Abstract
The woodwasp
Sirex noctilio F. (Hymenoptera: Siricidae) has become established in North America. A primary tactic for the management of
S. noctilio in the southern hemisphere has been the development of a biological control agent,
Deladenus siricidicola Bedding. This nematode has a bicyclic life cycle including a mycetophagous free-living and parasitic cycle. During oviposition, female
Sirex woodwasps inject a symbiotic fungus. Because
D. siricidicola only develops well on
Amylostereum areolatum (Chaillet ex Fries) Boidin (Russulales: Amylostereaceae) and North American woodwasps were thought to all have
Amylostereum chailletii (Persoon) Boidin as their fungal symbiont, the risk of unintended impacts from
D. siricidicola in North America was considered low. Specific polymerase chain reaction primers were designed to amplify the intergenic spacer region of
Amylostereum symbionts in a population of the native woodwasp
Sirex nigricornis F. located in central Louisiana (i.e., well outside the known distribution of
S. noctilio); identity of the symbiont was confirmed by phylogenetic analyses. Overall, 95 out of 100 fungal isolates obtained from the mycangia of
S. nigricornis were identified as
Amylostereum species. Contrary to expectations, 60% were identified as
A. chailletii (N 60), while 35% were identified as
A. areolatum (N 35). The remaining 5% of these isolates (N 5) were identified as
Bipolaris papendorfii (Aa) Alcorn,
Alternaria alternata (Fr.) Keissl,
Penicillium marneffei Segretain,
Scytalidium cuboideum (Sacc. & Ellis) Sigler & Kang, and
Hyphopichia heimii (Pignal) Kurtzman based on sequencing of the internal transcribed spacer (ITS) region. The five non-
Amylostereum isolates were likely contaminants during mycangia-spore extraction process. This study confirms the presence of
A. areolatum in a population of the native woodwasp
S. nigricornis well outside the known distribution of
S. noctilio.
Keywords
Amylostereum,
invasive species,
Sirex,
symbiont
Citation
Olatinwo, Rabiu; Allison, Jeremy; Meeker, James; Johnson, Wood; Streett, Douglas; Aime, M. Catherine; Carlton, Christopher. 2013. Detection and identification of Amylostereum areolatum (Russulales: Amylostereaceae) in the mycangia of Sirex nigricornis (Hymenoptera: Siricaidae) in central Louisiana. Environmental Entomology 42(6): 1246-1256.
