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Control of Phytophthora species in plant stock for habitat restoration through best management practices
Author(s) -
Sims L.,
Tjosvold S.,
Chambers D.,
Garbelotto M.
Publication year - 2019
Publication title -
plant pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.928
H-Index - 85
eISSN - 1365-3059
pISSN - 0032-0862
DOI - 10.1111/ppa.12933
Subject(s) - phytophthora , biology , biodiversity , habitat , botany , species richness , ecology
Emergent plant pathogens represent one of the most significant threats to biodiversity, and exotic Phytophthora species have recently emerged as a serious problem in restored habitats in California and in nurseries producing the plant stock. It is hypothesized that ‘best management practices’ prescribed through a Phytophthora Prevention Programme ( PPP ) could be useful in minimizing phytophthora disease incidence. To understand the magnitude of the problem and the efficacy of the PPP , plants in restoration nurseries were evaluated for (i) the Phytophthora species assemblage present in the absence of the PPP , and (ii) the effectiveness of the PPP to reduce them. Sampling included 203 plants grown in the absence of the PPP , and 294 grown implementing the PPP . Only samples collected in the absence of the PPP were Phytophthora ‐positive, and cumulatively yielded 55 isolates from 13 different taxa, including 1 putative interspecific hybrid genotype. There were 21 novel Phytophthora –plant species combinations. The most common Phytophthora species was P. cactorum . Four plant species had the highest disease incidence, namely: Diplacus aurantiacus (50 ± 11.2%), Heteromeles arbutifolia (33 ± 9.6%), Ceanothus thyrsiflorus (30 ± 8.4%), and Frangula californica (30 ± 8.4%). Disease incidence in nurseries after the implementation of the PPP dropped to zero ( P < 0.001), and was unaffected to any significant degree by nursery differences, or plant species tested. This study identifies a large number of novel ‘plant species × Phytophthora species’ combinations, and provides for the first time strong evidence that the PPP significantly reduced Phytophthora in plant stock for habitat restoration.