Fly Parasite Complex
(Unit Of 15,000)

Reduce Fly Populations with a Natural Predator

FREE Shipping!

Item Number: PBE250


In Stock! Ships directly from the manufacturer.


In Stock! Ships directly from the manufacturer.


Price includes delivery via Priority Mail (US Postal Service) either to your mailbox, or to a Post Office box.

Price includes delivery via Priority Mail (US Postal Service) either to your mailbox, or to a Post Office box.

Insects are sent out Monday through Wednesday. Place your order at least 3 business days in advance of desired shipping date (Monday holidays will delay processing of order). Unless you specify otherwise, we will send your Beneficial Insects on the next possible shipping day. You could also request delayed delivery in the Order-Specific Comments box.

Muscidifurax raptorellus, Muscidifurax zaraptor, and Spalangia cameroni are tiny wasps that don’t bother humans, but parasitize the pupae of many species of flies found in areas with livestock, breaking the life cycle of the flies.

You cannot place too many parasites. You can place too few. For dairies, feed lots and horse stables, we recommend between 300 and 500 parasites per animal per month during the fly season (March to October or November depending on weather). For confined hog operations, this number will be between 200 and 400 parasites per animal per month. Chickens require from 1 to 5 per bird per month. If your fly problem is very severe, these numbers should be increased; the first and second releases especially should be doubled or tripled.

  • Begin release program as soon as the weather begins to warm up.
  • Flies reproduce at a faster rate than the the fly parasites, so reintroduction on a regular basis is important.
  • Release every 1- 4 weeks during all warm months, generally March or April (once temperature reaches 80°F) through October.
  • For later starts, double the rates for the first 2 releases.
  • Use in conjunction with PVF&GS Fly Trap for best results.

Note: These creatures will die if left in direct sunlight or in a rural mailbox on a hot afternoon, or in cold weather. We only guarantee viability if someone accepts and inspects the insects immediately upon delivery. Be sure to open your box when you receive your order to prevent these beneficials from suffocating. You must contact us immediately upon delivery if you suspect a viability problem. Because of this, often the best address to use is a work address. If the Post Office is instructed to leave the package in a cool, safe place and it’s for a short period of time, viability should not be compromised, but cannot be guaranteed. If no one is available and no instructions have been left, delivery may be re-attempted the next business day. However, viability may be compromised and will not be guaranteed.


Application Season Fall, Spring, Summer Pest Control Class Beneficial Insect/Organism
Active Ingredient Beneficial Insect Application Frequency Multiple Application
Insect Control Flies
Application Season Fall, Spring, Summer
Pest Control Class Beneficial Insect/Organism
Active Ingredient Beneficial Insect
Application Frequency Multiple Application
Insect Control Flies

Useful Information

Use Instructions

Videos & Articles



What You May Need

Shipping Information

FREE SHIPPING via USPS Priority Mail to the lower 48 states. Ships directly from the manufacturer (tracking emails will not be sent — please call for tracking information). Cannot ship to the following states: HI, PR, VI, GU.

Shipping Weight: 1.00 lbs.


Wow, is it really true?

Despite our warm weather still lingering in September here in San Diego, there has been a sudden decrease in flies in our chicken run. Actually, scratch that... there are none. It is almost too good to be true! All I did was put up two new fly traps (which I use constantly anyway, and have been, with some success) and sprinkled a packet of these parasites about two weeks ago. Now, I can't find a single fly in the run! Either there has been a miraculous extinction of flies, or these parasites WORK!

Reviewed by on

A distinctly effective control for fly populations

I order these ever ~3 weeks during the spring/summer here in the Pacific Northwest, and distribute them outside of the kitchen, where the fly problem is most severe. I often wondered how efficacious these wasps were. Well, I found out this summer after I forgot and had five weeks between orders. The fly population exploded to at least 5x what it is normally, and after the latest shipment arrived and hatched, the numbers are again low and manageable. Between these and my Bug-A-Salt rifle, flies have gone from constant nemesis to almost-fun target practice.

Reviewed by on

Purchase Yearly

I have used these wasps for 2 years in a row now. They work so well I purchase them 2 twice a year to control flies from my chicken coop. Works great along with fly bait to kill the adults.

Reviewed by on

Great product

What a relief! On our urban lot, our dog run is too close to a patio for comfort. These wasps have promptly reduced the fly problem by at least 90%. I've ordered them twice and will continue to use them as recommended every year.

Reviewed by on

Very viable and excellent results

Ordered these twice. Delivered quickly. Parasites were noticeably viable. Easy to place and noticeable effects. Highly recommend. We have a horse and 100+ chickens. Always looking for a way to naturally address our fly issues. This is it!

Reviewed by on

Show More...

Write Your Own Review

The information provided in this box will NOT be published in your review.

By submitting your review for entry into our contest, you agree to the following: Each product review submitted will enter you into our monthly drawing for a $100 gift card, provided you chose to enter the drawing. Multiple reviews on the same product will count as one entry. One winner will be chosen at random every month. The winner will be contacted via phone and/or email. If we are unable to make contact with the winner within 30 days of the drawing date, that winner will forfeit their prize. We reserve the right to end this contest at any time, for any reason.

Write "HUMAN" in the field below.