Root aphids

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). 

The second invasion came in 1865 when attempts to control the root aphid Phylloxera through the importation and use of Phylloxera-resistant root stocks inadvertently introduced vine downy mildew, Plasmopara viticola, into the French vineyards. This stimulated what is regarded as the major breakthrough in fungicide use when Millardet, in 1885, acting upon a chance observation, developed the use of Bordeaux mixture, a cocktail of copper sulfate and lime, which is still used extensively in vines and many other crops. 

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. 

Akino, T. and Yamaoka, R. (1998). Chemical mimicry in the root aphid parasitoid Paralipsis eikoae Yasumatsu (Hymenoptera Aphidiidae) of the aphid-attending ant Lasius sakagamii Yamauchi and Hayashida (Hymenoptera Formicidae). Chemoecology, 8, 153-161. 

Volkl, W., Liepert, C., Bimbach, C. R., Hiibner, G. and Dettner, K. (1996). Chemical and tactile communication between the root aphid parasitoid Paralipsis enervis and trophobiotic ants consequences for parasitoid survival. Cell. Mol. Life Sci., 52, 731-738. 

Before planting, till to control weeds that may harbor armyworms, cutworms, and tarnished plant bugs, and to disturb corn root aphids. 

Corn earworms. 284,284 corn and, 6.77,79,414 mineral oil for, 477 neem for, 477 nematodes and, 458 pepper and,175, 176 pheromone traps for, 437 tomato-leaf spray for, 485 Cornflower. See Centaurea Corn leaf blight, corn and. 78 Corn root aphids, tillage and. 428... 

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). 

RH7988 FIELD EFFICACY AGAINST ROOT APHIDS BY DOWNWARD TRANSLOCATION AFTER FOLIAR TREATMENT OF RED CABBAGE... 

Red Cabbage Hybrid Red TREATMENT Foliar Spray Pemphigus populitransversus (Cabbage Root Aphid)... 

We may add two further interesting observations2 noted with radioactive O.M.P.A. The first is that examination of the transpired material from plants, the roots of which had absorbed the insecticide, failed to show that any radioactive material had been given off. The second observation is that aphids killed by feeding on such plants, and also the honey dew which they produced, were found to be radioactive. 

Pests are often classified according to where and how they feed on the plant (see facing page). Although this is convenient, these categories are not mutually exclusive. Many leaf-feeders also feed on stems some sapsucking aphids also feed on roots and flowers. 

Symptoms Tender young growth is most prone to attack, but aphids will also colonize leaves, stems, and, in some cases, roots. Leaves and shoots become distorted. Heavy infestation can kill a plant. Leaves are often coated with honeydew, a sticky substance produced... 

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. 

Many Insects have become specialists on crucifers and a few related plant families. These Include flea beetles, leaf beetles, cabbage root fly, aphids, cabbage butterflies and the dlamondback moth. At the same time, several polyphagous Insects such as the cabbage looper, armyworms and aphids are major pests of crucifers. Comparative studies on these specialists and generalists have provided valuable Information on host recognition and possible resistance mechanisms. 

A. Too many Whitefly is a big problem for greenhouse grown plants. Aphids, slugs, caterpillars, thrips, spider mites, and scale insects can also damage your plants. Root rot and stem rot can be problems. Fungal spots can appear in leaves. It is not known which plant viruses attack Salvia divinorum but many attack other sages. 

P. penecaeca is a very large aphid (3.8 to 5.0 mm), dirty grayish white in color, which has been recorded on the roots of H. tuberosus in northern India (Blackman and Eastop, 2000 Verma, 1969). 

T. troglodytes is a large, plump white aphid found on the roots of Jerusalem artichoke and other Helianthus spp. it is invariably attended by ants. This species occurs in Europe, western Siberia, Central Asia, and Japan (Blackman and Eastop, 2000 Eastop, 1953). 

---