ClRCU'AR NO. 63. SfCOND EOlTION Tnilcd States I )epartmen1 oj Vj^ric-uli urt» OF KN IOMi'1 ■ I (J I | ■ > \\ \KI ' KiMIIMil.l.ills IMI HOW lo ( OM'KOLTI^ 1 '• I . 1 1 . ( ' I I 1 1 n m ■ i - \ O ' In ( 'hurgt ol /.'/• rding I The roots of vegetable crop plants ol many kind destructive influence of maggots which injure them - certain Beasons. Several forms of injurious root-maggots are recognized, but ol these there arc three species which are much more destructive than the others. The most important are the cabbage maggot and the imported onion maggot, the former a specific enemy of cabbag< and Kh. 1 - Seed i tii maRgol p female from above; •/ lur\ a. froi Einenl of larva: f. ana I puparium— all much enlarged antbor'a 111 other cole crops, the latter <>f the onion. A third species, the Beed-cora jot, attacks the sprouting seeds of \»>\\\ onion and cote i rope and of a considerable variety of other plants, afterwards working into the roots and -t.ilks ben< ath the earth's surface. As the last-mentioned in-' 1 1 i- nearly omnipresenl and omnivorous, it will receive tir>t consideration. Those species ill belong to the genus Pegomya ( Phorbia ' of the di] "ib family Anthomyiida?. THE SEED-CORN MAGGOT. /'•'■■• - /.:t. Vegetable growers frequently find that planted Beed fails to develop, and, on looking for the cause, discover a small whit it which, from early-observed occurrence on - '"Trr-Utaic,! the 51 got. In more recent years it Ikis often l-r.-tL.,- t<> beans, whence another name, "bean fly." Many ££1 are subject to damage, c\bbage, turnip, radish, peas, onions, beets, and Beed potatoes being often much affected. This insect, which is generally distributed in the United States, is shown in its different stages in figure 1. senibl.es 1 thfe common bouse fly. The particularly distinguishing characteristic of tlit fly is a io\v of short bristly hairs of nearly equal length on the inside of the posterior tibia? or shanks of the male (fig. 1, a). The length of the wing is about one-fifth and of the body about one- sixth of an inch. T')'' 1 ^' is little doubt that the insect is of European origin and that it is increasing in destructiveness in this country. 1 In its earlier stages, also, the seed-corn maggot resembles the house fly. The maggot is footless and cylindrical, presenting in profile the appearance represented at use it a day or two after the plants are up, or are transplanted, and repeat every week or ten days until about the third week in May, in the North. Farther south thee applications must be made earlier in the season. 'A more extended notice is furnished in Bui. 33, n. s., Div. Hut., pp. 84-92. -In all material examined there are only <> or 7 cephalic spiracles (fig. 1. g), whereas in the other root-maggots here considered there are 11 or more. 'There i^ evidence that another maggol has been confused with this species. 'The mixture is effected according to directions furnished in Farmers' Bulletin 1l'7, p. 22 (1903 ed.), which will be furnished on application. • The us' of mineral fertilizer*. — Mini • Ful us ■'■ rents, particularly when employed jubI ' ftern Bhowei has thoroughly wet the ground. The principal fertilizers for this purpose are kainit, nitrate ol soda, and sulphate ori'h ly be used as top dressings before planting; orj il n'pt employed tiniil after- wards, they Bhould be applied as nearlj i- possible to the roots, the earth being turned away from the plants foi thya purpose. These Ferti- lizers possess the advantage ol acting also timulanl to plant growth, thereby facilitating recuperation from root-ma^gol attack. 1 Danger from «« of organic fertilizers. — Stable manure and organic fertilizers are apl t<> induce infestation, Bin< e the Bpecies under consider- ation is well known to develop in excremenl and other decomposing material. Numerous instances of this have come to the writer's knowl- edge during recent years. It is advisable, therefore, to avoid tin- u manure, rotted leaves, or other organic fertilizers, and to avoid planting in fields in which there have been infested or diseased plants. Hand methods.— As Boon as Beed fails to appear at the proper time or the plants -how Bigns of wilting and maggots are found to be present, eed may be hoed out or the injured plants pulled and destroyed, together with the young maggots. Most of the methods mentioned above have been used with success againsl onion maggots and other root-feeding Bpecies, and are all thai is required in many cases of ordinary infestation of vegetable roots. THE CABBAGE MAGGOT. /'/ gomya braasit a Bi >uch< Cabbage and related cruciferous crop plant- frequently Buffer Bevere injury from the attack of the cabbage maggot. Young plants are most seriously affected, the maggots eroding the outer Burface and boring into the interior of the roots, devouring the tender rootlet- ami frequently penetrating into the lower portion of the .-talk. This insect, known also as the radish maggot, is an imported pest, ami was firsl noticed ruining cabbage, cauliflower, and similar plantain New York State aboul half a century u'". It doc- mosl Berious injury throughout the northern tier of State- and Canada, attacking all tonus of crucifers, whether wild or cultivated. In thai region it is the cause of more or less 1"-- to these crops year alter year, hut as with other active inset.-, it is much more abundant in some Beasons than in others. Since 1902 it has not only been exceedingly destructive, but 1 It is frequently neceesarj to nee these fertilizers in large qoantitii -. In cab- bage ticMs a Fertilizer ol the proper composition i- applied before planting at the ran' of 1,000 i" 1,500 pounds to an acre. After the plants h owth, a top dressing ol 100 pounds <>i nitrate ol soda and 200 pounds superphosphate is added. When the heads aie beginning to develop, a third application ol aboul 800 pounds ol nitrate ol soda n> the acre is often desirable. I "i details consult Voorhees's "Fertilizers." has increased in injuriousness from year to year. Frequently entire crops over considerable areas are completely destroyed. Two or three generations of this maggot are indicated in the Northern States, and perhaps four or five in the South. METHODS OP CONTROL. Since this species also is a root-feeder, the remedies prescribed for the seed-corn maggot are applicable. In addition there are certain prevent- ive and other measures for its destruction that have been found success- ful, their use being justified by the great value of cabbage plants. Carbolic-acid emulsion, prepared as prescribed on page 2, and diluted about 3o times, is particularly applicable when this maggot occurs on radish and other plants than cabbage and cauliflower. Hand picking, although laborious, has the merit of being effective, and is practiced with considerable success by extensive cabbage grow- ers, although not practicable on radish and similar crops. It consists in pulling up the young cabbage or cauliflower plants, examining the roots for eggs and maggots, and either destroying the eggs and maggots by crushing with the hand or by washing the roots in a strong solution of soap and then replanting. In most cases the plants show no ill effects from this treatment after two or three weeks have elapsed. By looking closely, the minute white eggs may be seen about the stalks of young cabbages, and if the earth be raked away so as to expose the eggs to the sun these will dry up, thus preventing the maggots from hatching. Afterwards the plants should be hilled. Methods of cultivation. — Experience shows that comparatively little is to be expected from various farming methods which are sometimes perfect safegards against other insects. Whatever might be advised and found successful on one farm might, for one or more reasons, be found ineffective on another. By keeping the soil well hilled around the plants the cabbage develops more roots, thus affording more food for the maggots and still leaving enough roots to strengthen the plant itself. Crop rotation should be followed with any plants other than crucifers or onions. Witb these latter it is inadvisable, as the same atmospheric or other conditions which induce injury by the cabbage maggot seem to operate in increasing the numbers of the onion pest, which has a similar distribution. Fall plowing is advisable. Crop remnants of all crucifers, and particularly cabbage stumps, should be removed and destroyed, especially early in the season. Late in the fall a less number of maggots would be destroyed in this way, but it is always a desirable method for the protection of the crop against other pests which harbor in the old stalks or feed on the new leaves in early winter, to appear the next spring. \\ / ""'- "'i' 1 "" 1 •' , '"" 1 each plant, ha* often I Ivi remedy, bul those who have tried ii are almost equally divided efficacy. '' ' 8 well worth further experimenl where the gas limi i in ^ obtained fresh without difficulty. It maj frequently I- had for the ci »s1 "I carl ing. The bisulphide! carl treatment.— In i ed paper cards, which m, l presently be described, or other preventive methods here given are ""' employed, and the ins< real numbers al the roott cabbage, bisulphid of carl may be used, ttshould be applied b ""' r ""' B y 8te ra "itl, a Bpecial injector or Byringe, 1 taking i are thai the application i- nol made di- rectly i" tin- pi inta as it i- \ . . wvx likely to kill them. A hole is made a little distance (3 >■ cards. — The use <>t disks <>r pads .,t tarn .1 paper for the protection n\ cabbage againsl the oviposition of the ily was perfected in 1889 by Mr W H. Goff, who describes his cards and the manner of cutting them as Follows: ''''"• '''"'V"'"'; 1 " !V hexa « onaJ •"'"' in order to better ec mi» II1 " material, and a thmner grade oi tarred papei than th, |„ 1;UV ,„„„„„ feM '; '"'"'• ;W " "; , ;' , > chea Per,bu< bein lexible, the cards made f, " are more readilj placed about the plant without being torn blade ot the tool, whirl, should be made ,,„,-, blackamith is f0r froo 'aband bent in the for f a half hexagon, and then taking ™ : ; , :" ,, • ^ "•• , ! ache8 near, y to th « ''"■"«■'• - shown in fig. 5. The part mak- ng I,, star-shaped col i, formed from a separate piece ol steel, so attached to U ' ,,: '"" ' :, : i , '"" ak ', : "'' J """ with , '"' b,ade - Thelatte, is beveled fr ^ all around, so that by re ving the part making! ihaped cnl ' he ^g* may be ground on a [, is important that the angles in the blade be made perfect, and that its outlh ,,., half hexagon. •What is known as the McGowen injector, formerly man,, factnred at III v ^ • l,,u no longer for sale, has proved mosl successful. tor ii To H6e tlic tool, place the tarred paper on the cud to !hi per cent of the crop. I >< Fig 3. -Tarred paper card in outline, one-half -i/'- I after OofT). Fro. 4.— Showing how tool is used, dotted line indicating position of edge of tool (after Cioff). FlO. 5. -Tool for cutting cards, about one-fourth size after (Jofl The tarred ranis arc applicable to cabbage ami cauliflower only, but it is claimed by those who have employed them that they are cheaper, more practicable, and more efficient than any- thing else yet devised for preventing the ravages of the cabbage maggot. Success in using them is dependent upon their be- ing properly applied, io fit tightly, so that the rly is unable to obtain access to the stem for the deposition of her eggs. Cards must be re- newed and their use continued for each iimL'L'ot year to be effective. 1 THE IMPORTED ONION MAGGOT. Pegomya cepetorum Meade.) 2 The name "imported onion maggot'" is used for this insect because there are other onion-feeding maggots in addition to the seed-corn 1 A Wisconsin firm has used as many as 20,000 of these cards a year, and esti- mates the cost of material and labor at about $1 for the protection of I.ikmi plants. This shows its practicability on a large scale. -This species is commonly referred to in literature as Anthomyia and Phorbia ceparum Bouche. According to Mr. Coquillett, it is difficult to decide, from the description of the adults, whether or not 1'ouche's and Meade's species are identical. jot. 1 1- injury, which constitub the mewl impurtanl di iwba< tli"' culture of onions, ie mplished bj tin- i onsumption of th< bulb, inducing Bubsequenl d< < aj ol th< quenl destrui i ion. The il> and th( emhle preen din avert) - a little larger. The length ol the fly's bodj ie tboul thre< ixteenths and the wing ex] irly thn I an inch. The male i> graj with black bristles and hairs it has a white face with black hairs, and there are three dark lines on the body between the v :tii< 1 a i"\\ ol black spots on the abdomen. The female i^ a little the r, and inclined t" dark yellowish, with d pale yellowi As in the case of the cabbu two or three generation evidently the rule in the V >r1 h. REMEDll S. The methods of control prescribed for the Beed-corn maggol an quently aboul all that are necess n? foi this 3p< ciee In < infestation the bisulphid of carbon treatment, discussed on pa also other remedies advised for the cabbage maggot, are useful, with the exception "I the tarred cards, which can nol be conveniently nor economically used on union. The flies are probably attracted to old onion beds and t<> crop remnants; hence 'Iran field methods are advisable. Note — This circular lias been prepared to facilitate • orr< Bpondi due to the fact that the three root-maggots mentioned herein have I" i o extremely injurious during recent years. A monographic account, which has been of Bervice in the preparation of this circular, was published in 1894 i>.\ Prof. M. V. Slingerland (Bui. 78, Cornell Univ. Agl.Exp. Sta., pp. 181-577). It is now out of print. Approved : .1 w:i> Wilson, n. en tary. Washington, D. C. February VJ 1906. O 3 1262 05252 3221 DOCUMENT ^SISiwacEuawB,;