Host Acceptance Trials of Parasitoids from Indian Paratachardina lobata (Hemiptera: Kerriidae) on the Invasive Lobate Lac Scale in Florida

Sibylle Schroer, Robert W. Pemberton

Abstract


The invasive lobate lac scale identified as Paratachardina lobata (Chamberlin) (Hemiptera: Keriidae), native to southern India and Sri Lanka, is a severe threat to native and economic plants in southern Florida. In an attempt to find appropriate control against the invasive scale, 3 parasitoid species associated with P. lobata in its native southern India were tested in host acceptance trials in quarantine. Ooencyrtus kerriae Hayat (Encyrtidae) and Coccophagus parlobatae Hayat (Aphelinidae) drill their ovipositor through the rigid lac covering of the scale, whereas Aprostocetus bangaloricus Narendran (Eulophidae) oviposits into the anal pore of the scale. Despite this apparent oviposition behavior, their reproduction on lobate lac scale in these tests failed. Ooencyrtus kerriae and C. parlobatae yielded insignificant numbers of offspring and A. bangaloricus did not reproduce on lobate lac scale in Florida. To investigate the lack of offspring, scales were dissected 2 months after parasitoid oviposition. No parasitoid development to the larval stage was recorded in the scales, but round blood cell accumulations were found, which appeared to be encapsulations of parasitoid eggs. These findings indicate a strong immune response of the invasive scale to the tested parasitoids. The unsuitability of the invasive lac scale as a host for these parasitoids suggests that the invasive lobate lac scale and the Indian P. lobata differ physiologically. Additional surveys are needed to find a better matching form of the invasive lobate lac scale in order to obtain more suitable parasitoids for the control of this serious pest in Florida.

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