Student Project Environmental influences on box blight epidemics

  • Lizzie Sharp University of Cambridge
  • Clare Hurst University of East Anglia
  • Jassy Draculic Royal Horticultural Society
  • Matthew Cromey Royal Horticultural Society

Abstract

Calonectria pseudonaviculata and C. henricotiae are two recently differentiated fungal species responsible for box blight, a disease that threatens the Buxus genus. Infection can be introduced to gardens on new plants and is spread through the use of tools. The fungus survives on stem lesions and fallen leaves when spores are dispersed by rainsplash. In this study, 195 Calonectria UK isolates collected by the Royal Horticultural Society (RHS) Advisory Service were identified to species level. Detached stem assays were performed to assess how long stem and leaf lesions remain infectious, and their sensitivity to fungicides. A survey was also carried out at three National Trust properties on the effect of clipping on box blight distribution and severity. It was found that C. henricotiae was only present in and after 2011. C. henricotiae is more thermotolerant, and the increase in prevalence may be a result of increasing temperature and longer dry spells in the UK. Sporulation could occur multiple times on both stem and leaf lesions in humid conditions, although spore production dropped markedly after six sporulation events. Fungicides were effective at preventing spore production on stem lesions. Long dry spells may also reduce Calonectria’s ability to sporulate, leading to limited box blight spread between plants.

Author Biographies

Lizzie Sharp, University of Cambridge

Lizzie Sharp was a Student Fellow at Royal Horticultural Society (RHS) for the duration of this study and a BSc student

Clare Hurst, University of East Anglia

Clare Hurst was a Student Fellow at the RHS for the duration of this study and an MSci student

Jassy Draculic, Royal Horticultural Society

Jassy Drakulic is a plant pathologist at the RHS, UK.

Matthew Cromey, Royal Horticultural Society

Matthew Cromey is a plant pathologist at the RHS.

References

(2002). Cylindrocladium pseudonaviculatum sp.
nov. from New Zealand, and new Cylindrocladium
records from Vietnam. Sydowia, 54: 23–34.
DART, N., HONG, C., CRAIG, C.A., FRY, J.T. & HU,
X. (2015). Soil inoculum production, survival
and infectivity of the boxwood blight pathogen
Calonectria pseudonaviculata. Plant Disease, 99:
1689–1694.
GEHESQUIÈRE, B. (2014). Cylindrocladium buxicola
nom. cons. prop. (syn. Calonectria pseudonaviculata)
on Buxus: molecular characterization, epidemiology,
host resistance and fungicide control. PhD
dissertation, Ghent University. Available online:
https://biblio.ugent.be/publication/4377930/
file/4377949 (accessed September 2019).
GEHESQUIÈRE, B., CROUCH, J.A., MARRA,
R.E., VAN POUCKE, K., RYS, F., MAES, M.,
GOBIN, B., HOFTE, M. & HEUNGENS, K. (2016).
Characterization and taxonomic reassessment
of the box blight pathogen Calonectria
pseudonaviculata, introducing Calonectria
henricotiae sp. nov. Plant Pathology, 65: 37–52.
HEALY, S. (2014). Biology and management of
box blight caused by Cylindrocladium buxicola. MSc
dissertation, Guelph University. Available online:
https://pdfs.semanticscholar.org/b6dd/3c2ef16eba
f23a4886ceacd30c3fec5fa97f.pdf (accessed August
2019).
HENRICOT, B. & CULHAM, A. (2002).
Cylindrocladium buxicola, a new species affecting
Buxus spp., and its phylogenetic status. Mycologia,
94: 980–997.
HISTORIC ENGLAND (2003). Clandon Park.
Available online: https://historicengland.org.uk/
listing/the-list/list-entry/1001171#contributionsbanner
(accessed August 2019).
LAMONDIA, J.A. (2015). Management of
Calonectria pseudonaviculata in boxwood with
fungicides and less susceptible host species and
varieties. Plant Disease, 99: 363-369.
LAMONDIA, J.A. & MAURER, K. (2017).
Calonectria pseudonaviculata dispersal mechanisms
and implications for boxwood blight management.
Phytopathology, 107(12): 201–202.
LEBLANC, N., SALGADO-SALAZAR, C. & CROUCH,
J. (2018). Boxwood blight: an ongoing threat
to ornamental and native boxwood. Applied
Microbiology and Biotechnology, 102: 4371–4380.
MILLER, M., SHISHKOFF, N. & CUBETA, M. (2018).
Thermal sensitivity of Calonectria henricotiae
and Calonectria pseudonaviculata conidia and
microsclerotia. Mycologia, 110(3): 546–558.
R CORE TEAM (2017). R: A language and
environment for statistical computing. R
Foundation for Statistical Computing, Vienna.
Available online: https://www.R-project.org
(accessed August 2018).
SHISHKOFF, N., & CAMP, M. (2016). The effect
of different temperatures and moisture levels
on survival of Calonectria pseudonaviculata in
boxwood leaves and twigs and as microsclerotia
produced in culture. Plant Disease, 100(10):
2018–2024.
VITALE, A., CROUS, P., LOMBARD, L. & POLIZZI,
G. (2013). Calonectria diseases on ornamental
plants in Europe and the Mediterranean basin:
an overview. Journal of Plant Pathology, 95(3):
463–476.
WEBSTER, E., CAMERON R. & CULHAM, A.
(2017). Gardening in a Changing Climate. Royal
Horticultural Society, London.
Published
2020-02-21
How to Cite
Sharp, L., Hurst, C., Draculic, J., & Cromey, M. (2020). Student Project Environmental influences on box blight epidemics. Sibbaldia: The International Journal of Botanic Garden Horticulture, (18), 37-51. https://doi.org/10.23823/Sibbaldia/2020.287
Section
Articles