What is Tuta absoluta?
Tuta absoluta or tomato leafminer, is a devastating Lepidopteran pest of tomato and other Solanaceae crops, including potatoes. Originating in South America, this pest has quickly invaded Central America, Europe, the Middle East, India and parts of Africa. Recent reports suggest that this pest has now been detected in South Africa and Zambia.
The moth is grey-brown in colour and 6-10mm in size. Tuta absoluta can reproduce very rapidly causing up to 100% crop losses on tomatoes. The larvae range in colour from green to light pink4 and tunnel within the leaf and fruit of the plant, producing irregular-shaped mines. In tomatoes, leaves and stems are severely damaged, and damaged fruit becomes unmarketable. Furthermore, affected plants are more susceptible to disease. Mainly the aerial parts of potatoes are affected, although damage to tubers has been reported.
Control of Tuta absoluta is challenging. The short generation time of this pest means that it has an increased capability of rapidly developing resistance to insecticides. The risk of resistance is increased when pest management protocols rely exclusively on a limited number of chemical insecticides 5. Furthermore, conventional control agents often have only low to moderate efficacy due to the nature of the damage and the fact that the larvae tunnel within the leaf, decreasing exposure time6.
Biological control may play an important role in managing Tuta absoluta, either as a stand-alone measure or as part of an Integrated Pest Management (IPM) programme. Pheromone traps are used to reduce the population numbers. Biological control methods including natural insect predators (used only with compatible pesticides) and bioinsecticides such as Beauveria bassiana, Metarhizium anisopliae and Bacillus thuringiensis amongst others have shown to be effective in the management of this pest.
Emergency registration of Eco-Bb for Tuta absoluta.
In response to a request from the South Africa Department of Agriculture, Forestry and Fisheries (DAFF), PHP has recently obtained an emergency registration for Eco-Bb to be used for the management of Tuta absoluta on tomatoes. Scientific evidence suggests that Beauveria bassiana strains are able to effectively suppress Tuta absoluta populations 1-3. Pest levels will be monitored and field trials will be conducted with Eco-Bb as soon as possible.
- Rodríguez, M., Gerding, M. and France, A., 2006. Effectivity of entomopathogenic fungus strains on tomato moth Tuta absoluta Meyrick (Lepidoptera: Gelechiidae) larvae. Agricultura Técnica, 66(2), pp.159-165.
- Klieber, J., and A. Reineke. “The entomopathogen Beauveria bassiana has epiphytic and endophytic activity against the tomato leaf miner Tuta absoluta.” Journal of Applied Entomology (2015)
- Marta, Rodríguez S., Gerding P. Marcos, and France I. Andrés. “Entomopathogenic fungi isolates selection for egg control of tomato moth Tuta absoluta Meyrick (Lepidoptera: Gelechiidae) eggs.” (2006).