Tuta absoluta: The South American tomato leafminer

Tuta absoluta (Lepidoptera: Gelechiidae), also known as the South American tomato leafminer, is native to South America and was accidentally introduced to Spain in 2006. By 2010, the moth had spread to rest of the Europe and Mediterranean. It reached the Middle East by 2011 and in 2012 in invaded Senegal in West Africa and Ethiopia in East Africa. It then spread to Kenya, Uganda and Tanzania by 2014 and also reached India during the same year. And in spring of 2016, it was confirmed in Nepal and Bangladesh. This invasive moth is one of the most serious pests of tomatoes, causing up to 80-100% crop loss. It also affects other solanaceous crops, such as potatoes, peppers, and eggplants.

Tuta attacks tomatoes by laying eggs on the underside of the leaves and sometimes on the stems and fruits. Once the larvae hatch, they mine into the leaves and also bore inside the stems and fruits to feed, often leaving the fruit unmarketable. And they’re prolific: a female leafminer will lay around 260 eggs in her lifetime of 30-40 days.

The insect deposits eggs usually on the underside of the leaves and to a lesser extent on stems and fruits. After hatching, the larvae mine into the leaves and also bore inside fruits and stems, often leaving the fruit unmarketable. It also alters the plant growth structure. The adult moth has a wingspan around one centimeter. In favorable weather conditions, ten to twelve generations can occur in a single year. It is a serious pest of both outdoor and greenhouse tomatoes.


Threat to the United States

While Tuta has not yet invaded the United States, we believe it is only a matter of time. In the western hemisphere, it has moved from South America as far north as Costa Rica. If Costa Rica is unable to contain it, it could move north and eventually cross our border with Mexico. In addition, it could be introduced from across the Atlantic or Pacific, either through accidental introduction (for example, if a tourist brings back an infected tomato) or through importation. The USDA is taking Tuta very seriously – they have created regulations on imports from Tuta-affected countries and have set up pheromone lures around the country to monitor for the leafminer.

While there is no silver bullet to eradicate Tuta if it does enter the United States, the best protection is early awareness and action. We recommend using pheromone lures to monitor for Tuta. It is also important for travelers to be aware of the pest so that they do not bring back infected tomatoes from abroad. Farmers should report leafminer damage on their tomato crops immediately to the USDA or local extension offices. Identifying the South American tomato leafminer can be difficult, due to the existence of similar-looking tomato pests.

If the pest does enter the United States, quarantine measures will be necessary to impede its rapid movement. For this, we are working with the Biocomplexity Institute at Virginia Tech on a project to model the spread of Tuta absoluta using human movement as a variable in addition to bioclimactic regimes. In this way, we will be able to find the most likely routes that the leafminer will spread once introduced, and this in turn will allow us to recommend the most effective quarantine measures.

Timeline and Spread of Tuta

Tuta graphic (3)


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