Léo Ramos ChavesWhen he turned 70 at the end of 2014, agricultural engineer José Roberto Postali Parra was required to retire from Luiz de Queiroz College of Agriculture (ESALQ), a unit of the University of São Paulo (USP) in Piracicaba, where he had acted as director. But the specialist in biological control of agricultural pests never even considered abandoning his research at the school’s Department of Entomology and Acarology. “I have been fighting my whole life, and I’m not going to stop working now that biological controls are gaining ground in Brazilian agriculture,” he says. This form of combating pests that affect planted crops uses their own natural enemies, such as insects, mites, and even microorganisms to combat problems in the fields. Instead of resorting to chemical insecticides, which if used incorrectly can harm humans and the environment, farmers try to destroy or at least reduce the presence of the attacking pest with the help of a small wasp, for example, or a fungus present in nature.
Parra has dedicated more than four decades of research to understanding the biology of natural enemies of pests and their interaction with the environment, such as sugarcane borers and greening of orange groves, and has developed methods to breed insects and mites that have proven helpful to farmers in the laboratory. Parra is thoughtful when he admits that biological control is not the solution for all pests, but can be useful and help reduce the use of pesticides in agriculture. “Brazil leads the world in the use of chemicals in agriculture,” he states. “Our farmers have this culture.” In this interview, Parra tells the story of insects and pests in Brazilian farming and comments on topics which are important to agriculture in the country, such as the use of transgenic varieties and the adoption of organic practices.
|Biological control of agricultural pests|
|Undergraduate degree in agronomy (1968), master’s (1972) and doctorate (1975) in entomology at the Luiz de Queiroz College of Agriculture at the University of São Paulo (ESALQ-USP)|
|341 scientific articles, 20 books written or edited, acted as advisor to 61 master’s and 50 doctoral candidates|
In what crop are biological controls most commonly utilized in Brazil?
Sugarcane is the classic example. Today between 9 and 10 million hectares are planted with sugarcane in São Paulo. Nearly half of this area of sugarcane in the state uses biological controls. They are used to combat the moth whose larva is known as the sugarcane borer [Diatraea saccharalis] and the spittlebug Mahanarva fimbriolata, a pest that attacks the roots of the plant. The borer caterpillar is destroyed by releasing the wasp Cotesia flavipes, an insect from Trinidad and Tobago which was introduced in the country in 1971. Cotesia is used in 3.5 million hectares of sugarcane. The wasp I work with, Trichogramma galloi, has been used to combat borer eggs in about 500,000 hectares of sugarcane. Different natural enemies can be used to attack different stages of these pests; stages of development in insects are eggs, larvae, pupae, and adults. A fungus called Metarhizium anisopliae is used to control the spittlebug.
What other crops have used this method?
There is an interesting story that involves biological control of citrus greening disease, also known in Asia as HLB or huanglongbing, which makes the leaves of orange trees turn yellow and kills the plants. Greening is caused by the bacteria Candidatus Liberibacter, which is transmitted to plants by a small insect, the psyllid Diaphorina citri. Because of greening, citrus farmers began to apply insecticides to their groves 20 to 30 times a year in an unchecked battle against the psyllid. We tried to use biological controls by releasing small wasps of the species Tamarixia radiata, which originates in Asia but was found here in São Paulo. We released the wasps in the groves, but they died. The orchards had citrus greening disease, but they did not have the psyllid Diaphorina citri.
So why did they have the disease?
We found that the primary outbreaks of the disease came from areas outside the orchards, from organic areas, from backyards, from myrtle, which is the host plant of the psyllid, and from abandoned orchards. FUNDECITRUS [Brazilian Fund for Citrus Protection] estimated that these neighboring areas totaled 12,000 hectares. We began to release the wasps in these areas to avoid primary outbreaks. It worked. Today the Citrosuco company has five bioproduction centers for wasps, FUNDECITRUS has another, and there is a farmer starting to breed these insects. Now citrus growers put baits on the edges of their groves, yellow glue traps, which detect the moment that the psyllid arrives in the orchard. In the United States, citrus greening disease has practically wiped out citrus farming in Florida. They knew how to use biological controls, but didn’t do it. They thought that just improving the nutrition of the plant would be enough to combat the disease. Alone, biological controls do not solve all the problems. They are just one component of IPM, integrated pest management, which appeared in the late 1960s and early 1970s. You need to use healthy young trees, remove sick plants, and apply insecticide within reason.
Isn’t the United States prominent in biological pest control?
Actually, they do not use biological controls to the extent that they advocate in the books they publish on the subject. Use of chemicals is also a part of their culture. This is even true in California. IPM was a public policy which began during Richard Nixon’s term [1969–1974]. Other presidents came and went, and by the end of the Clinton administration [1983–1992], it was established that 75% of American farmers would have to use IPM. But they only reached 4% to 8%. It’s not easy. Today there are large companies in the area of biological controls. The leader is Koppert, a Dutch company. In second place is Biobest, from Belgium. Third is BioBee, from Israel. The large multinationals in the area of insecticides, like Bayer, Syngenta, and Monsanto, now also have companies for biological controls. This system is most widely used in Europe, mainly in the Netherlands and Spain. This is the perfect time for Brazil in biological control. I’m retired, I turned 70 at the end of 2014. But that’s not going to make me stop working. I’ve fought my whole life and now that biological controls are getting more established I am not going to stop.
More recently, a wasp began to be used to fight a caterpillar that attacks various crops in central Brazil. Is it working?
In March 2013, a significant pest appeared in fields in the state of Goiás, the earworm Helicoverpa armigera. It attacks up to 200 host plants and affects crops including soy, cotton, oranges, and coffee. There was no way to control this caterpillar with chemicals. Farmers had to use biological controls, utilizing a virus, NPV, which combats the caterpillar itself, or wasps in the genus Trichogramma, which attack their eggs. The problem is that occasionally not enough insects were available for everyone to use this method. Now companies dedicated to providing biological products for this market are beginning to emerge in Brazil. Just within FAPESP’s PIPE [Innovative Research in Small Businesses] program, there are 11 startups involving biological controls. The Bug company, in Piracicaba, started in my lab. ProMIP, which works mostly with mites, also began in ESALQ, from the work of professor Gilberto Moraes. Young people are very enthusiastic about establishing companies. But I am worried. If the companies are not professional, they can tarnish the image of biological control. Our work has to be slow, but safe. We cannot rush. When there is a mistake, farmers will be slow to return to biological controls.
Was there some event that demonstrated this in Brazil?
Something like this happened in the 1970s with the fungus Metarhizium. An Italian who was an advisor to the FAO [the United Nations Organization for Food and Agriculture], Pietro Guagliumi, introduced this fungus in the Northeast, where the sugarcane spittlebug was a problem. But there the problem was more in the leaf of the plant, while in São Paulo it was in the root system. The spittlebugs that cause these problems are very similar. They began to use the fungus in the Northeast and it was a success. But soon unprofessional companies emerged which began to sell contaminated fungi. After that, the biological controls didn’t work. It took years for this method to be used again, not only in the region but across all of Brazil.
What kind of agricultural pests can be combated by biological controls and which ones cannot?
IPM works like a house that has a foundation composed of some items. You have to know the influence of the climate, the pest, and the right time to control it. Some people confuse natural enemies with agricultural pests. The natural enemies are also part of this foundation. They are responsible for the natural levels of mortality in an agricultural system. Pests have a natural enemy, and this natural enemy also has its own natural enemy. There is a trophic chain. Everything would be in balance if we weren’t planting so much soy and sugarcane to meet human food needs. Monocultures cause imbalances. On top of the house’s foundation are the methods of controlling pests, like biological control, which can also use pheromones, planting different crops, chemical products, and transgenic plants. All these measures are intended to keep pests at a level below economic damage, taking into account social and ecological criteria as well as the economic aspect. As I said, biological control is not the solution for all problems. There are some crops where it can be used more and others in which it will be less. In crops where there are many insects, it is difficult to use biological controls. In this case, the solution is to use selective chemicals that kill the pest, but not its natural enemy. There are tables available to farmers that recommend these products for a variety of situations. In some crops, like potatoes, tomatoes, and even cotton, Brazilian farmers use a lot of insecticide.
Is this more of an economical or cultural question?
Brazil leads the world in the use of chemicals in agriculture. The country has an exclusively chemical culture, something difficult to change. This is the big problem. Farmers say that their fathers and grandfathers always used insecticide. They want to see the insect that’s attacking the crops dead on the ground after they apply the pesticide. We have less of a tradition of biological control than other Latin American countries like Peru, Colombia, and Venezuela, which were very motivated by researchers from California. Our agriculture has been significantly influenced by those who worked with chemicals. DDT was synthesized in 1939, and everyone imagined that all the problems in agriculture were solved. Then a serious problem emerged. There were biological imbalances, water pollution. The American biologist Rachel Carson wrote a famous book on this topic in 1962, Silent Spring. From 1940 to 1960, biological pest control went through a dark time. Until IPM arose, which was the scientific community’s response to inappropriate use of pesticides, a way of controlling pests that takes into account the economic aspects, which cannot be ignored, but also the ecological and social aspects.
When did biological control emerge?
It is thousands of years old. The Chinese used natural enemies to control citrus pests before Christ was born. Biological control as we know it today actually began in 1888 in California. Riverside and Berkeley are the two major centers. That area had a serious citrus pest, the cottony cushion scale, which is actually a scale insect, Icerya purchasi. The Americans went to Australia, which is where the insect probably originated, got the Vedalia beetle (Rodolia cardinalis), and introduced it in California. The following year, the case was considered a success. We imported the first insect to Brazil in 1921. In São Paulo, an American wasp was introduced, which parasitizes the white peach scale insect. But it didn’t work. There were several episodes like that. Around 1924, the coffee berry borer appeared, Hypothenemus hampei, a small beetle from Africa that attacks this crop. Researchers from the Biological Institute and a professor at ESALQ, Salvador de Toledo Piza Junior, went to Africa and brought a wasp from Uganda, Prorops nasuta, but control of the pest didn’t work very well. Coincidentally, about 20 years ago they came to me because they found this wasp in the region of Ribeirão Preto. They wanted to reproduce them, since today there are techniques to breed them.
At that time, was the technique to breed this wasp also imported?
At that time, there was no breeding technique. That was the time of so-called classical biological control, when everything was done in a rudimentary form, when some insects could be bred on a small scale without any technology. Researchers went to where the pest originated, got its natural enemies, and introduced them into the plantation that had the problem. Since there were no techniques to breed the insects, few natural enemies were introduced. This type of introduction is consequently called inoculative release. When only a few are released, the response is not immediate. The insects need to multiply in nature. This situation created an image that biological controls only produced a long-term outcome, in perennial or semi-perennial crops. Today native enemies are more widely used, since there are many restrictions on importing insects.
You have a patent for the production of a semiochemical, a sexual pheromone used to control a citrus pest. How did this come about?
The one who works with pheromones is José Maurício Simões Bento, my department colleague at ESALQ and vice-coordinator of the National Institute of Science and Technology for Semiochemicals in Agriculture, where I am a coordinator. We have a patent for the pheromone used to control the moth Gymnandrosoma aurantianum, which is known as the citrus fruit borer. This moth lays its eggs on the fruit, and when they hatch, the caterpillars go into the oranges, which rot and drop. The female of this species produces a substance, a pheromone, that attracts the male for mating. We have studied the sexual behavior of females to know where they mate in the tree, and have learned to synthesize this pheromone in the laboratory. We created a trap with a tablet that gradually releases this synthesized substance, and we put these traps in the orange trees. So we deceive the males and attract them to the trap. This tablet was created by our partners at the University of Tsukuba in Japan. It is enclosed in plastic—which was a great technological idea—that controls the release of the substance over 30 days. If you remove the plastic, all of it is released in one day. Some farmers have taken off the plastic and then complained that the method didn’t work. We had to give seminars to convince people not to take it off. Over 10 years using this biological control method, which cost US$50,000 for development, farmers in São Paulo saved US$1.3 billion on unnecessary application of insecticides.
Do these cases of economically successful control stimulate research in the area?
The other day I was talking with the president of Koppert, a company with a presence in 27 countries that has a subsidiary in Piracicaba. He told me that biological control is used in 90% or 95% of greenhouses in the Netherlands. These are large greenhouses, covering 10 or 20 hectares. But you can’t compare this with Brazil. Here in the Midwest, for example, a single producer might have 100,000 hectares of soybeans. I always say in lectures that Brazil is undisputedly the leader in tropical agriculture. But because of our large size, tropical agriculture is cruel for biological controls. We need to develop a model for tropical biological control. We can’t manually release insects over 100,000 hectares. You have to use a drone or a plane. You can’t walk through 100,000 hectares of soybeans to know when is the right time to release the insects. Remote sensing is needed to keep track of this issue. We are still in early days in this regard. But our biological control programs are among the largest in the world in terms of area managed.
How did your interest in entomology come about?
I did the scientific track [one of the variations in the old high school curriculum, with an emphasis on the exact and natural sciences], I had very strong leanings towards the area of biology and imagined I would be a doctor. I lived in Campinas, in the neighborhood of the IAC [the Agronomy Institute]. My house was the first one after the IAC. In the last year of the scientific program, I went on a field trip to ESALQ and fell in love with the school. I did the prep course and went to study agronomy there in 1964, always with the idea that I would stay at the IAC. During college, I went to the institute on weekends and holidays when I was in Campinas. In my second year of agronomy, I began to work with entomology. I received a scientific initiation scholarship from CNPq [the Brazilian National Council of Scientific and Technological Development]. When I graduated in 1968, I even had a few published articles. I entered the IAC six months after graduating, after a competitive examination process.
In the IAC were they already working with biological controls?
I started in a slightly different area, plant resistance to insects, with the cotton root borer [Eutinobothrus brasiliensis]. I did my master’s there, but went to ESALQ. I was looking for a genotype of cotton that is resistant to the borer. But I ended up leaving the area of entomology and went over to climatology at the IAC to study the influence of climatic factors in insect development. While I was still working at IAC, I also did my doctorate at ESALQ on the coffee leaf miner, the moth Leucoptera coffeella, which attacks the leaves of this crop. In 1974, I was invited to go to ESALQ. At that time, there was no competitive process for the university. I accepted the invitation and began to work on insect biology. Then in 1977 and 1978, I did my post-doctoral studies at the University of Illinois in the United States. After that I came back to Brazil and started to work with biological controls. At ESALQ there was already a tradition of biological control in entomology. The head there, professor Domingos Galo, had already used it in the cultivation of sugarcane. During my post-doc in the United States, I studied artificial diets for insects. In Brazil I was a pioneer in this area, which is the foundation for biological control. To create natural enemies, you need to know how to raise the pests. I developed this area, which had been essentially prohibited in Brazil because all the components were imported. I had to develop breeding technology that was adapted to our conditions.
Today, are there laws governing the use of biological controls in Brazil?
Since there is a lot of ignorance, our laws are entirely based on the use of chemicals. They wanted to even put a skull on biological products like they do with chemicals. The approval process is time consuming, but it’s improving. Today there are 41 biological products waiting for approval by the three public bodies responsible for this process: MAPA [the Brazilian Ministry of Agriculture, Livestock and Supply], ANVISA [the Brazilian Health Regulatory Agency], and IBAMA [the Brazilian Institute of the Environment and Renewable Natural Resources. There is also an entity that brings together companies from the sector, the Brazilian Association of Biological Control, better known as ABCBio, where I am a member of the technical committee. We advise on how to perform quality control in this sector. We can’t let the companies take care of this, it has to be done by an agency linked to a university or to some research center. Today there still is no independent quality control for biological products.
Are you part of any of these companies?
No. I followed and encouraged the formation of Bug. Across Brazil everyone says I’m the owner of the company, but this is because it was the product of ex-students and a technician who worked in my lab. Today there are several companies and I only have scientific connections with all of them.
What do you think about organic agriculture?
It may have its place. Today there are even large economic groups in this sector. But I think that there is a lack of knowledge about who is practicing this type of agriculture. There are not many possibilities to be exclusively organic. People have a lot of questions. But it is an interesting market, with potential. There is a lack of research in this area. There’s a lot of romance, poetry, and ideology.
Do organic producers use biological controls?
As far as I know, they use very little. They talk about it a lot, but they don’t use it very much.
Do you think that organic farming could be an alternative for large-scale production, or does it lend itself to small projects?
This issue has to do with the challenges of developing tropical biological controls. Since organic areas are not so large, it would be even easier to use biological control in these properties. But in organic agriculture there are problems related to plant growth, since they don’t use fertilizers and the crop is less vigorous. Not using inputs leads to other issues that must be dealt with, and biological control ends up going unnoticed. Few people around the world are researching organic agriculture.
Are you in favor of transgenic crops?
Today in the scientific literature, so far no harm has been attributed to transgenics. I think that they are a control method like any other, but they have a limited period of validity. In a very short time, transgenic resistant insects are selected and another transgenic will be required. This is how it works with old crop varieties which are being replaced with newer, more pest-resistant varieties. I’m not against transgenics; I am against saying that it’s the solution to all our problems. Transgenic sugarcane will not be the end of biological control in this sector, as some say. Resistant pests always emerge. Transgenic soy controls the earworm Helicoverpa armigera, but not stinkbugs or other pests. For these, some other biological measure will be needed.