Smyrna times., 1963-11-14
Mite-Killing Fungus Found
By Delaware Az Scientists

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University ofDelaware have m-
covered biological phenomen-|
ON that may save soybean pro-
ducers thousands of dollars
each year.
The discovery was revealed
at the 35th annual meeting of
the eastern branch of the En-
tomological Society of Ameri-
ca by DR.. w. A. Conell, as
sociate professor of entomol-
ogy, John A. Mellott, a grad
uate fellow In entomology, and
Alan L. Morehart, research
associate in plant pathology.
In research conducted at the
University they isolated fun
gus that destroys the Straw
berry spider mite, costlypest
of soybeans and vegetable
crops.
The discovery was made last
summer when a serious out
break of these mites was sud-
denly halted. This nauural-oc-
curing control caused the re-
searchers to look for and find
fungus spores that actually de-
stroyed the mites. They we're
able to isolate the fungus and
establish that 1t was one that
occurs in soybean fields under
unknown circumstances.
So far, according to More
hart, they have been unable to
match the characteristics of
the fungus with any of the l0l
known fungi, which leads to the
possibility that 1t may be COM
pletely new kind.
Entomoligists were convinced
prior to this find that some
thing had checked other straw
berry mite outbreaks, but no
one had been able to estab-
lish the killers identity.
Mellott says that in their
observations the pests hadbeen
controlled by a disease caused
by the natural occurring fungus
spores. The disease killed the
mites in various stages of de-
velopment late In the growing
season, giving almost complete
natural control.
The significance of this dis
covery is difficult to measure
In dollars and cents, but DR..
Dale Bray, chairman of the
department of entomology at the
University of Delaware, says
this may offer growers an eff
fective biological control meth
cd for a crop pest that up
to now has gone pretty much
unchecked. He says the mites
infest thousands of acres of
soybeans on the peninsula each
year causing reduction in yields
and beans of inferior quality.
According to Mellott, the
mites attack the leaves IN the
growing plants and destroy the
chlorophyl1 which is the growth
producing substance that all6ws
the plant to manufacture food.
The results are reduced yields
and seeds that are of inferior
quality.
While many miticides have
been used to control Straw
berry spider mites, none have
been particularly effective. The
mites build up so rapidly that
a single application hasn't Civ
en- the desired control, and ad-
ditional applications cost more
than their value to the crop.
1t is hoped that through the
isolation of this mite killing
fungus a whole new control tee
Unique can be developed. Mel
lott believes the fungus might
be produced artifically and the
spores could then be sprayed
or busted on fields where mite
damage is a problem. One ap-
plication might control the
mites during the entire growing
season at low cost.
So far 1t hasn't been possi-
BILE to produce the fungus m-
der laboratory conditions but
Morehart is working on it. New
techniques will have to be de-
veloped, he says, before large
supplies necessary in a con-
troll program can be produced
artificially.
The scientists all agree that
additional information and test
ing is needed before the real
value of the fungus can be de-
termined, but it does show pro-
mise.
Biological control of insects
isn't new. But new developments
like this fungus control tech