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Scouting Citrus for Pests - Page 26
Aphids are unarmored, having legs, antennae, and cornicles (tailpipes) which produce defensive excretions. Most reproduction in Florida is parthenogenic (asexual), males being rare or non-existent. Also young are born live so populations can build up quickly. Winged forms are produced for dispersal under crowded conditions. Nymphs and adults secrete copious honeydew and are usually attended by ants. Spirea aphid (green citrus aphid) Aphis citricola is small, dark green, with black legs and cornicles. Affected leaves curl tightly and remains so. Spirea aphid is rarely attacked successfully by parasitic wasps and is not a vector of citrus tristeza virus (CTV). The Brown citrus aphid Toxoptera citricida (BCA) is native to the orient and present in south
America since the 1930's. Introduced into the Central America and the Caribbean, including Cuba in the early 1990's and first detected in Florida in 1996 its host range is limited to citrus and near relatives. It is very prolific under favorable conditions and is the most efficient vector of CTV. All citrus budded to sour orange is inevitably killed out within a few years after BCA is introduced. Also transmits "stem pitting" strains of CTV not yet seen in Florida which cause stunting and reduction of fruit size and yield. Attacked by the wasp L. testicipes which seldom, however, successfully emerges.
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