The Houston daily post. [volume] (Houston, Tex.) 1886-1903, 1896-01-18
SWEET POTATOES.
Fungus Diseases nnd Insect Enemi
,riilers

Fungus Diseases nnd Insect Enemies OF
the Tubers.
Bulletin No. Sc of the Texas agricultural
experiment station contains the follow
ing:
There are several fungus diseases which
live upon the sweet potato and produce
the condition known as rot. Only those
| which have been the most destructive
here will be discussed Perhaps the most
serious one the grower has to deal with
is the soft rot lRnizopus n.eracans), THIS
| fungus is not found III attendance in the
| field, but does tho most serious work in
the store room. The potato. when at
! tackled, at once bect mes soft and worth
| less and gives off an offensive odor My
| celium Tor irould) soon grows over the
| tHber in white feltlikc mass. The tuher
bruised places Will appear u dark, pow
| dery mass of spores. The fungus does
| its most serious work soon after Dig
ging while the potatoes are going through
| i'll small piles in a dry. cool place and
be watched carefully until they are dried
and the potatoes are well cared for the
| fungus will ALMOST stop in two weeks,
when the tubers are ready for storing,
| In handling the potatoes bruise them
as little as possible ana thus leave no
| place whore the diseases may enter. 1t
| they be put away In dry, cool place
| be sprinkled among them We'll, this fun
gus Will do hut little injury. 1t Is very
serious sometimes If this is neglected, de-
s,roying hundreds OF bushels IN snort
time. yet 1t can easily be held In check,
| nCN rot CerutOcystis hmbriatn) has
been the most serious disease we have
| had to contend with In the store room.
| Al! the light red skin varieties, such as
bcen injured most,
the white skin varieties next, and the
| purple skin varieties have resisted the
disease best This disease appears upon
the tubers In the form OF dark brown
or olive patches, which are very irregular
| in outline If tuber be eaten when only
very small infe Jted spot Ia founs on
1t, the whole will have an unpleasant
bitter taste. Some have attributed this
| bitter taste OF the tuber to freezing. which
IS a mistake. We have had several of
these diseases In the laboratory ut once.
and have been studying them under "a
| microscope during the past two years.
! spores from discussed potatoes have been
placed IN sound potatoes and the disease
produced, so there can be no doubt as to
the cause a tuber when infected with
this disease becomes dry and inofensivc.
1t sometimes attacks young plants in. the
bed, producing what is known as BLACK
shank" Diseased potatoes should never
be bedded out to grow slips or sets from
Diseased slips should never be planted
in the field. a field which has grown dis.
eased sweet potatoes should not be used
again for the same purpose for two OF
three years. As before stated. 1t Is best
70 grow rotatocF for e'.ed from vine cyl,
| tings, because they are much less liable
TO carry disease which Will infect next
years crop.
| stem rot tNeCtrla tpmeOeb prot, byron
D. Halstead has dcscribcd this disease
which he found occurring on egg plants
under the common name Of egg Plant
stem rot" We have found It Occurring
with black rot OH sweet potatoes both IL
the field and In the storage room, The
disease appears in small pink colored
| spots on all PARTS of the potato. THESE
pinldsh spots, witen placed under q micro
scope. are seen 10 be sporc sacks, con
tanning immense numbers OF spores. We
have succeeded In making a pure cultur,
of this disease, and infected a potato with
the spores. The potato shriveled up and
BECAME very hard and dry.
While this potato became very dry
shrivcled and hard in the laboratory. vel
In the field whore the soil Is damp tn,
infected tubers are rather soft, and the
spores, which occur IL pinkish spots ap
pear all over the surface.
have not yet noticed IT upon the Young
plants bu, 1t is evidently carried to th'
probable also that spores. may come from
egg plants and cause infection.
Sweet potato scurf (Monilochaetes infns
cans) produces dark. rusty, brownist
tuhers when dug. The disense spread'
some after the cron Is dug. II causes the
does Potatoes havIrr this sourf on Their
should not Of course he ueoa for seed.
INSECT ENEMIES.
Injury by cut worms flea beetles, tor
tose beetles and saw flies can he pre-
ping them before they are planted IN the
following preparation: London purple
three ounces lime. two pounds; and water
twenty-five gallons. We have dipped tn,
plants in twenty-five gallons of Bordeau>
> mixture which contained three ounces o.
London purple. to prevent injury from
r both insects and fungus diseases, but th'
experiments have not gone far enough Il
enable us to give positive statements II
regard to this treatment for diseases.
new insect enemy, known as Sweet
Potato Root Borer" tCylas formicarus)
appeared along the coast of the State a
Matagorda Island some ten years ago
: aud Is now making itss way further VI
0 into the State. Last year we found a few
, in our tests here. Growers can not be toe
, careful to destroy all infected potatoes
g by burning them as this seems to be The
| only way of checking the insect, Pota'
toes should be examined carefully befort
pantnEi Plant ,nssc on daf Z
have come from Cuba, is of blacg ant
red color. and in It's fun grown state
resembles tho common corn weevh II
In bulletin No. % the varieties were
! divided into three Glasses. The CLASSES
were based upon the character OF the
foliage; the first included those with rounc
or entire foliage the second included those
with shouldered foliage, and the thirc
included those with lobed or split foliage
I These classes included the three mat
: divisions of sweet potatoes. as regards
: foliage If the description Of the foiag,
be taken in connection with descrlptiof
I which may not be easily distinguished
! The great number of local names winch
{ are given variety in different localities
where 1t may be cultivated is to be de
: plored. and should be discouraged by. al
4 who are Interested In this most excellent
vegetable for the South. AZ the head Of
each class occurs a figure illustrating Tho
foliage of each.
|