menu toggle

Beetle management from past to present

By MWI Animal Health

The control of the Lesser Meal Worm, better known in the broiler industry as the “Darkling Beetle” has been a challenge from time to time to say the least. Many industry management strategies and husbandry changes have added to that challenge.
chicks primping

Each year, beginning in late July and lasting through mid-November, the phones begin to ring and the concern about litter beetles reaches levels of great intensity. After the summer heat has driven the beetles’ life cycle to its optimal speed, from egg to egg laying adult, we sometimes see great numbers of beetles in poultry houses in the fall and begin to question our practices. Let’s take a look back at how things used to be and compare them to how things are now, so that we can understand a little about what is going on, why, and what can potentially be done to aid control.

As late as 12-15 years ago, nearly all broiler integrators had beetle “programs” that were haphazard and quite varied. Many companies allowed the producers to determine when and how to go about controlling beetles on the farms. This resulted in various approaches and tremendously varying 16 Integrated pest management Continued on next page results. In addition to that, litter management was quite widely left up to the producer. Total house cleanouts were often frequent with much of the litter being applied in local proximity to the farms. The typical integrator would have seen producers completely remove the litter from the poultry house a minimum of once annually to as often as every flock before installing new bedding material. Once or twice a year an insecticide would be applied to the bare floor of the facility prior to the new bedding. Insecticides were provided by some companies with consideration of rotating active ingredients and chemical classes, while others allowed the producers to select the products to use. Furthermore, the minimum litter/bedding depth 10 years ago was much less than what is required today. We also had fewer solid-walled houses, with many having “light” curtains.

Fast forward to the present and we see much has changed. Nearly every broiler integrator has an intensive beetle control program, with most utilizing a custom applicator. Also, nearly every integrator has changed how poultry litter is managed with requirements for greater litter depth and much less frequent complete litter removal. Complete cleanout is a physical method of beetle control because many of the beetles and larvae are carried out of the house during clean out. This does not necessarily mean they die, but removing them from the house reduces the population at placement of the next flock of birds. When the litter is rarely removed either partially or completely, and windrowing of the litter is not a common management tool, beetle control efforts become totally reliant on chemical control. This means that greater pressure for chemical resistance is placed on the limited number of insecticide classes available for use in poultry houses for beetle management.

One other consideration is that, as an industry, we also have nearly completely transitioned to solid walled houses with low light intensity production. “What difference does that make,” you ask? Well the beetles are primarily nocturnal so the low light environment is conducive to their propagation.

Summary of changes then and now

Then (12 - 15 years ago)

  • Frequent complete litter removal
  • Lower depth of litter required (2–4”)
  • Lower frequency of built-up litter
  • Insecticide applied to the bare floor
  • High volumes of water used to apply
  • Insecticide often mixed with disinfectant
  • Varied control of insecticide rotation
  • Individual producer-applied program
  • Varied program and application
  • Light side curtain-walled houses


  • Infrequent complete litter removal
  • Greater depth of litter required (6–8” minimum)
  • Litter reused each flock resulting in older, deeper litter
  • Insecticide applied to top of bedding only
  • Low volumes of water used to apply
  • Insecticides rarely mixed with disinfectants (which they should not be)
  • Integrator-approved/managed insecticide rotation
  • Custom applicator-applied program
  • Uniform program and application in a complex
  • Solid-walled houses with lower light intensity

Often, changes in the broiler industry's husbandry practices and how they affect the darkling beetle populations can be compared to quality deer management. When managing property for a healthy whitetail deer population, one often has other species (such as the wild turkey) proliferate along with the deer. That is because most all of the management strategies that benefit the whitetail deer are also good for the wild turkey. That is also the case with the industry’s best management practices for optimal broiler growth and performance. Those practices are exceedingly beneficial for optimal litter beetle growth and performance.

What are things we can do to improve our probability of success in our darkling beetle control efforts? These are some effective strategies:

  • Partner with a reputable custom applicator.
  • Use only insecticides approved for poultry housing and production animal facilities.
  • Use products according to their labeled direction. Do not exceed the maximum labeled rate.
  • Use the highest labeled rate on all approved products.
  • Rotate between chemical classes, not just trade names and active ingredients.
  • Use a reduced amount of water application method, generally around 1 gallon per 1,000 sq. ft.
  • Use a dedicated piece of equipment for applying insecticides and keep it cleaned, maintained, and calibrated.
  • Do not mix insecticides with other chemicals (i.e. herbicides, cleaners, disinfectants, etc.).
  • Apply insecticides to the top of the bedding, whether built up litter or new bedding material.
  • Apply insecticides as a final step prior to house setup. Do not disturb the litter (drag, till, smooth) after applying insecticides.
  • Incorporate IGRs (Insect Growth Regulators) into a program. These aid in breaking the life cycle of the beetles.
  • Utilize the MWI Animal Health Entomology Laboratory to detect chemical resistance.

Other things a producer can do to enhance beetle control:

  • Use a quick-kill insecticide to treat for beetles while working the litter. Beetles typically become agitated and active after tilling, caking, and windrowing. This is a great time to contact active and exposed beetles.
  • Preheat the house prior to the custom applicator treating the houses. Preheating gets the beetles more active compared to a cold house. This is referring to warming the house prior to insecticide application and is not referring to the preheating required for brooding.
  • Do not treat houses in addition to the custom applicator (if used). Often the applicator and producer use different classes of chemicals which may affect insecticide resistance and future insecticide class rotations.
  • Incorporate Boric acid into a program. Boric acid is in an insecticide class alone and not utilized in the normal chemical class rotations. Boric acid can greatly enhance a chemical beetle control program.
  • Treat the exterior of the poultry houses to prevent newly arrived beetles from entering. This also aids in controlling flies and other insect vectors.

While the challenge for adequate darkling beetle management has increased, all is not lost. There are still steps we can take to improve our probability of success.

Complete cleanout is a physical method of beetle control because many of the beetles and larvae are carried out of the house during clean out. This does not necessarily mean they die, but removing them from the house reduces the population at placement of the next flock of birds.