Aphis gossypii

BIOLOGY/ECOLOGY Dispersal mechanisms Flight range of winged adults is very limited. Long-range dispersal of eggs, immature stages and adults is manmediated with the transport of infested plant material. Reproduction The taxonomic status of this alien aphid is problematic, and hence the interpretation of biological information is difficult. Moreover, different biotypes exhibiting host preferences have been reported and a genetically differentiated cucurbit host race has been identified. In Europe, it reproduces exclusively by apomictic parthenogenesis, and can produce nearly fixty generations a year under favourable conditions. In the USA, it can be holocyclic with a broadleaved tree (e.g., Catalpa, Rhamnus) as the primary host. However, sexual reproduction has been occasionally observed in France on Hibiscus syriacus as primary host. This aphid is closely related to European Aphis species of the frangulae group utilizing Frangula alnus as primary host. In the USA, Japan and China, they can be holocyclic with Hibiscus, Catalpa or Rhamnus trees as primary hosts. The optimal temperature for reproduction is reported to be about 21-27°C. Viviparous females produce a total of about 70-80 offspring at a rate of 4.3 per day. Developmental periods of immature stages vary from 20.7 days at 10°C to 3.8 days at 30°C. Known predators Predators include midges, anthocorid bugs, lacewings, syrphid fly larvae and ladybeetles. Several aphidiid and aphelinid hymenopteran are parasitoids. Resistant stages (seeds, spores etc.) Unknown. Female Aphis gossypii surrounded by larvae on foliage