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Brachycaudus schwartzi (= Brachycaudus prunicola schwartzi)Peach curl aphid, Brown peach aphidOn this page: Identification & Distribution Other aphids on the same host Damage & ControlIdentification & DistributionAdult apterae of Brachycaudus schwartzi are shiny yellowish-green to greenish-brown to dark brown (see pictures below), usually with some orange-pink suffusion especially around their siphunculi, and with broad dark segmental stripes. The antennae are shorter than the body length, with the terminal process 2.3-4.8 times as long as the base of antennal segment VI. The rostrum generally reaches beyond the middle coxae with the apical rostral segment 0.9-1.1 times as long as the second hind tarsal segment. The dorsal cuticle is extensively sclerotized, but is partly segmentally divided especially on the anterior tergites, and does not extend laterally to the spiracles (cf. Brachycaudus persicae, where sclerotization of the dorsal abdomen is almost complete, extending laterally to the spiracles and not segmentally divided). Marginal abdominal tubercles (=circular membranous areas, which are clearly visible on marginal sclerites just anterior to the siphunculi on the yellow form) on abdominal tergites II-IV are mostly greater than 18 μm, and are often as large as or larger than spiracles (cf. Brachycaudus prunifex and Brachycaudus prunicola, which have marginal abdominal tubercles on abdominal tergites II-IV, if present, mostly less than 18 μm, and smaller than the spiracles). The siphunculi are dark and short. The cauda is short and rounded, shorter than its basal width and pigmented. Immatures are greenish with dark scleroites, with an orange-pink suffusion over their posterior tergites. Note: Brachycaudus schwartzi is very similar to Brachycaudus prunicola, and is sometimes treated as a subspecies thereof, viz. Brachycaudus prunicola ssp. schwartzi; see Cocuzza et al. (2007).
First image above copyright Zdenëk Hyan, second image copyright Mihajlo Tomić The alate Brachycaudus schwartzi (not pictured) is orange-yellow with a discontinuous black dorsal abdominal patch. The antennae are shorter than the body, and bear 25-37 secondary rhinaria on segment III, 7-14 on IV and 0-1 on V. The siphunculi are cylindrical, short and dark. The cauda is short and rounded. The clarified slide mounts below are of adult viviparous female Brachycaudus schwartzi : wingless, and winged.
Micrographs of clarified mounts by permission of Roger Blackman, copyright AWP all rights reserved. Brachycaudus schwartzi is monoecious holocyclic on peach (Prunus persica). In spring colonies of this species cause severe curling and distortion of peach leaves. Sexuales develop in autumn. Brachycaudus schwartzi is found in Europe, West & South Asia, North Africa, South America and southern states of North America. Other aphids on the same hostBrachycaudus schwartzi has only been confirmed to occur on 3 Prunus species (Prunus padus, Prunus persica, Prunus serotina), although it has (likely) been misidentified on several others.
Damage and controlInfestation of peach trees with Brachycaudus schwartzi causes damage to leaves and young shoots, which become crumpled and deformed. This can arrest bud development leading to the fall of young fruit. Deposition of abundant honeydew affects plant photosynthesis which reduces fruit yield. The aphid can also vector Plum pox virus (PPV) which causes Sharka disease of peaches, and necessitates obligatory 'eradication' of infected peach trees. In recent years most Brachycaudus schwartzi control has been done by use of organophosphate insecticides. However, this practice has led to considerable environmental damage, and efforts are being made to move to biological or integrated control methods.
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