Revised September 1998
Issue No. 374
Susan E. Halbert and Lawrence G. Brown
January/February, 1996
Introduction
The brown citrus aphid (BrCA), Toxoptera citricida (Kirkaldy), is one of the world’s most serious pests of citrus. Although BrCA alone can cause serious damage lo citrus, it is even more of a threat to citrus because of its efficient transmission of citrus tristeza closterovirus (CTV). One of the most devastating citrus crop losses ever reported followed the introduction of BrCA into Brazil and Argentina: 16 million citrus trees on sour orange rootstock were killed by CTV (Carver 1978). The aphid was first reported in Venezuela in 1976, and by 1987, 6 million citrus trees on sour orange rootstock had been killed (Roca-Pefia et al. 1995). BrCA is also a major pest in Asia where it is native (Carver 1978; Tao and Tan 1961).
BrCA was first detected in Florida in early November of 1995 in metropolitan Dade and Broward counties. BrCA was discovered early after its introduction (probably about 4 months). The initial distribution of the pest implicated introduction on infested plant material rather than natural spread from the Caribbean. One year after BrCA was detected, infestations could be found south and east of a line from Melbourne (Brevard Co.) to Ft. Myers (Lee Co.). This is consistent with Wellings’ (1994) estimate that aphids colonize at a rate of 250 km/yr. By the end of 1997, the entire Florida citrus production area had been colonized.