What is a Grain Mite?
Grain Mite Description
2 different species:
1. Grain mite - Lepidoglyphus destructor
2. Storage/Mould mite - Tyrophagus longior
Just visible to the naked eye, these mites reach 0.5mm in length and can be seen moving slowly on the surface of grain or associated produce. Grain mites are commonly a pale, grey to white colour.
Larvae have 6 legs and they increase to 8 legs during the nymph to adult stage.
Have a wide distribution, especially in warmer climates. However, they can be found in warm grain stores worldwide.
They thrive in warm, moist conditions and prefer humidity levels of 80% with an optimum temperature of 20oC. These mites will survive colder conditions but will die without moisture.
Grain Mite Behaviour
Both species require a high moisture habitat and are common in food processing where stored produce is kept at a high humidity level, which also results in fungal growth.
A female will lay hundreds of eggs during the course of her lifecycle. Eggs are laid daily and are distributed singly or scattered across the surface of the grain. Egg to adulthood is a short phase so an infestation can take hold quickly.
These mites have a unique phase in the lifecycle called the hypopus, this is a nymphal resting stage, where the young mites don’t feed and are more resistant to control measures.
Risks associated with Grain Mites
The Grain Mite feeds on a wide variety of products, cereals, dried vegetable materials and dried fruits.
Mite populations in grain stores can build up very quickly. They have a preference for feeding on the cereal germ and contaminate grain with allergens that adversely affect its palatability. They also feed on mould and spread fungal spores, further damaging the grain.