How many times have you
purchased a package of beautiful, red, ripe strawberries from the grocery store
only to have them spoiled by grey fuzz a day or two after you get them home?
That unappetizing fuzz is
called grey mould, and it’s caused by the fungal pathogen Botrytis cinerea.
Other common fungal diseases of strawberry include powdery mildew and
anthracnose. These diseases pose big problems for growers, who traditionally
apply fungicides to control them. And many fungicides are not even an option
for organic producers.
Fortunately, USDA
Agricultural Research Service (ARS) scientists are on the case, looking for
ways to keep strawberries mould free without fungicides.
Ultraviolet-C (UV-C)
irradiation has been studied as a way of killing microbes by damaging their
DNA, but at effective doses, it damages leaves and fruit. ARS scientists
Wojciech Janisiewicz and Fumiomi Takeda discovered a way to sidestep this
problem. They demonstrated that UV-C irradiation of strawberry plants—followed
by a period of darkness—resulted in drastic kill of the Botrytis pathogen, the
powdery mildew fungus, and anthracnose. In fact, the technique increased UV-C’s
killing power 6- to 10-fold, depending on the pathogen, with no damage to the
leaves, flowers, or fruit.
A bonus? The treatment also
reduced spider mite infestations, and that could mean less pesticide use, too.
The scientists think the dark
period following the UV-C treatment deprives the pathogens of the light needed
to activate their DNA-repair mechanisms. They’ve filed a patent application on
the technology, which is now called PhylloLux and includes applications of two
beneficial yeasts. They have also automated the technology for large-scale
applications. The scientists are working with an industry partner to develop a
robot that can treat a field of strawberry plants at night on commercial farms.
Janisiewicz and Takeda work
at the ARS Appalachian Fruit Research Station in Kearneysville, West Virginia.
Their method for controlling fungal plant pathogens, and even spider mites,
would greatly reduce product loss to strawberry growers and processors and
reduce pesticide use. It will also benefit consumers who lose strawberries to
mould before they can consume the entire package.—By Sue Kendall, ARS Office of
Communications.
Another smart example of the role of precision horticulture now expanding around the globe.
