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Effect of infestation depends greatly on host plant and transmitted viruses. Spring populations on peach cause severe leaf curl and shoot distortion. In potato, PLRV symptoms are leaf rolling and tuber stem necrosis. In sugarbeet, beet yellows viruses (BYV, BYDV, BWYV) cause yellowing in older leaves, chlorotic spotting, and thickening of the leaves, which become leathery and brittle.
On many crop plants (for example, potato, brassicas, sugarbeet) M. persicae only occurs at low densities, particularly on older leaves. Large colonies of the tobacco form (nicotianae) occur on growing stems and younger leaves.
Due to the variable regulations around (de-)registration of pesticides, we are for the moment not including any specific chemical control recommendations. For further information, we recommend you visit the following resources:
M. persicae is the most important aphid virus vector. It has been shown to transmit well over 100 plant virus diseases, in about 30 different families, including many major crops. Persistent viruses transmitted include Beet western yellows virus, Beet yellows virus, Beet mild yellowing virus, Pea enation mosaic virus, Bean leaf roll virus, Potato leaf roll virus and several viruses of tobacco (for example, Tobacco vein-distorting virus, Tobacco yellow net virus). Many more are transmitted by the non-persistent method, including Potato virus Y, Cucumber mosaic virus, Clover yellow vein virus, Alfalfa mosaic virus, Pepper veinal mottle virus, Plum pox virus, Lettuce mosaic virus and Tobacco vein mottling virus.
Direct feeding damage can result in stunting and reduced root weight, but populations on most crops do not reach levels causing obvious symptoms such as chlorosis or leaf curling, and the production of copious honeydew with associated sooty mould. However, significant yield losses can arise from direct damage on potatoes (Sexson et al., 2005) and visible distortion of leaves can occur on peach in the spring as well as on peppers and flower crops in greenhouses.
M. persicae is a major pest everywhere potatoes are grown. It is the most important vector of Potato leafroll virus (PLRV), which causes leaf roll and tuber rot necrosis. Seed potatoes have low tolerance for PLRV and low aphid populations can be very damaging.
Yield losses in sugarbeet due to beet yellows are more serious if infection occurs early in the season and can be up to 30-50%, with an increase also in the impurities present in the harvested sugar.
On peach (the primary host) the aphid causes twisting of the young leaves and on nectarines, pitting on and discoloration of the young fruits (Barbagallo et al., 2007).