Zealand’s land-based primary industries need to get ready for more, and
more serious, crop disease as climate change causes more and longer
droughts, according to new research. In the journal Australasian Plant Pathology
the authors say that climate change is expected to bring more droughts
in many parts of New Zealand, and more droughts are “likely to increase
the severity of a wide range of diseases affecting the plant-based
from the Bio-Protection Research Centre, Scion, Lincoln University, AUT
University, Landcare Research, and the University of Auckland analysed
the potential impact of climate-change-induced drought on several
commercial plants and their diseases. They found that in most instances
“increased drought is expected to increase disease expression”.
probable negative effects of drought include “…a predisposition of
hosts to infection through general weakening and/or suppressed disease
resistance”. More frequent and more severe droughts could also lead to
“emergence of enhanced or new diseases of plants that can reduce primary
plant disease pressures are expected to occur… with potentially
devastating impacts for New Zealand’s productive sectors,” the authors
the news is not all bad. “Drought may reduce the severity of some
diseases, such as Sclerotina rot of kiwifruit and red needle cast (RNC)
of radiata pine,” they said. And in some cases it could “activate
systemic defence mechanisms resulting in increased resistance to
an extended case study the authors said that the effects of increased
drought on New Zealand’s Pinus radiata industry would depend on many
factors, including whether drought happened early or late in the season.
is urgent need to study the impacts of the different levels of drought
and different levels of RNC severity to understand the thresholds at
which radiata pine plantations would still accomplish their economic and
author Dr Steve Wakelin, of the Bio-Protection Research Centre and
Scion, said it was essential that more research was carried out so each
industry could prepare for the effects of drought.
industries, such as agriculture and horticulture, may have time to
gradually change over the next 20 or 30 years, to avoid the worst
effects of drought or even take advantage of any opportunities the
changing climate may bring.
plantation forestry does not have the luxury of flexibility. What is
planted now will need to not just survive but thrive in whatever climate
and disease conditions are prevailing in the next 20, 30, or 40 years.
essential that primary industries with a long production cycle start
assessing and addressing the risks and opportunities a much drier
climate will bring.”
Publication date: 5/7/2018