HOW AGRICULTURE LEARNS FROM NATURE
Symbiosis in crop protection
Biologicals are gaining increasing acceptance from farmers worldwide as a fundamental part of crop protection: biological crop protection agents offer highly targeted ways of controlling pests and diseases, and provide new resistance
management strategies. Researchers at Bayer CropScience are working on new products, including biologicals, to
­promote sustainable agriculture in the future.
Nature can be unforgiving, even taking life on occasion, such
as that of a voracious gypsy moth caterpillar. Not much is
now left of its chitinous exoskeleton and its body is covered in
white fuzz. A fungus discovered that this caterpillar is a nutritious source of food and promptly devoured it from the inside
out. Researchers at Bayer CropScience are starting to take a
closer look at this kind of microorganism. “Fungi and bacteria
can be very successful biological crop protection agents in the
fight against pests, while at the same time having an excellent environmental profile,” explains Dr. Peter Lüth, Managing
Director of Prophyta. Acquired by Bayer CropScience in 2013,
his company specializes in biologicals, meaning active substances derived from natural sources such as plants, bacteria
or fungi.
Bayer CropScience is committed to integrated solution
strategies – in other words, selecting the appropriate seed
and using a combination of chemical and biological crop protection agents. And biologicals are becoming an increasingly
important addition to Bayer CropScience’s product portfolio;
biologicals are a promising technology for the future, and the global
market segment for biological crop
protection agents is expected to
grow faster than those for chemical
crop protection agents and agricultural seed.
Lüth and his team are concentrating chiefly on fungi. A former
One milliliter of
agronomist and plant researcher,
Lüth founded his company over
BioAct™ DC contains
20 years ago, and since then has
50 billion ­spores.
learned much about how fungi
can be bred and converted into
marketable products. “The product BioAct, for instance, which consists of spores of the
fungus Paecillomyces lilacinus strain 251, helps control
nematodes,” Lüth explains, the cumbersome name rolling
easily off his tongue. The fungus infects the eggs of nematodes, destroying them before the voracious pests can hatch
50
billion
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Complete concentration on the roots: nematologist Dr. Varghese
Thomas from Bayer CropScience in Davis, California, USA checks the
roots of plants for nematode damage.
and eat their fill of the roots of grapevines, corn plants or
banana plants.
The great advantage of this biological agent is that the fungus in BioAct™ attacks only plant parasitic nematodes, especially
the juvenile stages and eggs, without harming any other soildwelling organisms. “Biological crop protection products have
a very targeted effect, which also reduces the risk of resistance
developing,” Lüth says. Other products such as ­Serenade™ fungicide, Sonata™ fungicide and Requiem™ insecticide, which
are already produced and marketed by Bayer CropScience,
likewise help to reduce fungal and pest infestation by means
of various mechanisms, thereby expanding the options for
crop protection.
Photos: Peter Ginter/Bayer AG (8), BPIA (1)
Biological Crop Protection AGRICULTURE
Natural artwork: fungi present in the product Contans™ are grown here on a plate as part of the quality control process.
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Under control: every stage in the production of biological crop protection products is checked. While Daniel Karsch and Dr. Peter Lüth (photo left, left to right) take
samples of freshly grown fungal spores in the fermentation room in Wismar, Tamara Meragelman and Danielle Roberts-Scott (photo right, left to right) analyze culture
media that will be used to grow bacteria in Davis, California.
“Microbes have different abilities than chemical agents, because
they can not only produce substances to control diseases and
pests, they can also enter into a relationship with the plant,
living with it in symbiosis,” explains Dr. Mike Miille, Head of
Business Management Biologics at Bayer CropScience. Biological crop protection agents are therefore often more than just
active substances, and using fungal spores and bacterial prod-
ucts can yield additional benefits. For example, Serenade™ – a
product made from the patented bacterial strain Bacillus subtilis strain 713 – helps farmers keep common fungal diseases
such as the gray mold Botrytis in check. Serenade™ has the following features: its anti-fungal proteins known as lipopeptides
break down pathogen cell membranes, while its anti-bacterial
compounds prevent the growth of pathogenic bacterial cell
Natural mixture against
spider mites
They make themselves at home in places where they can initially remain undetected: spider mites spin their webs on the underside of leaves and live off the
plant sap. But they too have natural enemies. A plant extract from the Mexican
tea plant kills them as well as other insects such as whiteflies and aphids. The
compounds responsible for this effect are called terpenes, secondary plant substances that also occur in citrus fruits and tomatoes. They cause the skin of the
insects to soften and impair cell function, thus killing the pests. Scientists at
Bayer CropScience have succeeded in mimicking this mixture of natural plant
products in the laboratory: the product Requiem™ contains a combination of terpenes that resembles the extract from the insecticidal plant.
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Biological Crop Protection AGRICULTURE
Biological crop protection with a triple effect
Serenade™ is one example of biological crop protection for fruit and vegetable growing and large-scale oilseed rape farming. The product
consists of a patented strain of bacteria (Bacillus subtilis strain QST713) that helps keep common fungal diseases like gray mold under
control. The efficacy of the bacterial strain is thanks to the different modes of action shown below. It strengthens the roots, makes plants
more tolerant to stress and increases yields.
Without pest control
Biological pest control with Serenade™
Plant is treated with bacterial
fermentation product.
Fungal cells or other
pests infest the
crop …
The effect:
lipopeptides
destroy the
fungal cell
membranes, …
… and spread to the leaves
and roots.
The effect:
the fungal infection weakens the plant
overall.
walls. It also activates the plant’s immune system and positively influences plant growth and yield. The roots become
stronger, the plants healthier and more stress-tolerant – and
crop yields rise.
Targeted crop protection programs combining chemicals
and biologicals help secure the global food supply; after all,
even today more than 40 percent of crops and food stores
worldwide are lost to fungal diseases, insect infestation and
weeds. “We must optimize agricultural production on every
single hectare of land by means of sustainable practices,”
emphasizes Dr. Jonathan Margolis, Head of Biologics R&D at
Bayer CropScience in Davis, California.
… ­secondly, antibacterial compounds prevent
growth of pathogenic bacterial
cell walls,…
… and thirdly, the product activates the
plant’s immune system and influences
plant growth and yield.
Biologicals are therefore one of four critical building blocks of
integrated crop solutions at Bayer CropScience, alongside the
selection of improved seeds, the use of chemical substances and
complementing services.
Biologicals are one of the four critical building
blocks of integrated crop protection
What’s more, farmers can arm their fields and plantations against
harmful fungi with biological crop protection agents shortly
before or even on the day of harvest, to save a crop from spoiling.
Biological crop protection products have yet another advan-
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Bayer scientists searching for new products: Melanie Röpcke (photo, above) tests the growth of fungi in a small fermenter. Her colleague Kelly
Simoes, meanwhile, is searching for the perfect bacterial culture that could form the basis for a new biological crop protection product (photo,
above right). In the greenhouse, Cecilia Wilson, Tracy Webb and Dr. Tad Smith (photo, bottom right, left to right) investigate the effect of the microorganisms on ­strawberry plants.
tage: they can often be applied at various timings within
the growth cycle, making crop protection more flexible and
keeping bananas, grapes and citrus fruits fresh longer even
after the harvest. While biological solutions are mainly used
in fruit and vegetable farming at present, Margolis and his
colleagues in Davis, California and at Prophyta in Wismar, Germany have a number of other ideas in the pipeline: “Biological
crop protection can also be effective for other crops,” Lüth
points out.
The foundation for success: 20 years of experience
with fungal microorganisms and their preferences
The product Contans™, for example, comprises spores of the
fungus Coniothyrium minitans, and protects oilseed rape plants
against the feared fungal disease white mold, and lettuce, tomatoes and carrots against rotting. “Over 20 years ago, we detected
the ability of this fungus to protect oilseed rape plants against
another fungus in the lab,” Lüth explains. Today, Contans™ is
registered in over 20 countries, but it took a long time to reach
this point. “In the early 1990s, we had little experience with how
a fungus can be multiplied and then packaged and stored as a
crop protection agent first in the lab, and then on an industrial
scale,” the pioneer explains. Lüth and his employees therefore
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developed a special technology for producing the fungal spores
and shepherded it to successful market introduction. The entrepreneur even received the German Environment Award in 2002
in recognition of his achievement.
Enhanced yields thanks to an optimized nutrient
supply and modified fermentation conditions
“Before we breed a fungus, we must know exactly what its
preferences are, meaning the conditions under which it grows
best,” says Daniel Karsch, Production Manager at Prophyta. It
all starts with the right nutrients: for Coniothyrium minitans,
Karsch collaborated with a farmer who grows the very nutrient
this fungus likes best. It is produced for this purpose and sent
directly to the production facility in Wismar, where it is added
layer by layer into a 1,000-liter fermenter, which is finally filled
evenly with fungal spores. “After about a month in controlled
growth conditions, the fungus has formed innumerable new
spores,” Karsch says, lifting the top cover. A black, crumbly mass
is visible, from which spores are harvested.
Karsch and his team are constantly working to optimize
fermentation conditions to attain peak yields. Most of the
microbe-based biological pest control solutions marketed by
Bayer CropScience have 2 years or more shelf life even at ele-
Biological Crop Protection AGRICULTURE
Bill
Stoneman
“Biological crop protection
products meet growers’
needs precisely”
Bill Stoneman is Executive Director of the Biopesticide
Industry Alliance (BPIA). research spoke with him about
current developments in the field of biologicals.
Why are biologicals getting more and more important in crop
protection?
Biological control agents are safe, effective and fit very well into
sustainable food production systems. More and more new biological products are reaching the marketplace with greater investment in proof of efficacy, broader testing across geographies and
with advanced technology and fine tuning to meet the growers’
pest control needs. With several older chemistries leaving the
­marketplace, biologicals are meeting growers’ needs.
Who will profit most?
Specialty agriculture and horticultural crops are still our main
focus. Often these growers have the technology and know-how
to use biological control effectively on smaller acreages. This
is changing, however, and more and more products are being
developed for commodity production. Post-harvest uses are also a
growing market for our industry.
Where do you see the biggest progress – in fungicides,
­insecticides, herbicides or nematicides? And why?
I worked mainly in the fungicides area, so that is where I tend to
consider the best opportunity for growth. Others would disagree
and focus on insect control.
vated temperatures. This aspect needs to be managed carefully
for fungal microorganisms, however. But Lüth and Karsch are
steadily working on new formulations with longer shelf-lives,
and through intense research, Bayer scientists are gradually
getting wise to fungi and other microorganisms, understanding more fully how biological crop protection products can
optimally benefit plants in the field – because the unforgiving
side of nature can sometimes be a big help.
www.research.bayer.com/biologicals
Further information on this topic
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