Respect for your privacy is our priority

The cookie is a small information file stored in your browser each time you visit our web page.

Cookies are useful because they record the history of your activity on our web page. Thus, when you return to the page, it identifies you and configures its content based on your browsing habits, your identity and your preferences.

You may accept cookies or refuse, block or delete cookies, at your convenience. To do this, you can choose from one of the options available on this window or even and if necessary, by configuring your browser.

If you refuse cookies, we can not guarantee the proper functioning of the various features of our web page.

For more information, please read the COOKIES INFORMATION section on our web page.


Refuse
Accept

News

Tuta absoluta: the threat extends, solutions multiply

24/05/2018 - François-Xavier Branthôme
Russia: Tomato moth found in Kuban region
In mid-May, the Russian press revealed that the Krasnodar region was recently invaded by the tomato moth (Tuta absoluta).
The tomato moth originates from South America where it has become a serious threat since 1980 to tomatoes grown both in greenhouses and in open fields. In 2014, Tuta absoluta was included on the list of pests targeted by quarantine measures in the Russian Federation. The pest has already crossed the border of the Krasnodar region and if it spreads further, it can harm not only tomatoes but other Solanaceae family varieties too. In 2015, the tomato moth was discovered in the region by the Kunpanova Polyana company, over acreage of 56 ha, and by the Rosinka company over acreage of 17 ha.

In order to prevent further spreading of this moth in the Krasnodar region, agronomists working at greenhouse complexes, growers and farmers need to be informed of the risks and be prepared to take all necessary measures to localize and deal with zones affected by the dangerous pest. 

A modelling system to track the tomato leafminer
Almost at the same time, researchers at Virginia Tech announced they have created a modelling system that tracks the tomato leafminer along trade routes, enabling warnings to be issued for the first time to countries bracing for invasion by the pest that threatens tomato crops worldwide.

Through the modelling system, researchers showed that the insects spread in Nepal along the trucking routes of tomato shipments. The models not only showed that food-transport systems are linked to the new incursions, but also demonstrated the role of humans. Muni Muniappan, director of Virginia Tech’s Lab for Integrated Pest Management, said the new research provides key details about the spread of pests. “Human activities – like carrying infested materials on airplanes, ships or vehicles – are instrumental to how pest invasion occurs,” said Muniappan, who sounded the alert on the worldwide “tomato emergency” in 2015, a year before the leafminer destroyed 80% of Nigeria’s tomato crop.

The tomato leafminer’s next strike is expected to be into Southeast Asia. The Virginia Tech lab’s two awareness-creating workshops in Cambodia in 2016 provided tools for farmers, policymakers, and scientists bracing for the invasion.
The research team that created the modelling system explained it might be of use to other industries as well, such as improving food flows and transportation logistics. Though centred on Nepal, the research can be adapted to other countries and pest invasions, such as a stink bug invasion that has reached Europe, scientists said.

Tuta absoluta is native to South America but was accidentally introduced to Spain in 2006. Now, it plagues Europe, Africa, the Middle East, and Central and South Asia. 

New tomato variety resistant to many insects
Scientists from Wageningen University & Research have discovered that a wild tomato from the Galapagos Islands is resistant to a wide range of pest insects. This variety is closely related to the cultivated tomato, making the resilience easier to interbreed into the latter and ultimately making tomatoes resistant to many different types of insects.

Cultivated tomatoes are far more vulnerable to pests and diseases than some of their wild relatives. The process of breeding modern tomatoes has resulted in the loss of a lot of their natural resistance, while wild varieties have remained much better at coping with insects.

Scientists have been working to reverse this by reintroducing resistances from wild tomato varieties via breeding. The problem is that most of these plants are very distant relatives of the cultivated tomato and scientists have yet to successfully interbreed the required traits. The wild tomato from the Galapagos Islands, however, is genetically very similar to the cultivated tomato. Moreover, its resistance is coded within a single chromosome, which should make cross-breeding into existing plants much easier. “We have been busy with this research since 2010,” said Ben Vosman, a scientist at Wageningen University and Research. “We worked with samples of the wild tomato variety Solanum galapagense from a gene bank. The first discovery was that this tomato variety is resistant to whiteflies. Then it turned out that it is actually resilient to a lot of other insects too, including the green peach aphid and caterpillars of the beet armyworm. That was a very pleasant surprise.” 

Cultivated tomatoes are easily affected by pest insects. One is the whitefly, which transmits viruses that infect the plants and eventually kill them. This fly is normally controlled by pesticides. “If we can make cultivated tomatoes resistant to whiteflies, this will directly benefit the environment,” Vosman states.

While this problem is still relatively manageable in greenhouses, for example through integrated control, there are pests there too. In field crops, the problems with insects are much bigger. “We expect most of the gain to be in field cultivation and in the tropics,” Vosman continues.

Equipping tomatoes with pest resistances
A study carried out by researchers at the IBMCP (Institute of molecular and cellular plant biology) at the Polytechnic University of Valence (UPV) has showed how tomato crops that have been genetically modified can increase their resistance to aggression by the Tuta absoluta insect pest.

Plants are sessile organisms, which means that they are born, develop, and die in the same place. Because they cannot escape a number of attacks, evolution has provided them with a wide genetic diversity that allows them to overcome various situations of stress. However, each year, approximately 40% of the world’s agricultural production is lost because of parasites and other pathogenic agents, and 13% is caused by insect infestations.

In order to face this threat, it is necessary to reinforce the various defense mechanisms of the plant. One of the alternatives being studied involves incorporating defensive genes into the plants thanks to genetic engineering techniques. Some of these genes can belong to other plant species that are quite a distant from phylogenetic point of view, such as the protease inhibitors found in barley.
Professor José Pío Beltrán, who is a research leader at IBMCP, explained that his team has studied the in vivo effects on Tuta absoluta of two inhibitors (serine protease and cysteine protease) extracted from barley. These inhibitors were incorporated separately then together in the different transgenic tomato plants used to feed the Tuta larvae, which subsequently showed a sharp drop in weight. Only 50% of them reached the adult stage and among these, many presented wing malformations and reduced fertility features.
Other research work has shown that incorporating protease inhibitors in transgenic tomato plants can increase their attractiveness for insects that prey on Tuta absoluta like Nesidiocoris tenuis, without having any adverse effects on them. Furthermore, IBMCP researcher Luis Cañas explained that “transgenic plants have increased their production of trichomes and modified the emission of volatile organic compounds.” Beltrán concluded: “Consequently, our work has shown that it is possible to put together an integrated management system against Tuta absoluta by simultaneously combining transgenic cropping techniques and biological control.”

Source: hortidaily.com, nrnews.ru, vtnews.vt.edu, Virginia Tech, Wageningen University & Research
 
Back

________________________________________

Editor : TOMATO NEWS SAS -  MAISON DE L'AGRICULTURE - TSA 48449 - 84912 AVIGNON Cedex 9 - FRANCE
contact@tomatonews.com
www.tomatonews.com

 

 

Supporting partners
Featured company
SUGAL
See directory
Most popular news
Featured event
15th World Processing Tomato Congress and 17th ISHS Symposium on Processing Tomato
Other events
Our supporting partners
Library Z-Library