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ARS Home » Southeast Area » Fort Lauderdale, Florida » Invasive Plant Research Laboratory » Research » Publications at this Location » Publication #206399
Title: Host acceptance tests of parasitoids from Indian Paratachardina lobata on the invasive lobate lac scale in Florida

Author
item SCHROER, SIBYLLE - UNIVERSITY OF FLORIDA
item Pemberton, Robert

Submitted to: Florida Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/31/2007
Publication Date: 9/3/2007
Citation: Schroer, S., Pemberton, R.W. 2007. Host acceptance tests of parasitoids from Indian Paratachardina lobata on the invasive lobate lac scale in Florida. Florida Entomologist. 90:545-552.

Interpretive Summary: An invasive insect called the lobate lac scale (Paratachardina lobata), native to southern Indian and Sri Lanka, attacks many economic and native woody plants in southern Florida. Chemical control of the pest is impractical in the infested natural areas and the pest lacks natural enemies in Florida. Biological control research was developed to attempt to find controls for the pest in Florida. Surveys in India led to discovery of four parasitoids of P. lobata. In this present study, these parasitoids were obtained from India and tested against the invasive lobate lac scale in the quarantine laboratory to learn their ability to parasitize the insect. Ooencyrtus kerriae (Encyrtidae) and Coccophagus sp. (Aphelinidae) oviposited through the rigid lac covering of the scale, whereas Aprostocetus bangaloricus (Eulophidae) oviposited into the anal pore of the scale. Despite this apparent oviposition behavior, their reproduction on lobate lac scale in these tests failed. A mean of only 3.5 (±7.6) O. kerriae and 1.6 (±3) Coccophagus sp. adults emerged. Neither Aprostocetus bangaloricus nor Marietta leopardina (Aphelinidae) produced any offspring. Dissections of the scales were made two months after parasitoid oviposition to learn more about the absence of parasitoid offspring. No development of the parasitoids to the larval stage was found in the scales, but round blood cell accumulations were found, which appeared to be encapsulations of parasitoid eggs. These findings indicated a strong immune response of the invasive scale to the parasitoids from P. lobata. The unsuitability of the invasive lac scale as a host to these parasitoids suggests that the invasive scale and the Indian P. lobata differ physiologically. Additional survey is needed to find a better matching form of the invasive lobate lac scale in order to obtain more suitable parasitoids for control of the pest in Florida.

Technical Abstract: The invasive lobate lac scale identified as Paratachardina lobata (Hemiptera: Keriidae), native to southern India and Sri Lanka, is a severe threat to native and economic plants in southern Florida. Four parasitoid species, from southern India associated with Paratachardina lobata, were tested in quarantine to determine their ability to parasitize the lobate lac scale which is invasive in Florida. Ooencyrtus kerriae (Encyrtidae) and Coccophagus sp. (Aphelinidae) drill their ovipositor through the rigid lac covering of the scale, whereas Aprostocetus bangaloricus (Eulophidae) oviposits into the anal pore of the scale. Despite this apparent oviposition behavior, their reproduction on lobate lac scale in these tests failed. A mean of only 3.5 (±7.6) O. kerriae and 1.6 (±3) Coccophagus sp. adults emerged. Neither Aprostocetus bangaloricus nor Marietta leopardina (Aphelinidae) produced any offspring. To investigate the lack of offspring, scales were dissected two 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 parasitoids from P. lobata. The unsuitability of the invasive lac scale as a host to these parasitoids suggests that the invasive lobate lac scale and the Indian P. lobata differ physiologically. Additional survey is needed to find a better matching form of the invasive lobate lac scale in order to obtain more suitable parasitoids for control of the pest in Florida.