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Ministry of Agriculture, Food and Rural Affairs

Stigmaeid Mites

Zetzellia mali (D. Epstein, MSU) Zetzellia mali and Typhlodromus pyri Mite eggs: European red mite (left), phytoseiid (middle), Zetzellia mali (right) (NYS Agric. Expt. Station, Geneva, NY)
Click to enlarge.

Beginner

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 apple orchards.  Populations depend to some extent on the numbers of apple rust mites available as prey.  Adults and nymphs are predaceous and feed on eggs and immature European red mite and two spotted spider mite, and all stages of apple rust mite.  Newly hatched larvae attack mostly apple rust mites. Z. mali persists in the orchard 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. Z. mali is not likely to provide effective biocontrol on its own – it prefers to feed on apple rust mite and does not require many prey items to survive.

Period of Activity
Tight cluster to pre-harvest

Insects Attacked
European red mite, twospotted spider mite and apple rust mite.

Monitoring and Management
Count numbers of predatory mites, including Z. mali and A. fleschneri, when conducting leaf sampling for phytophagous mites. These mites are sensitive to broad spectrum insecticides.  In combination with other phytoseiids mites or other mie predators these mites contribute to the maintenance of pest mite populations below.

Advanced

Scientific Names
Zetzellia mali (Ewing) and Agistemus fleschneri (Summers)

Identification
Agistemus fleschneri and Zetzellia mali are difficult to distinguish from one another.

Eggs:  Eggs are round and yellow and smaller then a spider mite egg.

Nymphs: Nymphs are lemon yellow but turn reddish yellow after feeding on European red mites.

Adults:  Adults are lemon-yellow mite and diamond-like in shape, though its gut may take the colour of prey following feeding.  They are 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.

Both stigmaieds are relatively slow moving, compared to other predatory species.  

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 apple orchards.  Z. mali overwinters as an adult female under bark and becomes active early in the spring, feeding on overwintering European red mite eggs and rust mites. It can be fairly effective in controlling low-density pest mite populations.. Females begin to search for overwintering sites in September but may be found on leaves as late as November. Populations depend to some extent on the numbers of apple rust mites available as prey.  The biology of A. fleschneri is similar to that of Z. mali.  There are four generations per year.  Populations do not increase as rapidly for stigmaeid mites as for phytoseiid species because the time required to complete development is much longer. Z. mali is the most widespread stigmaeid in Ontario. 

Adults and nymphs are predaceous and feed on eggs and immature European red mite and two spotted spider mite, and all stages of apple rust mite.  Newly hatched larvae attack mostly apple rust mites. Z. mali persists in the orchard when prey is 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. Z. mali is not likely to provide effective biocontrol on its own – it prefers to feed on apple rust mite and does not require many prey items to survive. As with other mite predators, Z. mali also feeds on the eggs of its rivals. Stigmaeid mites consume about one to two mite eggs a day.

Period of Activity
Tight cluster to pre-harvest.

Insects attacked
European red mite, twospotted spider mite and rust mites.

Monitoring and Management
Count numbers of predatory mites, including Z. mali and A. fleschneri, when conducting leaf sampling for phytophagous mites. These mites are sensitive to broad spectrum insecticides.  In combination with other phytoseiids mites or other mite predators these mites contribute to the maintenance of pest mite populations below economic thresholds.