Lettuce root aphid

Phillips, S.W., Bale, J.S. and Tatchell, G.M. 1999. Escaping an ecological dead-end asexual overwintering and morph determination in the lettuce root aphid Pemphigus bursarius L. Ecological Entomology 24 336-344. 

Lettuce is the most pest- and disease-prone member of the Asteraceae. Common pests include slugs, cutworm, leaf aphids, and root aphids. Linder cover, downy mildew and gray mold (botrytis) can be a problem, especially in cool, damp conditions. Cultivars with resistance to aphids, downy mildew, and various physiological disorders are available. For more advice and information, see the A-Z of Plant Problems ipp.320-341). 

Small, yellow-white, wingless, waxy pests with dark spots on the abdomen, found among lettuce roots during summer. Overwinters mainly on Lombardy poplar, moving in June to lettuce and sow-thistle. Root colonies can persist into winter, and may survive in the soil until the next season. See a/so Aphids. 

Phloem-systemic aphicides are the most useful in controlling root aphids that live underground. Even soil application of xylem-systemic insecticides are not very effective against these pests. In sever field trials on lettuce, cabbage, and Christmas trees, RH7988 had shown excellent control of root aphids by foliar treatment. Results of one such trial firom California is shown on Table VIII (10). 

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