Biological control of insect and mite pests on tomatoes: Survey of the
natural enemy fauna of South Africa
Although a number of natural enemies for control of horticultural pests
are available from overseas companies, it is impractical to import natural
enemies in large numbers into South Africa because of environmental concerns and
import restrictions, and distance and costs involved.
A joint initiative by ARC-PPRI Insect Ecology Division together with the
Tomato Producers' Organisation aims to utilise South Africa’s fauna of natural
enemies (parasitic wasps and predacious insects, mites and spiders) for the
biological control of the ten most important insect and six most important mite
pests on tomatoes as listed in Table 1.
|
TARGET INSECTS |
|---|
| SPECIES1 | ORDER and FAMILY | COMMON NAME |
|---|
| 1. | Bemisia tabaci (Gennadius) | Hemiptera, Aleyrodidae | Tobacco, cotton or sweetpotato whitefly |
|---|
| 2. | Trialeurodes vaporariorum (Westwood) | Hemiptera, Aleyrodidae | Greenhouse whitefly |
|---|
| 3. | Macrosiphum euphorbiae (Thomas) | Hemiptera, Aphididae | Potato aphid |
|---|
| 4. | Myzus persicae (Sulzer) | Hemiptera, Aphididae | Green peach aphid |
|---|
| 5. | Frankliniella occidentalis (Pergande) | Thysanoptera, Thripidae | Western flower thrip |
|---|
| 6. | Thrips tabaci Lindeman | Thysanoptera, Thripidae | Onion thrips |
|---|
| 7. | Liriomyza trifolii (Burgess) | Diptera, Agromyzidae | American leafminer |
|---|
| 8. | Phthorimaea operculella (Zeller) | Lepidoptera, Gelechiidae | Potato tuber moth |
|---|
| 9. | Chrysodeixis acuta (Walker) | Lepidoptera, Noctuidae | Tomato semi-looper |
|---|
| 10. | Helicoverpa armigera (Hübner) | Lepidoptera, Noctuidae | African cotton bollworm (often wrongly referred to as
American bollworm) |
|---|
|
TARGET MITES |
|---|
| SPECIES | ORDER and FAMILY | COMMON NAME |
|---|
| 1. | Tetranychus urticae Koch2 | Acari, Tetranychidae | Two-spotted spider mite |
|---|
| 2. | Tetranychus cinnabarinus
(Boisduval)2 | Acari, Tetranychidae | Common red spider mite |
|---|
| 3. | Tetranychus evansi Baker & Pritchard | Acari, Tetranychidae | Tobacco spider mite |
|---|
| 4. | Tetranychus lombardinii Baker &
Pritchard | Acari, Tetranychidae | Crimson spider mite |
|---|
| 5. | Tetranychus ludeni Zacher | Acari, Tetranychidae | Dark-red spider mite |
|---|
| 6. | Aculops lycopersici (Tryon) | Acari, Eriophyidae | Tomato rust mite |
|---|
1Although Agrotis spp. (Lepidoptera: Noctuidae;
cutworms) are important pests no suitable insect natural enemies have been
identified to date and other control measures have to be used.
2These two taxa belong to a complex of closely related species;
some acarologists consider T. cinnabarinus to be a good species, but
others recognise it as a junior synonym of T. urticae.
Survey of natural enemies
Qualitative surveys of natural enemies of key pests in three tomato-producing
areas in the Northern Province, the North-West Province, and Gauteng Province,
have been conducted. During the surveys, 42 sites in the three provinces were
visited from November 1999 to April 2000. Based on the results of these recent
surveys, scientific literature and records of specimens collected previously,
potential biological control agents were selected for further evaluation against
the ten most important insect and six most important mite pests on tomatoes.
