IAC Sugarcane Program validates the efficiency of biologicals in the field

The IAC Sugarcane Program of the Agronomic Institute of Campinas (SP) conducted a series of experiments using biological nematicides and insecticides on sugarcane. Different products were evaluated using different application methods and their respective responses were analyzed.

Among the results, the efficiency of microorganisms of relatively new use in sugarcane farming stands out, such as the fungus Cordyceps for controlling sugarcane leafhoppers and microvepsa Tetrastichus in controlling the sugarcane borer. The IAC is the institution that most evaluates the use of biological nematicides in sugarcane management in Brazil and shares this information with the sugarcane industry.

“Regarding the results of these more recent technologies, in general, the reductions in the borer population were significant, the infestation intensity rates fell to less than half of the untreated area,” says the researcher from the IAC, of the Agribusiness Research Directorate (Apta), of the Secretariat of Agriculture and Supply of the State of São Paulo.

Currently, biological nematicides account for approximately 80% of all sugarcane cultivation in Brazil, according to the scientist. This technology is widely adopted by Brazilian sugarcane growers and, in just a few years, has surpassed the use of chemical nematicides," she comments.

In addition to nematodes, other pests are also controlled with high efficiency.

biological. The sugarcane leafhopper is controlled with the innovative Cordyceps fumosorosea, recently tested in studies conducted by the IAC, which evaluates the effectiveness of this fungus in controlling this pest that affects sugarcane roots and stalks and can cause productivity losses of up to 60%. This recent technology stands out for its effectiveness in parasitizing leafhopper adults and nymphs, reducing their populations. The IAC also continues to evaluate traditionally used fungi, such as Metarhikum anisopliae.  

As for the sugarcane borer, the Institute studies Tetrastichus howardi, a microwasp that parasitizes sugarcane borer caterpillars and pupae, causing their death. Although its adoption in sugarcane is recent, it has shown promising results against one of the most destructive pests in sugarcane fields, affecting productivity and stalk quality for the industry. Added to these analyses is the traditional use of parasitoid microwasps as cotesia flavipes e Trichogramma galloi.  

According to the scientist, biological nematicides are made up of several species of Bacillus or by fungi that parasitize nematodes. Many products are mixtures of several species of bacilli or of these with fungi, resulting in various types of natural pest protection.  

There are different ways to apply the various biological products. Management depends on the pest and the recommended product. The IAC evaluates most options in experiments involving applications on both plant sugarcane—the first sugarcane to emerge from the plantation—and ratoon sugarcane—the result of regrowth after the first cut.

These studies are developed in partnership with DMLab, plants and other companies in the sector.

Entomopathogenic nematodes combat sugarcane weevil

For biological control of the sugarcane weevil - Sphenophorus levis -, another aspect is the use of entomopathogenic nematodes, microscopic worms that live in the soil and have the ability to infect and kill insects.

This technology resurfaced after the arrival of new imported strains, now tested under different field conditions by the IAC to evaluate the viability of these nematodes applied with vinasse, as well as to determine the minimum soil moisture required for these organisms to perform well. A series of trials evaluates the effectiveness of these entomopathogenic nematodes for controlling soil pests, especially Sphenophorus levis.

In Brazil, the first work involving biological control of pests by these entomopathogenic nematodes, still in the 1990s, was developed by Leila Luci Dinardo-Miranda, who at the time worked with Migdolus fryanus, another important pest known as the sugarcane rhizome borer.

Choosing biological or chemical products depends on the context

The cost-benefit of biological control in sugarcane farming varies greatly depending on the product used. "There are biological products that are cheaper than their chemical counterparts, and vice versa, and prices vary significantly," says the researcher, who has been integrating different pest management solutions for decades.

There's also a wide range of responses. "Depending on the pest and the situation, it may be more appropriate to use biological or chemical methods, and in some cases, it may be advisable to use them together in management. Often, they complement each other," she states. She explains that these tools aren't always used in isolation. They're generally part of a comprehensive integrated pest management program.

From the state of São Paulo to the Midwest, the work of the IAC Sugarcane Program has directly contributed to the adoption of more sustainable practices, which reduce dependence on chemical inputs and promote greater ecological balance in crops.

"The sugarcane industry is extremely receptive to biological control. When a new tool is validated, there's an immediate effort to test, adapt, and implement it on a large scale," says the researcher with the IAC Sugarcane Program, who conducts experiments at mills in the state of São Paulo and throughout South-Central Brazil.

Biological control of leafhoppers and borer has been carried out for years

For leafhoppers—an insect that attacks plant roots in its nymphal stage and leaves in its adult stage—biological control primarily relies on fungi applied during the rainy season. Metarhizium anisople has been used for nearly three decades, and in the Northeast, this use has been around even longer. However, in recent years, other fungi have also been used to control leafhoppers.

To control the sugarcane borer, other egg and caterpillar parasitoids are currently being studied at the IAC. This is the case of Tetrastichus howardi, which acts in the caterpillar and pupa phase (intermediate phase between the caterpillar and the adult insect). A very traditional caterpillar parasitoid is cotesia flavipes, used since the late 70s. This wasp is released into sugarcane fields to parasitize the borer larvae, interrupting their life cycle and reducing damage to the crop. There is also the Trichogramma galloi, an egg parasitoid that acts preventively, rapidly reducing the pest population.

The researcher emphasizes that these biological resources can be used together or in conjunction with chemical products.