In the U.S., about 1 billion pounds of pesticides are used annually, 90 percent of which are used by the agricultural sector. There are many problems with the indiscriminate use of these , like the fact that 82 percent of domestic fruits and 62 percent of domestic , to say nothing of the risks of pesticide poisoning faced by the 2.5 million farmworkers in the U.S., about 60 percent of whom live in poverty.
Crop land does not exist in a bubble, which means some of the pesticides sprayed onto the land end up contaminating neighboring fields, soil, water and air. Even in the case of systemic pesticides, which are taken up into the plant as a whole via pesticide-treated seeds, about 95 percent of the substances ends up not in the plant cells where it was intended but blown off as dust or permeating the soil and water.
Then there’s the fact that nature eventually finds a way to outsmart the pesticides, such that we’ve seen the emergence of pesticide-resistant superweeds and super insects. The pesticide industry’s response, rather than admitting defeat, is to encourage the use of more pesticides and more to go with them, but it’s a vicious cycle.
Glyphosate-resistant superweeds like pigweed are now driving farmers to seek out dicamba-resistant crops, but dicamba-resistant weeds have already sprouted in some states, raising serious doubts that piling more pesticides on crops will help farmers, or the environment, in the long run. The ultimate solution is not to fight against nature with the use of harmful chemicals, but rather to work with it, and even learn from it, embracing the natural tools already in existence to keep pests in check: namely, wildflowers.
Wildflowers Could Slash Pesticide Use
Wildflowers are home to many beneficial insects, including lacewings, ladybugs, hover flies and parasitic wasps, the latter two of which are natural predators to common crop pests like cereal leaf beetles and aphids. While some farmers have experimented with planting wildflowers around the border of their crops, the Center for Ecology & Hydrology (CEH) in the U.K. is taking things a step further, initiating a five-year trial that will sow wildflower strips into the center of crops in 15 farms and evaluate the results.
“Lining the perimeter of a farm with wildflowers asks that the beneficial insects leave this habitat and to trek into the fields to chow down on their prey. But most of the good guys aren’t particularly mobile,” Modern Farmer explained.
The new in-field stripes, however, make it easier for the beneficial insects to move about the fields and reach all the way to the center. The wildflower stripes also go beyond another method of natural pest control known as beetle banks, in which raised strips are planted tussock and other grasses to attract ground beetles. According to CEH:
“In-field wild flower strips move beyond beetle banks in a number of important ways. Perhaps the most important is that their focus is on supporting diverse communities of predatory and parasitic insects that kill pests. Research increasingly suggests that complex communities of predators and parasitoids are the most effective at controlling pests.
Rather than just promoting predominantly ground active predators, we need to support those in the canopy or those that target internal pests living in stems or seed pods. By sowing specific grasses and wildflowers we can target the resources provided by in-field strips and normal field margins to benefit the greatest diversity of important predators.”
Wildflower Strips Work to Naturally Ward Off Pests
The CEH study builds off research published in 2015, which planted flower strips along 10 winter wheat fields and compared the outcome with fields planted with wheat control strips. The results were promising, showing strong reductions in the density of cereal leaf beetles (CLB), a major cereal pest in Europe, Asia and North America, as well as plant damage caused by them. In fact, the fields with wildflowers had 40 to 53 percent lower beetle density and 61 percent less beetle damage compared to the control fields.
“Our study demonstrates a high effectiveness of annual flower strips in promoting pest control, reducing CLB pest levels below the economic threshold. Hence, the studied flower strip offers a viable alternative to insecticides,” the researchers wrote.
Past research has also shown wildflower strips can help to naturally control pest aphids in lettuce crops, while they have the added benefit of attracting beneficial pollinators. One study revealed the frequency of pollinator visits was 25 percent higher for crops with adjacent flower strips compared to those without.
“The in-field flower strips … provide early season pollen and nectar resources for important crop pollinators, such as bumblebees and solitary bees,” CEH noted. “In this respect they should provide dual benefits — enhanced natural pest control and crop pollination.” The fact that wildflowers serve two beneficial purposes stands in stark contrast to the increasing use of pesticides, which is furthering the emergence of superweeds and insects while decimating beneficial pollinators.
One study involved 18 years of U.K. wild bee distribution data for 62 species, which were compared to amounts of neonicotinoid use in oilseed rape, a crop grown to produce . The researchers found evidence of increased wild bee population extinction rates in response to systemic pesticide () seed treatment. Overall, about 50 percent of the total decline in wild bees was linked to the pesticides.