Start fly parasite releases when flies first appear so the beneficials can build on the first generations of flies. Good early control is easier and more economical than trying to catch up after fly populations explode.

Fly parasites attack fly pupae, helping prevent the next generation of flies from emerging. For best results, use them as part of an integrated program with sanitation, moisture management, and optional adult fly traps.

• Choose your mix: Standard (FP) Mix or Harsh Weather Mix (FPH)
 
• Release regularly: usually every 1-2 weeks; 3-4 weeks may work in preventive or maintenance situations
 
• Support the program: sanitation, traps, clean-out and drying manure in breeding areas, and other biological controls
 
• Expect progress: a noticeable reduction in flies often occurs in about 4-6 weeks

Need help choosing?

Use the Fly Control Program Planning Form below or contact us for a personalized recommendation.

Fly Parasites

Standard Mix (FP) - our general-purpose mix for temperate weather and indoor use

Harsh Weather Mix (FPH) - a more stress-tolerant mix for hot, dry, or cooler, drier outdoor conditions

Filth breeding flies, house flies, stable fly, lesser house fly

1 Unit

FP2

15.00

FPH2

17.30

2+ Units

13.90

15.20

5+ Units

11.90

12.40

1 Unit

FP10

23.50

FPH10

24.50

2+ Units

20.30

23.10

5+ Units

19.80

21.10

10+ Units

18.50

19.90

20+ Units

Inquire

17.60

1 Unit

FP50

69.50

FPH50

76.00

2+ Units

67.00

73.00

10+ Units

65.80

67.50

Effective, Economical Biological Fly Control

Start early for best results. Rincon-Vitova fly parasites are tiny beneficial wasps that help prevent flies by attacking fly pupae before adult flies emerge. Regular releases during fly season combined with sanitation and optional trapping—provide an effective, economical way to reduce fly populations before they build up.

To improve performance in different conditions, we offer two seasonal fly parasite mixes:

• Standard Mix - our general-purpose mix for temperate weather and indoor use
• Harsh Weather Mix - a more stress-tolerant mix for hot, dry, or cooler, drier outdoor conditions

Preventive fly control is easier, more effective, and usually less expensive than trying to catch up later.

Important

Fly parasites do not kill adult flies directly. They help prevent the next generation by attacking fly pupae, so best results come from starting early and combining them with traps and sanitation.

Choose Your Mix

Rincon-Vitova offers two fly parasite mixes to better match different climates and seasonal conditions.

Standard Mix (FP)

Our general-purpose mix for temperate weather and indoor use, including barns, enclosed poultry areas, calf areas, kennels, and other more protected environments.

Harsh Weather Mix (FPH)

A more stress-tolerant mix for hot, dry, or cooler, drier outdoor conditions, where tougher parasite species generally perform better. We adjust species ratios by season and region to provide more dependable biological fly control throughout the year.

Choose Your Unit Size

Our fly parasite units contain parasitized fly pupae from which beneficial adult parasites emerge after placement.

FP2 or FPH2 - very small areas or light preventive seasonal inoculation.

FP5 or FPH5 - half-size unit for small areas with low to moderate fly pressure.

FP10 or FPH10 - standard unit for small areas and starter programs.

FP20 or FPH20 - for moderate fly pressure or larger breeding areas.

FP50 or FPH50 - for larger operations or heavier fly pressure.

FP1BULK or FPH1BULK for very large operations.

FP10 Standard Unit: Each FP10 contains a minimum of 10,000 parasitized host fly pupae and produces a strong emergence of beneficial fly parasites, with total numbers varying by the species mix and season.

WHEN TO START

Start releases before flies become abundant.

• In seasonal climates, begin when weather starts to warm and the first flies appear.
• In warmer climates or indoor animal facilities, releases may be helpful year-round.
• It is much easier and more economical to prevent a fly buildup than to catch up after flies are already abundant.

Preventive releases almost always work better than delayed releases.

HOW OFTEN TO RELEASE

For most situations, release fly parasites every 1 to 2 weeks during fly season.

Weekly releases are best when:

• Fly pressure is already moderate to high
• manure stays wet
• breeding is continuous
• flies are migrating in from neighboring properties
• sanitation is difficult or inconsistent

Every 2 to 4 weeks may be adequate when:

• fly pressure is light to moderate
• manure is kept relatively dry
• sanitation is good
• traps and other controls are used consistently

Regular releases usually work better than occasional large releases.

Heavy fly pressure, wet breeding areas, or incoming flies from nearby properties usually require more units and/or more frequent releases.

• All FP sizes also apply to FPH sizes

MULTI-SHIP SAVINGS

Fly parasites work best when released regularly through the season. To support effective preventive programs, we offer savings when you schedule multiple ship dates in advance:

• 3 or more ship dates: 4% off
• 8 or more ship dates: 6% off
• 16 or more ship dates: 8% off

Your program depends as much on how many fly breeding areas you have as on how many animals or how the manure or decaying organic matter is produced. Likewise, where you place the fly parasites must be near all fly breeding areas, but NOT directly into wet manure or saturated spots.

Good placement areas include:

• edges of manure piles
• under feeders
• along fence lines
• bedding accumulation zones
• around calf hutches
• near wet food
• poultry litter edges
• loafing sheds
• stall corners and other protected breeding sites

Avoid placement where units may be:

• flooded or soaked
• buried in deep wet manure
• heavily trampled
• exposed to pesticides or near toxic bait stations
• where birds and rodents can find them

Place them where flies breed, but where the parasites can emerge and disperse successfully.

These tools can help improve placement, protect fly parasites after release, and reduce adult flies while your biological control program builds. In many situations, combining fly parasites with release stations or traps makes the program more convenient, more durable, and more effective.

Protective Release Stations

Durable release stations help protect fly parasites after placement from moisture, trampling, and disturbance. They can improve convenience and consistency, especially in stalls, loafing areas, poultry areas, calf areas, and other locations where the units might get wet or be stepped on.

Bucket Fly Trap

Our new bucket fly trap fits 3-, 5-, or 7-gallon buckets and uses durable window screen construction for long life, compact shipping, and easy storage. It offers an economical reusable alternative to disposable bag-style fly traps for reducing adult fly pressure.

NZI Biting Fly Trap

For biting flies, our NZI Biting Fly Trap provides effective fly reduction with no chemicals and no moving parts. It is especially useful where horse flies, deer flies, and other larger biting flies are a problem.

EcoTrap Jumbo Bag Fly Trap

Available Mid-April

Fly parasites are the core of the program, but some situations benefit from additional biological tools. When fly pressure is already high, breeding areas stay wet, or conditions are difficult, these products can help add pressure on flies in other life stages or in breeding areas where fly parasites alone may not be enough.

BaLance Fly Spray

BaLance Fly Spray uses spores of the insect-eating fungus Beauveria bassiana. It can be a valuable addition when adult flies are already abundant or when you want a broader biological fly management program. Think of it as a complement to fly parasites, not a replacement.

BaLance Darkling Beetle Spray

BaLance Darkling Beetle Spray also uses Beauveria bassiana spores, formulated for darkling beetles and related pests in poultry and other facilities where these insects become a problem. It may be especially useful where darkling beetles contribute to sanitation and pest management challenges.

Beneficial Nematodes for Flies

Beneficial parasitic nematodes (Steinernema feltiae) can help in moist breeding areas where flies are developing. They are best suited to damp or wet conditions and generally perform best above about 55°F. Nematodes can be especially useful in places where moisture makes fly breeding hard to interrupt.

Hister beetles (Carcinops pumilio)

Tiny beetles that mainly eat fly eggs and maggots in packed manure, especially helpful in poultry houses. To colonize, release in a moist manure pack where flies are starting to breed, a small clump on every pile. They do not travel easily between piles. At around 80F, the second generation of adult beetles will appear in 4 to 6 weeks. At 60F, reproduction is much slower. 10 days advance notice required.

15 oz bottle treats up to 50K sq ft

BalEnce Darkling Beetle Spray, an insect-eating fungus (Beauveria bassiana spores)

Beneficial parasitic nematodes for flies (Steinernema feltiae) for moist conditions over 55F

1 billion per acre

section

Hister Beetles (Carcinops pumilio) fly predator in packed manure

Fly eggs and maggots.   Release into 1-3 wk old manure pack depending on fly breeding

10K per manure pit.

HIS2

2K/cup

180.00

HIS10

10K/cup

850.00

Fly Parasite Frequently Asked Questions

1. Do the wasps kill adult flies?
• No. Fly parasites do not kill adult flies directly. They attack fly pupae, helping prevent the next generation of flies from emerging.
• For best results, combine fly parasites with traps and sanitation to reduce adult flies while the parasites suppress future generations.
 
2. How soon do they work?
• Fly parasites usually need several weeks of regular releases to noticeably reduce fly populations.
• Because they attack developing flies, they work best as a preventive program. If flies are already abundant, combine them with traps, sanitation, and reduction of wet breeding areas for faster improvement.
• Note: Fly parasite populations increase geometrically and take time to build, with a noticeable reduction in flies usually occurring in about 4 to 6 weeks.
 
3. Which mix should I choose?
• We offer two fly parasite mixes:
  • Standard Mix (FP) - our general-purpose mix for temperate weather and indoor use
  • Harsh Weather Mix (FPH) - a more stress-tolerant mix for hot, dry, or otherwise more challenging outdoor conditions

If you are unsure, Standard Mix is the best choice for most customers.

Contact us if you would like help choosing the best mix for your conditions.

 
4. How often should I release them?

For most situations, release fly parasites every 1-2 weeks during fly season.

 

Weekly releases are best when:

• fly pressure is moderate to high
• breeding areas stay wet
• flies are coming in from nearby areas
• you are starting after flies are already noticeable
 

Every 2 weeks may be adequate when:

• fly pressure is light to moderate
• sanitation is good
• manure is kept relatively dry
• traps and other controls are used consistently
 

Monthly releases may be appropriate when:

• you are on a preventive program, starting early in the season before flies become a problem
• you have excellent sanitation and low fly pressure
• you are in a maintenance phase where the parasite population has already become established
 

Note: Fly parasite populations increase geometrically and take time to build, with a noticeable reduction in flies usually occurring in about 4 to 6 weeks.

Regular releases usually work better than occasional large releases.

 
5. Where should I place them?

Place fly parasites near fly breeding areas, but not directly in wet manure.

 

Good placement areas include:

• edges of manure piles
• under feeders
• bedding buildup areas
• stall corners
• fence lines
• calf and poultry areas
 

Place them where flies breed, but where the parasites can emerge successfully.

6. Can I still use fly parasites if flies are already abundant?
 

Yes. Start fly parasites right away, but combine them with traps, sanitation, and reduction of wet breeding areas for faster results.

 

Fly parasites help suppress future generations of flies, so when adult flies are already abundant, the best results come from using them as part of a broader fly management program.

 

Odors can signal a biological process gone wrong that needs attention. They also attract flies to food and to places where they lay eggs. Controlling odors from decomposing organic matter, manure, and dirty drains can reduce fly attraction to compounds such as skatole from fermenting manure and alcohols from fermenting sugars. The goal is to shift decomposition away from anaerobic microbes that thrive without oxygen and toward more aerobic, balanced biological activity.

Start by Drying the Material

The first step is always to reduce excess moisture. Drier organic matter is less attractive to flies, less favorable for breeding, and easier to manage biologically.

EM-1 (Dr. Higa's Original Effective Microorganisms)

EM-1 can help shift decomposition toward a more balanced microbial process and is often used to help accelerate composting and improve the biological condition of manure and organic wastes. Available in quart and gallon sizes.

Invade Bio Cleaner

Invade Bio Cleaner helps clean dirty drains, pipes, and other problem areas where organic residues support odors and small fly breeding. It combines cleaning action with biological support to help break down buildup.

Invade BioFoam

Invade BioFoam is designed to cling to vertical and hard-to-reach surfaces in drains and similar problem areas. It helps clean filthy drains and pipes where organic residues and odors contribute to fly attraction and breeding.

BioWorld Odor Neutralizer

BioWorld's Odor Neutralizer helps intercept and neutralize odors in the air and on surfaces. It can be useful as part of a broader odor management program, especially where odors continue to attract flies even after sanitation efforts begin.

ITEM

DESCRIPTION

CODE

QUANTITY

PRICE

EM-1, quart, Dr Hilga's Original Effective Microorganisms

Fly parasites work best when combined with other fly management practices: improve sanitation where possible

Fly parasites work best when combined with other fly management practices:

• improve sanitation where possible
• reduce wet breeding areas
• keep manure drier when practical
• use baited traps or sticky traps to reduce adult flies
• avoid broad insecticide use in release zones

Fly parasites help suppress future generations of flies. Traps and sanitation help reduce adult flies now. Together, they work much better.

Get your supplies lined up early before temperatures rise. Preventive releases work better and cost less than trying to catch up after flies build up.

Email orderdesk@rinconvitova.com or phone us at 800-248-2847 to place or adjust your order. If you are unsure, start early and call us for help and sign up for our quarterly newsletter about fly control newsletter.