When talking about pest control in Brazil, farmers, in general, think about agrochemicals. It is a “culture” ingrained in Brazilians that has always been difficult to change. It is a type of control that has been used since 1939, after the discovery of the insecticidal properties of DDT by Paul Müller, research that earned him a Nobel Prize. From then on, a “family culture” was created that all agricultural problems would be solved with the use of agrochemicals. No matter how much there is talk about control alternatives, Brazilian farmers like to apply a chemical product and see the pest dead in the soil. Brazilian Economic Entomology was born and grew based on chemical methods.
However, the negative results resulting from inappropriate application of chemicals are clear. Due to the increasing occurrence of problems, researchers began to emerge concerned with solving them; Among them, biologist Rachel Carson stood out, who in 1962 published the book Silent Spring, which bluntly drew attention to the consequences of incorrect use of chemical products. Other work followed and at the end of the 1960s research emerged with the philosophy of Integrated Pest Management (IPM), which envisaged the use of a set of measures to keep the pest population below the level of economic damage, leading to economic, ecological and social criteria are taken into account.
Some American researchers stood out, among them Marcos Kogan, a Brazilian based at the University of Illinois, USA, who transferred the technology to soybeans, which were expanding in Brazil, which made this crop one of the first to use the MIP in the country.
As part of the set of measures that make up the IPM, Biological Control occupies, alongside pheromones, cultural methods, transgenic plants, etc., a prominent place, and chemicals, provided they are properly used, can be included as products selective treatments that kill pests but not natural enemies.
Biological Control as an applied technique began with the introduction of the Australian ladybug (Rodolia cardinalis) to control the citrus “white aphid” in orchards in California. The studies that culminated in this introduction were developed at the university of that American state, considered the cradle of modern Biological Control. In 1989, this same university held a symposium in Riverside to commemorate the centenary of the first successful introduction of a natural enemy to control a pest.
However, the action of natural enemies to control pests has been known since ancient times, as before Christ, the Chinese transported colonies of predatory ants to control caterpillars in citrus. Biological Control (CB) can be technically defined as “a natural phenomenon that consists of the regulation of plants and animals by living organisms, called agents of biotic mortality”. Every plant and every animal has its Biological Control agent.
But man, in the early days of humanity, unbalanced the system, which was all in harmony, for obtaining food on a large scale, causing, currently, for example, large continuous areas of soybeans, rice, beans, etc. were planted. Alongside this, indiscriminate applications of chemicals began, intensifying the imbalance.
What is currently recommended is to use CB, not necessarily isolated, but in many cultures, as part of the MIP, to rebalance the system.
There are different Biological Control agents, which can be divided into macro and micro-organisms. Didactically, it can be said that the first group corresponds to those that can be seen with the naked eye, such as insects and mites. Micro are those visible only under microscopes and are composed of fungi, viruses, bacteria, nematodes, etc.
Everyone, whether macro or micro-organisms, requires technology for their quality and large-scale production. In the case of macros, the biggest bottleneck is the automation of biological control agent production, as, currently, 70% to 80% of the production cost of these control agents is due to labor. In the case of micros, the most important factor is the formulation.
In practice, the farmer gives preference to microorganisms, as they are more similar in application to chemicals, and also have a “shelf-life”, that is, you can buy a box of a product containing a fungus and use it within a few months. This does not occur for macro-organisms, as they must be produced and released, otherwise, the biological agents die within a short time.
Brazil is a producer of “commodities” and, therefore, a large exporter. To continue this “status”, it is essential to adopt practices such as Biological Control, as international markets are increasingly demanding waste-free products. Sustainability is the “magic” word nowadays. And restrictions, including policies, tend to increase more and more to meet this sustainability.
Brazil has a type of agriculture that is not easy to carry out Biological Control, as there are large areas with successive plantings of different crops. Pests follow each other and increase their local population without having to migrate to other crops.
So, just as the country is a leader in Tropical Agriculture, it can become a leader in Biological Control for tropical regions. This is the big challenge: developing a CB model suitable for tropical conditions, as most CB strategies were developed for protected crops, such as in Europe.
Therefore, you cannot simply copy models from other countries. It is necessary to develop a specific program for Brazilian agriculture in open fields, in which a single farmer plants thousands of hectares of a single crop (corn, soybeans, etc.).
To increase the use of CB, it is necessary to change the “farmer culture”. And for this, it is necessary to publicize what Biological Control really is. There are still many myths (Parra, 2019). The main one is that this farmer’s “culture” cannot be changed; another is that CB is “easy”; that the cost must be cheaper than chemical control (without considering the ecological and social advantages); which is a long-term method (based on the beginning of CB, where there were no mass insect breeding techniques and, therefore, the insects had to multiply in the culture, as they were released in small quantities and thus would only serve for perennial or semi-perennial crops) and that CB would be the only solution and not part of an IPM program, currently recommended.
The ease mentioned as a myth can lead to failure, especially for microorganisms, whose production, if not carried out carefully, tends to lead to product contamination problems and low efficiency.
Fortunately, the “culture” is changing, as last year CB generated around R$500 million in the Brazilian market, still a small amount compared to chemicals. But the increase in this movement will come with a change in “culture”. And there is a milestone for this great change. In 2013, Helicoverpa armigera was found for the first time in Brazil, a pest with more than 200 hosts that attacks cotton, soybeans, citrus, corn, etc. At the time, there was no chemical product registered for the pest. And the farmer had to use a virus already sold in other countries and Trichogramma pretiosum as an egg parasitoid. Both worked great! It is a shame that the offer of these inputs did not meet all interested parties at the time. This change is accompanied by the emergence of small CB companies, such as (startups) (Bug Agentes Biológicas and Promip, both out of USP/Esalq, for example) and large ones, such as Koppert, the largest CB company in the world that entered the Country in 2010. Currently, almost all chemical companies have a biological product in their portfolio.
The São Paulo State Research Support Foundation (Fapesp) has an incentive program for small businesses (Pipe). A large number of CB startups (around 15) started to appear. The increase in the supply of biological inputs will encourage the use of this control technique.
There are still few products registered in Brazil compared to the 440 existing in the world. It is interesting to remember that there have been CB companies in Brazil since the 1980s in Alagoas (Biotech), later Biocontrol (Sertãozinho-SP), among others, alongside sugarcane mill laboratories and independent laboratories producing parasitoids to control the sugarcane borer (Diatraea saccharalis).
What is done in CB with macro-organisms is the release of a large quantity of insects or mites to control the pest. Therefore, there is a need to master breeding techniques for two insects: the pest and the natural enemy, sometimes with artificial diets that replace the natural food for the pest. This is Augmentative Biological Control (also called Applied), which has a rapid effect on the pest, like insecticides, and is more accepted by the farmer. As these are large areas, there is a need to produce large quantities of insects, which often require automated systems. There are other types of CB for smaller areas, such as the Classic CB method, which uses an exotic natural enemy, releasing small quantities, and the results are long-term, but lasting, serving perennial and semi-evergreen crops. And the Conservative CB, which is more for small areas and aims to maintain and, if possible, increase the natural enemies that already exist in the area (combined with other techniques such as the use of selective products and resistance management).
And more recently a new procedure was mentioned in CB. External Management (Diniz et al., 2019), in which the natural enemy is released outside the cultivation site (where the pest is desired to be reduced), and is used for disease-transmitting pests such as the citrus psyllid (Diaphorina citri ), which is a vector of the bacteria that cause Huanglongbing (HLB) or Greening. In this case, the natural enemy, the parasitoid (Tamarixia radiata) is released outside commercial orchards in places where there is a focus of the disease (in which contaminated insects reproduce), such as abandoned or organic orchards, areas with myrtle (host of the psyllid). ), backyards or even areas without insecticide application.
Brazil has a great diversity that can be explored, both macro and microorganisms. These microorganisms have already been widely used, millions of hectares are currently treated with Trichoderma harzianum (fungus for disease control, but also as a nutrient for plants), Metarhizium anisopliae, Beauveria bassiana, Bacillus thuringiensis, B. subtilis, Cordyceps fumosoroseus, etc. . to control sugarcane leafhoppers, pasture hoppers, coffee borer, whitefly, caterpillars in general and citrus psyllid, among others. Specific viruses are sold for various Lepidoptera, and mites for vegetable crops and flowers.
Among the macro-organisms, sugarcane is the crop where most CB measures are applied: to control the borer, the larval parasitoid Cotesia flavipes is used in more than three million hectares and the egg parasitoid Trichogramma galloi in more than two million hectares.
The species Trichogramma pretiosum has been used in cotton and soybeans for Lepidoptera, in avocado for Stenoma catenifer, in tomato for Tuta Absolute, and in tobacco for Phthorimaea operculella.
Other parasitoids have been used to control the brown soybean bug (Euschistus heros), in this case, Telenomus podisi; T. remus and/or Trichogramma pretiosum for control of Spodoptera frugiperda with many other potential agents and in studies in different cultures. In all cases, it also depends on greater production and supply of parasitoids and predators to the farmer.
A list of natural enemies used in Brazil is presented in Table 1.
The advances in CB are evident in Brazil with the increase in the critical mass of people interested in studying the topic, trained in postgraduate courses in recent years. This is currently a global trend, as there is a desire for sustainable agriculture in a short space of time. Therefore, there is a need for investment, training of human resources and organization around CB.
Until 2019, the Brazilian Association of Biological Control (ABCBio) existed, which concentrated the companies that defined guidelines on the subject in Brazil. This association was recently incorporated by CropLife, which, in general, is related to crop protection.
Investments begin to appear. Large agrochemical companies concentrate their efforts on having biological products in their portfolio. The government begins to invest, with a large biocontrol program developed at Esalq, and supported by Embrapii, linked to INCTI and researcher Ítalo Delalibera.
In February, SPARCBio, the CB Center of Excellence, was launched, in which there is a partnership between the University of São Paulo (USP), Fapesp and the company Koppert Biological Systems.
SPARCBio is based in the Department of Entomology and Acarology at Esalq/USP and will carry out work ranging from prospecting new agents to incorporating CB into IPM programs (Figure 1).
In addition to the importance of research, this Center, which is coordinated by professor José Roberto Postali Parra, will seek to disseminate CB at different levels, from pre-university, university, postgraduate and obviously even the farmer.
It is obvious that there are still challenges, cited by Parra (2014), including, in addition to changing the farmer's culture, problems with the transfer of technology to the field; pest monitoring, supply of biological inputs (need for more companies to emerge in the area); quality of available biological material, storage and transport logistics (considering the country's territorial extension); own and more appropriate legislation; release technology, among others. Since the new agriculture is very dynamic and involves extensive areas with transgenics, these must coexist, in the best way possible, with biological products.
These obstacles are beginning to be overcome in some items such as the release of macro-organisms and pest monitoring and the farmer is adapting to Agriculture 4.0. Thus, in sugarcane, of the areas treated with T. galloi (> 2 million hectares) 91% of releases of the parasitoid are made using drones. At the same time, studies with equipment adapted to drones will allow sampling of pests, to release control agents, using remote sensing.
Brazil is moving forward, however, so that society is not disappointed, CB studies involve different stages and for such development. Sometimes it takes a few years, as in the case of Trichogramma, which required 15 years of inter and multidisciplinary research involving everything from prospecting for the biological control agent, its taxonomy, to evaluating the cost-benefit of offering it to the farmer (Figure 2) .
Studies are being initiated in many areas, and the challenges for tropical regions in “open fields” are different from anything that has already been done in the world. Therefore, the big challenge is to develop a CB model for tropical regions made with great criteria and science.
José Roberto Postali Parra, Alexandre José Ferreira Diniz and Aloísio Coelho Júnior, USP/Esalq
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