- Author: Kathy Keatley Garvey
That would include the larvae of Tuta absoluta, a South American tomato leafminer. In its adult stage, it's a moth in the family Gelechilidae. In its larval stage, it's a major agricultural pest.
Since 2008, it has invaded much of Europe, northern Africa, and the Middle East, according to a California Department of Food and Agriculture post.
It hasn't yet invaded the United States, but scientists say it has moved from South America as far north as Costa Rica.
The bug "is a serious and devastating pest of tomatoes, causing crop losses as high as 80 to 100% in areas where it is found," according to a Pest Alert article published by the UC Statewide Integrated Pest Management Program. "This insect bores into leaves, stems, flowers, and fruit, often leaving the fruit unmarketable and altering plant growth structure through destruction of stem apical buds or flower buds. To manage this insect, growers may be forced to greatly increase the number of insecticide applications to their tomato crops."
The article, by UC Davis scientists Kris Godfrey of the Contained Research Facility, and Frank Zalom and Joanna Chiu, both of the Department of Entomology and Nematology, points out that the "South American tomato leafminer spreads via commercial trade of plants and fruit infested with eggs, larvae, and pupae. The adult moths can fly, but it is not known if this movement contributes significantly to its spread. There are numerous regulations in place that should limit the spread of the South American tomato leafminer in imported commercial tomato plants and fruit. However, movement of fruit and plants by private individuals is not as strongly regulated."
Enter Kyle Lewald, a doctoral candidate in the laboratory of UC Davis molecular geneticist/physiologist Joanna Chiu. He will present his exit seminar on "Using Genomic Data to Understand and Prevent the Spread of Tuta absoluta" at 4:10 p.m., Wednesday, Feb. 22 in 122 Briggs and also on Zoom. The Zoom link:
Chiu, professor and vice chair, UC Davis Department of Entomology and Nematology, will introduce him.
"Tuta absoluta is a serious agricultural pest of tomato plants," Lewald says in his abstract. "While initially discovered in Peru, it has rapidly invaded tomato fields around the world over the past century, causing widespread damage to the industry. The recent affordability of whole genome sequencing of insects opens the door to a wide number of applications to understand and control this pest."
"Using long read sequencing, we produced and annotated a highly contiguous T. absoluta genome assembly," Lewald noted. "Sequencing of individuals collected across many locations in Latin America allowed us to investigate population structure and diversity levels, as well as identify divergence times and possible migration events occurring between regions. Understanding these historical events can be key to predicting and preventing future invasion events. We also used comparative genomics between morphologically similar gelechiid species to develop efficient molecular diagnostics, allowing field researchers and stakeholders to identify Tuta absoluta rapidly to support quarantine and treatment efforts."
Lewald, who holds a bachelor's degree in molecular and cell biology (2016) from UC Berkeley joined the Chiu lab in 2018.
The UC Davis Department of Entomology and Nematology's winter seminars are held on Wednesdays at 4:10 p.m. in 122 Briggs Hall. All are virtual. Urban landscape entomologist Emily Meineke, assistant professor, coordinates the seminars. (See schedule.) She may be reached at email@example.com for technical issues.