In the field, the right flower arrangement can improve organic pest control

Jan 17, 2014 by Ann Perry
ARS horticulturist Eric Brennan has found that randomly interspersing alyssum plants throughout rows of organic lettuce helps maximize visits by hoverflies that prey on lettuce pests. Credit: Stephen Ausmus

Studies conducted in an organic lettuce field managed by the U.S. Department of Agriculture (USDA) indicate that there's more to sweet alyssum than just good looks. Agricultural Research Service (ARS) horticulturist Eric Brennan has identified ways to improve how the pretty white flowers control aphid pests that prey on lettuce leaves. ARS is USDA's chief intramural scientific research agency.

Lettuce growers in California's central coast plant alyssum to attract adult hoverflies that feed on the flower's pollen and nectar. After eggs laid by the well-fed females hatch, the voracious larvae prey on currant lettuce aphids—an important primary insect pest of lettuce in the region. The aphids are particularly difficult to control because they colonize the interior leaves of the lettuce plant.

Brennan, who works at the ARS U.S. Agricultural Research Station in Salinas, Calif., wanted to figure out the most cost-effective alyssum planting patterns in lettuce fields to help organic producers maximize their profits. At a working research farm in Salinas that is certified for commercial organic production, he established experimental beds with eight different planting combinations of alyssum and romaine lettuce.

For two growing seasons, Brennan evaluated how alyssum biomass and flower production varied with alyssum planting density and how competition between lettuce and alyssum affected the biomass of both plants. In beds where alyssum had been planted in addition to a full complement of lettuce, the alyssum produced more blossoms per gram of alyssum dry matter.

This response indicated that the alyssum and lettuce planted in this pattern may have been in stronger competition for nutrients needed to support biomass production. But the resulting boost in blossoms increased alyssum's value as an insectary plant, which is a flowering plant cultivated in crop fields because it attracts insect predators to feed on pests.

Brennan has also concluded that randomly interspersing alyssum plants throughout all the lettuce rows could minimize competition between lettuce and alyssum and encourage adult hoverflies to forage for pollen and nectar more evenly throughout the field.

Results from this study were published in Biological Control in 2013.

Explore further: Flower power fights orchard pests

More information: Read more about this work in the January 2014 issue of Agricultural Research magazine.

add to favorites email to friend print save as pdf

Related Stories

Flower power fights orchard pests

May 14, 2013

Washington State University researchers have found they can control one of fruit growers' more severe pests, aphids, with a remarkably benign tool: flowers. The discovery is a boon for organic as well as ...

Researchers test effects of LEDs on leaf lettuce

Nov 19, 2013

In the life cycle of plants, most developmental processes are dependent on light. Significant biological processes such as germination, shade avoidance, circadian rhythms, and flower induction are all affected by light. Recent ...

New romaine lettuce lines launched

Jan 18, 2011

California and Arizona, the two largest lettuce-producing states, account for more than 95% of the lettuce grown in the United States. Since the early 1990s, the states' lettuce crops have been subject to ...

Recommended for you

Citizen scientists match research tool when counting sharks

3 hours ago

Shark data collected by citizen scientists may be as reliable as data collected using automated tools, according to results published April 23, 2014, in the open access journal PLOS ONE by Gabriel Vianna from The University of Wes ...

Researchers detail newly discovered deer migration

10 hours ago

A team of researchers including University of Wyoming scientists has documented the longest migration of mule deer ever recorded, the latest development in an initiative to understand and conserve ungulate ...

How Australia got the hump with one million feral camels

11 hours ago

A new study by a University of Exeter researcher has shed light on how an estimated one million-strong population of wild camels thriving in Australia's remote outback have become reviled as pests and culled ...

Former Iron Curtain still barrier for deer

17 hours ago

The Iron Curtain was traced by an electrified barbed-wire fence that isolated the communist world from the West. It was an impenetrable Cold War barrier—and for some inhabitants of the Czech Republic it ...

Humpback protections downgrade clears way for pipeline

Apr 22, 2014

Environmentalist activists on Tuesday decried Canada's downgrading of humpback whale protections, suggesting the decision was fast-tracked to clear a major hurdle to constructing a pipeline to the Pacific ...

Maine baby lobster decline could end high catches

Apr 22, 2014

Scientists say the number of baby lobsters settling off the rocky coast of Maine continues to steadily decline—possibly foreshadowing an end to the recent record catches that have boosted New England's lobster fishery.

User comments : 0

More news stories

Citizen scientists match research tool when counting sharks

Shark data collected by citizen scientists may be as reliable as data collected using automated tools, according to results published April 23, 2014, in the open access journal PLOS ONE by Gabriel Vianna from The University of Wes ...