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

Pesticide Waste Collection (Clean Day) Event

The Georgia Dept. of Agriculture will host a Pesticide Waste Collection (Clean Day) event on September 30, 2106 at the Cordele State Farmers Market in Crisp County from 9:00am to 3:00pm. The Georgia Department of Agriculture is excited to have the funding to support this excellent program as a benefit to all Georgia citizens and the environment. The collection day is open to all who would like to participate.  Due to collection limits, pre-registration is required and must be completed by September 26, 2016.  Additional information and registration forms can be found online at http://agr.georgia.gov/georgia-clean-day.aspx

Don’t leave pesticide waste sitting around in storage waiting for an accident or spill to happen, take advantage of this rare opportunity to dispose of pesticide waste safely and responsibly.

For more information, please contact:

Rick Hayes
Georgia Department of Agriculture
19 MLK Jr. Dr. Room 410
Atlanta, Ga. 30334
Office: 404-656-4958 Ext. 4113
E-Mail: ricky.hayes@agr.georgia.gov

Related Post:

Disposing of Excess Pesticides in a Safe Manner

What are these bees making nests in lawns in early spring?

Ground bee nests are usually in groups - image taken by Diane Stephens, Houston County Master Gardener
Ground bee nests are usually in groups – image taken by Diane Stephens, Houston County Master Gardener

Ground or Digger Bees Attack Lawns

The first sign of ground or digger bees in lawns may be strange little mounds of soil with a hole nearby. The ground bees will be flying over this area. Ground bees are solitary bees that dig and nest in the ground. These bees live one per hole but there may be many holes in an area creating ground bee communities. There are many types of ground bees that vary in color and range from one-half to three-quarter inch in length. Some types of solitary wasps live like this as well.

 

Female ground bees dig nests in the ground up to six or so inches deep in which to raise young. The bees pile earth around the sides of the hole. These bees can be very active in March and April. The female ground bee stocks the nest with pollen and nectar to feed the young bees. Some solitary wasps stock their nests with insects.

 

Ground bees typically cause little problem. The digging should not be enough to damage the lawn. The bees are not very aggressive and probably will not sting. You should be able to work and mow grass around them with few problems. People that are allergic to bee stings may want to be cautious when working around the bees.

 

Close up of ground bee nests - image taken by Diane Stephens, Houston County Master Gardener
Close up of ground bee nests – image taken by Diane Stephens, Houston County Master Gardener

We do not recommend chemical controls for ground bees or wasps. These bees can be beneficial – serving to pollinate plants or destroy harmful insects. They will probably only be around for four to six weeks and then disappear until next year.

 

If you must control them, use cultural controls.

 

  • Ground bees like dry soils. Water the soil when bees first become active. Apply one inch of water once a week if it does not rain.
  • Ground bees nest in dry areas where the grass is thin. Find and correct the problems making the turf thin. This may involve soil sampling, irrigation, soil aeration or other practices.
  • Find ways to thicken the turf in these areas to reduce ground bee problems. Know the needs of the turf grass and meet them!
  • In areas that will not grow grass, mulch the area.

 

If you must use a pesticide, watch during the day to see where the holes are located. After dark, dust these areas with carbaryl (sold under the name Sevin and other names) dust. A dust insecticide should cling to the bee’s body better than a spray. Keep people and pets out of the area while it is being treated.

 

The bees are not generally harmful and pesticides are toxic. The cure may be worse than the problem. Try to put up with the bees if you can. These bees may be difficult to control and may return year to year. If you have ongoing problems with them, follow all recommendations very carefully. See this site where I found much of this information http://www.ces.ncsu.edu/depts/ent/notes/O&T/lawn/note100/note100.html

 

There is one large caution in connection with ground bees and wasps. Ground bees are not aggressive but can look like other bees and wasps that are very aggressive and harmful. Make absolutely certain that you are not dealing with a yellow jacket or bumble bee nest. Both of these insects can literally cover you with stings very quickly. They can also have extremely large nests in Georgia. If you ever get into trouble with these, run until you escape them. Running inside may help. Do not stop to swat, roll on the ground, etc.

 

Before you begin control of any stinging insect, make certain of your pest. This or other websites can help you identify the lawn invader http://aces.nmsu.edu/ces/plantclinic/documents/t-10-waspsandbees.pdf.

 

One difference between ground bees and other bees or wasps is that ground bees live by themselves and make many holes in the ground. Yellow jackets and bumble bees have many insects per hole. Use the following from Dr. Will Hudson, UGA Entomologist, as a guide for identification.

Many holes with one 1 bee per hole = solitary bees (like ground bees) that sting only as a last resort.

 

One hole, many bees = social bees (like yellow jackets and bumble bees). Keep away!  These are non-reproductive workers that will sacrifice themselves in defense of the nest.

For insects other than ground bees, you may want to hire a pest control company or a wildlife removal company. They should have the training and equipment to do the job properly.

Please share this information with others in the landscape industry. For more information:

Call your local Extension Agent at (800) ASK-UGA1 or locate your local Extension Office

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.

Ambrosia Beetles begin flying in Jan and Feb!

Will Hudson, UGA Extension Entomologist

 Asian or granulate ambrosia beetles are tiny (<1/8″) wood-boring insects that attack the trunks of young and weakened trees and shrubs. Ambrosia beetles tunnel into stems and construct galleries where they raise their young. Beetles carry on their bodies a fungus that grows in these galleries producing ambrosia which feeds both adults and larvae. Ambrosia beetles can also carry the spores of disease pathogens that infect the tree. The growth of these fungi can lead to weakening or death of the tree.

Ambrosia beetle sawdust 'toothpicks' - Byron Rhodes, UGA, Bugwood.org
Ambrosia beetle sawdust ‘toothpicks’ – Byron Rhodes, UGA, Bugwood.org

As ambrosia beetles tunnel, they push sawdust out through their entry hole. This sawdust can cling together forming short ‘toothpicks’ sticking from the infested stem. These toothpicks make it easy to identify ambrosia beetle attacks.

Wind or rain may destroy these toothpicks leaving just the small holes and scattered sawdust from the beetle. Since the entry holes are only about the size of a #2 pencil lead, close inspection is necessary to detect these attacks in time to treat. Ambrosia beetles attack many types of trees and shrubs including crape myrtles, cherries, oaks, sweet gums, pecans, peaches and others.

The ambrosia beetle’s first flight occurs with mild weather typically in February but possibly as early as January. Cold weather will put them off for a while, but we usually see a big emergence of the granulate ambrosia beetle ranging from February in south Georgia to early March in north Georgia.

Young trees in nurseries and trees that have been in landscapes for less than three years old are vulnerable to attack even if they are not obviously stressed. This is especially true during the green-up period. Prompt action can save these trees if the number of attacks (“toothpicks”) is less than 4 – 5 per tree.

Growers of nursery trees and shrubs, as well as landscapers with new trees, can apply a spray to protect vulnerable trees. The spray should be repeated every 10 – 14 days until the plants are completely leafed out.

If applied in time, pyrethroid insecticides can repel the beetles even after plants are attacked. Pyrethroids like permethrin (Pounce, Astro), Talstar, Decathlon, or others will work. Once the trees have leafed out completely, they are less attractive to the beetles unless the trees are under stress. Prevent stress to shrubs and trees to lower chance of ambrosia beetle injury.

Spray affected trees, being careful to cover the trunk completely. Monitor the trees for signs of wilting of the new leaves, a sign that a pathogen has been introduced. Once the wilting starts, the tree will probably die. Do not assume the attack will be fatal, since trees may recover. Also watch treated trees to see if new toothpicks develop – a sign that the ambrosia beetles are still active.

Nursery trees that are attacked should be sprayed and separated from the rest of the block (if possible), and watched closely for signs of wilting. Nursery trees that are attacked but don’t wilt may not need to be destroyed. If they leaf out and seem healthy and no further toothpick formation is noted, then the small holes will heal quickly and leave no permanent damage.

If you see toothpicks on larger trees, the tree is probably severely stressed. If attacks are confined to one limb, pruning is an option. If the attacks are on the main stem, prepare to remove the tree if it dies.

Considering the history of this pest in Georgia, there is a good chance that any given nursery or landscape will suffer little or no damage and spraying will not be necessary. Watch susceptible trees or shrubs closely for beetle attacks.

Traps can be used to monitor the activity of this pest. For more information on constructing Ambrosia beetle traps see Activity Monitoring in this publication.

Winter Insect Management Calendar

Bagworm

Information supplied by Kris Braman & Will Hudson, UGA Entomology Department

As you visit landscapes, scout for these insect pests this winter. Notify your client when you find damaging levels of insects or mites.

Click on the insect names to find information to help you identify & manage these pests. Notes after the insect’s name explain what you should do for each insect if control is necessary.

This publication offers help to manage landscape pests. –

For pesticide recommendations, see the Pest Control Handbook.

Shrubs 

  • Southern red mite (azalea, camellia, holly) – Scout and spray a miticide for these pests
  • Armored scales (boxwood, camellia, holly, gardenia, etc.) –  Treat with dormant oil

Trees

  • Bagworms – Prune them out. These bags contain hundreds of eggs that may hatch next May
  • Maple borers – Prune out small branches with these pests. Improve health of the tree with proper care
  • Bagworm
    Bagworm, John-H. Ghent, USDA Forest Service, Bugwood.org

    Lecanium scale – Treat with dormant oils

  • Spruce spider mite – Spray for these pests
  • Twig pruners and twig girdlers – Prune and destroy dead branches, and pick up and destroy fallen branches to prevent insect emergence next year.
Lecanium scale, Andrew J. Boone, South Carolina Forestry Commission
Lecanium scale, Andrew J. Boone, South Carolina Forestry Commission, Bugwood.org

Turf

Please share this information with others in the landscape & turf industry. For more information:

Call your local Extension Agent at (800) ASK-UGA1 or

Locate your local Extension Office at http://www.caes.uga.edu/extension/statewide.cfm

Pest Management Handbook (Follow all label directions when using any pesticide) – www.ent.uga.edu/pmh/

Some Facts About Florida’s Genetically Modified Mosquitoes

Richard Levine is Communications Program Manager at the Entomological Society of America and editor of the Entomology Today Blog.
Richard Levine is Communications Program Manager at the Entomological Society of America and editor of the Entomology Today Blog.

Some Facts About Florida’s Genetically Modified Mosquitoes from an article in Entomology Today by Richard Levine

A deluge of news articles about the possible release of genetically-modified mosquitoes in the Florida Keys swept the Internet. The modified mosquitoes, if approved, would be used to control mosquito populations without pesticides, and would lower the chances of Floridians being exposed to mosquito-borne diseases like dengue and chikungunya.

Some of the articles were somewhat alarmist. The Washington Post, for example, managed to use the words “Genetically modified killer mosquitoes” in its headline and later referred to them as “Frankenstein mosquitoes.”

Read entire article here.

Fall Management of Large Patch Disease in Turfgrass

Large patch disease - Alfredo Martinez, UGA
Large patch disease – Alfredo Martinez, UGA

Alfredo Martinez, Extension Plant Pathologist

Large patch disease of turfgrass is most common in the fall and in the spring as warm season grasses are entering or leaving dormancy. Large patch is caused by the fungus Rhizoctonia solani. It can affect zoysia grass, centipedegrass, St. Augustinegrass and occasionally bermudagrass.

Symptoms of this lawn disease include irregularly-shaped weak or dead patches that are from 2 feet to up to 10 feet in diameter. Inside the patch, you can easily see brown sunken areas. On the edge of the patch, a bright yellow to orange halo is frequently associated with recently affected leaves and crowns. The fungus attacks the leaf sheaths near the thatch layer of the turfgrass.

Large patch disease is favored by:

  • Thick thatch
  • Excess soil moisture and poor drainage
  • Too much shade which stresses turfgrass and increases moisture on turfgrass leaves and soil
  • Early spring and late fall fertilization.

If large patch was diagnosed earlier, fall is the time to control it with fungicides. Consult the Pest Management Handbook , Turfgrass Pest Control Recommendations for Professionals  or your local Extension Office for fungicide recommendations. Fall fungicide applications may make treating in the spring unnecessary. Always follow label instructions, recommendations, restrictions and proper handling when applying pesticides.

Cultural practices are very important in control. Without improving cultural practices, you may not achieve long term control.

  • Use low to moderate amounts of nitrogen, moderate amounts of phosphorous and moderate to high amounts of potash. Avoid applying nitrogen when the disease is active.
  • Avoid applying N fertilizer before May in Georgia. Early nitrogen applications (March-April) can encourage large patch.
  • Water timely and deeply (after midnight and before 10 AM). Avoid frequent light irrigation. Allow time during the day for the turf to dry before watering again.
  • Prune, thin or remove shrub and tree barriers that contribute to shade and poor air circulation. These can contribute to disease.
  • Reduce thatch if it is more than 1 inch thick.
  • Increase the height of cut.
  • Improve the soil drainage of the turf.
  • Apply lime if soil pH is acidic (i.e. less than 6.0 – except on centipede lawns). Soil pH of more than 6.5 can encourage take all infections.

See the current Georgia Pest Management Handbook for more information. Check fungicide labels for specific instructions, restrictions, special rates, recommendations and proper follow up and handling.

Additional resources:

Turfgrass Diseases in Georgia or Enfermedades de los céspedes en Georgia

Turfgrass Diseases: Quick Reference Guide or Enfermedades de Cespedes Guia de Referencia Rapida

UGA Pest Management Handbook

Turfgrass Pest Control Recommendations for Professionals

When is the best time of year to control fire ants?

Fall is the best time to control fire ants!

Original story by Sarah Lewis, student writer with the UGA College of Agricultural and Environmental Sciences

“April and September are good times to apply baits, once at the start of the season and toward the end to help control before they come back in the spring,” said Will Hudson, a professor with the UGA College of Agricultural and Environmental Sciences.

Fire ants are most active in warm weather. Fire ant season can last 10 to 11 months out of the year in the most southern areas of Georgia. Controlling ant colonies before they produce a mound is important. However, Hudson says that once a treatment program is in effect, timing is not all that important.

Baits and sprays

The general rule of thumb is if the area is one acre or less, don’t use baits. Re-infestation is more likely from colonies outside of the yard when baits are used.

One important thing to remember is the difference between ‘no mounds’ and ‘no ants.’ “There is a difference between eliminating ants and controlling them,” he said. “Baits do not eliminate ants because there is no residual control. A new colony can still come in and be unaffected by the bait laid down prior to their arrival.”

To eliminate mounds completely, apply baits every six months, Hudson said. “There will be invasion in the meantime, and you will still have fire ants, just not enough to create a new mound,” he said.

Hudson recommends treating lawns smaller than an acre with a registered insecticide in a liquid solution. This should rid the lawn of fire ants for one to three months. If you choose a granular product, measure carefully to be sure you apply the correct amount of material and get good, even coverage, he said.

The least effective treatment option for most people is individual mound treatments, according to Hudson. Treating mounds in general is going to be an exercise of frustration, and killing an entire colony by treating just the mound is a challenge, he said.

Minimal impact

Baits are considered to have minimal environmental effects for those who chose not to use hazardous chemicals. Once the bait is out, there is hardly anytime for anything to come in contact with it before the ants get to it.

Nonchemical options include using steam or boiling water. “We recommend using boiling water to treat a mound near an area such as a well where you do not want any chemicals,” Hudson said. “Using hot water is very effective, but the problem is you are not always able to boil the water right next to the area you want treated.” Carrying the boiling water can inflict serious burns, so extreme caution should be used when treating with this method.

There are products on the market that are approved by the Environmental Protection Agency and labeled as organic. Hudson says organic designation is a “slippery” definition. There is an official USDA certification and many states have their own set of regulations when labeling a product as organic. This labeling can mean the product is either a natural product or derived from a natural product. “While there are a few products that qualify as organic, with most baits the actual amount of pesticide applied is minimal,” he said.

Realistic expectations

Hudson says to be careful when choosing a product because the labels can be confusing, even deceptive, and it is difficult to make the right choice. For assistance in selecting a product, contact your local UGA Cooperative Extension agent.

“The most important thing to remember is that you need to be realistic in your expectations,” Hudson said. “If you are treating mounds, you need to be prepared. You are going to chase the mounds around the yard.”

For more information on selecting a control measure:

Find pesticide recommendations in the UGA Pest Management Handbook

Fire Ant Control Materials

Managing Imported Fire Ants in Urban Areas

Fall is the best time to treat for fire ants

 

New online book joins the IPM series

IPM bookMatthew Chappell, Associate Professor UGA & Statewide Extension Specialist (Nursery Crops)

The book IPM for Shrubs in Southeastern US Nursery Production Volume 1 is now available via iBooks for viewing on an iPad at the link below and as pdf files for viewing on a laptop, desktop, and most mobile devices at the link below that.

IPM Select Shrubs: Vol. I

IPM_Shrub_Book

Also, our previous book, IPM for Select Deciduous Trees in Southeastern US Nursery Production, is also available in iBooks for viewing on an iPad at the link below and as pdf files for viewing on a laptop, desktop, and most mobile devices at the link below that.

IPM Select Trees

http://wiki.bugwood.org/IPM_book

We will be publishing 4 more volumes of the shrub book over the next few years, with each book covering 4-7 genera of woody ornamentals.