Plant diversity could provide natural repellent for crop pests

October 12, 2016, Michigan State University
Fields with a variety of plants seems to attract fewer plant-eating insects, such as three-lined potato beetles, than farm land with just one type of crop. Credit: William Wetzel, Michigan State University

A new study has unveiled why a field with a variety of plants seems to attract fewer plant-eating insects than farm land with just one type of crop.

Scientists and farmers have puzzled over this pattern that makes protecting crops from pests a challenge.

Research published in the current issue of Nature and led by William Wetzel, a new Michigan State University entomologist and the study's lead author, is shedding light on this interaction. Plants suppress their insect enemies by being variable, not just by being low quality on average as is typically thought.

After studying 53 species of insects, the researchers found that bugs have narrow ranges of nutrient levels where they flourish. If the being fed on are too nutrient rich or poor, the insects are less likely to thrive. Bugs surrounded by diverse plants are harmed much more by low-quality plants with the wrong nutrient levels than they are benefited by high-quality plants with high nutrient levels.

"Farm fields can create monocultures where pests may find the perfect nutrition to be healthy and reproduce," said Wetzel, who conducted the research during his doctoral work at the University of California, Davis. "Planting fields with higher plant nutrient variability could contribute to sustainable pest control."

Many large farm fields are monocultures because plants are bred to be as identical as possible. What are the solutions for larger growers to add diversity into their farming to discourage pests, while maintaining the same level of productivity?

Crop varieties could be bred with variable nutrient levels in the parts eaten by insects, for example the leaves or roots, while the parts ate by consumers could be consistent. Or farmers could plant new mixtures of or genotypes that differ in .

A Japanese beetle munches on a leaf. Credit: Bill Ravlin/Michigan State University

With Wetzel's move to MSU, he intends to take this research to the next level. His program is using modern genetic resources to develop a model system for manipulating plant trait diversity in field populations and measuring the effects on insect populations and plant damage.

"The community of stellar agricultural and ecological scientists here and core facilities for chemistry, along with greenhouses and field research centers, is helping me test new hypotheses for how plant diversity influences insect ecology at large scales and in the field where it matters," said Wetzel, who's with the College of Agriculture and Natural Resources. "I'm excited about bringing the work to MSU because of the potential to collaborate with an exciting array of molecular biologists, physiologists and landscape ecologists, as well as Extension specialists who bring new knowledge where it is most needed."

Explore further: Plant diversity alleviates the effects of flooding on crops

More information: Variability in plant nutrients reduces insect herbivore performance, Nature,

Related Stories

'Neighbor-plants' determine insects' feeding choices

February 14, 2014

Insects are choosier than you might think: whether or not they end up feeding on a particular plant depends on much more than just the species to which that plant belongs. The quality of the individual plant is an important ...

Insect community driven by plant hormones

May 13, 2014

Plants are not solitary, defenceless organisms but rather the centre of a vibrant community consisting of tens or even hundreds of insect species. Plants possess a wide range of defence mechanisms that are activated in response ...

Dicamba drift affects non-target plants and pollinators

December 3, 2015

Dicamba herbicide drift onto plants growing adjacent to farm fields causes significant delays in flowering, as well as reduced flowering, of those plants, and results in decreased visitation by honey bees, according to researchers ...

Recommended for you

Scientists ID another possible threat to orcas: pink salmon

January 19, 2019

Over the years, scientists have identified dams, pollution and vessel noise as causes of the troubling decline of the Pacific Northwest's resident killer whales. Now, they may have found a new and more surprising culprit: ...

Researchers come face to face with huge great white shark

January 18, 2019

Two shark researchers who came face to face with what could be one of the largest great whites ever recorded are using their encounter as an opportunity to push for legislation that would protect sharks in Hawaii.

Why do Hydra end up with just a single head?

January 18, 2019

Often considered immortal, the freshwater Hydra can regenerate any part of its body, a trait discovered by the Geneva naturalist Abraham Trembley nearly 300 years ago. Any fragment of its body containing a few thousands cells ...

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

not rated yet Oct 12, 2016
who would have thought
at least I have a paper to cite next time I bring this up in a serious discussion

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.