Stigmaeid Mites
Scientific Names
Zetzellia mali (Ewing) and Agistemus fleschneri (Summers)
Identification
Agistemus fleschneri and Zetzellia mali are difficult to distinguish from one another. Both stigmaieds are relatively slow moving, compared to other predatory species.Eggs:
- Round and yellow
- Smaller then a spider mite egg
Nymphs:
- Lemon yellow but turn reddish yellow after feeding on prey
Adults:
- Lemon yellow mite, though its gut may take the colour of prey following feeding
- Diamond-like shape
- Slightly smaller then either adults spider mites or A. fallacis
- Agistemus can be distinguished from Zetzellia by the presence of a honeycomb pattern visible on the posterior half of the back
Often Confused With
European red mites - Adult female Agistemus can be confused with European red mite, but do not possess the rows of raised spines or hairs on the back.
Interaction With Host
Along with phytoseiids, stigmaeid mites are the most abundant predatory mites in North American vineyards. Adults and nymphs are predaceous and feed on eggs and immature European red mite. Z. mali persists in the vineyard when prey are scarce, surviving on pollen, sap and fungal spores. It is less mobile than other predatory mites, and slow to travel to new feeding sites in search of prey.
Period of Activity
Spring to late summer.
Insects Attacked
European red mite.
Monitoring and Management
Note the number of these predatory mites when counting European red mites. These predatory mites are sensitive to broad spectrum insecticides. In combination with other phytoseiids mites or other mtie predators these mites contribute to the maintenance of pest mite populations below threshold levels.
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