A typical warm, wet British summer provides ideal growing conditions – and not just for your grass and weeds. Insects thrive as well.

It’s this time of year – just as our horses go out more – that the amount of hard feed used can drop considerably. This means that it lasts for longer in the storage bin and is fair game for anything small or furry that fancies a nibble.

Residues of winter feed use, the crumbs and spillages accumulated over the past nine months or so, are also manna for insects. Wherever there’s grain, the tiny grain or flour mite (Acarus siro) is capable of setting up residence, not only in farm-stored grain, but also in animal feeds, breakfast cereals and flour. Mites aren’t poisonous, but they do spoil food and make it unpalatable.

When conditions (food, moisture and warmth) are right, a 2,000-fold population growth can occur within a month. Any time from spring to late autumn is breeding time for mites, especially if the feed room is dusty and dirty, spillages aren’t cleared up quickly or feed is at the end of its shelf life.

If your feed room has that stale honey-like aroma, the chances are you have a mite problem. If you open a bag and it contains fine dust or if when you buy it from your feed merchant there’s a light brown dust on the surface or around the stitching, then you, and probably your supplier, have a mite infestation.

Should this happen, a thorough clean in every nook, cranny and window ledge will be necessary, preferably with a vacuum cleaner. A brush just sends the mites up into the air, so they land and re-infest.

Storage and hygiene

  • Keep the feed room clean and dry. Leaks or spills should be cleaned up immediately and a thorough clean-out, inside and behind storage bins, should be yard routine.
  • Use old feed up before adding new – both forage and hard feeds.
  • Check the shelf-life of bought-in products, and alter ordering patterns so that feed is used well within them, especially during summer. Cereals such as oats and barley are harvested in August, so the grain you buy in June is almost a year old.
  • If your horse is at DIY livery with communal storage, the risk of mites is only kept low if everyone maintains a clean feed store.
  • Keep feed in a dry, well-ventilated area, out of direct sunlight, to prevent both spoilage from mites and the deterioration of vitamins and oils. I have found feed for field-kept ponies kept in metal dustbins at the side of the Field – nothing is more likely to make feed go off than “cooking” it in this way.
  • Choose a good feed supplier with a clean, well-maintained store and good stock rotation.