International IPM Program Drives Sustainable Management of Tomato Leafminer
By Yelitza C. Colmenárez, Ph.D., and Donna Smith
The lepidopteran pest Tuta absoluta is one of the world’s most devastating phytophagous species affecting tomato plants and fresh tomatoes, causing high levels of crop production loss, especially when no control strategies are implemented. Tuta absoluta—sometimes known as the tomato leafminer, tomato pinworm, or tomato moth—continues to cause crop losses in the Americas, where it originates, but more recently it has invaded production areas in Europe, Asia, and Africa, owing to the globalization of commerce and trade, which, along with other factors, is considered responsible for the increase in invasive species.
Given T. absoluta‘s economic importance, management strategies have mainly focused on pesticides with a wide range of organic micropollutants that negatively impact the environment, mostly due to biomagnification and bioconcentration. Thus, more sustainable strategies need to be used alongside chemical control, including biological control agents such as parasitoids, predators, and entomopathogenic microorganisms; botanical insecticides; and pheromones and plant resistance.
In an article published in May 2022 in the open-access Journal of Integrated Pest Management (JIPM), researchers at the Centre for Agriculture and Bioscience International and several universities in Latin America detail case studies in sustainable management efforts for T. absoluta through CABI’s Plantwise program. (Co-author of this article Yelitza C. Colmenárez, Ph.D., is lead author of the report in JIPM.)
Tuta absoluta Management From a Plantwise Perspective
Plantwise is a global program led by CABI that helps farmers handle plant health problems through a national network of plant clinics, established in each country through which the program is implemented. The clinics are run by trained plant doctors, from whom farmers can obtain practical advice. During its 10-year implementation, there were more than 3,700 plant clinics in 34 countries around the world, where plant doctors provided diagnoses and management advice for any problem and any crop, benefitting farmers who need help with the plant pests and diseases affecting their crops.
In Latin America and the Caribbean, Plantwise was operational in Barbados, Bolivia, Brazil, Costa Rica, Grenada, Honduras, Jamaica, Nicaragua, Peru, and Trinidad and Tobago.
In Bolivia, plant clinics were considered a standard procedure to enhance the technical abilities of extension officers and farmers, and there is evidence that they have led to increased crop yields and quality. Likewise, in Costa Rica efforts have been made to implement plant clinics in collaboration with key institutions in the country.
All Plantwise countries have developed pest management guides called “Green and Yellow Lists” with the help of experts in entomology, phytopathology, nematology, and acarology, as well as agricultural extension agents from different institutions (e.g., public universities, the Ministry of Agriculture and Livestock, and research institutes) to develop precise advice on dealing with some of the most important pests.
The plant clinics have allowed researchers to determine the distribution of T. absoluta and identify the tomato cultivars most frequently associated with this pest in Bolivia and Costa Rica; it has been found to be most widespread in the department of Santa Cruz, followed by Cochabamba (five localities), Chuquisaca, Tarija, and Tiraque in Bolivia, while in Costa Rica it has been reported from Alajuela Province, where T. absoluta feeds on eight cultivars.
In Bolivia, T. absoluta management recommendations evolved greatly between 2012 and 2018. When the plant clinics were first established, farmers were predominantly advised to use chemical control; from 2012 onward, however, chemical use diminished and soon stabilized, reaching levels between 35 percent and 49 percent of recommended treatments. Meanwhile, alternative management strategies (e.g., biological, ethological, and cultural controls) began to increase in Bolivia, thanks to the influence and recommendations of the plant clinics.
During Plantwise implementation, the technicians who delivered this advice to the farmers when visiting the plant clinics were also trained in integrated pest management (IPM) and were thus familiarized with more sustainable methods of managing the key pest population. Cultural control-based recommendations, including lower-leaf pruning and elimination of crop residues and infested fruits, among others, have shown a steady increase since 2014. They reached levels of 35 percent and 31.8 percent in 2016 and 2017, respectively, similar to the 2016 chemical control levels. Ethological control recommendations, such as the use of pheromone traps, showed a discrete increase from 2014 to 2016 (12 percent to 15 percent), but in 2017 and 2018 reached a range of 25 percent to 27.1 percent.
As demonstrated in Bolivia and Costa Rica, the Plantwise program has brought substantial change to the ways in which farmers deal with pests, including T. absoluta, based on substituting or complementing chemical control with more sustainable strategies, due partially to the plant doctors’ recommendations.
Positive performance outcomes can impact the extension advisor’s ability to efficiently carry out a given task, giving them the confidence to perform similar tasks in the future. Reducing the overuse of insecticides in tomatoes alongside a higher IPM adoption rate provided a great case study illustrating the importance of field extension professionals in advising growers. It proved the importance of investing in technology transfer to improve food quality and, from a broader perspective, overall quality of life.
The positive results presented through the case studies shared in JIPM should encourage governments to invest more money in these basic principles. It is certainly much more efficient than attempting to mitigate the consequences associated with the misuse of pesticides, such as pollution, public health issues, and pest resurgence, among other problems.
Journal of Integrated Pest Management
Yelitza C. Colmenárez, Ph.D., is director of the CABI Brazil Centre and regional coordinator of Plantwise in Latin America and the Caribbean, based in Botucatu, São Paulo, Brazil. Email: email@example.com. Donna Smith is a communications manager at CABI Switzerland.
This article is adapted from an article originally published on the Plantwise Blog. Republished with permission.