Brownsville herald. [volume] (Brownsville, Tex.) 1910-current, 1915-03-11
DROP
PREVENTATIVE
IS SUGGESTED
PATh0l0GIST INVESTIGATES DIS
EASE WHICH-ATTACKED vEGE-
TABLE IN VALLEY.
SHOULD BE CONTROLLED, AND SUG-
GESTI0NS WITH THAT IN VIEW
OFFERED.

Lettuce growers Of the Lower Rio
Grande Valley during the present season
have been much concerned over a disease
that has become in evidence. and with a
view To finding the cause of the trouble
and Il preventative measure, If possible, Il
sample of the diseased vegetable was sent
10 w. A. Orton, pathologist in charge of
cotton and truck disease and sugar plant
Investigations, IL the United States de-
partinent Of agriculture. The matter was
taken up with the department BY George
H.. Toolan, secretary of the San Benito
Commercial club, and the samples were
sent in by A. y. Tandy, Cameron county
farmers cooperative demonstration agent.
The following reply has been received
from Mr.. orion:
'The lettuce plants sent IN reply To our
recent telegram were received and they en-
abled u To determine the cause of Your
lettuce trouble a. certainly as if we had
sent a specialist down.
"The disease l. the lettuce drop
NrlcrotinIa libertiana. This i 4 very
serious trouble which affects lettuce. cab
bage, celery and sometimes potatoes, to-
matoeS and other vegetables over a wide
area. II i, however. particularly serious
IN the gulf region. Florida truckers have
long suffered serious losses from il. If
You will examine some of the dying lettuce
or cabbage plants carefully YOU will find
ON the decayed portions near the soil level
a whitiSh mould and on closer examination
OF tins later stage you will find numerous
small, hard, irregular, black bodies, which
are the ~~clerotia or the resting stage of the
fungus.
This disease occurs only where this
fungus has been introduced. Ii generally
begins in a small way and spreads and be-
comes more abundant from season 10 sea
son a. the amount of Infection increases
until II may become practically impossible
Ia grow a lettuce crop on "A piece of infect
ed land. The drop i also an enemy of
greenhouse lettuce, but under glass it has
been for a long time satisfactorily con
trolled by ~terilizing the soil with steam.
a method which =. Of course, impractic-
able in a large scale field culture. We be-
llcve that drop can be- controlled under
field conditions, but up 10 this time no one
has made a satisfactory demonstration of
this. The line Of attack upon the disease
i based upon the facts that the fungus ~
it occurs on plants in the field has no
spore bearing stage, but propagateS itself
only through the formation ~ these scle-
rotia, which. after n seasons rest i'm the
ground, send up tiny. mu~hroom-like off
shoots called aposhecia. which. produce
large number Of spores.
"ConSider now two other ,,uints: First,
that the drop fungus does NOT attack 4
plant except through some dead leaf: see
ondly, that II does not form IL resting
bodies or Sclerotia until the later stages
Of decay have been reached. and You will
see that the disease j. perfectly con
trollablc through sanitary measures. Ia
other words, all diseased plants should be-
removed from the field a. soon a. the wilt
* observed and destroyed by putting them
ON a brush pile where they will burn after
they have dried out. or by burving them
under a couple of feet of earth. For the
same reason when the crop j. being gath
cred the dcbriS-rootS. discarded leaves.
etc.-Should To- taken off - ~ not to af-
ford the fungus any breeding place.
"Such measures will be- particularly ef-
ticaciouS in fields where the drop j. show
INC up for the first time and toNa limited
extent. whereas IN the worse affected fields
where the disease has been present two or
three years and where there are. doubt
less. a great many sclerotia remaining over
from the previous crop. this method will
have To be- combined with rotation of crops.
Tor which purpose YOU may use any grain.
corn. c"wpea>. cotton or vegetable other
than those known 10 be- subject 10 the drop.
Il regret 10 advise there j. nothing that
can be- done to check the disease in a field
Iready attacked. Only preventative meas
nre~ can he used to avoid IL reoccurrence
another season"