Balaustium medicagoense Meyer & Ryke

Halliday, R. B., 2005, Predatory mites from crops and pastures in South Africa: potential natural enemies of redlegged earth mite Halotydeus destructor (Acari: Penthaleidae), Zootaxa 1079, pp. 11-64 : 29

Balaustium medicagoense Meyer & Ryke

Balaustium medicagoense Meyer & Ryke, 1959b: 310 .

Balaustium medicagoense: Agriculture WA, 2000: 1; Halliday, 2000a: 8; Halliday, 2001a: 327. Balaustium cf. murorum: Southcott, 1976: 145 ; 1978: 18.

Balaustium murorum: James, 1995: 58 ; James et al., 1995: 648.

Specimens examined: Site 94­5, 101 females, 7 N, 5 LV; Site 94­7, 1 female; Site 99­5, 3 males, 3 LV; Site 99­19, 10 females, 1 N; Site 99­25, 1 female; Site 99­28, 2 females;Site 99­29, 1 N; Site 2000­1, 5 females; Site 2000­19, 3 females; Site 2000­20, 26 females; Site 2000­21, 5 females, 1 male; Site 2000­23, 1 female; Site 2000­24, 3 females; Site 2000­25, 1 female.

Balaustium medicagoense was described from South Africa but also occurs in Australia ( Halliday, 2001a). It has been regarded as a beneficial predator in southern Australia (James, 1995; James et al., 1995, as B. murorum ), but it can also be a significant pest of cereal crops (Agriculture WA, 2000). It appears to have been introduced into Australia from South Africa. Australian specimens previously identified as B. murorum ( Southcott, 1976, 1978; James, 1995; James et al., 1995) belong to this species.

The sex ratio in the available collections is heavily biased towards females (159 females: 4 males). The significance of this observation is not clear, but further research on its biology may show that it is usually thelytokous.