When To Monitor Kansas Trees For Emerald Ash Borer Activity

Early, regular, and targeted monitoring is the most practical tool Kansas landowners, municipal foresters, and arborists have to slow the damage caused by emerald ash borer (EAB). This long-form guide explains when to inspect ash trees, what to look for during each season, which monitoring methods are most effective, and how to use inspection results to make timely treatment or removal decisions. The recommendations are tailored to Kansas climate patterns and urban-rural contexts and are written for people who manage individual trees, streetscapes, windbreaks, or natural areas.

Why timing matters for EAB monitoring

Emerald ash borer is a wood-boring beetle whose life stages and damage signs appear at different times of year. Monitoring timed to those life stages increases the chance of early detection, prevents unnecessary treatment, and helps prioritize limited resources for the trees most likely to be infested.
Key reasons to monitor on a schedule:

• Detect presence before widespread canopy decline makes treatment ineffective.
• Confirm adult emergence windows so traps and visual inspections are most productive.
• Schedule insecticide applications and trunk injections when trees will actively translocate systemic products.
• Identify high-value trees that should be treated or removed before they fail and become safety hazards.

EAB biology and its effect on monitoring timing

Understanding the basic life cycle of EAB clarifies why certain months are more important for different monitoring techniques.

• Overwintering occurs as larvae under the bark in galleries. Larvae resume development in spring.
• Pupation and adult emergence generally happen in late spring to mid-summer (timing varies with latitude and local temperatures).
• Adults feed on ash foliage, mate, and lay eggs in bark crevices through summer.
• Larvae feed in the phloem and outer sapwood throughout summer and fall, creating S-shaped galleries that disrupt nutrient flow and gradually kill the tree.
• Many external signs (crown dieback, epicormic shoots, thinning) appear only after several generations of infestation, making early detection crucial.

In Kansas, typical seasonal windows are:

• Late spring (May-June): adult emergence begins; best time to deploy and check traps and to start visual searches for fresh D-shaped exit holes.
• Summer (June-August): active adult feeding and egg-laying; visual signs on foliage and early canopy thinning appear; trap catch peaks.
• Fall (September-October): larvae continue feeding; signs of decline become more apparent.
• Winter (December-February): leaf-off period ideal for spotting canopy dieback, woodpecker activity, and bark splitting; bark peeling reveals galleries.

These windows shift slightly each year depending on temperatures and growing-season length; warmer years advance adult activity.

Practical, season-by-season monitoring schedule for Kansas

Below is a practical schedule you can follow. Modify it based on local weather (early springs) and whether EAB has already been detected nearby.

• Winter (December-February)
• Scan ash-lined streets, windbreaks, and woodlots for dead branches, snapped leaders, and trunk cracks.
• Look for clusters of small D-shaped holes, bark flakes, and heavy woodpecker damage on trunks and lower limbs.
• Prioritize trees with more than 30-50% crown thinning for further action; such trees have reduced treatment success.
• Early spring (March-April)
• Complete a baseline inventory and health assessment for high-value and high-risk ash trees.
• Plan and schedule deployment of traps and girdled trap trees.
• Arrange professional treatment applications if you plan to use systemic insecticides; prepare to apply when soil temperatures and sap flow increase.
• Late spring to summer (May-August)
• Peak monitoring window for adult beetles. Check traps and visually inspect trunks and lower crown for fresh D-shaped exit holes and canopy thinning.
• Monitor for increased woodpecker activity and epicormic shoots (sprouts from trunk or base), which often indicate stress.
• Consider targeted branch-sampling or bark peeling on suspect trees to find galleries if safe and permitted.
• Fall (September-November)
• Inspect for new signs of decline before winter.
• Remove heavily infested, hazardous trees while leaves are still on the ground to reduce risk of limb failure during winter storms.
• Record findings, map infestations, and plan treatment cycles for the following year.
• Year-round
• Re-inspect treated trees at least once per year and after extreme weather.
• Maintain records of inspection dates, observed symptoms, and any treatments or removals.

Monitoring methods and when to use each

No single technique works in every situation. Use a combination of methods timed to the life stage and season.

• Visual inspection (year-round)
• Best initial tool. Look for canopy thinning, epicormic shoots, increased woodpecker strikes, bark splitting, and D-shaped exit holes.
• Winter is excellent for seeing structural decline and woodpecker damage because leaves are absent.
• Trapping (spring through fall)
• Purple prism traps and pheromone-baited traps are used by state and professional programs to detect adult presence. Deploy in late April to May and check through September.
• Traps are most useful for landscape-scale detection; homeowners should coordinate with county extension or state programs rather than DIY sticky traps.
• Girdled (trap) trees (late spring-summer)
• Girdling a branch or small-diameter ash to attract adults can increase local detection–but it kills the girdled tissue. Use only under guidance, and remove girdled trees promptly.
• Bark peeling and branch sampling (late winter-spring)
• When suspecting infestation, removing discreet sections of bark to look for S-shaped galleries and larvae is definitive. Conduct in winter when larvae are present and visible, and always follow safety and legal guidelines.
• Professional diagnostic services (any time)
• Certified arborists and extension services can perform confirmatory sampling and advise on treatment windows.

Which trees to prioritize and how often to inspect

Not all ash trees carry the same risk. Prioritize monitoring and management by value, location, and health.
High-priority trees (inspect 2-4 times per year):

• Street trees, high-use park trees, or specimen trees with cultural or historic value.
• Ash trees in areas where failure would cause property damage or safety concerns (near sidewalks, roads, powerlines, parking areas).
• Trees showing early signs of stress or woodpecker activity.

Medium priority (inspect annually, plus targeted checks May-Aug):

• Ash in residential yards that are healthy and low-risk for causing hazards if they decline.

Lower priority (inspect every 1-2 years unless signs appear):

• Isolated ash in remote areas or natural stands where the cost of treatment outweighs value.

How monitoring results should guide action

Use inspection outcomes to make timely decisions:

• No signs detected and EAB not known nearby: continue routine monitoring; consider preventive treatments only for very high-value trees and after consulting a professional.
• Early detection (few exit holes, minor thinning): treat with systemic insecticide if the tree is a high-value or critical asset. Treatment success is higher when canopy loss is under ~30-50%.
• Moderate to severe decline (extensive dieback, large woodpecker damage, >50% crown loss): removal is often the safest and most cost-effective option. Treating such trees rarely restores them and can present hazard risk.
• Confirmed local detection in neighborhood or county: increase monitoring frequency across your properties and consider proactive treatment for high-value trees; prepare removal plans for weakened trees.

Timing insecticide applications relative to monitoring

If you choose chemical protection for valuable ash trees, timing of application affects uptake and efficacy.

• Soil-applied systemic products (e.g., imidacloprid) are most effective when roots are active–generally late spring through early summer when soil temperatures consistently exceed about 50degF.
• Trunk injections (e.g., emamectin benzoate) are typically applied in late spring to early summer; some products provide multi-year protection and should be applied by a certified applicator.
• Rapid-acting options (dinotefuran) are useful for trees with high EAB pressure or when quick reduction of larval activity is needed; these are often applied in the same seasonal window.

Always use label directions and consult a certified arborist. Improper timing or application can reduce effectiveness and increase environmental risks.

Recordkeeping and reporting responsibilities

Good records improve long-term management and help community programs respond.

• Maintain an inventory with species, size (DBH), planting location, inspection dates, and symptom notes.
• Photograph suspicious signs (close-up of holes, gallery, or woodpecker damage) with date-stamped images.
• Report confirmed or suspected EAB to your county extension or state plant health authority. Early reporting supports containment and eradication efforts at the landscape scale.

Practical takeaways — a short checklist

• Inspect ash trees at least once per year; high-value trees 2-4 times per year.
• Peak monitoring for adults: late May through August in Kansas. Winter inspections reveal decline and woodpecker activity.
• Use a mix of visual inspection, traps (where part of a program), and professional diagnostic peeling.
• Treat only healthy to moderately declining trees; remove trees with >50% crown loss.
• Time soil and trunk insecticide applications for late spring to early summer for best uptake.
• Keep clear records and report suspect EAB to local authorities.

Final considerations for Kansas landowners

EAB continues to spread and can be difficult to control once established. In Kansas, the combination of hot summers and cold winters does not prevent infestation–EAB has proven adaptable across temperate U.S. climates. The most effective approach is a planned program of seasonal monitoring, early treatment for high-value trees, removal of hazardous or heavily infested trees, and replanting with non-ash species to diversify future canopies.
If you manage municipal or multiple properties, develop a written monitoring plan that includes seasonal inspection calendars, prioritized tree lists, and contractor contacts for treatment and removal. For homeowners, start with an annual winter visual check and add a targeted late-spring inspection for adult activity. When in doubt about signs or treatment options, contact a certified arborist or your county extension for diagnostic help and specific recommendations tailored to your location and objectives.