most consider them a temporary nuisance pest only and find that vacuuming or wiping them up with a soft sponge or wet cloth is sufficient. Be aware that they can smear and leave a red stain if crushed.

Tim Gibb, Turfgrass Entomologist

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Skunks and Raccoons causing Havoc?

We continue to receive reports of spring-time turfgrass damage caused by raccoons or skunks. These animals are not feeding on the grass but rather are foraging for below ground, high populations of white grubs. As the vertebrates forage, they turn over great clumps of turfgrass resulting in an area that resembles a war zone.

Sometimes high populations of grubs can be reduced by using insecticides during the spring-time. Such insecticides should not be applied to control grub damage but may be warranted if severe secondary damage occurs as a result of skunk or raccoon activity. Suitable insecticides include compounds with good contact/oral activity such as trichlorfon (Dylox) and carbaryl (Sevin). Remember, however, that if the vertebrates are hungry enough, they will forage for dead grubs as well as live. It may take several days or even a week for the dead grubs to decompose enough to reduce their attraction to vertebrates. During this period of time, the turfgrass may continue to suffer nightly decimation. Direct control of the vertebrates is usually the preferred management tactic.

Raccoon and Skunk Management:

Raccoons are protected furbearers in most states, with seasons established for running, hunting, or trapping them. Most states, however, have provisions to control furbearers that are damaging property. Striped skunks are not usually protected, but the spotted skunk is fully protected in some states. Because legal status and licensing requirements vary, it is best to check with state wildlife officials before implementing any control procedures.

A number of techniques have been used in attempts to frighten away raccoons and skunks from various areas, but none are effective for more than a day or so. These techniques include the use of lights, radios, dogs, scarecrows, plastic or cloth streamers, aluminum pie pans, tin can lids, plastic windmills, etc.
A variety of materials have been used in attempts to repel these pests, again with a lack of proven effectiveness. These materials include blood meal, dog feces, mothballs and dirty laundry. There are no poisons or toxic gases available for raccoon and skunk control.

Live Trapping:
For most turf professionals and homeowners, live trapping and removal of the offending animal is the most practical approach to preventing the damage.

Raccoons
Raccoons are relatively easy to catch in traps, but it takes a sturdy trap to hold one. Traps should be at least 10 x 12 x 32 inches (25.4 x 30.48 x 81.28 cm) and constructed with heavy materials. Commercial models readily available for raccoons include the Havahart ™ Professional Raccoon Trap No. 1079; Nos. 3, and 3A; or Tomahawk™ Nos. 108, 108.5.

Some raccoons readily enter live traps upon first encounter while others remain wary of the traps for several days. Therefore, pre-bait the traps by placing baits in and around the traps and twist-tie the trap door open for 2 -3 days. This will allow the raccoon to feed freely and become accustomed to the " strange metal object that provides free food" and increase the success of capturing wary individuals. Disguising the exterior of the trap with wood or branches, bushes, or other natural items may entice the raccoon to interact with the trap.
Effective baits include sweet corn, sardines and other fish, cat food, melons, fried bacon, and cooked fatty meat. Tiny amounts of baits should be placed in a trail leading into the trap, with the major portion of the bait placed at the back end or closed end of the trap. When baiting for raccoons where pets are active outdoors, use jelly and honey as these baits are generally not attractive to cats and dogs, but work well for raccoons. Raccoons are also attracted to shiny objects. Adding a wadded up piece of aluminum foil in the trap may help to stimulate their curiosity and attraction.
Raccoons have agile, elongated "fingers" which allow them to pry open lids of garbage cans as well as steal baits through the sides of some traps. To prevent this, place logs, stones, or similar objects around the sides of the trap to create a barrier between the bait and the raccoon (the Havahart Pro™ Raccoon model is specifically designed to prevent bait theft). Sometimes, raccoons will tip over cage traps and shake out the bait, so traps should be staked down to the ground or attached to some nearby object with wire.
Place traps in areas of greatest activity. When raccoons are visiting sod lawns from wooded areas, they tend to follow well establish trails that offer protection, such as fence lines, building perimeters, and trails beneath available shrubbery. Try to identify such areas and locate the traps along these trails.

Skunks
Skunks can be live-trapped using the same methods and trap sizes as described above for raccoons.
Fish (canned or fresh), fish-flavored cat food, chicken parts, bacon, or peanut butter on bread are effective baits. The trap should be set in the areas receiving damage. When placing traps in open areas such as on fairways, leave both doors open to allow the trap to accommodate an animal approaching from either direction.
If skunks are kept in a darkened trap they will remain relatively calm, and be less likely to spray (release their scent). Therefore, cover traps prior to placement with an old blanket or piece of thick burlap. Handle trapped skunks carefully and avoid sudden, jarring movement or loud noises that may frighten the skunk. Striped skunks seldom spray when these precautions are taken, but the spotted skunk is less predictable.

Vertebrate pest management professionals should be contacted as to the proper procedures of handling trapped skunks. Some state wildlife agencies advise against relocating skunks as they may present a problem for others, or they may pose a health hazard -skunks are one of the major carriers of rabies. In many locales, trapped skunks can be brought to the local animal shelter for proper handling or possible disposal procedures.

Tim Gibb, Turfgrass Entomologist

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