Pair Alyssum with Lettuce

Jennifer Duffield White

Whether you harvest lettuce or just sell starters at the garden center, here’s one new piece of research that will have you reaching for alyssum. New studies conducted by USDA Agricultural Research Service horticulturalist Eric Brennan have shown better pest control when alyssum is planted near organic lettuce in certain formations. In particular, randomly planting alyssum between lettuce plants may be very effective for aphid control.

The reason? The alyssum attracts a beneficial insect, the hoverfly. Hoverflies lay eggs nearby, then, once hatched, the larvae hop on over to the lettuce to prey on currant lettuce aphids—a pest that plagues California growers by colonizing the interior leaves of lettuce plants.

While many growers have already adopted the practice of planting alyssum with lettuce, Brennan wanted to figure out the most cost-effective planting patterns. For two years, he evaluated how alyssum biomass and flower production varied with planting density. In beds where alyssum was planted in addition to a full complement of lettuce, the alyssum produced more blossoms per gram of alyssum dry matter, making it more valuable as an insectary plant.

Want to learn more? Agricultural Research has more info on the research www.ars.usda.gov/is/AR/archive/jan14/lettuce0114.htm. GT