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Occurrence, incidence and associations among fungal pathogens and A grilus auroguttatus , and their roles in Q uercus agrifolia decline in C alifornia
Author(s) -
Lynch S. C.,
Zambino P. J.,
Scott T. A.,
Eskalen A.
Publication year - 2014
Publication title -
forest pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.535
H-Index - 49
eISSN - 1439-0329
pISSN - 1437-4781
DOI - 10.1111/efp.12070
Subject(s) - biology , incidence (geometry) , veterinary medicine , botany , ecology , optics , medicine , physics
Summary Synchronous decline of oak ( Q uercus spp.) trees in woodlands has been described in E urope and eastern N orth A merica as a complex interaction of stressors that predispose, incite or contribute to tree death. This study presents a 2‐year (2010–2011) assessment of the role of pathogens in coast live oak ( Q uercus agrifolia ) woodlands in southern C alifornia where oak mortality occurs in locations that are infested and uninfested by the goldspotted oak borer ( GSOB , A grilus auroguttatus ). Cumulative coast live oak mortality was not significantly different between sites and was weakly correlated with D iplodia corticola and GSOB incidence and negatively correlated with annual relative humidity. Multiple logistic regression models explained the presence of individual fungi or GSOB at the tree level. Fisher's exact test analysis determined that the presence of D . corticola, F usarium solani, D othiorella iberica, C ryptosporiopsis querciphila and D iatrypella verrucaeformis were each related to origin of sample location on tree, and C . querciphila was additionally related to symptom type on the bole. Multiple linear regression models showed high correlation between environmental variables and plot‐level incidence of both GSOB and D . corticola . Disease incidence ( DI ) for D . corticola was highest in GSOB ‐uninfested locations. Jaccard index of association ( J ) showed that D . corticola was negatively associated with the presence of GSOB , F . solani and C . querciphila . Results suggest that oak decline in C alifornia is an example of a complex syndrome involving strong regional differences in factors that are associated with the problem.