99.S:rf >/ C>n< lRE\ I nited States Department DIVISION OF KNTOMOLOG' l ill HEX i< vn ( OTTON-BOLL » EE1 II . Imlkonomu* grandit Boh. BCOPE OF l III: CIECUL LB. < n« ni. ii So. \\;is pablished in April. 1805, and contained ;i briel report of the observations madcap to that tunc, ami the conclusions based on those observations, concerning the Mexican cotton bolJ weevil, an insect of Centra] a in ri ic; i ii origin \\ Inch, during I «9 1. attracted considera- ble attention in the cotton fields of south Texas. The m\ esti- ■ -ii was continued daring the sununer, fall, and early w inter of 18U5, especially by Mi. Schwarz, who visited Texas in May and June ami again from < October to I >c cember, and by Mr. Townsend, who was stationed in the State during the greatei part of the summer. The writer went to Texas in mber, and in company with Mr. Schwarz carefully Btndied the condition of affairs at that season and talked with many prominent cotton growers. The object of the present circular is to lay before cot- ton planters the results of this supplementary investigation. In order to make it complete iii itself, such facts as are needed are repeated from < 'uvular No. ti. '•i:\ik \i. \riM..\i: \m l. \m> METHOD 01 WORK. This insect is a small, grayish weevil, of the shape and general appearance Bhown in fig. l. a, and measuring a little less than a quar- ter of an inch in length. Ir is (bund in the cotton fields throughout the season, puncturing and laying iU eggs in 1 md bolls. The larva, of the Shape and appearance >ho\vn at fig, 1. <■. and ine.i-.iir- 1 2 iiijj, a little over three-eighths of an inch in length wlicn fall grown, live within the buds and bolls and feed upon their interior substance. Tlic squares attacked usually drop, but most of the damaged bolls reriiaiu upon the plant and become stunted or dwarfed, except late in the season, when they either dry or rot. DISTRIBUTION. Tins insect through its ravages caused the abandonment of cotton culture around Monclova, Mexico, about 1862. Two or three years ago Fig. 2.— Map Bhowing distribution of tlie Mexican cotton-boll weevil. cotton was again planted in that vicinity, but the weevil immediately reappeared and destroyed the crop. At Matamoras the weevil was noticed eight or ten years ago. About 1893 it crossed the river at Brownsville, and in 1894 was noticed in the country around San Diego, Alice, and Beeville. At the close of the season of 1S!I4 the insect occu- pied a territory extending to the north a little beyond Beeville, a few miles to the east of that point, and southwest to the neighborhood ol Realitos, on the National Mexican Railway. The greatest damage seems to have been done along the lower Nueces Biver. During 1895, and particularly in the latter part of the season, it extended its range to a considerable extent. Toward the east it was found in moderate abundance along the vallej ol the friiadalouj>e Kivei iil Victoria, Tbomaston, and Cuero. North of it- « »l< I range it extended to Kenedy, Floresville, and 1 1 1 : 1 1 1 \ points in the conntrj lying between the latter place ami Cuero. a Bingle Held was found near Ban Antonio which ••mi tainri I weevils in large numbers, ami in the same way a single Held was found far t<» the east at Wharton in which the weevils had appeared late in the season. The exael localities where tin' insect «;!•< found 1 1 in in ^ 1805 are indicated <>n the accompanying map. nam R \i ii i - roH \ wit II \i:i is. The insect passes the winter in the weevil Btate. 1 1 oau be found on the cotton plant until late in December, and, in fact, as long as any portion of the plant is green. It is tun ml most abundantly iu theearlj winter bidden bel w i«-n the in- \ olucre ami the boll, and later it frequently works its way < l< >\\ n into tin' dry and open bolls. All the specimens found l>> M r. Bchwarz in such Bituatious in the late Bpriug of 1895 were dead : but Si r. Tow nsend found a I'cH li\ ing in .March. The dry boll is probably not a fre- quently successful hibernating place. Judge S. G. Borden, <>t' Bharpsburg, however, writing under date of January 27, 1896, states that the weevil at that time was being found nearly every day in the dry bolls; bul this statement lacks the sig- nificance which it might other w ise lia\ e hail as bearing oil thequestion of hibernation from the fact that no heavy frost had probably occurred up to that time at Bharpsburg. With the cutting of the plants or with the rotting or drying of the bolls as a result of host, the adult weevils leave the plant and seek shelter under rubbish at the surface of the ground, or among weeds and trash at the margin of the fields. Here they remain until the warm of spring, « hen they By to the tir>t buds on such volunteer plant- as may come up in the neighborhood. They feed on these and lay their on the early squares, ami one. or perhaps two. generations are developed iii such situations, the number depending upon the character of the season ami the date of cot ton planting. By the time the planted cotton has grown high enough to produce squares the weevils have become more numerous, and those which have developed from the gen- eration on volunteer cotton attack the planted cotton, ami through their punctures, either tor feeding or egg-laying, cause a wholesale shedding of the young squares. It seem- to he an almost invariable rule that a si pi a re m which a weevil has laid an egg drops to the -round as a result of the work of the larva; in the square on the ground the larva reaches full growth, transforms to pupa, ami issues eventually as a beetle, the time occupied in this round approximating four week-. Later, as the bolls form, the weevils attack them also and lav their ui\ batched larva In young sq ooarlv full-grown I < r, pupa in young boll picked from ground eggs in them, and the Larvae develop in the interior just as with the squares. The bolls, however, do not drop. Figs. •">, a, and :>, b, show the larva- in the squares, and fig. 3, c, shows a young boll cut open and the pupa in its customary position. There, is a constant succession of generations from early spring until frost, the weevils becoming constantly more numerous and the larva- and pupa- as well. A single female will occupy herself with egg-laying for a considerable number of days, so that there arises by duly an inex- tricable confusion of generations, and the insect may be found in the field in all stages at the same time. The polls, as we have just stated, do not drop as do the squares, but gradually become discolored, usually on one side only, and by the time the larva becomes full-grown generally crack open at the tip. While in a square one usually finds but a sin- gle larva, in a full-grown boll as many as twelve have been found. In any case, how- ever, the hatch- ing of a single larva in a boll results in the de- struction of the boll to such an extent that its fiber is useless. Where no seri- ous frost occurs in Dec ember, the insects all, or nearly all, reach maturity and enter hiber- nating quarters, although larva- have been found on into .January at Sharpsburg. When- ever a heavy frost comes in this month, or before, the observations of last fall show that those insects which have not reached the beetle stage are nearly all killed. From this fact it follows that the insect will probably not prove as injurious in other portions of the cotton belt as it is in southern Texas. It was found during the latter part of 1895 that the weevil was present in a number of localities in which it was not known by the planters themselves to occur. It is impor- tant that every planter who lives in or near the region which we have mapped out should be able to discover the weevil as soon as it makes its appearance in his fields. Where a field is at all badly infested the absence of bloom is an indica- tion of the presence of the insect. In the early part of the season the weevils attack the squares first, and these wilt and drop oil". A field may be in full blossom, and as soon as the insect spreads well through it hardly a blossom will be seen. This dropping alone, however, is not a sufficient indication of the weevil's presence. Squares are fm.s shed from other causes, but if a sufficient number of fallen squares are cut open the cause will be apparent. The characteristic larva of the weevil will be quite readily recognizable on comparison with the figures which we publish herewith. Fig. 4.— Mature I mil cut opcu at left, Bhowing full-grown larva ; tin- one at the right iidi cut iiinl shovt mil; feeding punctures and ovipositiou marks. i ^w —Late fall boll show- bow beetles hid* i « een boll and involucre. 5 As staled above, tin' bolls do not drop. The punctures made i>\ the weevils in feeding, howevei,aie comparatively characteristic, and where a boll is discolored and baa begun to crack nl the tip the larva oi the I hi p. i can be st tii w i' bouFI i (Hi!)ic mi cutting it open. Late in the Beason the weevils tbemse veswill be found between the involucre and the boll, as shown in fig. 5, or in their ubsence the feeding marks and the yel low, granular excrement which collects iu the involucre at the base of tin' lioll arc excellent unheal ions, POP1 LAB N \Mf.s. In south Texas, among Spanish speakiug people, the insect is gener- all) kuown as tl picudo, 1 a descriptive name w hich refers ti> the snout in beak <>i the insect. English Bpeaking planters general Ij referred to the insect at first, as "the sharpshooter, a term winch for man} years lias heen applied to any insect which causes through it-- punctures the Bhedding ol the squares oi the rotting ol the bolls. A s there are sev- eral native insects that are commonly called sharps] ters, ami whidh, though injuiious, aie by mi means t<> he compared with tliis insect, it becomes necessai y to discourage in c\ ery waj the use of the word sharp- shooter as applied to this weevil. This was attempted iu the first edition of the ci i cnlai by illustrating one of the commonest ot the insects ordi nai ih termed sharpshooters, calling attention to the radical differences winch exist between it ami the weevil under consideration. The adop lion nt the term •• .Mexican <• 'tt mi boll weevil "for the new pest is recom- mended. The tei m sharpshooter is now much less generally applied to the weevil than it was at first. Planters generally now referto it as the hull weevil, or the Mexican weevil, or the Mexican hull weevil. PARASITES LOT) NATURAL ENEMIES. It is sate to say that little assistance will he derived from the work of natural enemies and parasites upon this insect. Of the former none nt' any importance have heen found. Several parasites, however, have heen found to attack it. and in one or two localities sonic little good has resulted from their work. They have onlj heen abundant, how- ever, late in the season, alter the weevil has completed its damage for the year and at a time when a minimum of good can he accomplished bj the destruction of the larva. The majority of the weevils in a given field fail to hibernate successfully, being killed bycold weather or some other cause, so that the work of parasites at this time does not count. Careful estimates, however, show that from 15 to 20 per cent ot' the weevil larva? iii fallen squares in November at Beeville and Kenedy were destroyed by parasites. There is a hare possibility that in the original home of the weevil south .Mexico and some Central American States, as well as certain of the West Indies) more efficacious parasites could he loiiiid, hut this possibility is hardly sufficiently strong to warrant the expense ot' a search expedition. REMEDIES. In considering the matter of remedies we must start with the state incut that experience has shown that none of the general applications of insecticides will he of the slightest value against this species. There are measures, however, which cotton planters may adopt and which, it' carried out generally at the right time, will postpone the appearance of the insect in injurious numbers for one or two generations, even if they will not prevent an undue multiplication of the species. These measures are directed against the over wintered weevils and the larva- of the first generation, since where the insect has once become numerous nothing can be done to save the crop from practical destruction. We have noticed that the weevils first appear in spring among clusters of young squares on the most advanced cotton plants. This suggests the possibility of trapping these earliest beetles by means of a very few cotton plants especially grown for this purpose. These plants must be grown at convenient points, must be protected from frost, and forced by watering, so that they will branch out and acquire buds even in advance of the volunteer cotton. The weevils which issue from hibernating quarters on the first warm days will be attracted to these plants at once, and can be easily collected and killed, if the plants are examined daily until the cotton in the fields has become of some size. It is not likely that this plan will appeal to the average cotton planter, but we are convinced that much good can be done by its gen- eral adoption. The fact that the spring generation develops only upon volunteer cotton has suggested the possibility that the insect will not spread beyond the region where volunteer cotton will grow in spring, but unfortunately this possibility is by no means absolutely to be relied upon. Nevertheless, the destruction of such volunteer plants as come up in corn fields and in abandoned fields which, the previous year, were planted to cotton, can not be too strongly recommended, for it is a matter of observation that the shade afforded by the corn or the rank- growing weeds which come up in abandoned fields is especially favor- able to the development of the weevils. While the plants arc young, and where labor is as cheap as it is in south Texas, a great deal of good can be accomplished by picking and burning the fallen squares, and if this is done promptly a large number of the insects will be destroyed. It should be done at least twice, at intervals of three weeks, during the period while the plants are small. As soon as the plants begin to branch out, however, this method becomes impracticable, on account of the difficulty of finding the squares on the ground. The idea of picking the affected bolls during the cotton picking was suggested in the first edition of the circular. It was thought that the affected bolls could be so readily recognized that many thousands of the insects could be destroyed by the cotton pickers by picking these affected bolls and carrying them away in a separate receptacle to be burned. The amount of extra labor involved m this operation, how- ever, would be very considerable, and the affected bolls in many instances are not to be recognized at a glance. These measures, aside from the last one, 'together with early planting and clean cultivation, comprise all that can be done to save the crop of 1896. It is obvious, however, that no general adoption ot these simple measures will be brought about this year, and that the probabilities are strong that the insect will be quite as injurious as in 1895, if not more so. A good first crop will probably be secured if the climatic conditions are favorable, but the top crop is sure to be destroyed by the weevils. This destruction, judging from the experience of the past two years, will probably take place in September in most of the localities where the weevils were present in 1895, and at this time the prospective loss of the top crop will at once become evident from the absence of bloom. The prospect of anj further picking of cotton beiug thus rendered so extreme!) small, a suggestion i^ obtained a^ to whal i^ perhaps, after all. t hf most practical waj of reducing the numbers of the wee\ il ami Becnring Approximate immunity for the summei of 1897, ami that in in tin- rutting down ami burning of the plants a I a time when it lici oiues evident thai the cotton yet to be gathered n ill be verj small in quantity, in manj localities during the past sum met tin> could have been done to very great advantage as earlj as the beginning oi October, and several large growers of cotton in Nueces and Duval count it's have decided to undertake t ln^ means next year. The success of tins measure "ill naturally depend upon uniform it) oi action among tin- planters oi a given region, and the difficulty of securiug tln> uni formity is the main argument to be used against it. Onlj about hall the «ottou in Duval County, for example, seems to be grown by the proprietors of the land; the remainder is grown bj renters, who will be not at all disposed to cut down their plants bo long a> a chance remains of picking a bandful of cotton. In this waj the plants iu many fields will doubtless be lefl Btanding until toward the cud of I December. Could anything like uniformity '»<• secured, either by legislation 01 otherwise, it is in thi^ fall destruction of the cotton thai our besl hope I i( B it the present outlook ; ami in t In s connect ion the further 8Ugges tion should be made that not all the plants in any given Held should be destroyed in this way. All the insects which are in the larval and pupal condition will be destroyed when t he cotton is burned, but those which may be in the beetle stage will, by flight, escape alive. It', there tore, a certain 1 umber of the plants are lefl Btanding in every field, these plants will attract the remaining beetles, which "ill settle upon them, so that they may readilj be collected day after day ami deal roved. If the plants are all cut down and burned, the beetles will spread I. it and wide: but if a few are left Btanding in this way, the weevils will concentrate upon them in Mich a way that they can lie easily handled. Where there is obvionsh n certain amount of cotton still to be gath- ered after the early part of'October, it may be an object to postpone this cutting down and burning of the plants. We have found that the Weevil continues to breed and may be found in the bolls in all Stages Up to the time of the flrsl frOSl The Cutting and burning will then accomplish a considerable amount of good, even if done during Novem- ber, although October would be tar better. Prom the present outlook, therefore, the best hope which the cotton planters in the affected region will have lor the future will be in follow ing this last-described method in the fall of 1896, and the more thor- oughly and uniformly (and, in fact, the earlier this is done in any given locality the greater will be # the chance for a good crop the following year. Unfortunately, after talking with many cotton planters in this region, we are by no means >ure that the plan \\ ill be at all generally followed, for the reasons BUggested above; and B8 the prospects ,,1 these planters themselves, a- well as the owners of cotton plantations in adjoining regions as yet nninfested, will depend almost entirely on the general adoption of this plan or some better one which ma\ yet be dis covered, it becomes necessary to look forward to the enforcement of remedial work by legislation. It will be greatly to the interest of all growers of cotton in the prolific district lying to the northeast of the region at present infested to urge the passage of an act during the >ession of 1896-97 which will bring about tin' enforcement of remedial work in 1897. This act should pro UNIVERSITY OF FLORIDA 8 • IIIIIIIIIIIWH 8 In,,l,lll, 3 1262 09216 4556 vide for the appointment of commissioners m each county upon the application of a certain number of the citizens of that county. These commissioners should be empowered to enforce remedial work, to levy penalties, or to have the work done by their own agents, the cost to be assessed upon the property* Jt will he well to let this law have a wide bearing' and not to confine its application to this particular insect, but cover all injurious insects, in case of future emergencies of a similar nature. Such a law should be passed in every State in the Union. Though it might remain inoperative for years, its application would be available in case of any sudden emergency, such as the introduction from a foreign country of a new injurious insect, or the sudden multi- plication and spread of any one of our native species. SUMMARY OF REMEDIKS. (1) Trapping over- wintered beetles by means of a few early planted cotton plants. (2) Destruction of volunteer plants in corn fields or abandoned fields. (.'!) ricking fallen squares as fast as practicable, from the time the squares are formed on the plant. (4) Cutting and burning the cotton stalks as early in the fall as prac- ticable, and, if possible, plowing the cotton fields at the same time. (5) Trapping the last weevils in the field by means of a few plants left standing. There can be no doubt that tbis insect is the most serious enemy to the cotton plant with which cotton growers in this country have had to contend, and every effort should be made to prevent its farther spread. The writer believes that this can be accomplished, if. by con- certed action of the planters, the recommendations just made are carried out throughout the infested region. L. O. BOWAED, Entomologist. Approved: Chas. W. DABNEY, Jr., Assistant Secretary. Washington, l>. 0., February 12, 1896.