Pest Alert: February Monitoring for Granulate Ambrosia Beetle

Post authored by Paul J. Pugliesea and Shimat V. Josephb

aUGA County Extension Agent/Coordinator (Bartow County), Cartersville, GA
bAssistant professor, Department of Entomology, University of Georgia – Griffin Campus.

Fig. 1 Adult beetle (left) and “tooth pick” symptom (right)

Granulate ambrosia beetleXylosandrus crassiusculus (Mot.) [Previously known as the Asian ambrosia beetle]

Introduction: Granulate ambrosia beetle (Fig. 1) is a serious pest of woody trees and shrubs in Georgia. These tiny beetles were first detected in South Carolina in the 1970’s and have spread across the southeastern US.

Host plants: Woody ornamental nursery plants and fruit trees are commonly affected. In spring or even in late winter (around mid-February), a large number of beetles can emerge and attack tree species, especially when they are young. Some highly susceptible tree species include Styrax, dogwood, redbud, maple, ornamental cherry, Japanese maple, crepe myrtle, pecan, peach, plum, persimmon, golden rain tree, sweet gum, Shumard oak, Chinese elm, magnolia, fig, and azalea.

Biology: The female beetles land on the bark of woody trees. Then, they bore through the soft wood and vascular tissues (xylem vessels and phloem) of the tree. They settle in the heartwood and begin making galleries. Eggs are laid in these galleries. Adults introduce a symbiotic fungi into the galleries as a food source for the developing larvae.

Symptoms: The initial sign of infestation is presence of boring dust pushing out of the bark as “tooth picks” (Fig. 1). Severely infested trees with granulate ambrosia beetle may show symptoms of stunting, delayed leaf emergence in spring, and extensive defoliation.

Fig. 2 Timing is a key factor in effectively managing Granulate ambrosia beetle. Monitoring traps placed in early February are useful for the early detection of beetle emergence and infestation.

Monitoring and management: Once adults of granulate ambrosia beetle bore through the bark, there are limited control options to mitigate the problem. Those settled beetles in the heartwood of the tree are less likely to be exposed to insecticides. Also, the beetles do not consume the wood, which further minimizes their pesticide exposure. Pyrethroid insecticides such as bifenthrin or permethrin can be used as preventative sprays to repel invading females. Thus, the insecticide-application timing becomes critically important for management. The insecticide applications can be timed with trap captures or adult activity. The simplest method to determine adult activity in the area is using alcohol and a bolt of wood (Fig. 2). A wood bolt (about 2 to 4-inches in diameter and 2-feet long) can be utilized. Any hardwood species such as maple will work for building traps. A half-inch diameter hole drilled at the center of the bolt, about a foot deep, is filled with alcohol and the opening can be closed using a stopper cork.  Ethyl alcohol or grain alcohol with 95-percent alcohol content (190-proof) can be found at most liquor stores. Hang several bolt traps along the woodland border of a nursery at waist height to determine beetle emergence and activity. Sawdust tooth picks (Fig. 2) begin to appear on the bolt when they are infested with adult beetles. Once tooth picks are detected on a bolt trap, daily scouting should occur on nearby trees.

An immediate spray using a pyrethroid insecticide on nursery trees is warranted upon detection of tooth picks on the bolt trap.  Be prepared and ready to act quickly as soon as beetle activity is confirmed.  If practical, the entire nursery should initially be treated with an area-wide application to repel beetle activity.  If individual trees are found to be infested, immediately destroy infested trees and follow up with targeted spray applications in blocks with beetle activity. Generally, pyrethroids are not effective for more than a week as their residues quickly breakdown. Re-application of the insecticide is generally required at weekly intervals until spring green-up is complete in areas where the beetle pressure is moderate to severe.

Healthy trees can withstand a low level of beetle infestation. Timely irrigation and adequate fertilization of trees throughout the growing season will increase a tree’s tolerance to beetle infestation.  Closely monitor traps throughout the spring for a second emergence of ambrosia beetles. Ambrosia beetles can have multiple generations throughout the year and are strongly attracted to trees that are drought stressed, injured, or excessively pruned.  Pay close attention to irrigation needs during extended summer and fall drought periods to minimize tree stresses.  Avoid mechanical wounding of trees with maintenance equipment that could invite ambrosia beetles to attack.    

When to deploy monitoring traps: The monitoring traps should be deployed starting the first week of February in Georgia because warmer periods during a mild winter may trigger early beetle emergence and infestation.

References: 

  1. Frank, and S. Bambara. 2009. The granulate (Asian) ambrosia beetle. Ornamental and turf. Insect note. North Carolina State University.
  2. Wells. 2015. Managing ambrosia beetles. UGA pecan extension

Get updated on fire ant baiting

Get updated on fire ant baiting

Article written by Mike Merchant, Texas A&M Agrilife Extension Entomologist, in his blog Insects in the City

Fire ants remain the most prevalent outdoor ant pest in most areas of the southern U.S.  Throughout the U.S. we estimate the annual cost of fire ant control at over $6 billion.  But the cost of this pest goes far beyond measurable dollars.  Fire ants reduce the recreational value of our parks and backyards, disrupt wildlife populations, and send thousands to emergency rooms each year from their painful stings.

So as we get ready to enter fire ant season, it may be a good time to bring yourself and your staff up to speed on fire ant control. Many people are surprised to learn that fire ants are not an especially difficult pest to manage, once the biology and control tools are understood.

One of the best places to learn about fire ant management is the eXtension fire ant website, a place where the best information about fire ant is assembled by Extension agencies throughout the South. This information was recently summarized and presented in an informative webinar by Dr. Fudd Graham, fire ant specialist with Auburn University.   Dr. Graham focuses on fire ant biology and use of baits for fire ant control.

It’s worth knowing something about how fire ant baits work because they are the most economical, ecologically friendly, and effective control methods for fire ants. The webinar will provide you or your technician with an hour of training that should pay for itself many times over.


 

Mike Merchant is an entomology specialist for Texas AgriLife Extension. He works with pest management professionals, school facilities managers, extension volunteers, researchers and other extension professionals. His areas of specialty center on research on insects affecting man including spiders, scorpions, fire ants, termites and others. His program also focuses on training school maintenance professionals in principles of integrated pest management (IPM). His goal is to make schools healthier, cleaner places to study and live.

Winter is a good time to control Chinese privet and climbing fern

Privet - James H. Miller & Ted Bodner, Southern Weed Science Society, Bugwood.org
Privet – James H. Miller & Ted Bodner, Southern Weed Science Society, Bugwood.org

Information taken from this article in the Thomas County Ag News

Chinese privet (also called privet) is an invasive weed that escaped from cultivation. It is often found in landscapes and around old homesites, edges of fields and in low areas. According to Dr David Dickens, UGA Extension Forester, this time of the year, a foliar treatment is a good option to control privet.

Basal treatments of privet (spraying the stems) can be difficult because of the large number of branches. Dr Dicken’s says that dormant-season foliar sprays with 3-5% glyphosate provide effective control. Concentrations greater than 5% are not economical.

Take care to keep the spray off the foliage and young green bark of desirable plants. Since  many plants are dormant at this time of year, there should be less effect on non-target plants.

Privet seeds are only viable for one year so in areas where they continues to germinate, the seeds are being introduced by birds or other means.

Climbing fern - Chris Evans, Illinois Wildlife Action Plan, Bugwood.org
Climbing fern – Chris Evans, Illinois Wildlife Action Plan, Bugwood.org

UGA Extension Forester, Dave Moorhead, points out that this 3 – 5 % glyphosate spray will also work in controlling another invasive weed – climbing fern.

See the original article here for more information.

Read and follow all labeling directions when using any pesticide!

Goats and Sheep Battle Invasive Plants

The Athens-Clarke County Commission approved on June 3, 2014 a new law that will allow people inside the city limits to rent goats and sheep to help get rid of invasive plants on their property (info taken from the Center for Invasive Species blogspot). Read the following story to find out why.

The following article is by Merritt Melancon, news editor with the University of Georgia College of Agricultural and Environmental Sciences

Goats and sheep have a reputation for eating vegetation that most other grazing animals would not touch.

This trait makes them invaluable to people who need to raise livestock in tough climates, but it’s also made them popular for landowners who need to clear brush or invasive plants from overgrown parcels.

The nimble grazers can get into overgrown areas that even the most dedicated groundskeeper or gardener won’t chance. They’ve proven to be a low-impact, low-cost way to control invasive plants like privet, kudzu, honeysuckle and English ivy.

The practice of using sheep and goats to clear out unwanted brush is called targeted grazing, and many government agencies, municipalities and private landowners are using it to keep vacant lots, steep back yards, parks and right-of-ways clear of brush.

When is it time to bring in a herd?

Targeted grazing is a suitable option, whether a landowner is dealing with acres of stream bank, a detention pond or a small back yard, but it’s not meant to replace basic maintenance, said Brian Cash, owner of EWE-niversally Green sheep rental service in Dunwoody.

“We’re not a lawn mowing service,” Cash said. “We’ll do that, but we like to focus on overgrown yards and lots.”

Cash often works with new homeowners in and around downtown Atlanta who have purchased foreclosed homes with overgrown lawns and local government agencies needing to clear brush from public lands.

Sheep and goats are most useful when an area is so overgrown that no one else wants to clear it out. Even if its just a small yard, most homeowners, and many landscapers, don’t want to work in an area that’s choked with poison ivy, poison oak and briars, he said.

Sheep and goats are also useful in areas that are too steep or too wooded to use a tractor to clear out brush.

“If you can do it with a bush hog on a tractor, then that would be cheaper, but if you need a guy with a weed whacker out there, then I’m cheaper,” said herdswoman Jennif Chandler, of Shady Brook Farm in Colbert.

Chandler and her sheep have worked with the University of Georgia College of Agricultural and Environmental Sciences on the Athens campus to clear invasive plants including privet, kudzu and honeysuckle from along the bank of the Oconee River.

She also works with homeowners in the Athens area to clear Kudzu covered hills and backyards.

While goats and sheep are a surefire and efficient way to clear out a choked backyard or lot, there are a few things that homeowners should consider before buying a half-dozen goats or even hiring a service like Cash or Chandler’s.

They’ll eat everything

While herdsmen and women out on the West Coast are training goats and sheep to nibble around delicate plants like grape vines and other crops, targeted grazing isn’t a technique homeowners would want to try around their prize hydrangeas or a heirloom rose bush.

In fact, some ornamental plants are seriously toxic to sheep or goats. Examples include azaleas and Japanese yew.

“They’re not very discriminant,” said Sarah Workman, an Extension Agroforestry Specialist with the CAES. “If there’s something you don’t want them to eat, you need to protect it.”

While goats and sheep eat pretty much the same thing, sheep prefer broad-leaf weeds like ivy or kudzu, and goats seem to prefer woodier plants, Cash said.

Sheep usually can clear an area up to about a five-foot height, but goats can climb and take care of plants up to seven feet off the ground.

Because of their climbing ability, goats can take care of larger plants. However, that skill and natural curiosity, makes them more likely to escape and antagonize neighborhood dogs.

Cash usually sends a few goats along with his sheep herd to get the best of both worlds, but he’s careful to select his best-behaved goats.

Graze, wait and repeat

If a homeowner’s goal is to eradicate a specific invasive species, it may take repeated grazing to accomplish that goal, Workman said.

She and Chandler organized the first targeted grazing demonstration at UGA last year. The project, an effort to remove privet from a portion of the River Road area, is ongoing.”

These invasive plants are invasive because they are so persistent,” Workman said. “The idea is that the repeated introduction of the animals will deplete the root reserve of the (invasive) shrub.”

The shrubby stuff and woody vines are things that need repeated browsing,” Workman said. “And hopefully the more they’re eaten and knocked back, the less strength they have to regrow.”

Chandler’s sheep are scheduled to be back in action this summer to continue the eradication effort.

Managing the herd takes expertise

Herdsmen and women, like Cash and Chandler, have worked with their animals long enough to know how they’ll graze a specific area and how to meet homeowners’ goals for targeted grazing. Their customers get the benefit of that expertise when they rent their herds.

Another option is for a homeowner to purchase a few sheep or goats, but they need to be ready for the responsibility, said Will Getz, professor of animal science at Fort Valley State University’s Georgia Small Ruminant Research and Extension Center.

Zoning laws prohibit many suburban and urban homeowners from keeping any goats or sheep in their backyard. Additionally, suburban, urban and even rural landowners will face the challenge of keeping their herds contained and safe from neighborhood dogs or coyotes.

Moreover, there is the matter of food.

An acre of grass and brush can support about a half-dozen goats or sheep over the long-term, Getz said. If a landowner wants to load their land with more than six sheep or goats per acre, they’ll clear it out quickly.

“If you exceed that stocking intensity, then the animals are going to clear the area out more quickly,” Getz said. “But then you need to be prepared to sell them or otherwise get them off of your land when they’ve finished, either that or start buying feed.”

Homeowners interested it either renting or buying goats or sheep to clear their land should contact their local UGA or FVSU Cooperative Extension agent and the zoning or public development office in their county or city.