Speaker: Dr. Jonathan Larson, Extension Professor, University of Kentucky
Webinar Date: September 19, 2024
Moderator: Dr. Shimat Joseph, UGA Extension Entomologist
Duration: 50:24
NARRATIVE SUMMARY
Dr. Jonathan Larson, extension professor and co-host of the Arthro-pod entomology podcast, provided Georgia pest management professionals with valuable insights into Kentucky’s turfgrass and ornamental pest challenges, offering perspective on invasive species that may soon impact the Southeast. Dr. Larson opened by comparing regional pest pressures through golf course industry survey data, noting that Kentucky’s cooler climate and historic role as a climatic transition zone creates distinct pest patterns compared to Georgia’s warmer conditions. While Southeastern states average four annual insecticide applications treating 58 acres at over $16,500 annually, Kentucky’s central region applies insecticides less frequently with smaller budgets, facing different primary pests.
The white grub complex dominates Kentucky turf pest concerns, with Dr. Larson explaining identification techniques using raster patterns—the diagnostic hair arrangements on grub posterior tips that distinguish green June beetles, May/June beetles, masked chafers, and Japanese beetles. He highlighted unusual activity in 2024, including earlier-than-normal May/June beetle emergence shifting from May into April, increased green June beetle populations attracted to organic matter and manure-based fertilizers, and black turfgrass Ataenius (Ataenius spretulus) outbreaks on golf courses. This small grub species overwinters as an adult beetle rather than as a grub, producing two generations annually and requiring earlier prevention applications than traditional grub control timing.
Annual bluegrass weevil received extensive discussion as Kentucky’s major turf challenge since 2017-2018, with confirmed presence in Georgia since 2022. This native insect behaving as an invasive pest spreads primarily through sod importation, threatening cool-season turfgrasses on golf courses. Dr. Larson detailed identification characteristics, life cycle timing correlated with dogwood and forsythia bloom stages, and monitoring techniques including soap flushes and the tug test. He emphasized the weevil’s primary damage to Poa annua and creeping bentgrass, with symptoms often confused for drought stress until extensive root damage becomes apparent.
Dr. Larson addressed hammerhead worms—land planarians generating significant public concern despite being harmless predators of earthworms, snails, and slugs. He clarified misconceptions about their tetrodotoxin and rat lungworm vectoring capabilities, explaining that health risks occur only through ingestion and that simple disposal methods using salt or vinegar in sealed containers effectively eliminate them without environmental harm.
The presentation concluded with emerging invasive species threats including spotted lanternfly (Lycorma delicatula), confirmed in one Kentucky county and spreading through the Carolinas and Tennessee toward Georgia. Dr. Larson explained this hemipteran’s piercing-sucking mouthparts, preferred hosts including tree of heaven, walnuts, and grapes, and management strategies using pyrethroid contact sprays or systemic Dinotefuran injections. Box tree moth presented another imminent concern, with multiple Ohio counties near the Kentucky border heavily infested. This caterpillar devastates boxwoods through complete defoliation and trunk girdling, potentially requiring preventative applications of Acelepryn or BT products. Finally, Dr. Larson discussed Kentucky’s recent entry into fire ant territory, with hybrid cold-tolerant varieties now established in southeastern Kentucky counties, drawing parallels to Georgia’s longstanding experience managing this invasive pest. The session concluded with extensive Q&A discussion addressing spotted lanternfly treatment methods, box tree moth quarantine effectiveness, and temperature limitations on invasive species southward expansion.
YOUTUBE TIMESTAMPS
0:00 Introduction and Welcome
1:00 Dr. Jonathan Larson Introduction and Background
1:23 Kentucky’s Pest Management Challenges
2:04 Golf Course Industry Survey: Regional Comparisons
2:32 Southeast vs. Central U.S. Pest Pressure
3:46 Kentucky’s Climate: A Transition Zone
4:20 White Grub Complex: Kentucky’s #1 Turf Pest
4:39 White Grubs Rogue Gallery: Four Key Species
5:10 Grub Identification Using Raster Patterns
6:28 White Grub Life Cycles Explained
7:17 Black Turfgrass Ataenius: The Exception
8:09 BTA: Two Generations and Overwintering Strategy
9:12 May and June Beetle Emergence Shifts
10:30 May/June Beetle Three-Year Life Cycle
11:34 Green June Beetle: The Biggest Grub
12:28 Green June Beetle Behavior and Damage Patterns
13:27 Cultural Controls for Green June Beetles
13:49 Annual Bluegrass Weevil: Major Kentucky Challenge
14:29 ABW Spread: From Connecticut to Georgia
15:31 Sod Movement Theory for ABW Distribution
16:03 ABW Identification and Physical Characteristics
17:21 ABW Life Cycle and Metamorphosis
18:00 Expert Resources: Dr. Ben McGraw and Colleagues
18:53 ABW Overwintering and Emergence Timing
19:45 Phenological Indicators: Dogwood and Forsythia Bloom
20:25 ABW Host Plants: Poa annua and Creeping Bent
21:23 ABW Damage Symptoms and Misdiagnosis
22:18 Soap Flush Monitoring Technique
23:11 Accidental Monitoring: Reel Mower Clippings
23:42 Tug Test for ABW Detection
24:43 Hammerhead Worms: Public Concern Overview
25:13 Land Planarians: Biology and Behavior
26:02 Tetrodotoxin and Rat Lungworm Concerns
27:00 Hammerhead Worm Reproduction Myths
27:52 Safe Handling and Disposal Methods
28:40 Spotted Lanternfly: Invasive Species Alert
29:20 SLF Distribution: Pennsylvania to Georgia Border
30:00 True Bugs: Hemipteran Characteristics
30:55 SLF Damage vs. Other Invasive Insects
31:43 SLF Host Range: 70+ Plant Species
32:22 Honeydew and Sooty Mold Development
33:13 SLF Population Impacts on Outdoor Recreation
34:18 Box Tree Moth: Emerging Threat from Ohio
34:41 BTM in Kentucky: Boxwood Vulnerability
35:16 BTM European Spread and Devastation
36:03 BTM Caterpillar Identification
36:42 BTM vs. Melonworm Moth Confusion
37:06 BTM Life Cycle and Generation Predictions
37:58 BTM Damage Patterns: Silk Nests and Curlicues
38:27 Distinguishing BTM from Other Boxwood Pests
38:55 BTM Control Options Available
39:00 Fire Ants Arrive in Kentucky
39:28 Hybrid Fire Ant: Cold-Tolerant Variety
40:02 Fire Ant Distribution in Southeastern Kentucky
40:47 Learning from Georgia’s Fire Ant Experience
41:02 Presentation Conclusion and Q&A Invitation
41:34 Q&A: Annual Bluegrass Weevil in Georgia
42:13 Q&A: Fishing with Hammerhead Worms
42:47 Q&A: Spotted Lanternfly Treatment Methods
44:03 Q&A: National Tree Check Month for SLF Detection
44:47 Q&A: Box Tree Moth Quarantine Effectiveness
46:02 Q&A: Temperature Limits on BTM Southward Spread
47:00 Final Q&A and Closing Discussion
49:10 Webinar Title Clarification
50:06 Sign-In Sheet Instructions and Closing Remarks
QUESTIONS & ANSWERS
Q: What are the distinguishing features between different white grub species?
A: White grubs can be identified by examining the raster pattern—the arrangement of hairs and spines on the posterior tip of the grub’s abdomen. Green June beetles display a block letter “I” pattern, May/June beetles show spines that look like an open zipper, masked chafers have no distinct pattern (just a hairy surface), and Japanese beetles feature a distinctive “V” pattern that stands for their seeming victory over pest management efforts.
Q: Why is black turfgrass Ataenius becoming more problematic on Kentucky golf courses?
A: Black turfgrass Ataenius differs from other white grubs by overwintering as an adult beetle rather than as a larva, and it produces two generations per year. Traditional grub prevention applications timed between Mother’s Day and July 4th miss the early generation, which flies and lays eggs as early as mid-March. This early activity, combined with some product switches showing reduced efficacy, has led to increased BTA populations on golf courses.
Q: How did annual bluegrass weevil spread from Connecticut to states like Kentucky and Georgia?
A: The current theory attributes much of the weevil’s spread to sod movement. When golf courses or other facilities purchase sod from infested states, the weevil may be hidden within the sod and then escapes into the new location. Kentucky’s first detection occurred on a golf course that had recently imported sod, and Georgia confirmed its presence in 2022 through similar pathways.
Q: What monitoring techniques work best for detecting annual bluegrass weevil populations?
A: The soap flush method is most effective: mix one tablespoon of citrus-based liquid dish soap into a gallon of water, pour the sudsy mixture onto the suspect area twice (waiting 30-60 seconds between applications), then watch for five minutes as weevils emerge in the suds. Sampling six one-square-foot areas over 30-45 minutes provides reliable population estimates. The tug test also works—damaged plants slide out of the soil with minimal resistance, like pulling a straw from a cup.
Q: Are hammerhead worms dangerous to humans or turfgrass?
A: Hammerhead worms pose no danger to humans through casual contact or to turfgrass and ornamental plants. They are predators that feed exclusively on earthworms, snails, and slugs. While they contain tetrodotoxin and can theoretically vector rat lungworm, these health concerns apply only if someone were to eat the worm. People can touch them without ill effects, though gloves are recommended for handling. They do not damage plants or turf.
Q: How should hammerhead worms be controlled if found on a property?
A: Despite myths about their immortality, hammerhead worms can be killed effectively. The recommended method is to wear leak-proof vinyl gloves, place the worm in a sealed plastic bag (Ziploc), then add salt or vinegar to the bag and watch it dissolve. Avoid chopping them up, as fragmentation is actually their primary reproductive method—cutting them only creates more worms rather than eliminating them.
Q: What are the primary treatment options for spotted lanternfly?
A: Contact pyrethroid sprays like bifenthrin applied to plant surfaces and the insects themselves provide immediate control as spotted lanternflies crawl through treated areas. For more specialized management, systemic Dinotefuran can be injected into trees either through soil or trunk injection. This is particularly effective when used on Tree of Heaven as a trap tree strategy, killing large numbers of spotted lanternflies that preferentially feed on this invasive host plant.
Q: What makes spotted lanternfly different from other invasive insects like Japanese beetle or emerald ash borer?
A: Unlike Japanese beetle or emerald ash borer, spotted lanternfly rarely causes direct tree mortality. While it can damage over 70 host plant species and build massive populations, trees generally don’t die from spotted lanternfly feeding alone. The most conspicuous damage comes from honeydew secretion that promotes black sooty mold growth, which can be extensive enough to kill understory plants beneath infested trees. The pest’s main impact is on human outdoor recreation and specific agricultural crops like grapes and walnuts.
Q: Will box tree moth quarantines prevent its spread from Ohio into Kentucky and Georgia?
A: Quarantines will likely help delay spread rather than prevent it entirely. The Ontario, Canada quarantine kept box tree moth contained for quite some time before it eventually broke through and moved south. As northern states learn more about the pest’s behavior and develop insecticide timing recommendations, Southern states will benefit from that knowledge. One key difference is that U.S. pest managers have access to more chemical control options than European counterparts, which may help slow the invasion.
Q: What temperature limitations might prevent box tree moth from successfully establishing in Georgia?
A: Box tree moth survival in Ohio suggests it will likely survive in Kentucky and Tennessee, but there may be a southward limit around Georgia or northern Florida where temperatures become too warm. The pest requires diapause (overwintering as a semi-mature larva in a silk hibernaculum), and extreme heat may either allow too many generations per year or prevent the necessary overwintering stage. The exact temperature threshold remains unclear, but patterns from European climate zones suggest Georgia may approach the southern boundary of suitable habitat.
Q: How are fire ants now present in Kentucky despite decades of predictions they would never reach that far north?
A: Kentucky is now dealing with hybrid fire ants—a cross between red and black fire ant species that produces more cold-tolerant offspring. These hybrids have established populations in southeastern Kentucky counties including Whitley, McCreary, Knox, Bell, and Laurel, all near the Tennessee border. The northward expansion crossed previously drawn “lines they’ll never cross,” demonstrating that hybrid vigor and climate shifts can overcome historical temperature barriers.
Q: What advice does Kentucky Extension have for golf course superintendents dealing with annual bluegrass weevil for the first time?
A: Monitoring requires patience—expect to spend one to two growing seasons developing a feel for the pest’s presence and activity patterns. Dr. Larson’s team spent two years finding adults but never recovering larvae despite extensive sampling efforts. Using phenological indicators like dogwood bloom (coinciding with L1 larval stage) and forsythia half-bloom (peak adult emergence) helps time scouting efforts. Tools like Weevil Track from Syngenta provide region-specific tracking assistance for timing management applications.
ADDITIONAL RESOURCES
Dr. Jonathan Larson Contact Information:
University of Kentucky Extension
Co-host, Arthro-pod Podcast
Pest Management References Mentioned:
- Dr. Ben McGraw, Penn State University (Annual Bluegrass Weevil Expert)
- Dr. Albrecht Kopenhofer (ABW Research)
- Dr. Pat Vittum (ABW Research)
- Syngenta Weevil Track Tool
Detection and Reporting:
- National Tree Check Month (August) – U.S. Forest Service
- Report suspected spotted lanternfly to county extension agents
- Box tree moth quarantines active in southwestern Ohio counties
Related Topics:
- Soap flush monitoring technique for weevil detection
- Tug test for billbug and weevil damage assessment
- Phenological indicators for pest timing
- Trap tree strategy using Tree of Heaven for spotted lanternfly management
For technical questions about Kentucky pest management, contact the University of Kentucky Extension. For Georgia-specific pest concerns, contact your local UGA Extension office.