A26-lancMl*r Farming, Saturday, Juna 11, 1994
(Continued from Pago At)
that they arc not absolutely certain
that the insect is the entire cause of
the problem.
Damage to leaves on plants had
been thought to be caused by late
spring cold, and Barbara Goulart, a
Penn Slate associate professor of
honticullurc and extension spe
cialist in small fruits, said the dam
age could possibly be a combina
tion of cold damage and thrips
capitalizing on weakened plants.
However, in a telephone inter
view Thursday, she said that she is
“90-pcrccm” sure it is the Eastern
Flowers Thrips. tause for concern
about the accuracy of that determi
nation is because the species of
thrips is indigenous (naturally
occuring) in the state and similar
damage had not been previously
recorded.
Also supporting the belief ihai
Thrips are to blame is the possibili
ty that populations of Thrips may
have been heavy because of very
good winter survival.
It is possible that the insulative
effects of the heavy snows, despite
the record cold and length of cold,
has lead to a higher incidence than
normal of overwintering survival,
and thus to higher populations of
insects emerging in spring.
Except for production losses
and the detraction from the appear
ance of the fruit, strawberries are
safe to eat and should not be a
cause of concern for the cosuming
public.
However, for the producer, the
strawberry crop may be severely
damaged. One producer estimated
a 75 percent loss compared to last
year’s production from the same
field.
Depending On
Extension
The help lo strawberry growers
is coming almost solely from Penn
State University’s College of Agri
culture, though resources in the
stale arc limited.
Goulan said that Hcllerick is
somewhat of a “hero” in discover-
A way to test for Eastern Flowers Thrips in an area is to
check ctovtr flowers. Tap the clover flower against the palm
of the hand and look very closely for small, lice-like insects.
In heavily infested flower heads a number of thrips should
be visible crawling on the palm. The insects are not danger
ous to people and will not bite. Nor will they cause any prob
lem if accidently ingested.
Thrips May Be Cause Of Strawberry Problem
ing the thrip and getting the system
going to determine the extent of
the problem.
Using the Penn Slate computer
system, Hcllcrick has requested
other extension agents to
check fields in their respective
counties and report that informa
tion back to him.
As of Wednesday, Hellerick
said he has received confirmations
of damage from Bucks, Chester,
York, and Franklin counties, in
addition to Lancaster.
The extension agent said that
producers across the northern tier
of the state and in New York may
want to check fields now, in order
to determine whether or not they
can lake action to prevent signific
ant losses
In the meantime, Penn State
University and its extension
researchers and agents arc working
to determine the extent of the prob
lem. Producers can help by report
ing infestations to their local agent.
Since the problem does not pose
any type of health risk to the publ
ic, the identity of the producer
reporting a heavy infestation is not
necessary for general public
knowledge.
' If work by Penn State reveals
that there is a wide-spread signific
ant problem that may require a
request for federal assistance, they
will inform officials at the state
Department of Agriculture.
Once Penn Slate makes the
determination of the extent of the
problem and documents it, then
PDA will review the university’s
findings and process a request for
aid, if one is made, based on the
nature of the problem.
In the meantime, the PDA is tak
ing no active role in determining
whether or not there is a problem,
according to Carl Valley, PDA
entomologist. Valley did help Hel
lerick however, by identifying the
thrip samples Hellerick gave to
him as the Eastern Flower Thrips,
of which little technical informa
tion is available.
Lancaster County Extension Agent Bruce Hellerick show strawberries suffering
from an infestation of Eastern Flowers Thrips which is thought to be causing a severe
degradation on the quality of the fruit.
Valley said he doesn’t have
expertise on the thrips, and Penn
Stale is currently without a resi
dent entomologist who does. Gou
lart said she has been depending
entirely on support from Cornell
University for entomological
expertise.
It is known however, that Thrips
concentrate their feeding on the
buds, flowers and vascular por
tions (the tubes carrying plant
juice) which arc hidden.
Currently the liny, yellow
whitish insect arc being found in
the flowers and between the cap of
the strawberry and the fruit.
The appearance of affected fruit
would be dullness, appearance of
sccdiness (caused by a lack of fruit
development to expand and dis
tance seeds), while lips on the fruit
and a lack of apparent maturity.
Plants are also showing some
leaf damage, which early on
caused Held agents to suspect cold
damage, but which actually could
have been caused by thrips feeding
on developing plant buds in early
spring, or through egg laying
activity.
According to information disse
minated by Hellerick, “Thrips are
small, slender, active insects less
than '/■ -inch in length with two
pair of wings which have a fringe
of feather-like hairs around the
slender margin.
‘The Eastern Flowers Thrips
(EFT) is believed to be the most
abundant and widely distributed
thrips in the United States.”
According to the information,
“(Female thrips) insert their eggs
in leaf slits made by the saw-like
ovipositor. Egg hatch in two to
seven days. The entire life cycle is
completed in two to four weeks,
depending on temperature. Many
generations occur each year, but
the largest populations are present
from late spring to midsummer.”.
Finding Thrips
To look for thrips, examine the
fruit at the junction of the cap and
Thrip-affected strawberries on the left are dull, seeds
close together, small sized, and show uneven maturity. The
ones on the right are shiny, plump and even in color. Notice
also, the white area between cap and fruit on the strawberry
in the upper right, as compared to the daifc area on the
strawberry on the left with the same area exposed.
ihe fruit. If there is a browning
around the junction, and if the fruit
appears somewhat dried near the
area, it is probably infected.
Researchers have been finding
five or more thrips per berry.
The insects arc difficult to see.
They are the size of ihe hairs on the
strawberry fruit, but tallowy in col
or. They will move around when
disturbed from their secretive
feeding areas in (lowers or in the
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