A common flowering landscape plant may help control woolly apple aphids in Washington orchards.
Sweet alyssum, a low-growing ornamental, attracts a host of spiders and predatory insects. They, in turn, go after the orchard pest, according to a news release.
In Washington State University research that compared plots of apple trees with sweet alyssum to those without, the plots with the flowers had fewer aphids.
Lessando Gontijo led the research project while a doctoral student in the WSU Department of Entomology.
Upon further inspection, the researchers found a diverse population of beneficials in the alyssum plots. But were they really responsible for reduced aphid numbers?
The scientists then sprayed the flowers with protein marker and later captured insects and spiders some distance from the flower plots.
The beneficials tested positive, proving they had visited the flowers.
The work was published in the July edition of the journal Biological Control.
In the past, aphids had been controlled when growers sprayed for codling moth.
In recent years, growers have moved toward softer approaches, including the use of mating disruption.
Mating disruption involves flooding orchards with female pheromone, which confuses male codling moths and reduces their chances of finding a female with which to mate.