Reducing the riskof Fusariumhead
blight disease for irrigatedwheat
I
n this articlewediscuss the recent undertaking at theARC-Small
Grain Institute (ARC-SGI) todevelopdiverseFusariumheadblight
and Deoxynivalenol resistant wheat germplasm for the South
Africanwheat industry in a targetedpre-breedingprogramme.
Fusarium head blight, also known as scab, is one of the most
destructive diseases of wheat.
Fusarium graminearum
(
Gibberella
zeae
) is the predominant causal organism on wheat and barley. In
South Africa, Fusarium head blight is predominantly caused by
Fusarium graminearium
and has become an increasing concern for
producers/researcherswithin the expanding irrigation areas.
The most prevalent casual
Fusarium
species within a specific
production area are restricted to specific geographical regions and
climatic conditions. Considering global climate change, adoption
of different tillage practices and an increase in irrigated wheat
production areas, Fusarium head blight has spread into new and
different wheat production areas.
Acontinual concernwith the increasedproductionof irrigatedwheat
is the potential for Fusarium head blight epidemics. There are a
number of different springwheat irrigation production areas across
South Africa and within the different provinces, namely cooler
irrigation, warmer irrigation, Mpumalanga, Eastern Free State,
KwaZulu-Natal and FishRiver irrigationproduction areas (
Figure 1
).
In South Africa there are various different climatic conditions and
micro-environments createdwhich are also dependent on irrigation
systems and water sources used that play a role in Fusarium head
blight disease development across the various irrigation production
areas (
Photo 1
).
In South Africa, Fusarium head blight can be severe under high
inoculum pressure in combination with the planting of highly
susceptible cultivars, high moisture availability during anthesis,
maize-wheat crop rotation and conservation agriculturepractices.
Yield lossesof up to50%arepossibleonsusceptiblecultivarsgrown
under conditionswhichareoptimal for Fusariumheadblight disease
development. Characteristic Fusarium head blight symptoms are
white bleached spikes and curled-out awns just after flowering
(
Photo 2a
).
Apart from the disease reducing the crop yield, grain can be
damaged (tombstone kernels) and contaminated with mycotoxins,
such asDeoxynivalenol, (
Photo 2b
).
61
June 2014
ON FARM LEVEL
Pest control
Fusariumheadblight disease / Irrigation /Wheat
SCOTT SYDENHAM
and
CATHYDEVILLIERS,
ARC-Small Grain Institute
Figure1: Thedifferent springwheat irrigationareaswithin the summer rainfall
regionof SouthAfrica.
1: Apictureof a central pivot irrigation system commonlyusedby irrigation
producers inSouthAfrica.
2a: Ableachedwheat spike showing signs of
Fusarium
infection.
2b: A picture comparing perfectly healthy uninfected kernels (left) and in-
fected characteristic tombstonewheat kernels (right).
1
2b
2a
