Southern
Research Station

• Authors: Schulz, Ashley N.; Mech, Angela M.; Cram, Michelle M.; Asaro, Christopher; Coyle, David R.; Lucardi, Rima D.; Lucas, Sunny; Gandhi, Kamal J.K.
• Publication Year: 2018
• Publication Series: Scientific Journal (JRNL)
• Source: Forest Ecology and Management
• DOI: 10.1016/j.foreco.2018.03.013

Abstract

Matsucoccus macrocicatrices Richards (Hemiptera: Matsucoccidae) is the only species within this genus that feeds and reproduces on eastern white pine (Pinus strobus L.), and at the time of its description, was not observed or known to  cause  serious  damage.  With  eastern  white  pine dieback  occurring  extensively  throughout  the  Appalachian Mountains, researchers are now in search of the contributors to this dieback phenomenon. Since its recent discovery (2007) far outside  its  historical  range,  M.  macrocicatrices,  and  cankers  associated  with  Caliciopsis pinea  Peck,  are regularly present on symptomatic trees throughout the range of eastern white pine. Little is known about the re- lationship between M. macrocicatrices and the fungal cankers commonly found on eastern white pines expressing dieback symptoms. For this study, we evaluated the relationships between both focal organisms and the extent of dieback symptoms on tree seedlings to identify contributing factors affecting symptomatic trees. We assessed the insect-pathogen  complex on  270  eastern  white  pine  seedlings  from  nine  states  that  include  the  Appalachian Mountain  range.  There  were  positive  correlations  between  M.  macrocicatrices  and  seedling dieback,  cankers  and seedling dieback, and M. macrocicatrices and cankers in both the southern and northern portions of the Appalachians. About  95%  of the  observed  M.  macrocicatrices cysts and  shells  were associated  with cankers,  especially C.  pinea- dominated  cankers,  which were exceptionally  abundant  on  severely  affected seedlings.  The most  prevalent  fungi isolated from cankers  without  apparent  fruiting  bodies  of  C.  pinea  were  in  the  genus Phaeomoniella.  Trials  were conducted to test the pathogenicity of C. pinea and other fungal isolates. Of the 15 fungal species tested, C. pinea was the only pathogenic species that formed girdling cankers on eastern white pine seedlings. We postulate that there is a facultative relationship between M. macrocicatrices and C. pinea, forming an insect-pathogen complex that is con- tributing to eastern white pine dieback and significantly impacting its regeneration dynamics in North America.

• Citation: Schulz, Ashley N.; Mech, Angela M.; Cram, Michelle M.; Asaro, Christopher; Coyle, David R.; Lucardi, Rima D.; Lucas, Sunny; Gandhi, Kamal J.K. 2018. Association of Caliciopsis pinea Peck and Matsucoccus macrocicatrices Richards with eastern white pine ( Pinus strobus L.) seedling dieback. Forest Ecology and Management. 423: 70-83. https://doi.org/10.1016/j.foreco.2018.03.013.
• Keywords: Canker, Fungal identi cation, Insect-pathogen, complex Pathogenicity test, Scale insect
• Posted Date: July 16, 2018
• Modified Date: July 31, 2018

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