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FRANKFORT,
Ky. — After a 17-year absence, one of the largest
known broods of periodical cicadas will emerge this
spring throughout Kentucky, and Agriculture Commissioner
Richie Farmer is warning vineyard and fruit tree growers
to be aware of the coming of Brood X.
“From sheer numbers alone, these insects are going
to present trouble -- to the engines of vehicles and
other mechanical devices, to just about every aspect
of outdoor life during their above-ground timespan.
The real damage to agriculture will come from the cicadas’
laying of eggs,” Commissioner Farmer said. “Secondary
damage will also occur after hatching, as nymphs feed
on sap from plant roots during their lengthy stay below
ground.”
Periodical cicadas – having black bodies, bright
red eyes, and amber wings with orange veins –
usually emerge in mid- to late May as ground temperatures
reach 64 degrees Fahrenheit. Cicada numbers will continue
to increase and then, usually in early to mid-June,
female cicadas begin laying eggs. In early August, the
eggs hatch and nymphs fall to the ground to burrow into
the soil, where they will live for the next 17 years.
This year’s hatching, called “Brood X”
by entomologists, can cause major agricultural damage
during the egg laying process, said Barry Skipper, Director
of the Kentucky Department of Agriculture’s Division
of Environmental Services. The female slits the bark
on pencil-thin twigs and lays eggs inside the wounds.
Females prefer grapevines or the branches of young apple,
peach or pear trees. While mature trees and shrubs usually
survive emergences of cicadas, young trees may be fatally
harmed.
Since egg laying is the immediate danger to vineyards
and young fruit trees, emergence should be considered
as a signal to begin protecting plants, Skipper said.
A week or so after emergence, females are ready to lay
eggs. Plants can be protected in three ways: covering,
spraying or pruning.
Small trees can be covered with a protective netting
of cheesecloth, Skipper said. Be sure to secure the
bottom around the trunk to prevent the insects from
crawling up from below. This covering will have to stay
on for the next four to six weeks. Plastic should never
be used for covering since it would eventually burn
the foliage on small trees, he said.
Insecticides can be used to reduce damage by cicadas
but several applications may be needed, Skipper said.
Certain organophosphate and carbamate insecticides are
labeled specifically for periodical cicada control.
Several synthetic pyrethroid insecticides are labeled
for landscape trees and shrubs. Nurseries under a routine
spray schedule should be sprayed according to intensity
of the outbreak, which can range from a few cicadas
in some areas to massive numbers in other areas. Those
using insecticides should always read and follow label
directions, he said.
Skipper said a third alternative is to prune out wounds
before eggs hatch, especially in fruit orchards where
juveniles feeding on roots may decrease fruit production.
Although this is a time-consuming process, it may be
a viable alternative considering the production life
and long-term value of fruit trees.
“This outbreak is different than, and in addition
to, the cicada which is present every year,” Skipper
said. “The annual cicadas are green- and black-bodied
and have clear wings with green veins. These insects
do the same type of damage as the 17-year periodical
cicadas, but the outbreak of Brood X will create a bigger
problem with just sheer numbers.”
For more information on the 17-year cicada emergence,
contact Ray Siegel, Structural Branch Manager for KDA’s
Division of Environmental Services, by phone at (502)
564-7274 or by e-mail at ray.siegel@kyagr.com.
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