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White Mites Phytoseiulus persimilis
White Mites   Phytoseiulus persimilis  


Mites in worm bin by Jerry Avillion

Mites in worm bin by Jerry Avillion

Mites are the second most-common invertebrate found in compost. They have eight leg-like jointed appendages. Some can be seen with the naked eye and others are microscopic. Some can be seen hitching rides on the back of other faster moving invertebrates such as worms, millipedes and beetles. Some species eat fungi, yet others are predators and feed on nematodes, eggs, insect larvae and other mites and springtails. Some are both free living and parasitic. One very common compost mite is globular in appearance, with bristling hairs on its back and red-orange in color. Most mites are not harmful to you, your worms, or your plants. Brown predatory mites are very rarely found in worm bins.

Mite populations can bloom to incredibly high numbers in a short time. There is really no need to worry about them because mite population blooms are cyclical and will decrease naturally with time. They are the types of mites that eat
dead decaying organic material just like the other beneficial organisms in the worm bin, so there is usually no need to take action against them.

Conditions That Can Lead To Mite Infestation

  • Too much water - Bedding that is too wet creates conditions that are more favorable to mites than worms. Avoid excessively wet beds by improving drainage, and turning bedding frequently.
  • Overfeeding - Too much food can cause an accumulation of fermented feed and heat up worm beds plus lower the pH of the beds. Adjust feeding schedules so that all feed is consumed within a few days. Modify feeding schedules as the seasons (and temperatures) change because worms consume less food in colder temperatures. Maintain beds around a neutral pH 7.
  • Excessively wet or fleshy feed - Vegetables with a high moisture content, pulp from juicing, or blenderized waste can cause high mite populations in worm beds. Limit the use of such feed, and if high mite populations are discovered, discontinue the use of this feed until mite populations are under control.

Ways to Reduce Mite Populations

  • Uncover the worm beds and expose them to sunlight for several hours to allow bedding to dry a bit. Reduce the amount of water and feed.
  • Place pieces of watermelon or cantaloupe rind or potato slices on top of the worm beds. Mites are attracted to the sweetness of the rinds or peels and will accumulate on them. The rinds or peels can then be removed and dropped in water or buried.
  • Heavily water, but do not flood, the worm beds. Mites will move to the surface, and worms will stay below the surface. Use a hand-held propane torch to scorch the top of the bed and kill the mites. This procedure may be repeated several times, at three day intervals, if needed.
  • Remember that mites are a common invertebrate in vermicomposting systems. No need to get upset or worried, everything will be fine and the mite bloom will be over in a few weeks. Taking no action is sometimes the best action; let nature take its course.

© 2008 Happy D Ranch

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