Advances in research allowed registering the first biocontrol agent for leaf miner in Brazil. Solution avoids the use of chemicals in crops and does not affect human health or the environment. Leaf miner is an important pest of several vegetables and ornamental plants, such as melon, tomato, beans, potato, and chrysanthemum. Melon is one of the crops that is most affected by the pest. International standards do not allow the exports of fruit with chemical residues. Parasitoid wasp is tolerant to high temperatures, allowing its use in crops in the Brazilian Semi-arid region. Wasp is already used in the control of leaf miner, but the mass rearing of the parasitoid was still a challenge in Brazil. Research carried out by Embrapa Semi-arid Region, in partnership with the University of São Paulo's Luiz de Queiroz College of Agriculture (Esalq/USP) and the Rio Grande do Norte Agricultural Research Corporation (Emparn), made it possible to develop a system for the mass breeding of parasitoids of the leaf miner, a pest of dozens of crops. As a natural enemy of the insect pest, the parasitoid is used in biological control programs. This is the first biological control agent against the leaf miner in Brazil and it was quickly incorporated by the production sector and registered, in July, at the Ministry of Agriculture, Livestock and Food Supply (Mapa). The commercial version of the Neochryoscharis formosa parasitoid for the control of the insect was developed by Topbio Sistemas Biológicos, with the technical cooperation of Embrapa. The leaf miner of the genus Liriomyza is considered an important pest for several vegetables and ornamental plants such as melon, tomato, beans, potato, and chrysanthemum (watch the video below). “Among the main natural enemies of this insect, are its parasitoids, small wasps that can attack the larvae of flies still inside the leaves”, explains the research coordinator, the biologist Tiago Costa Lima. “Some species of these wasps were already used as alternatives for the biological control of the leaf miner since the 1980s in Europe and North America. However, the knowledge for the mass breeding of the parasitoid wasps was not yet available”, added the researcher. Video explains how the leaf miner acts and presents its parasitoids In this sense, the work started by Esalq and concluded by Embrapa Semi-arid Region aimed to develop a system that would allow mass breeding and that could be adapted for the multiplication of different parasitoid species. Steps of the process The technology establishes methodologies for each step of the process until the biological agent is obtained. One of the solutions of the system is collecting leaf miner larvae as they emerge from the leaves. For this, a structure that allows collecting the larvae on large scale was developed, with low labor costs and no need of manipulating the insect. “The process involves several important steps: definition of the fly species to be used (as a base for the reproduction of the wasp); choice of the host plant, which should have fast growth and be easy to maintain; and work in the laboratory, where it is necessary to know the biology of the fly and of the parasitoid.” Lima highlights the importance of investments in basic science, recalling that studies of this kind usually take a long time. “It has been 15 years of work, with the involvement of several institutions, including basic research until the development of an efficient system for the mass breeding of the leaf miner parasitoid. This result is quite relevant, contributing to the expansion of the biological control and management of this pest in the country”, points out the scientist. Public-private tuning The first biological control agent against the leaf miner in the country counted on the joint forces of the research carried out by the public sector and the entrepreneurship of the private sector. In 2017, the Topbio Sistemas Biológicos company selected Neochrysocharis formosa, a parasitoid of the leaf miner that occurs in the melon-farming areas of the state of Rio Grande do Norte, aiming to transform it into a new product for biological control. Melon is especially targeted by the leaf miner. The difficulty in controlling the pest with synthetic insecticides and the demands of melon-importing countries for fruit free of agrochemical residues increased the need for biological solutions to control the problem. For this reason, Topbio Sistemas Biológicos contacted Embrapa in order to upgrade the technology already made available by the public institution, aiming to rear the parasitoid at an industrial scale. A technical cooperation agreement was signed with Embrapa Semiarid, which allowed carrying out more studies about the biology of N. formosa. The manager at Topbio, Marcos Bellini, explains that the initial idea was to search for a native parasitoid that was common and occurred naturally in Brazil. “We collected dozens of samples in the melon-growing region of the states of Rio Grande do Norte and Ceará, and we managed to select the N. formosa parasitoid, which is abundant, occurs constantly throughout the year, and is present in the whole country, which is why we chose to work with it”, Bellini shares. The studies carried at Embrapa showed that N. formosa has a high tolerance to high temperatures, being able to complete its egg-adult cycle at a constant temperature of 37ºC (98ºF). This characteristic is important for the use of this parasitoid in melon crops in the Northeastern Sertão – a subregion with semiarid climate and characterized by Caatinga vegetation. For Bellini, Embrapa played an important role in this work. “The system developed at both institutions was the kickoff so we could make the necessary adaptations for an industrial-scale production”, he adds. This cooperation was also highlighted by the researcher Tiago Lima. “The role of Embrapa is not to commercialize the final product. That is why it is important to transfer the technologies developed during research, allowing the products to arrive at the market. When companies are interested in developing technologies from Embrapa, we reaffirm our tuning with the productive sector”, he concludes. In Brazil, 32 startups dedicate themselves to research on biological control In 2020, the country had a high record of low-impact agricultural products. The amplification of the biological control market was confirmed in the recent publication of CropLife Brasil, with data of the Blink consulting firm, pointing to a growth tendency of 33% in the sector in 2021. Another mapping performed by Embrapa, in Radar Agtech Brasil 2020-2021, showed that there are already 32 startups dedicated specifically to biological control and integrated pest management, focusing on the commercialization or development of technologies against pests and diseases, population control, and optimization of input use. Mapa has been noting the evolution of this market. In 2020, 95 low-impact products were registered in the country, the greatest number reached since the first records. To have an idea of the growth curve, in 2018, the second year with the highest indexes, only 52 products were registered. Mapa considers as low-impact products those that have active ingredients that are biological, microbiological, biochemical, from vegetable extracts, and that act as growth regulators. This data show the growing investment in an agriculture that is more sustainable and technified and that uses less chemical products. Embrapa reunites its work in this area in its portfolio of biological inputs, which currently includes 96 active studies on the biological control of pests, the promotion of plant growth, and phytochemicals. Photo: iStock