Lettuce root aphids can be distinguished from other aphids found on lettuce by their short antennae (less than one-third body length) and undeveloped cornicles. They are found on lettuce roots in clustered colonies covered with a white powdery wax. Where lettuce or related weeds are not available, these aphids overwinter in the egg stage on the bark of Lombardy poplar. They develop to adults and reproduce once on poplar before migrating to lettuce. On lettuce they begin to feed and reproduce; winged adults develop that can spread from field to field. Lettuce root aphid is a serious pest mostly where lettuce is planted near Lombardy poplars.

                                                                                     

Susceptible Plants- are lettuce, low thistle, and Lombardy poplar, a common winter host.

Symptoms- Plants heavily attacked by the lettuce root aphid may wilt during the day. The developing heads remain soft, fail to develop properly, and yields are reduced. Extremely heavy aphid populations over a prolonged period can cause collapse and death of the plant. Individual rootlets turn brown and die. Masses of white, woolly material and lettuce root aphids are present on roots.

Green Lacewing Larvae in Bottle

Prevention and Control- If infested lettuce grows rapidly, a satisfactory crop may often result. Avoid stressing plants and maintain optimum water levels. To help reduce an infestation, eliminate cracks where aphids enter the soil and attack plant roots. If an infestation occurred on the previous crop, work the soil deeply and allow it to dry thoroughly before replanting to lettuce. Tilling or discing an infested crop will not eliminate the population before replanting.

Do not plant lettuce near Lombardy poplars where lettuce root aphids overwinter. Plant root  lettuce aphid resistant cultivars, Crop rotation  is an important component of pest and disease control..

Biological Control-  "Aphid Parasite Aphidius colemani" or "Aphid Predator Aphidoletes aphidomyza"

Insecticidal Control-  such as Concern® Garden Defense Multi-Purpose Spray a neem oil based insecticide is organically acceptable for severe outbreaks of lettuce root aphids

MYCOTROL O® is an organic insecticide containing spores of the insect-killing fungus Beauveria bassiana GHA strain. It is specifically formulated for use in organic agriculture and is OMRI Listed. The benefits of using a spore based insecticide are that it is compatible with beneficial insects, it is completely safe for you and the environment, and can be used up to the day of harvest.

SucraShield - Insecticide/Miticide; OMRI listed - is a sugar-based insecticide/miticide that gives fast-acting control for hundreds of soft-bodied insects like aphids. The active ingredient, a sugar ester, attacks the target pests and causes rapid dehydration. SucraShield™ biodegrades into sugar and water in the environment. SucraShield™ is allowed for use in organic agriculture under the USDA National Organic Program and is registered with the WSDA for Organic Farming and Gardening.

Lettuce Root Aphid Controls offered by Arbico Organics

SucraShield - Insecticide/Miticide $23.89	MYCOTROL O® - Organic Insecticide	Ladybug Beetles Hippodamia  $45.95