Strong genetic structure among populations of the invasive avocado pest Pseudacysta perseae (Heidemann) (Hemiptera: Tingidae) reveals the source of introduced populations

In 2004, the avocado lace bug (ALB) Pseudacysta perseae, was discovered in San Diego County, CA, USA. Historically, California avocado producers have relied on biological control for suppression of injurious pests. A fundamental step in identifying biological control agents is determining the source of the invasive population, thus allowing a focused search of that area for natural enemies most closely adapted to the invasive pest genotype. In an attempt to determine the geographic area of origin for ALB to assist incipient biological control efforts, mitochondrial and microsatellite markers were used to compare the genetic profile of the California population of ALB with that of populations from the pest’s known range in the US, Guatemala, Mexico and the Caribbean. Both types of marker revealed evidence for strong genetic structure among the sampled populations. Mitochondrial sequences narrowed the geographic origin of the California population, to populations in Texas and several Mexican states. This geographic range was refined further with the analysis of allele frequencies at eight microsatellite loci which identified ALB populations in the state of Nayarit, Mexico, as the most probable origin of the California population. Any effort to identify natural enemies of ALB for use in biological control in California should therefore focus on Nayarit. The strong genetic structure present among the ALB populations studied is discussed with regards to the potential influence of cytoplasmic incompatibility-inducing endosymbionts, host plant variation, and the putative native range of this pest.