Managing Mites For Mealworms

What Causes Mite Infestations

• Mites generally like high temperatures and humidity. Remove these 2 factors and more times than not they disappear.
• Will readily take hold if you don’t have good hygiene. You should replace frass and old wet food regularly.
• Entry is often through food by not storing substrate in sealed containers or from breeding sources (ie came in from pet store originally).
• Poor ventilation, particularly in the corners (See below important note).

Important Note:

In our consultations many businesses who experience mites note they develop in the corners first then spread out. The corners have poor ventilation (isles have best ventilation when using pedestal fans). Increasing the ventilation (including the corners) is a quick and cheap way to reduce the infestation. 

6 Steps to Eradication

In reality it is very difficult to remove all mites (ie washing or manual methods), and in most cases its managing the environment and climate which will make them go. Below are 6 Key Concepts to incorporate into eradicating mites.

1) Pest Management Plan

Refer to the Pest Management Plan for guiding concepts and principles to help you implement the following steps.

Air tight drums or 20L containers can be used to store substrate to prevent mites entry. 

2) Prevention and Early Detection

Prevention

• Prevention and early detection are will reduce the scale and duration of an infestation. Refer to Preventing Pests Section for ideas.
• Keep substrates in air tight containers and freeze the substrate. (Refer to Storing Substrate Section)
• Prevent excessive high temps (over 28 degrees) and high humidity (over 60%). Reducing these two factors is essential as stops them in their tracks and makes the following steps far more effective. See Humidity section and climate control section below on tips to reduce humidity.

Early Detection

• A stitch in times saves nine. Early detection will reduce the amount and duration of problem. If you haven’t seen mites before they can be easily mistaken for mold. Look at adjacent photos to help reduce the confusion with mold. You can click on the photo to see the mites close up.
• At the early stages mites are at low numbers and when they climb up the tray walls they can be confused with small substrate particles. One way to distinguish a mite from substrate is to look at a small white dot on the side of the tray wall, and if it moves its a mite. You may need to look very carefully and sit and watch for 30 or more seconds to see it move. Move to another white dot and repeat. If any move you have mites.
• As a routine job you should inspect trays for mites during maintenance, harvest and every time you remove food from the substrate storage drums.

In high densities mites can gather into clumps which look like brown or grey mold.

Mites on beetles can look like a mold infestation. This grey mold looking covering is mites when you look closely.

Large amounts of mites often climb out of the container and fall onto the ground. In high densities this can look like dust or mold.  We cleared a section of the mites with my hand to show the difference between normal floor and mites.

3) Climate Control

• Lower Temperature to around 20 degrees which is lower than productive growth but reduces prevalence of mites. Once infestation has passed you can return temperatures to 20-25 degree range. If you have climate control adjust air conditioner or thermostat. If you don’t have climate control find a cooler location, but try to avoid temperatures lower than 15-20 degrees (see tip below-Dew point).
• Lower humidity temporarily to 40-45% range to help remove mites, then return to 50-60% range after infestation.  Lower humidity levels over the long term may affect molting and pupa survival rate however most infestations will be under control within 7-12 days depending on the severity.
• If you don’t have climate control try to remove the farm from heat and humidity sources as much as possible.

Tip:   

Avoid lower temperatures (less than 10-15 degrees ) as this get below the dew point which will encourage precipitation of humidity onto the substrate and tray sides. This will fuel mites even further. Click her for further information on Dew Point.

Many breeders in our consults report that increasing cleaning and lowering humidity often makes Mites go away (Crickets and Mealworms). For crickets you may wish to maintain higher humidity , so you can start with increasing humidity, see if this works, if not then lower humidity .

Air conditioning (back) will lower temperatures and humidity. Dehumidifier (Front) will lower humidity.

4) Clean, Replace and Filter

Many of the mites and their eggs reside on the tray walls, the substrate and the frass. You can remove the bulk of the mites and egg source by doing the following steps.

5) Containment

• Isolate contaminated containers with oil ( we used olive oil) or Vaseline smeared with a 2 inch band on the top of tray.
• We found Vaseline to be difficult to clean on a regular basis. Olive oil worked well and easily washes off with water and detergent.

Wiping Tray Sides

Use unscented baby wipes to wipe the inside of the tray and remove mites that have climbed up the sides. Avoid wiping the 2 inch oil/ vasoline barrier at the top of the tray.

Wipe and wipe again….In high densities you will need to wipe the sides daily. In medium density every second day. In low density as often as required.

A 2 inch band along the top of the tray sides, trapes mites as they try to move out of the tray.

6) Moisture Traps

Mites need water to reproduce and grow. Now that you have removed most sources of free water (lowered humidity and reduced or removed wet foods), they will be thirsty for water. The following traps work best once you have removed existing water sources such as wet food and lowered humidity to around 50%. We add the following traps to attract the mites which we then remove and clean them daily or as required for low numbers.

You only need to add one of these traps to reduce humidity to a minimum. We found the food traps worked best in high densities and the water traps worked well in both high and low numbers, however this many vary on setup so try both and see which one performs better.

Water Traps

Add small containers with  filled with water on top of the substrate. Small containers with low profile sides work best as they make it easier for mites to fall into the water. *See adjacent photo). In high densities they will climb the sides and fall into the water. In low densities they will climb the sides.

Food Traps

You can make a Food trap by adding a piece of moist carrot onto an adapted Pupa Platform. Refer to the Building a Pupa Platform section for building instructions. For the food tray, you can remove the cutlery liner as it is not needed.

Water Trap on left and Food trap on right. Water traps work best when they have shallow sides to allow easy entry of mites into the water. 

Water in the water trap is cloudy due to numerous mites having been trapped and killed. 

Food trap with carrot on top. Mites are drawn onto the trap and carrot in high densities. Remove, clean and replace daily with high densities.