EU biological control project produces new virus to fight tomato leaf miner
Tomato leaf miner larvae feed on leaves and fruits, from seedlings to mature tomato plants. Infestation is often followed by infections by secondary pathogens rendering infested crops unmarketable, if not totally destroyed.
Tomato and other Solanaceae are among the most widely cultivated vegetables in Europe as well as worldwide. Production of several of these crops is threatened by infestation of the invasive tomato leaf miner Tuta absoluta. The pest is originating from South America and is now invading field and greenhouse production sites in Europe. Since 2006, the tomato leaf miner has rapidly spread across southern Europe and the Mediterranean area, including Spain, Portugal, France, Italy, Northern Africa and more recently Australia. The insect has also been found in commercial greenhouses in the Netherlands, United Kingdom, Germany and several other countries.
In the EU project BIOCOMES – coordinated by Wageningen University & Research (WUR) – a large, international consortium of thirteen commercial companies and fourteen research institutes worked together on the development of new biological control products.
The BIOCOMES objectives were to identify and characterize some baculoviruses suitable for control of tomato leaf miner as well as potato tuber moth and Guatemalan potato moth; to select the most virulent strain for greenhouse and field testing; to optimize the production of the virus by ensuring its genetic and biological stability; to optimize the application strategy for the control of insect pests of solanaceous crops and develop a biocontrol agent ready for marketing
The availability of these products is becoming more and more important in order to control pests and diseases in plant crops in a sustainable and environmental friendly way. After four years this ambitious EU project has proved to be an excellent example of how a public-private cooperation can make the difference.
Although the development of new biological control products generally takes quite a long time, the BIOCOMES partners have successfully developed several new products with commercial potential. BIOCOMES coordinator Jürgen Köhl of WUR therefore concludes that the results after four years of BIOCOMES are very good. “Eleven biological control agents are now in development, with two already on the way to registration. In addition, several new insects will be marketed as biological control agents. It is important to point out that these are all products which may have a major positive impact on the environment when replacing chemical crop protection. And without this public-private partnership these products would not have reached the market!”
BIOCOMES Biological Control Agents (BCA) against tomato leaf miner
For control of tomato leaf miner, chemical insecticides have been applied and biological control strategies have been evaluated. However, Tuta absoluta already shows resistance to many chemical insecticides. Tomato leaf miner is currently controlled by spraying specific synthetic insecticides.
As larvae are internal feeders it is difficult to achieve an effective control through application of chemical insecticides. Moreover, tomato leaf miner can rapidly evolve strains with resistance to insecticides that have been previously effective. Failure by synthetic insecticides has also been reported in many countries.
That is the reason why the development of efficient biological control tools is essential. Some satisfactory results have been achieved with application of predators and parasitoids with entomopathogenic nematodes, as well as with the spraying of Bacillus thuringiensis products. However, more efficient bio-control agents need to be developed and reliable control strategies have to be established.
At the end of the BIOCOMES project, isolates of the entomopathogenic baculovirus PhopGV have been selected for their virulence to tomato leaf miner, among other pests. The isolates will be characterized by biological and molecular means and will be tested in greenhouse and field trials. Based on these findings a product for combined control of pests will be soon developed.
Wageningen University recently announced that two new products are now ready to be submitted for registration. One virus product to combat the tomato leaf miner Tuta absoluta and a fungus product to control fusarium in cereals. “Commercial exploitation of these products is almost certain,” Köhl says enthusiastically.