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Gypsies and beetles and frass - oh, my!

Gypsies and Beetles and Frass - Oh, My!

Have you ever had to move your barbecue indoors because gypsy-moth caterpillars staked a claim on your backyard? Folks in the Northeast have fought vendettas against gypsy moths for years, but more recently the battle has spread as far south as Virginia and as far west as Oregon (see the March/April 1989 issue of AMERICAN FORESTS). If this invasion has happened to you, you've experienced first-hand the world of forest pests in suburbia.

Homeowners beset by critters ranging from gypsy moths to bark beetles are more likely to think of the invaders simply as pests rather than as forest pests. The gypsy moth and bark beetle ignore forest and municipal boundaries. If your backyard or favorite city park is within the insect's range and offers appetizing fare, the bug will see only an open invitation to dine and take up residence.

Forest pests in wooded areas can be an ugly enough scene, but as many communities have discovered, the presence of forest insects in residential areas can be downright dangerous. City and suburbia are where the insects and people collide, and the aftermath is seldom a pretty sight. Homeowners aiming to protect their property's value and preserve the enjoyment of their outdoor spaces want the problem eradicated at any cost. Others are more concerned about the health effects of spraying insecticides. People who are not troubled by an invasion may take a dim view of neighbors who spray, and with reinfestation possible from untreated yards, emotions can heat up quickly.

The decisions people are driven to make as a result of insect outbreaks are not always rational. Many people suffer from a deeply ingrained fear of insects, or entomophobia. "We've had people hire contractors to take down all their trees, because they didn't want to live through another gypsy-moth attack," says David Shaw, superintendent of the Monmouth County Shade Tree Commission in east-central New Jersey. Not wanting to put up with another invasion of caterpillars is understandable to anyone who has seen the gypsy at work (see "Mission: Search - Scrape - Destroy" on page 62), but some landowners mistakenly believe that cutting the infested trees will rid them of the pest. Or they think that the defoliated victims are dead, not realizing that it takes more than one gypsy-moth attack to kill most trees.

Forest pests in residential areas, as insufferable as the insects can be in areas populated by humans, do present one of the few opportunities to educate people about forests and forestry. The bugs get people's attention, then state and local foresters have a captive audience. Monmouth County is an example of a community that has taken an educational opportunity and run with it. This year marks the 21st year of the county's gypsy-moth program, administered by its shade-tree commission. A clear indication of the program's success is that in 1970 the commission received 8,000 phone calls from upset or confused homeowners, but last year only 156 people called in with questions about the gypsy moth.

David Shaw attributes the success of the county's program to its educational campaign and a spray program that picks up where the state's efforts leave off. Monmouth is the only county in the state with a supplementary gypsy-moth program to protect trees in areas that have low egg-mass counts and do not qualify for state help, Shaw boasts.

Every fall, the county sends crews out to survey for signs of the moth. The number of egg masses and type and size of trees determine if aerial spraying will be needed the following spring. After the county survey, the state's Department of Agriculture re-checks the area and eliminates locales that do not fit its criteria for aerial spraying. Recreational areas, sparsely populated forestland, and blocks of less than 50 acres that do not meet the state's criteria are then scheduled to be treated by the county.

"Sometimes the county ends up spraying more acreage than the state," Shaw says. Even after the spraying begins, the county will monitor and spray "blow-in" infestations that were not evident at the time of the surveys. These infestations would cause heavy defoliation if left untouched until the following year, Shaw explains.

Last year, Monmouth County treated 650 acres, but Shaw estimates that 4,000 to 5,000 acres will need to be part of the county program in 1990. The anticipated upswing in Monmouth County's gypsy-moth population is due to "blow-ins from surrounding communities that do not have a supplementary program," Shaw asserts.

When the surveys are completed and the spray blocks determined, a municipal coordinators' meeting is held. Representatives from the county and the state agricultural department learn about the current year's program, and the municipal coordinators go back to their responsibilities. Each municipality then advertises a public meeting to discuss that year's gypsy-moth program with the residents. At that meeting, a resolution declaring the gypsy a public nuisance must be passed before any action is taken.

All interested landowners are given a brochure that tells them what they can do year-round to minimize the moth problem on their property. If their lot is scheduled to be sprayed by either the state or the county, the municipality notifies them as well as any other landowners within 250 feet of the block slated for spraying.

Each morning, the county contacts the police in the towns on the schedule. During the day, the radio stations are notified of locations to be sprayed the following day and what was treated that day. The county maintains three methods of radio communication with its helicopter pilot - through county car radios, the county radio room, and the police radio. Spraying begins at about 5:30 a.m. and lasts until 9 a.m. The pilot takes a time-out from 7:30 to 8:30 while children are walking to school or waiting for school buses.

Besides education and awareness, a key to the success of Monmouth County's program is David Shaw. In addition to his duties as director of the Holmdel Arboretum, Shaw has supervised the county gypsy-moth program since its inception. In 1989, he met with two individuals who came forward with objections to the spray program. Both homeowners had no trees on their property, but their properties were within 250 feet of a spray block, so they were notified of the spraying. Shaw took the time to explain to them that their properties would not be sprayed.

Farther south and west, bark beetles take over as the No. 1 forest pest crossing the line into residential areas. In the South, the main culprits are the southern pine beetle along with three species of engraver bark beetles and the black turpentine beetle. According to Ronald F. Billings, principal entomologist for the Texas Forest Service, engraver beetles have been particularly troublesome. "We include engraver beetles and what the homeowner can do about them in our talks with residents," Billings says.

Unlike the gypsy moth to the north, bark beetles are not controlled by aerial spraying. High-value trees may be sprayed with insecticide, but the decision is made on an individual basis and is isolated to that person's yard.

As messy as the gypsy moth can be, it at least gives homeowners a few years to fight back. Bark beetles, on the other hand, can kill a tree rapidly, often before a landowner realizes that the beetles are present.

"Most people don't know their tree is in trouble until the needles turn yellow or red, and then it's too late to save the tree," Billings says. By then, the beetles have moved on to greener pastures, but it is not too late to save nearby trees, he adds.

Owners of ornamental pines in the South and West need to arm themselves with information about bark beetles and how to cope with bark-beetle attacks. In the South the beetles mature in about a month, so as many as eight generations a year are possible, compared to the gypsy moth's one generation annually. Once established, bark beetles will attack any pine tree but seem to zero in on those weakened by natural stress - old age, drought, prolonged floods, hard freezes, fire, lightning strikes - or manmade causes.

The latter include damage to trunk or tree roots during yard work and construction. Urban and suburban trees are more prone to being inflicted with these types of injury than are trees in lightly populated areas. In regions where pine trees are numerous, bark beetles have reached epidemic proportions for several years following urban expansion. These epidemics are magnified if urbanization coincides with weather-related stress such as drought, flooding, or windstorms.

Education can help homeowners in southern and western communities realize that a single damaged or unhealthy pine tree in the neighborhood endangers all the pines. Early detection and prompt action are essential for control. Pine trees struck by lightning may be attacked by bark beetles within hours, so a lightning-speed response is needed.

Besides looking for trees that are especially susceptible to bark-beetle attack and having them removed immediately, residents can learn how to monitor the trees in their yards every few days during spring and summer. Fading needle color is the most obvious sign of bark beetles, but homeowners must also look for an earlier sign - popcorn-size lumps of pitch called pitch tubes, which appear on the tree's trunk at varying heights depending on the species of beetle.

Homeowners can also learn preventive measures, such as how to water and fertilize pines to keep them healthy and beetle-free. Trees to be left at building and landscaping sites should be carefully selected and protected during construction. The natural tendency to leave large pines around a new home is not a good idea, since overmature trees are prime targets for beetles. The Texas Forest Service suggests that if trees cannot be protected during and after construction, remove them beforehand when it is less costly. Thinning backyard woodlots to reduce stress among competing trees is also recommended, but only if thinning can be done without harming the trees that are to remain.

The natural human tendency is to consider forest insects as pests that do not belong in residential areas. But those same bugs might see the problem in reverse - as people invading their turf. Many trees in cities and especially suburban areas are scattered remnants of forests left from before the days of urban expansion. The forest pests are following natural instincts and acting as if the trees were still part of the forest.

Perhaps the key to educating the public about forest pests in their backyards is this: We like trees in our cities and backyards, but we must take the good with the bad. Forest pests come as a package deal if our cities are to have trees and our homesites are to be wooded. As we can see from Monmouth County's 20-year war with the gypsy, we will never look out on wooded backyards that are completely bug-free. But we can shed our fear of the insects through education and awareness. And we can come to a truce by keeping forest pests at levels that are livable for homeowner and insect alike.


Sounds like a war is being waged, doesn't it? You bet, and it's occuring on my quarter-acre lot and on thousands of other parcels of northern Virginia and Maryland real estate that have been invaded by the voracious gypsy moth. Our beautiful, stately oaks are threatened, and we're fighting a noholds-barred battle to save them.

Let me share my experience, which might appropriately be described as the Great Gypsy Moth War - or maybe Mission Impossible. Little did I realize what impact this pest, which made its first major appearance in my yard around 1986, would have on my so-called discretionary time.

Since the gypsy first took up residence in my yard, I have often spent over an hour every day for the eight weeks of May and June in a not-so-trivial pursuit. My late-afternoon crusade has consisted of finding and killing caterpillars to reduce defoliation and future moth populations - and thereby perform the homeowners' role in IPM (Integrated Pest Management).

The stark realization that I had a problem came one June evening in 1986 when I heard what sounded like rain but turned out to be caterpillar frass (excreted oak leaves). No one likes to comb processed oak leaves out of his or her hair - neither does he want to spend time constantly sweeping patios, decks, and concrete driveways to reduce the staining caused by the excrement. This cleanup goes on for most of the eight-week period when caterpillars are proceeding with their nocturnal feeding binges in the treetops.

Having keen perception for the obvious, I knew on that June evening that I had a situation needing a multifaceted plan of attack. Wrapping each of 30 of my trees with a burlap strip and twine was part one of my strategy. Armed with the knowledge that the caterpillars feed all night and then come down during the heat of the day seeking shade, I knew that they would congregate under the burlap skirts, and this would ease their removal.

Just before dusk I would move in for the kill with my modern weapons - a No. 10 coffee can filled with bleach and a knife to flip the ugly creatures into the lethal solution. (If preferred, the liquid can be ammonia or detergent water.) This highly specialized strike force (me) resulted in a kill of 4,118 caterpillars in 1986, 7,154 in 1987, 26,401 in 1988, and 26,083 in 1989.

Within a few weeks came the critical phase. A large number of male moths started flitting about seeking mating opportunities with the flightless females. The results appeared on the birdhouse, woodpile, ivy-covered trees, lawn furniture, and a split-rail fence: the chamois-colored egg mass, each containing 500 to 1,000 eggs.

This egg-laying stage prompted the most important phase of the search-and-destroy mission, requiring me to look into the most unlikely places to locate the masses, scrape them off, and give them the No. 10 can treatment. At this point I must admit to becoming fed up with the whole scenario. But then you reach back for that extra reserve, knowing that each egg mass destroyed means up to 1,000 fewer caterpillars the following June.

The person bent on moth mayhem also becomes aware that reporting egg-mass counts to the county gypsy-moth officer before November is critical to the determination of which areas will be sprayed with Bt or Dimilin (see "Gypsy's Nemesis," page 64.) We tired warriors are always looking for any kind of help, such as fresh troops. Prudence dictates that the egg-mass hunt continue up to the emergence of the caterpillars in the spring.

I've tried it all (almost) - banding, parasitic wasps, Bt aerial spray, and Dimilin ground spray by a licensed contractor. However, if I can't convince my immediate neighbors (who are often renters) to take appropriate actions, they'll continue to supply my property with a new annual crop of swingers - so called because in the early stages the caterpillars exude a fine thread, which allows the wind to move them from place to place.

During the occassional times when I am gone over May and June (leading an American Forestry Association foreign tour, for example), my daughter falls heir to the gypsy-control chore. Now, you have to understand that bugs of any kind are not my daughter's thing. But she is fully aware of the importance of the battle and pitches in, after making sure all body surfaces are fully covered. A robot with clothes? An alien from outer space? Even our Siberian husky doesn't know what to make of the apparition that sallies forth in our backyard. If you're in need of a good belly laugh, drop by some June when the action is the hottest.

What's in store for us in 1990? Our collective data has shown that a serious outbreak is imminent - and our area is to be sprayed with Dimilin this spring. The 1988 spray with Bt must not have hit the "window of opportunity" with the precision needed, because our local moth population continued to explode. Had the timing and weather conditions been right, the treatment would surely have helped, and certainly a spraying hiatus in 1989 did nothing but exacerbate our problem.

Those who have experience with the gypsy moth will attest to the work involved in the continuing struggle to control its spread and damage. If you have been spared an invasion by the gypsy - which surely is appropriately named - count your blessings. Even if the insect has not roamed your way, you might wish to join those of us in the thick of the fight. At any rate, we all hope for a quick fix - that scientists will soon find a moth parasite or that a new virus called Abby will pan out as a control for this undesirable intruder. In the meantime the battle cry continues to be: Search - Scrape - Destroy!


The pharmacopoeia of biological and chemical controls commonly applied against the gypsy moth can be bewildering. What follows is a layman's dictionary of names you're likely to encounter.

Bt (Bacillus thuringiensis): a naturally occuring bacteria that can kill many moth larvae and is applied to moderate moth populations.

Foray: tradename for a product containing Bt, available only to professional pest-control operators.

Dipel: tradename for another product containing Bt, available in several formulations for professional arborists, pest control operators, municipalities, and other large-scale applicators. A few Bt formulations are packaged by companies such as Safer, Inc. in smaller packages, convenient for home garden use and are available in certain areas.

Thuricide: tradename for another over-the-counter product containing Bt and also specific to actively feeding caterpillars.

Dimilin: chemical insecticide that inhibits the development of a hard substance called chitin, which forms the exoskeletons of insects. Unable to molt, the insect dies. Dimilin is available only to professional pest-control operators and is applied to high populations.

PHOTO: Droppings from caterpillars mess up many a backyard picnic.
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Title Annotation:tree pests
Author:Davis, Norah Deakin
Publication:American Forests
Date:May 1, 1990
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