No-See-Ums (Biting Midges)

📐 FIELD GUIDE ILLUSTRATION

No See Ums (Ceratopogonidae) identification illustration with labeled anatomical features — PestControlBasics.com

Original illustration by PestControlBasics.com. Use anatomical labels above to confirm your identification.

🔬

PestControlBasics Editorial Team

Reviewed by Derek Giordano · Updated 2026

🔍 Identification

Adults: 1-3mm — barely visible to the naked eye; greyish; mottled wings; disproportionately painful bite for their size. Active at dusk and dawn (crepuscular) in calm conditions — wind above 5 mph grounds them. Peak seasons vary by species and region. Coastal, salt marsh, and freshwater wet areas have highest populations.

🧬 Biology & Behavior

Female midges require blood meal for egg development. They breed in wet mud, marshes, salt flats, mangrove areas, and moist organic soil. Unlike mosquitoes that breed in standing water, no-see-um breeding habitat is wet mud and organic material — much harder to eliminate. They pass through standard 18x16 mesh window screening.

⚠️ Damage & Health Risk

Intensely itchy, painful welts disproportionate to the insect's size; potential transmission of livestock diseases (bluetongue, equine encephalosis); significant nuisance impact on coastal recreation.

🔧 DIY Treatment

DEET 30%+ or picaridin 20% provides some protection (less effective than against mosquitoes). No-see-um-specific window screening (very fine mesh — 20x20 or finer) for screened porches. Fan-generated wind disperses them. Permethrin spray to vegetation near seating areas. Avoid outdoor activity at dusk and dawn in high-pressure areas.

👷 When to Call a Pro

Area foggers with permethrin or malathion in commercial settings (golf courses, resorts) provide temporary knockdown.

❓ FAQ

Does DEET work against no-see-ums?

DEET provides moderate protection — less effective than against mosquitoes. High concentration DEET (30-100%) is recommended. Picaridin 20% may perform similarly. Neither provides complete protection; combining repellent with avoidance of peak activity times (dusk, dawn, calm conditions) is the most effective strategy.

What screens keep out no-see-ums?

Standard 18x16 mesh window screens do NOT exclude no-see-ums — they're too small. No-see-um exclusion requires 20x20 or finer mesh screens, which significantly reduce airflow. This trade-off often makes fine screening impractical for whole-house use but useful for a screened porch or specific protected area.

Factor	Details
U.S. Range	All or most U.S. states
Regional Detail	Distribution varies — consult your local extension service for regional prevalence data.

Factor

Details

U.S. Range

All or most U.S. states

Regional Detail

Distribution varies — consult your local extension service for regional prevalence data.

📅 Treatment Timing Guide

Treating at the right time dramatically improves results. Pest control timed to the life cycle uses less product and achieves better long-term control.

Period	Action
Spring	Inspection and perimeter treatment before pest season starts.
Summer	Active monitoring and targeted treatments as needed.
Fall	Preventive treatment before overwintering pests seek entry.

Period

Action

Spring

Inspection and perimeter treatment before pest season starts.

Summer

Active monitoring and targeted treatments as needed.

Fall

Preventive treatment before overwintering pests seek entry.

💰 Professional Treatment Costs

Service Type	DIY Cost	Professional Cost
Initial inspection	Free (self-inspect)	$75–$150 (often credited to treatment)
One-time treatment	$30–$100 in materials	$150–$500
Annual service contract	N/A	$400–$900/year
Severe infestation	Often ineffective alone	$500–$2,500+

Service Type

DIY Cost

Professional Cost

Initial inspection

Free (self-inspect)

$75–$150 (often credited to treatment)

One-time treatment

$30–$100 in materials

$150–$500

Annual service contract

N/A

$400–$900/year

Severe infestation

Often ineffective alone

$500–$2,500+

Prices vary by region, property size, and infestation severity.

❓ Common Questions About Biting Midge (No-See-Um)

How do I confirm I actually have this pest (not something similar)?

The most reliable confirmation is a physical specimen — capture one and compare to reference images on this page. For cryptic pests (bed bugs, termites), look for secondary signs: frass, shed skins, mud tubes, or bites with a specific pattern. When uncertain, a professional inspection is faster than months of misidentification.

Can I treat this myself or do I need a professional?

DIY is effective for small, accessible infestations caught early. Professionals are worth the cost when: the infestation is inside wall voids or structural elements, multiple rooms are affected, you have health-risk pests (hantavirus, venomous species), or DIY has already failed twice.

How long until the infestation is completely gone?

Expect 3–8 weeks for most infestations with proper treatment. Insects with dormant life stages (pupae, eggs) extend the timeline because those stages are impervious to most insecticides. Follow-up treatments at 2 and 4 weeks catch each new cohort as they emerge.

What's the most common mistake people make treating this pest?

Treating only the visible pest population while ignoring the harborage site, entry point, or breeding location. Killing adults provides temporary relief but the population rebuilds from hidden egg cases, pupae, or new arrivals through unaddressed entry points.

🪰 Biting Midge (No-See-Um)