The distribution and abundance of phytoseiid mites (Acari: Phytoseiidae) on citrus in southern Africa and their possible value as predators of citrus thrips (Thysanoptera: Thripidae)
✍ Scribed by T. G. Grout
- Publisher
- Springer Netherlands
- Year
- 1994
- Tongue
- English
- Weight
- 610 KB
- Volume
- 18
- Category
- Article
- ISSN
- 0168-8162
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✦ Synopsis
Grout, T.G.. 1994. The distribution and abundance of phytoseiid mites (Acari: Phyloseiidae) on citrus in southern Africa and their possible value as predators of citrus thrips (Thysanoptera: Thripidae). Exp. Appl. Acarol., 18:61--71.
On citrus in Zimbabwe, Swaziland and South Africa, predacious mites of the subfamily Amblyseiinae are more common and found in greatc, numbers than phytoseiids of the subfamily Phytoseiinae. The author's survey and other collection data indicated that within the Amblyseiinae the genus Euseius Wainstein is the most widely distributed. Seven Euseius spp. have been recorded on citrus in the above countries but not more than one species has been found at any particular site and time. E. cirri (Van der Merwe and Ryke) has the broadest geographical distribution and is capable of suppressing population levels of the citrus thrips Scirtothrips atwantii Faure. However, it is not as effective a biocontrol agent as E. addoensis Wan der Merwe and Ryke) which occurs in higher numbers further south. An orchard comparison of the non-target effects of thripicides showed that E. cirri was more susceptible to sabadilla alkaloids (0.0024% AI) plus sugm-(0.96%) than to tartar emetic (0.398% A]) plus sugar (0.4%). The author's survey provides the first records of E. orygmus ~Ueckermann and Loots) and E. tutsi (Pritchard and Baker) on citrus in Zimbabwe. Typhlodromalus Muma spp. were not widely distributed but where they did occur they were often abundant and sometimes coexisted with Euseiu~" spp. Circumstantial evidence indicated that Typhlodmmalus spp+ may be effective thrips predators. The combination of Euseius and T.,;phlodromalus spp. may provide more effective biological control of citrus thrips than either species alone. Ambl),dromella Muma spp. were the only representatives of the subfamily Phytoseiinae currently found on citrus and they occurred only in the Transwtal and Natal provinces of South Africa. The possibility that Amblydromella spp. compete with Amblyseiinae is discussed.