(Aphis spiraecola)
Aphis spiraecola is a species of aphid described in 1914 by Edith Marion Patch. Its common names include green citrus aphid, Spirea aphid, and apple aphid. It is distributed worldwide, and is most abundant in the United States. It has a diploid chromosome number of 2n=8. Aphis is a genus of insects in the family Aphididae containing at least 600 species of aphids. It includes many notorious agricultural pests, such as the soybean aphid Aphis glycines. Many species of Aphis, such as A. coreopsidis and A. fabae, are myrmecophiles, forming close associations with ants. This species was first discovered by Edith Marion Patch in 1914. Patch discovered that A. pomi would feed and develop on Spiraea and A. spiraecola would feed and develop on Malus which confirmed that aphids were a highly variable species. Patch’s colonies on apple were decimated by a fungus so all transfer attempts to secondary hosts, which would have demonstrated the limited host range of A. pomi, were made using A. spiraecola from Spiraea instead. Later she suggested using the names A. pomi and A. spiraecola on the basis of the plants on which they were found thus leading to the names each species is known by today. Another species, A. citricola was described by van der Groot in 1912 while doing a study in Chile. This aphid became a synonym for another citrus aphid - Toxoptera citricida. In 1975, Hille Ris Lambers demonstrated that T. citricida referred to A. spiraecola, thus synonymizing T. citricola with A. spiraecola. A. spiraecola is globally distributed among temperate and tropical regions, including Asia, Africa, North America, Europe, and Oceania regions with the exception of cold regions. This species is thought to have originated in the Far East, dating back to at least 1907 in North America, Australia in 1926, New Zealand in 1931, the Mediterranean in 1939 (other sources say only in the early 1990s), Africa in 196, Israel in 1970, Germany in 2000, Hungary in 2004, Bulgaria and Serbia in 2007, the Baltic region in 2015, Kosovo in 2018 (Llugaxhi on 23 July), Slovakia in 2018 (Tvrdošovce on 2 May), the Czech Republic in 2019 (Bílé Podolí on 21 June, the United Kingdom in 2018 (Ash (near Canterbury) England on 13 July, after previous detections elsewhere in the UK in 1979 and 1996 did not go any further), and Denmark in 2019 (in the Pometum of the Taastrup campus of the University of Copenhagen on 20 July).