Property of the Unii: . Coven. :ular No. 80. United States Department of Agriculture, BUREAU OF ENTOMOLOGY, L. O. HOWAHU. Kntomologiit and CInct ul Hurciu. 1111 ■ILOft \rniv | I II ClIITTI KDKN, uii;: OF ITTACK. The melon aphis, or, as it is commonly known, the "melon touse," injures plants h\ piercing them with it- beak and sapping their vital- ity. It occurs from early spring to late in autumn <>n melons and other cucurbits <»t' all kinds, and on many other crop plants, and in as which favor its increase, notably in summers following springs that are cool and rainy, it frequently develops in enormous numbers and does \i'!\ serious damage, collecting in masses on the under sur- ■ \ the leaves of plants and causing them to curl, shrivel, and lose coldi', and interfering with the ultimate development of the fruit. Often it kills plant- outright, and destroys whole fields ot greatly reduces the \ ield of fruit An affected cantaloupe plant is illustrated l>\ figure 1 . The melon aphis, like ot her- of it- Kind, excretes "honej dew,' 1 l»ut this i- not so copious as in the case of many species of aphides, for example, eei tain forms which affect tree-. When, however, the aphis under discussion becomes unusually abundant, the honey dew covers the leaves of the affected plant- with a thin, sticky coating on which the white ea-t -kin- of the aphides adhere, and this attracts attention to injury, as doe- al-<> the wilting and dying down of the plant-. Some persons notice this honey dew. and are unaware of the presence of the insects. They speak of the injury as •"honey dew." and have even applied thi- name to the insect itself. Quite too frequently, by the time the presence ot' the melon aphis in injurious numbers is noticed, irreparable damage ha- been accom- plished and the insects ha\e for the most put migrated to other pastures. iik by many forma ol aphides, especially those which excrete honey dew more copiously, can be readily detected by the presence of insects which feed on the tion. kmong the-.' are flies, wasps, bees, and especially ants. The melon a phi-, however, i- not an especial favorite with ants, altho some common -]*•- illy found in attendance upon it. The pavement ant '/ the "iily 8] r been observed by the writer, and neither ant m >r aphis appears to In- in any way dependent on the other I once, contrarj to that which i- the case with many other aphides, particularly those which have root-feeding forms. [0248 \ -.»— Oti s%$$ DESCRIPTION. The melon aphis fa. minute, soft-bodied creature, of liable color usually oi some shade of green or greenish black; in its young and wingless stages, louselike in appearance; and of sluggish habit thru out its existence The general appearance of this splSes in ite most commody observable stages is indicated in figure 2, highly magnified A brief description of the stages figured will suffice for the present purpose. The coo- h as been described by Mr. Th. Pergande" us of regu- larly oval shape and measuring about 0.6 mm in length; yellowish <>r greenish when first deposited, soon chang- ing to jet black. The larval aphis or nymph (fig. 2, b) when first born or hatched presents no observable characters for com- parative description. It measures less than 0.5 and is pale in color, turning | ;l ter to yellow. The hist nymphal stage, corre- sponding to the pupa of other insects, is sufficiently illustrated at c that it requires no verbal description. The apterous or wing le-> female, which is viviparous ( gi v i n g birth to living young), is figured atrf. Great variation is exhibited in this stage, from pale yellow to very dark green with black nectaries or honey tubes and pal'e whitish-yellow lees and antenna'. This stage varies i„ length from 1.5 to l.s The winged female is illustrated at ,, bj Forbes, 12th Rept St. Km. 111. f. 1882 | 1883), pp. 83-91. Pig. 1. -cantaloupe leaves showing curling eaused by melon aphia aphideson lower surface. Slightly reduced (original). 8 from 1 .■_' to I . v . while the wings expand from I . ■■ to 6 ' \ darker form of the female is shown in profile at ab, and the antenna?, much enlarged, ;it an. The male has no( as yel been recognized. This i- l>\ far the moa( important and abundant aphis affecting 1 1 k • I « » 1 1 - and other cucurbits, and is m>t I i k » ■ I \ ii> be confused with am other species occurring habitual I3 on the same classof plants. Ii i>. indeed, a vev\ important pest, and, taken season after season, the worst aphis occurring in this count r\ . ad A** 5 1 aphis 1 winged female; aa, enlarged antenna ol Bame ofr, dark ^iiii; juice from surface of leaf; b, young nymph or larva; r, last - nymph; •/. wringl Allgreatlj enlarged (author's itlustrai DISTRIBT [ION. The origin of the melon aphis is doubtful, but is probably tropical, Bince ti»i— insect shows a decided preference for plant- of a tropical nature, such as the cucurbits, cotton, and orange. Southward the aphis occurs in the West Indies, in Mexico, and in Brazil, and doubt- less elsewhere in South America. It is very generally distributed tlmiout the United States, l>ut dor- more injury in the southwest than elsewhere. In Texas, Kansas, and Nebraska it i- particularly trouble- some to melons, and in the last two States t<> cucumbers, which are there extensively grown for pickling. Bui it ma\ at any time create "The squash aphis \ '■'■ ophora [Siphonophora] ctttwbiUe Middleton), a much larger species, more uniformly green, and of a moch lighter and brighter color, is often Found on cucurbits, bat seldom in sufficient numbers to cause noticeable damage more or less trouble in northern regions, particularly in Virginia, Maryland, Delaware, and New Jersey, where cucurbits are much cul- tivated. Occasionally it is injurious as far north as Minnesota and west to California. It has been collected also in Adelaide. South Australia. INSTANCES OF INJURY. The melon aphis first attracted notice thru its injuries to cotton in 1854, and from that time on it has done more or less damage year by year, and, in view of its rapacity, rapid multiplication, and omnivo- rous habits, will no doubt continue injurious in spite of all that can be done to repress it. As a melon and cucumber pest it was noticed in Florida and southern Illinois in 1880, and in the next three years caused considerable losses in those States and in Georgia. Soon after- wards it became recognized as a strawberry pest. In later years many other food plants were added to its known dietary. The years 1892, 1893, and 1898 were unusually bad ''aphis years." In 1893 information was received from a pickle company of Omaha. Nebr., of severe injury in that State. This company was growing between 30,000 and 50,000 bushels of cucumbers a year, and sev- eral hundred neighboring farmers grew this vegetable for the com- pany. Two-thirds of the crop grown in 1892 was destroyed by the aphis, and in 1893 half of the crop was lost. These injuries made it difficult to induce outside planters to grow for the company. In 1898 this species was extremely troublesome. In order that a good idea of its destructiveness may be had. some reports are cited. In January injury was reported on cucumbers in Florida and in May to strawberries in Delaware, where the insects were described as "taking everything clean. r By June this insect had been very injurious to watermelon in southern Texas, when it destroyed many acres of early vines. In July Texas correspondents reported the destruction of 1,001) acres of cantaloupes in one locality, and the out- break assumed such proportions as to cause much newspaper com- ment. One company reported that the ravage.- of this pest had cost them $20,000, and that agriculturists of that section had sustained irre trievable loss. In November a Pennsylvania correspondent reported losses to cucumbers grown under glass, and in December this aphis resumed its ravages to cucumbers in Florida. LIST OF FOOD PLANTS. The insect here considered is the most nearly omnivorous of any known species of aphis. The list of plants upon which it has actually been found feeding shows great diversity, and future observations may add many more host plants. It is partial to the plants that have previously been mentioned — melons and other cucurbits, cotton, okra, orange and other citrus fruit-, strawberry, and purslane but it attacks also clover, beans, beeta, spinach, tomato, bops, and pear, and several ornamental plants, including hydrangea, begonia, ground i\\ [Nepeta glechoma), \ i lypha, and morning-glory. From its abundance on some of these plants it has received n number of common as well as Latin synonym ical names, the former including cotton aphis, orange aphis, cucumber louse, and cantaloupe louse." It in frequently called also the " black aphis," especially in its occurrence in greenhouses. Mr. Pergande has found it feeding upon n large number of weeds, among which are shep herd's purse, pepper grass, pigweed i Imaranthus), dock (Rumex), bur- dock (Arctium), dandelion, lambsquarters (Chenopodium), plantain, chickweed, button-weed (Diodia), mallow, dogwood (Cornus), and Jamestown or jirason weed (Datura). Since these aphides are not at all particular as to their food, when thc\ migrate from their favorite plant- they -tart colonies on nearly an\ plant that chance- to he in their line of flight. The writer has -ecu asparagus and violet attacked, the hitter >jr<>\\ n in greenhouses. i 11 i. 1 1 1-1 1 >i:\ . Attack to cultivated plant- begins from early spring till consider- ably later, and i- made by winged individual- flying from weeds which serve as alternate food plants. Infestation naturally commences earlier in the South than northward, and ma\ be simultaneous with the appear- ance of the crop above ground. Soon after the plant- have developed leaves a few winged aphides can usually be found, and these are the forerunner- of myriads to follow. A- often a- a plant becomes exhausted of it- vital juice- by the sucking mouth part- of innumera- ble aphides, winged individuals are developed which migrate to other plant-, -o that migration in the case of thi- species i- carried on prac- tically thruout the season. Flight from one kind of food plant to another, or from one field to another, i- caused also by disturbance from the abundant natural enemies of the insect. The great num- bers of thi- species sometimes suddenly discovered on melon-, cotton. orange, and other plant- are often due to en forced migration on account of the death of other food plant- in the vicinity, such a- might !>•• caused bj atmospheric condition-, or bj the ravages of the aphides themselves, or of other insects. The removal of the crop on which the insect was at work will produce the same effect. \ \ 1 1 i: \t. i:\i mm -. There i- perhaps no 'better example, among insects, of a common and widespread species being held in abeyance and limited to innoxious "The synonyms incladi Stphonophora) cilri/olh Ashm., Aphis citrulii A-lnn., Aphii Forbes, Aphis forben Weed. It i- -till mentioned in literature a- numbers (save in exceptional seasons) by natural enemies than the melon aphis. The usefulness of these natural enemies, of which a large number have been recorded, in subduing the aphides can not be overestimated. Garden and field aphides generally are subject to attack by the same classes of parasitic and predaceous enemies. The number of species of insects known to prey upon the melon aphis is about 35. The list includes many ladybirds or "ladybugs" (Cocci- nellida')." which destroy the aphis both as beetles and a> larva", the maggots of certain syrphus-flies (Syrphidae),* which consume large numbers of aphides; aphis lions — the larvae of lace-wing flies, of the families Chrysopidse and 1 [emerobiidae." A number of species of para- sitic insects, chiefly minute forms of Braconidae, are also very impor- tant checks on the increase of aphides.'' Many. too. are destroyed by parasitic fungi. The insect enemies of these, as of other aphides, keep their hosts, in many portions of the country and in ordinary seasons, in nearly complete subjection. The parasites, in particular, are most effective in dry, warm weather. In cooler, moist summer weather, especially following t/t, xther species are Sci/mim* terminatus Say, S. caudalis Lee. S. cervicalis Muls. (A), Chilocorus biindnerus Muls., Exochomiis constristaius Muls. (H), and Hippodamia lS-punctata L. f'Syrphus flies include Syrpkus americanus Wied., AUograpta obliqua say. Baccha clavata Fab. {babista \Valk.),i?. lugens Loew. (H), /.'. cognata I. new. (H), 11. fusd- pennis Say (A), and Eupeodes volucris < >. S. An agromyzid fiy, Leucopis nigricorni* Egger, also preys on this aphis. Cecidomyiid enemies include certain undetermined species of Contarinia (Diplosis ). o Among the lace-wing flies are Chrysopa oculata Say, C. plorabunda Fitch, C. alUn- cornis Fitch (A),'', nigricornis Burm. (A), C. lineaticornw Fitch (A),'', attenuata Walk. (A ). Micromus posticus Walk., ami Hemerobius gossypii Ashm. (A). tf Parasitic^braconids include Trioxys testaceipes Cress., Lysiphlebus gossypii Ashm., /.. citraphis Ashm., L. cucurbitaphis Ashm., /.. minutus Ashm., Lysiphlebus sp., and Pachyneuron sp. A chalcis fly, Stenomesiw aphidicola Ashm.. lias also been reared. The species followed by ( II i were observed attacking Aphis gossypii on orange trees in Florida by II. en efficienl enemy, the nine spotted ladyhird, is shown in figure 3, f. One of the mosl abundant sryrphus-frj enemies i- illustrated bj li'Mllr I. fa*>^S& Of the nataral enemies which have been enumerated, ladybirds are particularly valuable, owing principally to the fact that the} are active al all seasons, especially at the outset of aphis attack. Parasites are most effective toward the end of the season, when they often reduce the aphides so thai few arc left to hibernate and produce other gen- erations of the pest the following year. The value of these natural enemies against aphides is such that entomologists frequently advise the employment of remedies only when the enemies are not present in abundance. Tlie possible utiliza- tion of natural enemies in the field will he considered on page-, 15 and 16 of this circular. In tobacco fumigation, which will presently lie considered, we have an almost ideal remedy, for the reason that, while aphides are all destroyed, a considerable proportion of the ladybirds and other hardy beneficial insects, which are practically always present on the infested vines, survive this treatment. Fig. 1.— A syrphus-fly (Syrphus ribeaii): a, fly: h. lateral view of head: r. larva or active immature form; '/, anal spiracles: i . thoracic spiracle of same. All much enlarged (original). METHODS OF CONTROL. The severe losses occasioned by the melon aphis in its seasons of greatest destructiveness could he largely mitigated and in many cases almost entirely prevented if the employment of methods for its con- trol were begun upon the insect's first appearance. For its successful treatment it is necessary to keep constantly in mind several of the facts that have already been given more in detail. In ordinary sea sons the species is controlled by the combined operation of natural elements and insect enemies, but at times when the weather is unfa- vorable to the development of these enemies the grower should be on the alert. The presenceof the aphides is often not detected until they are numerous, and even then they are not apt to be noticed unless the Inn-, ,■ surface of the leaves be examined. All things considered, the most satisfactory way of controlling this insect is by fumigation. As an aid. however, cultural methods are necessary. In the South spraying with kerosene and other emulsions is preferred to the bisultid of carbon method, and tobacco is now much used, especially in Texas. The encouragement of natural enemies gives promise of success. HIM I I II' .il i VKII'iN II Ml'. \ I l"\ This treatment of the melon aphis has been used successfully for Borne time, and i- valuable in small fields, but less profitable where cucurbit or other crops are grown over large areas. It consists in evaporating hisulnd of carbon under tubs, or similar ti<_dit receptacles, Buch a- pail-, buckets, or boxes. The chemical is employed ai the rate of a dram (about n teaspoonful) t«i each cubic foot of space; ;i tablespoon ful will serve for ordinary small tubs. This method of treating the plant does not injure it. and it' the tub tit tightly t<> the ground, so as to retain the vapor of tin- bisulfid, all of the aphides which are covered will In- killed. This method maj he followed sue cessfiilly in large fields it' the grower Ik- careful t<> watch tin- \ ines for the first appearance of the insects, and to treat Buch hills as require fumigation, remo> ing ami destroy ing plant- that arc badlj affected t<> prevent the spreading of the insects to others. ( ' w 1 1' >N. In the use <>l bisulfid of carbon a- a fumigant for aphides the usual precaution should be observed not to expos* //>■ fumes to fire. ill, operators must nut smok* during this process! A- tin- gas is lifa\ ier than air there is no danger, it' ordinary rare i- observed, that the funic-, will he inhaled by human beings. HYDRi (CYANIC-ACID i , \- I Kl \ nil M This gas, as has been demonstrated by Prof. K. I». Sanderson, can be u^-t\ in the field in much the same manner as the bisulfid <»t' car- bon, with wooden tubs or buckets. It has not, however, been adopted by growers and we do not recommend it. It possesses an advantage over bisulfid of carbon in that the cover used in gassing need not tit closelj to the earth. ( )n t he other hand, it \a decidedly mor* danger- ous to human lift inn/ must therefor* In handled with th* greatest care! Asa greenhouse insecticide this gas is a perfect remedy for aphides and other small- and soft-bodied insects. It i- used where tobacco is unsafe; for example, in violet bouses, violets being especially subject to ••-pot" after fumigation with tobacco. The method of applying hydrocyanic-acid gas is described in Circular No. 37 of this Office. I'YKl.l ma M POWDKR. 1\ rethrum or buhach insect powder, administered dry with a pow- der bellows to the lower surface <>f leaves, will kill the insects, altho these sometimes do not appeal- to be affected at first. A second or third applieat ion i- sometimes necessary. This i- an expensive rem- edy and can not J>e used with profit «>n large fields <>r on plant- with large leaves, like squash. In \.u Jersej and < Colorado many growers simply take oul and bury such badly infested plants as are noticed when the hills are turned for cultivation. 10 FUMIGATION Willi TOBACCO PREPARATIONS. Tobacco extracts and fumigating powders have been extensively used for a number of years by florists a- fumigants against aphides and other insects occurring in greenhouses, such as white fly, thrips, and other small, delicate, and soft-bodied insects. The extracts con- tain a larger proportion of nicotine than ordinary decoctions prepared by steaming waste stems and powdered tobacco, and are therefore much more effective, which is true also of the powdered forms of nico- tine. A number of these preparations are on the market and are advertised in the principal florists' journals and in other agricultural periodicals. They are used in various way-, and direction- are fur- nished with the packages purchased. The liquid preparations vary in strength from 35 or 4<> per cent up to 80 to 85 per cent nicotine. FIELD FUMIGATION" WITH TOBACCO. During the years 1904 to 1906 the employment of tobacco or nico- tine preparations in destroying the melon aphis in the field was the subject of experiment in Texas by Messrs ('. E. Sanborn and E. D. Sanderson." These have stated to the writer that, judging from their experimental use of this method and its practical use by extensive growers, it bids fair to become the best method of dealing with the melon aphis in its occurrence in the South. The process is in brief the fumigation of a dry preparation under a cloth-covered frame placed over the affected vines. In 1905 and 1906 the writer found that a very short exposure to tobacco fumes killed aphides, when other insect-, such as thrips, survived a considerably longer treatment. In practising this method Mr. Sanborn has used apparatus substan- tially as follows: Preparation of the frame and cover. — For vines 2 or 3 feet long he advises a light frame -4 by 6 feet, supported by legs 8 inches in length. Lumber three-fourths inch thick and -1 inches wide is suitable. Strengthen the frames by connecting the ends with aero—piece. Two diagonals are also used for strengthening the frame and for conven- ience in handling, the latter being attached after the cloth cover is in position. The cover is of muslin of a cheap grade (7 or 8 cents a yard) and sufficiently compact to prevent a passage of gas thru its meshes after being oiled. Its size should be about % 1 feet wider and 2 feet longer than the frame which it covers. This is sufficient for an 8-inch wall and a 4-inch lap to the ground. Dirt is placed about the bottom to keep the gas from escaping there. After the cloth has been cut and sewed into the sizes desired it is saturated in a vessel of linseed oil which tills the pores. It is then "An experiment with tobacco smoke as a remedy fortius species was made by Dr. S. A. Forlies in Issl'. The result was not a perfect success, for the reason that a bee smoker was used and the smoke was blown under canvas hay cape covering the affected plants. Nevertheless from 50 to 75 percent of the aphides were killed by Hi minutes' exposure. wrung out, slighth dried, and placed over the frame and held in place i>\ nailing the diagonals to the frame above the cloth. A gallon of linseed oil i> sufficient for rendering four covers of the size above specified sufficiently air tight for tin- method. The number '>i' frames for use depends upon the degree of infesta tion and the rapidity of the operators. Ordinarily about 10 frames are sufficient for one man's attention. pplication. The frame is placed over the inf< sted plant. One sheet of the fumigating preparation is torn into from two to four or more equal parts (according to directions <»n the package or as experience maj decide) and each part i - put in r tin fruit can under the frame near a corner and then ignited. The cans are perforated at the bottom by driving a large nail in at the side. It is well to use a long taper or fuse for lighting the fumigant, affording the more active beneficial insects time to escape from under the cover before the tobacco fumes are >_:i\<'n off. Earth is then heaped on the border of tin- cloth on the ground to prevent the escape of the smoke. The frame should remain in position ten <>r fifteen minutes, or longer if preferred. Each operator - 1 » < > 1 1 1 * 1 have enough frames to handle so that each frame in -ii.-. 'c--ii>n may remain on a vinr during the time mentioned. In localities where the aphis is most injurious local merchants who deal in insecticides Bhould be informed of the fact and requested to keep a supply of fumigating preparation always in stock. The best time for fumigating is when there is qo wind ami the vines air damp. In moderately dry weather, however, good results maj be obtained. Caution. Care should be exercised not to allow the dry fumigant to ignite. Lt should smolder only. Vines should not be disarranged except where they protrude a few inches beneath the cover. The lra\ es should not touch the top of the rover. Variations ",'///• fumigating frame. The frame described above has been used in the fumigation of young plant- in southern Texas. The size and make-up of the frames maj be altered or inipro\ ed l>\ the individual grower to adapt them to the size of tin- vines and the nature of the plant to be fumigated. Farther north than Texas manifestation of injury is not usually observable until the plant- have made consid- erably larger growth, and a larger frame, say about a foot high, will be found more desirable for general use. Unbleached cotton of com- pact mesh, at 1 M cents a yard, answered a- well a- the oiled "muslin" in experiments conducted by the writer, and their is a saving of time in its use. Moreover, it doe- not collect dirt nor -oil the clothing and other objects with which it comes in cont For the treatment of plants other than cucurbits, such a- cabbage affected by the cabbage aphis, eggplant, tomatoes, and other truck Mr. Sanborn advises a hood, using a frame made of two wire- Kent in a semicircle. Strong barrel hoop- ma\ be substituted, and the cover tacked to them at the top where they cross and at the bottom of the 12 hoops. ( )rnamental plants of low-growing sorts may bo fumigated by means of such a hood, while for moderately high plants, such as rose-, which are much affected by two common species of aphides, special covers may be constructed. VAPORIZING AND FUMIGATING TOBACCO IN GREENHOUSES. In the vaporization of tobacco — a practise which has been in use since about lsi'4-and which has largely superseded ordinary dry-tobacco fumigation in many sections tobacco stems or dried tobacco, in one or another of its various proprietary forms, are placed in a kettle, metal pail, or similar receptacle. A hose is then connected with a steam pipe, the nozzle inserted in the receptacle, and the house to be treated becomes saturated with the vapor of tobacco, with the resulting destruction of aphides and other soft-bodied insects that may be pres- ent, such as thrips or "white fly." Liquid preparations are more generally evaporated over alcohol or other lamps, or are placed upon steam pipes, or hot irons are put into the receptacles. For general greenhouse fumigation, fumigating powders are placed in shallow pans, and a few drops of kerosene are added to facilitate ignition. The dry fumigant is designed to burn slowly, so as to produce a smudge which, when dense, is fatal to aphides. This process of treatment may be applied at any time, by day or over night, and upon its completion the house is ventilated. In some cases the plants are syringed, but this is not necessary with plants like cucumbers. A surplus of moisture is to be avoided, owing to the liability of inducing "spot,"' mildew, and other fungous diseases on plants susceptible to such maladies. The amount of a tobacco compound to be used depends upon its strength, the plants to be treated, and the size of the greenhouse. Sev- eral forms are for sale under different trade names. It is not probable that these differ greatly from one another in value, but there is much dif- ference in their strength. They are put up in both dry and liquid forms. In experiments conducted on greenhouse cucumbers at the Massa- chusetts Agricultural Experiment Station, at Amherst, one of these preparations has been used successfully at the rate of 5 or 6 teaspoon- fuls to 1^ pints of water, and vaporized in a space of about 5,000 cubic feet. The length of exposure in this case was over night. Thus used. it does not injure delicate plants, like cucumber, but it kills all aphides and nearly all thrips — for which it was used primarily and which are not infrequently associated with aphides on the plants to be treated." "Thrips ami "white fly" (Aleyrodea spp. ) are more resistant to poisonous gases than are aphides; The former are must effectively destroyed while in the soft imma- ture stages. The adult thrips are hardier and, being winged and more active, spring and fly away, and are thus not SO easily brought in direct contact with insecticides like kerosene emulsion. The white flies, on the other hand, are more susceptible t<> poisons while in the active adult stage. The nymphs are of firmer consistency and comparatively resistant. Remedies for the greenhouse white tlv are discust in Circular No. 57. ta Tobacco in fine powder form dusted lightlj <>n verj young plants Berves both as a repellent and as a mulch, or fertilizer. It i- claimed i>\ some to deter the striped cucumber beetle; others report that it is not effect i\ o for this beet le. A successful fumigation or vaporization of a cucumber house infested with the melon aphis was made also in June, UK)6, :ii Ana costia, 1 '. ( . \ (I i tie re mi preparation was used, ami 66,000 cubic feet of greenhouse space was fumigated, 22 ounces of the liquid, <>r I ounce to 3,000 cubic feet, being employed The work was under the writer's direction and conducted h\ Mr. I. .1. Condit, with the cooperation of Mr. .1. \\ . Bryan, owner of the house. At the end of an hour and fifteen minutes, when the ventilators were opened and the greenhouse aired, the aphides were found dead and dying, and the cucumbers were unharmed. Bight evaporators were used in this instance, each holding a little less than 3 ounces of the liquid. It i- mite probable that a considerably smaller amount of the preparation, -a\ 1 ounce to 5,000 tail )ic feet, with an all-night exposure, would have accomplished the -aim' object The cost <>f fumigation is not above (2.50 for a house containing 64,000 cubic feet. C.\i noN. Before fumigating an entire greenhouse with anj sub- Btance a preliminary test i- always advisable to guard against acci- dents and to avoid waste of material. In the case of one liquid tobacco fumiganl used at Washington, the preliminary t'"-t showed that, employed at the strength advised by tin- manufacturers (/. .. without dilution), it ignited in the evaporating pan instead of vaporiz- ing. This trouble was obviated by diluting the fumigant with half it- amount of water, the further precaution being taken of placing a wire gauze lie nea tli the pan and over the flame. In the case of some alcohol lamps used for this purpose the flame is apt to be too strong, espe- cial!} if placed too near tin 1 evaporator. This causes the glass to break. l*>ra-- or other metal lamp- are therefore preferable. Unless the lamp- and wicks are of good quality and tit properly, the alcohol i- apt to ooze Out around the cork and bum on the sides <<\' the lamp and thus, al-o. cause breakage. A- a general rule it i- besl not to fumigate in bright 9unlight, and not when delicate foliage or flowers have globules of water on them. BPH M IN'- METHODS. Kerosen< emulsion <'/"/ soap solutions. The melon aphis could he much more readily dealt with if it were not for it- unfortunate ha Wit of feeding on the under surface of leai es which are often badly curled, a- -how n in figure 1 and for the further fact that in large fields, par- ticularly late in the -ea-on when the lea\e- are large, the vines gTOW so closely together, frequently becoming interlaced, that spraying by ordinary means is impracticable. (Jnderspraying i- an absolute neces -it\ . and a sprayer should he used lifted with an upturned elbow and a u nozzle of tbe Vermorel type to secure this effect. An dhow designed for this purpose is shown in figure 5. Kerosene-soap emulsion, the standard remedy for aphides, is the best insecticide for spraying purposes, but various soap solutions are used both for the melon and pea aphides. They are diluted with *> to illustrates the method of operating a knapsack sprayer so as to produce an underspraying. Spraying with water. — 'Where a lew plants only are to be protected, and it is possible to direct a strong stream of water upon them from a garden hose, syringe, or spraying machine, so as to wash off the insects, the aphis can be materially checked without the use of other materials. Such of the insects as come into direct contact with a stiff spray are unable to survive, while others that are dislodged from the plants do not succeed in returning. Many are wingless during the greater part of the season and unable to crawl any distance, particu- larly if the ground be dry and hot. Fig. 5.— Elbow attach ment fur underspray ing. Reduced. ' ' Ml i; M MM now . ^"^l methods give grt*te«i promise as re, lies. Clean garden mg or farming with Pall plowing should always be followed as these ,( ;r" " "^valuable meaBure of prevent! I injur 3 by this and othe, ...sects that are present in the fields. A as the crop is ofl ™»mn.nto should be gathered and burned. All weeds in the vicing should he kepi downthruoul the year, including late fall and carl y™*« n «.M hasalreadj I n shown, I ...,„, weeds of the he,d ;,1h1 garden are available a- alternate , '""' 1 P^ts and serve as the hibernating quarters of the aphides, which feed more or less thruout the warmer periods of winter. On weeds the insects can be found feeding, '" ;1 climate like that of the District of Columbia, until January, "even after heai \ frosts or snow," and again in March. ' OHTBOl in mii,,n iPHia n S IT1 RAJ I \nm\ The possible control of this pest with the assistance of its natural enemies, aided by a trap nop. if proposed i>\ .Mi. Sanborn, who has placed at the writer's d isposal advance sheets of lii^ publication in which this method i- described. Rape, which isof value for hog and sheep pasture. is tli« crop adviy Kale or mustard «*» • R r . pplylng should serve the plant 'l! r|,OM '' Thl8method ^^ ^ the fall when the trap cn>p is J^bage ^ aphis , {Aphis bra :, L.) is cl ly related to, but M"», •!-""<•' fron^the melon aphis. It winters over on .1,, trap '•--.-.■,i vears the writer has^obeerved that th« ,.,,,.,., tin , , ■ , 7, u '" ,,hwtrated '" ^""'" ■•: and the idea of employuTg Hu> ,„...,„> ...at,n,,„ ni :,h,„a,„nil .,„..„. ted to the writer in 19$ UNIVERSITY OF FLORI 16 ■ i ii r*.» ... „ ^jg j "^6 4648 crop and attacks it early in spring, when, umesa me natural enemies cnmc to the fore, it multiplies in great abundance. In the writer's experience .the ladybirds and other enemies soon gain the ascendancy and become so abundant that they are forced to migrate for food. The trap crop will ordinarily remain in condition to sustain aphides and their enemies until melons or other crops susceptible to melon- aphis damage have past the danger stage and are ripening. The farmer may exercise his own judgment in regard to the loca- tion of the trap crop. The writer believes that the greatest advanl would accrue from planting three or more rows of rape or kale on each side and. in the case of fields of more than 4 or 5 acres, by plant- ing additional rows between. Planted on all sides, the trap crop will attract aphides and their enemies from every direction, and this result will he facilitated by permitting the growth of weed- between the rows. In fact, weeds are a desideratum in these operations, since they furnish the best natural hibernating place- for the ladybirds and similar beneficial insects. It is advisable also to place boards, loose bark, or hollow logs about the margins of the fields to secure better facilities for hibernation. A- fast as one crop of rape, or whatever is used, matures, or its growth is stopt by the aphides (a- might sometimes happen), another planting should be made so a- t • > keep a constant supply of cabbage aphides on hand that the natural enemies may not migrate to other quarters. CONCLUSION. Many of the remedies that have been indicated as of service in the control of the melon aphis (with the exception of the last) operate against most other cucurbit insect-, several species of which are usually present. Thus the kerosene emulsion and soap solutions kill young squash hugs and act as deterrents to most other insects, and bisulfid of carbon will kill other soft-bodied insects besides the aphides, while fall plowing and clean cultural methods are valuable in destroy- ing the squash-vine borer. Tobacco fumigation, however, ha- little effect on these other insects as they occur in the field. Approved: James Wilson, S( crt tary of . igriculturi . Washington, I). C, Xoccmbcr /.£, 1906. O