1 ..... 7 i
CIRCULAR NO. 107. ...- l.;r l
United States It)ep; "t .
BUREAU OF ENTOMOLOG '
L. 0. HOWARD. Enl.n..l.I.i=Y ,nd ChL I
WHAT CAN BE DONE IN I)ES'T'IWI 4 l MI& ONI
WEEVIL DLIRIN THIIE Eit.ll
I'%' \W 11. 11 T "N: T. K I '
In Chirgr of Sor herni "*'i'*/.i C' ..i', *, n', T( I.l I 1 ,
I.MPORTI'O r.\.' iL' \ VI'I'H \\ [K.
The boll weevil iittra'cts grt.Lt t :,itention during the gri'ming season
of cotton, for the simple rt.-,I-n thlt its ,la;uuep is then most evident.
When the infestcl SliLIMarI are ailing by millions every d.Ly the pla;int'r
is driven to most strentiiiis E.ftrts to check the lot.s. The summer
season, however, is the one in which it is most dilhcult to combat the
weevil. The pest can be attacked in various w.iy at d.ilTTerc t seasons
of the year. This circular attempts to point out wh:at can be done in
the winter when the weevils are in hil'ernatin, quarti-rs and when nat-
ural conditions are a.sisting th, f-irmner greatly lby reiluinii: the number
that will be able to survive until spring. At this time the farmer can
undoubtedly accomplish more than by Iand-picking weevils and s?(q1:1r1.e
or any other direct imethoil of control that can be put into operation in
the summer seaon. A gre.t ailv.in!.ig, that winter work has in ni'n;MV
cases is that it involves I10 spt- i.11 outlay and ci'ileinuetlty adds nothing
to the cst of proltiuing cotion. The work can be done ilurin. the
quiet period of tilh \inter ainli at suoh times as N ill not interfere with
the general work of the pl.inta.tiiin. \'i n on i iiitittiiin, run 1.,r.,'vlyor
entirely by wages hinds" this wiirk would undoubtedly warrant an
outlay on the pa-rt of t Iie pla uter. .A a matter ,f fact the winter season
could well be male tlie nmost active of the year as f.ir as th- dl'.-tru'ction
of the weevil is concerned.
It is true that the Tex:aI f.armern have not p.iid much attention to
work against thi woovil in th winter, Iit this does not by :;i W' means
indicate that stch work will nit lie of prinj, imnpor(:iaii'., to the 1i' il ter-
in Louisiana anl M.is.siippi. N.itre has i lTiri fl.I ti' Texas f itrier
many advantag-s t\ (.r tilthe pl.tntur in ti-. eastern part of the cotton belt.
As has been point.il out in other piili-lin!ions nA the Purea.u i-f (d nto-
mology, the Mississippi \'ally planter will be (nnippllied to contend
against many more weevils each spring than thie liniati, conditions in
Texas have ever permitted to survive. For inrtinre. in the spring oif
1908 it was determined by Mr. Wilmon Npwell. sprecretairy rif the State
crop pest commission of Louisiana. that as many as 6.000 hibeprnated
weevils per acre made their appearance in certain cotton field in Avoy-
elles Parish, Louisiana. This shows a survival of weevils f.r iepyoni
what has ever been found in Texas. There are many other inli-ationns
of the special seriousness of the weevil problem in the Miislippi Va]-
ley. All this demonstrates that the planters in regions recently invaded
by the weevil must resort to every means of control that is known and
must utilize to the fullest extent such methods as the Texas farmers
may not have been compelled to practice.
The all-important-step in the control of the weevil is the destruction
of millions of individuals and the prevention of the development of
many more by uprooting and burning the cotton plants in the fall.
This is a step that indications show clearly is going to be indispensable
in the Mississippi Valley. In the light of what is now known it would
be folly for planters tu attempt to produce cotton unless they follow
this practice religiously. If, for any reason, the cotton plants have not
been removed in the fall, some good can be accomplished by their
removal later in the season. The proper thing to be done by the
planter who desires to reduce weevil damage to the minimum is to
combine the fall destruction of the plants with such measures, to be
taken later in the scaqon, as are outlined in this circular. The advice
now 'ir' a is not to d(f n'm1 uponi wii 1r iork altogo thir for the control
of the weevil. The irini, r irork i.no Mivly a svcmd step, to be taken in
connection wi th tl r tirurtioi of fthe r 'ils niid the pre rtion of the
?nahtrity of the fall broods h1 ipiwooling anl l,,,i ing the plants. Where
that step has not l,,n Ikei, thi. work outlined in this circular is the
main dependence of the plantbrs (it this iime.
WHERE WEEVILS ARE TO BE FOUND DURING THE WINTER.
The whole question of what can he done to destroy the weevils in
the winter depends upon where they are to be found. The Bureau of
Entomnologyhas taken pains to determine the localities in which the
weevils secrete themselves during the winter months. Some weevils
fly outside of the cotton fields into the timber before frost has killed the
cotton. Of course, such individuals as fly great distances from the
cotton fields, or into heavy timber, are entirely beyond thle reach of the
planter. The remainder of the weevils, however-those remaining in
and about the cotton fields-are more or less at thle mercy of the
planter for several months during the whiter.
In cotton fields and in their immediate vicinity weevils have been
found hibernating in four principal situations: First, in burrs and un-
opened bolls on thle plants; second, in bolls or portions of bolls that
have been knocked to the ground ; third, under such trabh as leaves
and grass abounding in most cotton fields; fourth, in the cracks in the
ground caused by drying.
The numbers of weevils found in the situations just mentioned show
clearly what opportunities thle farmer has for their destruction. On
January 16, 1907, a field near Wolfe City, Tex.. showed from 363 to
1,500 live weevils per bere in the burrs still hanging to the plants.
These were generally in the partly opened locks where weevils had
matured in the fail, hut some were in locks trom which all of the cotton
had been removed. On January 27, 1907, as many as 2,250 weevils
per acre were found on the ground in a cotton field near Dallas, Tex.
The number was determined by raking all of the trash carefully from a
square rod of ground and examining it in the laboratory. On Decem-
ber 18 living weevils at the rate of 1,056 per acre were found at Dallas.
On January 16 320 living weevils per acre were found in burrs and
under leaves and gras? in a cotton field at Victoria, Tex. On Novem-
her 15 4 weevils were foiml in the cracks around the bases of !2
cotton plii:nt grtwiiig near Il.ill.is. l indicates a total number df
weevils per :Irir in such sitlt1ii ii,,- in this ti.11 (I f I .'.1,
P'racti'ally aill of the weevils to be f1,I ii'l in the situations described
can be killed by r.aking and hiiriiiii, the trash, .xrilt those in cracks
in the ground, amil, tlihs., in the iI.ijI,,ity of ,.i.-s,. would Ipr,),;,ily be
crushetl by winter plowing ,f the ili-.-Is.
I'D M'INGi N i'r i:1i"' ri "F.
The point may be raised that winter Ipl' risi. by ,uriiiig the "\,i-,j'~
found in trash on thO surf;irt. ii1ii(t have the sae n ,tTr-t, as 1,irniin;.'.
On the contrary, experiments have shown that weevils can easily make
their wiay through several inches 4F soil. t '.ii-,i1i nitly such ".irk in
general is as likely to prtrt as to destroy the weevils. I f ,1,,rr,. if
helav'y rains sh,,uld foll iw immediately .il. r Ili' ,ig,. it is possible that
soile soils wMhld be so compacted as to ;,I,.iirt the iii,'-'ri'' of
weevils. Nt'e-rtlrl-lc-s, this could not 11:i11pi 11 under usual ,inliiiii:-.
In the ciase (Iof weevils in cr.i, k:. destruction would not result frou ,
huriiil but from rcrushlini.
What his jlust lin-c slateil should not be taken to mean that winter
plowing should not be fllmlowil.. As a matter of f.it t the winter work-
ing of the tield.s should be pr.it tic',Il. not only on g-nir.il pririiipl.-. but
to assist in procuring an carly crop. h['ir present prirpi-i, is merely to
point out how to destroy the boll weevil in the winter. ir'._lle-- of
its other hbeuefit-. winter plowing can not be ,l1'ptil-l,.d upon to actually
kill many devils.
w ',-:I:i\L.- "IAT CA.N BiE I-:\i'lI:11 ( O)T'.Irr ll : i pl, ( I I'IT N ri':I.I1 .
In .tilulition to tho-e in the cotton tiel'l- tliciis ,o-,h.- many weevils
in he nr-.i, lieil that have f,'iinI winter qi:irl,-rs ;'ltiuz t urni-riw-. in
ditths-. alming fr.nCt's. ail in the trash that is fr,.qu,.ntly ; il]'. -ii to
acIuIniulate .around seed houses. Fi' is .,iin the :tInt of destruction
;it thle coMniTi.ini of the f.irinr (':rrful ,iirii,-, If turn-rows and ditlL li.-
:r;nl clemin iiii of f'iir' comers and similar situations will result in tlih
de:ith of ni;iny weevils that niht survive to d,iiiimi. the cr-,p of the
Thle uirk of burning, anlI letn-ine the i>l.,iit.Ltii,, ,dnmldl- not stop
with the inirieliate viciitily of cotton fields. M:nily weevils I] into
corn f Nlilt, wi re thley liTiil siit:nile qu:irtT- for ir. i, the winter.
These liils, on a cotton pl.nt.atini. should be cleaned during the win-
ter as thoroughly aS the ti,-ils where cotton ls:i, been L'r iii,, or is to be
grrown during. the next season. It has been f,-uin that .-,ir,_'l.umin tli.l-
frnisi h exception:illv favor.a lle ippiirtuniti.s f)r hilk rii:tliii ii r ,I-\
The he:tvy stulble left by thils crop catches ur.k-s and g,'n,-r:il d. I-ri-
blown alic ut by thi, winlI. which tlin becomes lIT. iv matted. Here
Imaiiy weevils :ire to be fnimn, i diurini the winter. In IIi InIV cases in
Tex;is the earliest .ppi.iriinz weevils ;,l' i, greatest 'I-iinaI-, to the
crop have lieen shown to be ,.la.ur,.i ,,,, to n-,id1,iboring s,?ir'lhurn tit.1i-
which h.ivpe s--rved as winter qIU:irtrrs for the pest.
Many weevils unlouhtelly thfinl hili rn:itriig (lU:irr'r.s in trash Ml,,ii,
railroad rights of way as wt.)ll a al,,ng wa,,rii r,,ids. The importance
nf such means furnished the weevil f',r pas;,inu the winter becomes grit
where, as in many cases, the roads or railroads p.i.~- tHiir,,uh localities
UNIVERSITY OF FLORIDA
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3 1262 09216 5132
where cotton fields adjoin the public property. It should be the duty
of railroad and county authorities in such cases to assist the farmers as
far as practicable by removing the shelter for the weevil.
WEEVILS IN COTTON SEED.
Cotton seed has frequently been supposed to furnish exceptionally
favorable winter quarters for the weevil. It has been shown that many
weevils pass through the gins and are later to be found in the bulk cot-
ton seed in storage. Up to a certain time in the winter cotton seed is
very likely to contain live weevils. Many experiments, however, have
shown that very few are able to survive in this medium until spring.
This seems to be due principally to the absence of moisture. Repeat-
edly numbers of weevils have been placed in cotton seed in the fall.
Altogether 6,600 weevils have been used in these experiments. They
were placed under a variety of conditions. Although many have sur-
vived until the middle of winter, only two lived until the first of April.
It is therefore clear that cotton seed itself is not an especially dangerous
commodity. Although it is true that the earliest weevils frequently
make. their appearance in the vicinity of seed houses, this is to be
accountedd for by the fact that the insects find quarters under the build-
ing and under the trash that is allowed to accumulate in such situations
rather than in the cotton seed itself.
The climatic and labor conditions surrounding cotton production in
Louisiana and Mississippi leave no doubt that the planters in those
States must not overlook any important means of controlling the boll
weevil. This circular points out one impnr'ian, and inpxpe-nsire means
that can be practiced by every plain ier. It is of special importance in :
the humid regions recently invaded where fears of disaster are now ...:
commonly entertained. The Department of Agriculture urges that .
cotton raisers take advantage of the enemy while they have the oppor-
tunity and by the means herein described greatly increase the chances
for producing a crop the coming season.
,t ,l, iirif of A g rir nlfurr.
\\ASHINGTON, D. C., D,,,nil, r I'. 191/S.