Beneficial insects provide advantages for landowners in pest management
When conservation measures are implemented across the landscape, Thelma Heidel-Baker, a conservation biocontrol specialist with the Xerces Society, an invertebrate conservation organization, notes beneficial insects can provide natural pest control in agriculture systems.
“Numerous measures can be taken to support insects and insect communities that also promote good soil health,” says Heidel-Baker.
Often, when people focus on pest management, Heidel-Baker says landowners tend to focus on insects as a whole, neglecting the fact that only two percent of insects are actual pests.
“The rest of insects are for decomposing, making new soils and other things,” she explains. “Even though it’s easy to focus on the pests, other insects are vitally important.”
One study referenced by Heidel-Baker showed that beneficial insects may generate between $4.5 and $12 billion annually for U.S. crop production, a figure that increases to $100 billion when crops around the world are considered.
“This is a conservative estimate,” she says.
Beneficial insects are often present, but they aren’t easily seen or noticed, Heidel-Baker adds.
She explains, “Many of our beneficial insects are tiny. A parasitoid wasp is only one to two millimeters long. They can be extremely critical.”
“Just because the insects are tiny doesn’t mean they aren’t really important or that they don’t provide critical natural pest control,” she adds.
When looking at utilizing insects for pest management, Heidel-Baker says, “Habitat is the key component, as we have to make sure we’re providing the best environment for promoting insects.”
“Pests thrive in monoculture systems because those systems provide the plants the pest needs,” she explains. “Beneficial insects need a more diverse habitat because they are a very diverse community.”
Landscape complexity helps to enhance beneficial communities for insects, but there were also other challenges.
“Creating good habitat is not the only important piece,” she comments, “but there are a lot of other challenges that occur.”
Across the landscape, Heidel-Baker says the loss over 9 million acres of grassland and prairie have been converted to cropland because of the high value of crops, which is a detriment to insects.
“Another challenge is in the broad use of pesticides,” she comments. “Insecticides are used extensively across large expanses of acres.”
In particular, neonicotinoids are a concern because they are long-lasting, highly mobile compounds that are utilized worldwide.
Not only do the insecticides kill beneficial insects, they also kill the food for remaining beneficial insects.
“Because our beneficial insects are also predatory, if we kill all the pest insects, we need to provide an alternative prey source for those beneficial insects when we use insecticides,” Heidel-Baker notes.
Habitat for insects extends beyond floral resources and extends to the broader community of plants in a landscape. It also includes providing pollen and nectar to beneficial insects, as well as their prey.
Additionally, it is important to have shelter for egg-laying, reproduction and overwintering, as well as protection from predators and pesticides.
Beneficial insects are diverse in their nature, and native lady beetles are a well-known group.
“They’re great at feeding on soft-bodied insect pests like aphids, mealy bugs and more,” Heidel-Baker says. “In the larval stage, they are also predatory.”
Lacewings are another important in different stages of their life. The adults aren’t predatory, but their larvae are aggressive predators that move around to hunt and search for their prey.
Parasitoid wasps impact predators by laying their eggs in larvae, where they develop into amture wasps. Additionally, Heidel-Baker noted they require specific habitat because they don’t have any other prey than aphids.
Hover flies and the assassin bugs work in different ways to attack insect pests.
“Another important group as we think about soil health are predatory grounds beetles, which live at the interface of plant and soil,” Heidel-Baker says. “They are down at the soil surface, which are important for controlling predators like grubs, and they can be important for weed control.”
Because of the importance of beneficial insects, several farming practices can be implemented to promote insect growth.
She says, “Healthy crops ensure good things happen in our habitats. When crops are healthy, they create a resilience against insect pests that might occur in the first place.”
By deterring insect pests, the use of insecticides is alleviated, allowing plants to address pest issues on their own.
Healthy soils are the foundation of ensuring healthy crops, adds Heidel-Baker.
“One of the really important practices that has come to light recently to promote beneficial insects and soil health is the use of cover crops,” she says. “More farmers are looking at cover crops because they provide a ton of benefits across the farm.”
In addition to helping improve soils, cover crops can support insects and pollinators.
Heidel-Baker comments, “We know ag practices impact diversity and abundance.”
Heidel-Baker spoke during a National Association of Conservation Districts (NACD) soil health webinar in mid-November 2017. The webinar was hosted by the NACD Soil Health Champions Network.
Saige Albert is managing editor of the Wyoming Livestock Roundup and can be reached at firstname.lastname@example.org.