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Aloe vera aphidOn this page: Identification & Distribution Other aphids on the same host Damage & Control
Identification & Distribution
Adult apterae of Aloephagus myersi have an oval body, and are coloured orange-brown or dull-green (see two pictures below). There is a covering of whitish flocculent wax, but it is not usually thick enough to hide the body color.
First image copyright Jeffrey W. Lotz, Florida Department of Agriculture and Consumer Services, Bugwood.org;
Their antennae are 5-segmented, with the terminal process 0.25-0.4 times as long as the base (see pictures below of preserved specimens). The head has two small wax glands on the vertex. The eyes are small and 3-faceted. The rostrum is elongate, reaching to or beyond the tip of the abdomen (but it may be retracted as in the second picture below, and appear much shorter). There are rounded marginal tubercles on the prothorax and abdominal segments I-VI, and very small wax glands of the Melaphis-type behind each tubercle. The dorsum is sparsely covered with short spines arranged in transverse rows on the abdominal segments. The trochanter is completely fused to the femur. Siphunculi are absent. The subgenital plate is bilobed, and conceals the broadly rounded cauda. The body length of adult Aloephagus myersi apterae is 1.8-2.5 mm.
Images copyright Patrick Marquez, USDA APHIS PPQ, Bugwood.org.
The alate of Aloephagus myersi (not pictured) has a black head and thorax. There are sclerotic bars on tergites VII & VIII and rather large marginal sclerites. The antennae are black and about 0.22 times the body length . There is an extremely large elongated primary rhinarium on segment IV which is nearly half as long as the segment, a round primary rhinarium on segment V, the normal cluster of secondary rhinaria and a short tubular terminal process. The rostrum is extremely long, reaching to the end of the abdomen. Siphunculi are absent.
Aloephagus myersi is only known from its secondary host, Aloe species. Their primary host is presumed to be Pistacia in Africa, as emigrant alatae suspected to be this species have been collected from galls on Pistacia aethiopica in Kenya. Populations outside Africa are anholocyclic. On Aloe they live under the leaf bases, attended by ants. Aloephagus myersi has also been reported from the related plant genera Haworthia and Astroloba. It is thought to be native to Africa where it is widespread south of the Sahara, but is now found worldwide, in glasshouses in temperate climates, and can be a major pest.
Other aphids on the same host
Assuming Aloephagus myersi colonises Pistacia aethiopica, it is the only aphid recorded from that host.
Aloephagus myersi has been recorded on at least 18 species of Aloe. The specialist aphid Aloephagus myersi is the only aphid species to have been recorded on 13 of the 18 species of Aloe. Note: Despite its common name of Aloe vera aphid, it is unclear whether it does actually occur on that species of Aloe.
Blackman & Eastop list 9 species of aphid as feeding on Aloe spp. worldwide, and provide formal identification keys (Show World list). Of those aphid species, Baker (2015) lists 9 as occurring in Britain (Show British list).
Damage and control
Forster (1998) reported that the aloe aphid was most likely introduced to Australia in the 1970s on an importation of Haworthia spp. By the 1990s it was being found on collections of Alooideae from Queensland to Victoria. Damage is variable depending on the species of aloe affected. In the most severe cases the destruction of the growing apex with secondary fungal rots cause the death of the plant. Forster (1998) noted that the best control is to prevent infestation in the first place. Hence any new aloes in a collection should be completely immersed in a systemic insecticide before being placed with other plants. Where infestation does occur, application of a contact or systemic insecticide will kill the aphids. This is effective in a glasshouse, but less so in a landscape situation.