Leading experts identify the most-promising ‘green’ products for horticulture and row crops.
Worldwide, the use of conventional products that guard crops against weed pressure, disease and pests is increasing falling out of favour. Many products are being phased out in the EU and elsewhere.
Natural control of crop diseases and pests
Therefore, both manufacturers and research institutions are hard at work developing environmentally-friendly ‘green’ products. While there is some focus on development of ‘green’ herbicides, companies are putting much more effort into natural control of crop diseases and pests.
Beyond a lack of toxicity, there are many other advantages to using natural products in comparison to conventional. As RC Jagessar of the University of Guyana explains in a 2020 journal paper, these can include much lower cost, significantly lengthier protection (even throughout the entire growing period), high specificity, and even sequestration of inorganic nutrients such as phosphorus.
Future Farming searched for the top four most promising environmentally-friendly crop protection products, and here they are, with specific examples where possible.
1 – Pheromones
Pheromones are naturally emitted by insects for purposes such as attracting mates. As a natural crop protection product, they can be used to attract insect pests such as moths to a trap they cannot escape from, or to a device where they will ingest a natural chemical that kills them. “Pheromones are an optimal tool for both pest management and resistance management programs,” explains Odessa Hines, external affairs manager at BASF Agricultural Solutions North America.
BASF currently offers ‘RAK’ pheromones which disrupt mating of certain moths that infest pome fruits, grapes and stone fruits. Corteva Agriscience is working with M2i Life Sciences on pheromone use in crop protection.
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BASF RAK pheromone dispensers disrupt the mating behavior of certain moth species whose larvae damage grapes and fruit This helps growers to optimise yield while at the same time preserving biodiversity and the sensitive balance of the eco-system. - Photo: BASF
Bayer has launched a new pheromone product called ’Vynyty Citrus’ which guards against scale and mealybug (California red louse, citrus cotonet and South African cotonet) for up to 400 days, explains Dr. Rolf Christian Becker, Bayer’s R&D portfolio manager for Disease Management & Vegetable. Vynyty Citrus employs pheromones in combination with a natural pyrethrum insecticide that’s approved for organic farming.
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Bayer recently launched Vynyty Citrus, a biological and pheromone-based crop protection product to control pests on citrus farms. Vynyty Citrus is a container with an active liquid inside that does not generate resistance or residues in harvests or in the environment. - Photo: Bayer Crop Science
2 – Plant extracts
Pyrethrum is a well-known example of a plant extract with insecticidal properties. Made from finely-ground chrysanthemum flowers, it causes rapid paralysis and could be humanity’s oldest insecticide.
Many other plant extracts have long been used to control pests, including neem, caraway oil, seed fennel, quassia and ryania. In addition, Jagessar notes that extracts of onion, garlic, eucalyptus and tobacco are known to control many pathogenic fungi and insects. Certain essential plant oils have also shown efficacy with tobacco cutworm, Spodoptera litura and the green peach aphid.
Bayer’s new natural insecticide ‘Flipper’ is derived from a by-product of extra virgin olive oil. It controls aphids and whiteflies.
3 – Biostimulants
Natural plant biostimulants (PBs) enhance flowering, plant growth, fruit set, crop productivity, stress tolerance and nutrient use efficiency. According to a 2020 paper in Frontiers in Plant Science, the definition of PBs has been “rigorously debated over the last decade,” and under EU Regulation 2019/1009, PBs in the EU now can include a diverse range of substances including humic and fulvic acids, macroalgae seaweeds extracts, silicon, arbuscular mycorrhizal fungi and certain nitrogen-fixing bacteria.
Among other firms, Corteva Agriscience is developing many PBs with Ajinomoto Dadelos Agrosolutions and Simbiose (of Brazil) and is also commercializing other natural products with Simbiose for the protection of sugarcane, soybeans and corn. Susanne Wasson, president of Corteva Agriscience Crop Protection Business Platform, explains that last year Corteva launched a dedicated bio-products portfolio focused on PBs, pheromones and other biocontrol products.
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Tractor spraying soybean crops. Among other firms, Corteva Agriscience is developing many PBs with Ajinomoto Dadelos Agrosolutions and Simbiose (of Brazil) and is also commercializing other natural products with Simbiose for the protection of sugarcane, soybeans and corn. - Photo: ANP
4 – Biologicals
Although living organisms such as microbes are included in the definition of biostimulants, they are generally grouped separately as ‘biologicals.’ Among all types of natural crop protection products, biologicals have found wider acceptance because of all the R&D investments over the last decade, explains Kaustubh Borah, commercial & business development manager at FMC Plant Health North America.
Understanding how biological products complement synthetic product(s) is often key in product acceptance for non-organic growers
“Biologicals provide growers with a sustainable tool to address their evolving need to control pest and disease pressure,” he observes. “They deliver different modes of action compared to synthetics and can be used to broaden the spectrum of pest and disease control beyond those of synthetic products. Understanding how biological products complement synthetic product(s) is often key in product acceptance for non-organic growers.”
Microbe biopesticides have primarily been Bt-based (Bt is the bacteria B. thuringiensis), but Borah notes that they’ve evolved to include diverse molecules such as peptides, pheromones and enzymes for the control of detrimental fungi and nematodes.
Today, efficacious biologicals result in yield increases, but Borah says growers should also understand they can “help plants overcome difficult growing conditions, fight disease, and assist in regulating the plant’s uptake of nutrients and use of limited water.” Indeed, a plant’s abilities to withstand periods of drought and other tough growing conditions is becoming more critical as the impacts of climate change become stronger.
Hines notes that biologicals are mainly used currently on specialty crops in the fruits and vegetable market, especially on those grown under cover or in greenhouses, and only a small percentage is used in row/field crops.
However, she says BASF sees “great potential for growth” in biologicals for row crops, “not only as seed treatment, which is widely used today, but also as a soil and foliar application.” BASF’s biological fungicide Serifel is based on the bacterium Bacillus amyloliquefaciens strain MBI600, and provides broad-spectrum disease control and multiple modes of action. It is used in crops from grape, tomato and lettuce to strawberries and mushrooms, and “can easily be integrated into a program with BASF’s chemical fungicides.”
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BASF’s Velifer is a biological insecticide made from a proprietary strain (PPRI 5339) of the beneficial fungus Beauveria bassiana. It reduces target pests such as whiteflies at all life stages from egg to adult. It’s also effective against insect populations that have developed resistance to conventional insecticides and can be used frequently right up to harvest on fruit, vegetables and ornamental crops.
Nematodes are naturally-occurring microscopic worms already present in soil. Beneficial nematodes provide flexible pest control as they fit into both conventional and organic farming practices and work across glasshouse and outdoor-grown field crops, fruits and vegetables as well as turf.
In fact, in some cases, beneficial nematodes are the only option to limit the spread of destructive pests. “Nemasys R and Nemasys C are such solutions that control citrus root weevil and diapausing larvae of Codling moth respectively,” Hines says. “Our Nemasys L serves as a replacement for aldrin and carbofuran control for black vine weevil. We also offer the only biological control for slugs, Nemaslug.”
Inoculants are biological seed treatments based on rhizobia bacteria that support nitrogen fixation in legumes such as soybeans and peanuts. Key products from BASF include Nodulator and HiCoat, and in some regions, BASF also offers combinations of inoculants and biological fungicides such as Vault.
Scott Ewert, head of Seedcare at Syngenta Canada, notes that “we will be entering the Canadian biological market this year with a new corn and soybean seed treatment for suppression of key diseases and nematodes at the critical early stages of corn and soybean germination and seedling growth.”
Corteva Agriscience has a joint venture collaboration with Lavie Bio to commercialize seed treatments or products sprayed or applied to soil.