Crust and Flies

Do you have an exploding fly population?

Can you see a manure crust on the top of the manure pit?

High-fiber feed alternatives combined with greater water efficiency have increased the percentage of solids in a manure pit by 200% compared to barns built 20 years ago. Those two changes alter the amount of dissolved oxygen in the waste and change the decomposition process. Anaerobic bacteria become dominant and create a crust that becomes a breeding ground for flies.

PitCharger's crust digesting products can help break away and dissolve the crust. Enzymes and bacteria that are specifically designed to attack surface-covering fiber and solids.


What causes the crust?

Causes of crust include:

  • Low liquid-to-solids ratio when using water-saving strategies

  • Floating grain hulls and fibers in the feed

  • Non-digestible fiber in manure due to DDGS feeds

  • Hair and feed dust

A crust starts with a thin scum forming over the water surface; each day, more and more solids stay above the water level. The crust begins to build and becomes a perfect environment for maggots to mature. Fiber (distillers grains) helps to hold the manure above the water level. The crust becomes a thick floating layer of hard-to-agitate waste.



Flies breed in fresh manure (or any organic matter) that maintains the correct moisture content, 50% to 85%. A fly population buildup is easier and cheaper to prevent and control than to treat when established.

Flies develop from egg to larvae to pupa to adult. The speed of this development is temperature-dependent. Under ideal conditions, they can go from egg to adult in as few as six days. Female flies live for 3 to 4 weeks in the summer and produce up to 800 eggs, approximately 75 to 150, at 3 to 4-day intervals. Flies can migrate over a mile, but typically movement is limited to less than .06 of a mile.

Quick ways to deal with an exploding fly population:

  • Agitating the manure pit breaks up the crust and causes it to submerge drowning the eggs and maggots.
  • Turn on soakers and sprinklers inside the building to moisten the crust to a point that is too wet for eggs and maggots to live.
  • At the same time, put out fly bait to kill the adult flies.

A "Pit Tip"

How to apply Pitcharger in a pit with crusting....

Apply PitCharger under the crusting instead of pouring on the top of the crust. Use a PVC pipe with a funnel taped to one end and apply UNDER the crust.

"flies are close to non-existent."

“Since using PitCharger we haven’t had the crusting issue we previously had and flies are close to non-existent. PitCharger has done everything I was told it would do.”

- Karl Johnson, Mankato, MN

"It works great."

“We really love not having flies in the barns in the summer! Also, in the fall when pumping we used to see a lot of solids in the semi tanker when we got towards the bottom of the pit and that made for some tough pumping into the applicator in the field. Since using PitCharger we don’t have that at all. It works great."

- JoAnn Berry, Winterset, IA