L-v'-l ' ^ WILD

Its Characteristics and Control

Agriculture Handbook No. 298

Agricultural Research Service U.S. DEPARTMENT OF AGRICULTURE In Cooperation With Missouri Agricultural Experiment Station CONTENTS

Page Origin and distribution. _ 3 that resemble wild garlic 4 Description and growth habit 5 Classification ^ Structure of the wild garlic 6 Plant types 6 types 7 Reproductive cycles 10 Wild garlic: a pest ^^ Pest in small grains 14 Pest of pastures and hay fields 1^ Pest around homes, gardens, and noncrop areas.. 15 How wild garlic spreads. 1^ Control and eradication 1^ Cultural control 1^ Chemical control 1^ Precautions __ ^1 Parasites and diseases 20 Literature cited 22

Washington, D.C. Issued December 1965

For sale by the Superintendent of Documents, U.S. Government Printing Office Washington, D.C, 20402 - Price 15 cents WILD GARLIC Its Characteristics and Control

By Elroy J. Peters, J. F. Stritzke, and Frank S. Davis, Crops Research Division, Agricultural Research Service ^

Wild garlic {AlUum vineale L.) is a troublesome in the United States. Significant losses result from the "" odor and flavor that wild garlic gives to milk, small grains, and meat products. Other conunon names that have been used for vineale L. are field garlic, meadow garlic, garlic, onion, crow garlic, wild onion, and vineyard garlic (5, 27),^

ORIGIN AND DISTRIBUTION

The geographical origin of wild throughout western and central garlic is diflScult to determine. It where it is found as far probably originated in the area of north as southern Norway, Sweden, the Mediterranean Sea {18), and Finland; and east to the Wild garlic is found in many Dneiper, Crimea, and Transcauca- areas of the world. It has spread sian regions of the U.S.S.R. (Í5, 31), It is rare in Austria ; fairly com- mon in Hungary, Italy, Spain, and Portugal {12) ; and has been re- ^ Dr. Peters and Mr. Stritzke are at the Missouri Agricultural Experiment Sta- ported in North and the tion ; Dr. Davis is at the Texas Agricul- Canary Islands {12), Wild garlic tural Experiment Station. has spread from Europe to Aus- This handbook was prepared in coop- eration with the Field Crops Department, Missouri Agricultural Experiment Sta- tion, and is published with the approval of the director. (Journal Series No. ^ Italic numbers in parentheses refer to 2731.) Literature Cited, p. 22. tralia (2), New Zealand {36}, and garlic head was present for every the United States. Is is particMi- nine heads of wheat {28). larly troublesome in Sweden, Eng- Wild garlic has continued to land, and the United State« (13, 20, spread and now infests a large part 27, 28), of the United States. It grows as Wild garlic was probably intro- far south as Georgia, Mississippi, duced into the United States from and Arkansas ; and as far north as France in the 17th or early pari: of Massachusetts, New York, Ohio, and Michigan {10), It is a serious the 18th century {3,15). After its pest on the eastern seaboard and introduction into the United States, extends west to Kansas and Okla- it became a serious weed problem. homa {30). Wild garlic has been Pipal cited a report showing that as mentioned as the cause of garlic- early as 1754, in Philadelphia, an flavored milk in Wyoming {6). infestation of wild garlic in a Infestations also are present in wheatfield w^as so heavy that one western Oregon and Washington.'^

PLANTS THAT RESEMBLE WILD GARLIC

In the United States, wild garlic appear, and then the plants sometimes grows in association with mature and disappear before warm other bulb formers such as Omitho- weather. Star-of-Bethlehem sel- gahim mnbeJlatum L., AJlhim ole- dom grows over 8 inches tall. It Tdceum L,, A. cernuuinx Roth, A. has flat , which have a white Tïiutahïle Michx., A, canadense L., stripe down their center (fig. 1, A). Hemerocallis fulva L., and Ziga- The leaves arise from the base of denus Nuttallii Gray. the plant. The terms "wild garlic" and Wild garlic can be distinguished "wild onion" are often used inter- from wild onion and star-of-Beth- changeably for many of the bulb lehem by its striate, nearly round formers. In the United States, the hollow leaves (fig. 1, C), which are species most commonly found with attached at the lower half of the wild garlic are wild onion {A, cana- plant. Wild onion and star-of- dense L.) and star-of-Bethlehem Bethlehem have their solid flat {Omithogolum unnbellatuni L.). leaves attached at the base of the The wild onion, like wild garlic, plant. Moreover, wild garlic has begins growth in mid-August or underground hardshell , which early September and matures in late are absent on wild onion and star- May or early June. Wild onion of-Bethlehem. Also, the old bulb grows 1 to 2 feet tall. It has flat coat of wild garlic is thin and mem- leaves (fig. 1, 5), which arise from braneous, but the coat of wild onion the base of the plant. is fibrous matted. Star-of-Bethle- Star-of-Bethlehem often is plant- hem does not have the "onion" odor ed as an ornamental and then of wild garlic or wild onion. spreads to lawns, gardens, yards, and waste places. It begins growth ^ Personal communication from Dr. soon after the ground thaws in Marion Ownbey, Dept. of Botany, Wash. early spring. Small, showy white State Univ. \

Figure I.—Cross sections of blades of star-of-Bethlehem, wild onion, and wild garlic: A, Leaf of star-of-Bethlehem showing white striation at the center of the solid flat leaf; B, flat solid leaf of wild onion; C, round, hollow leaf of wild garlic.

DESCRIPTION AND GROWTH HABIT

Classification be classified as belonging to the Am^aryllidaceae family. Five varieties or forms of Allium, Wild garlic is a bulbous perennial vineale L. have been described in monocot that has classically been in- the United States {15). These are : cluded in the Liliaceae family. {a) forma ty2)icum Beck, with a However, Hutchinson (i^) includes loose umbel containing both aerial Allium in the fam- bulblets and flowers; (6) forma ily. He considers the umbellate comfactum Thuill, with a compact to be of greater taxo- head consisting only of aerial bulb- nomic importance for classification lets, which are greenish or whitish ; (c) forma fuscenscens Ascherson than the character of superior or and Graebner, with a head contain- inferior ovary, wliich is usually ing reddish bulbils; {d) forma used to distinguisli Liliaceae from crinitum Jacob, with bulbils on the Amaryllidaceae. His views have head tipped with long, green, capil- been supported by other workers lary appendages; and (e) forina (5, 26); and at present (1965) it capsidiferum Koch, with a umbel appears that Allium will eventually consisting of flowers only. Three forms of wild garlic have The flowers have a greenish to been identified in England, but purple perianth with lanceolate to their status as varieties has been elliptic segments. The segments questioned by Richens (31). Tran- are obtuse to acutish and about as sitions between forms are often long as the stamens {10). Seeds of noted, and they appear to be de- the scapigerous plant are black, pendent upon Mendel i an allelic flat on one side, and about one- genes {15). Most AlUuni species eighth inch long. have 16 chromosomes, but Allium The nimiber of scapigerous vineaJe L. has 32 chromosomes, a plants in a wild garlic stand varies. number that indicates that A. Under conditions in the British vineale L. is tetraploid {15). Apog- Isles, Richens observed that about amy is a common occurrence in A. 30 percent of the wild garlic popu- vineale. lation consists of scapigerous plants Iltis {15) also observed what he in any one season {31). The rest thought to be genetic differences in of the population was made up of color of aerial bulblets. Seed from nonscapigerous plants (fig. 5), plants with purple bulblets pro- which are shorter and less con- duced plants with purple leaf spicuous than the scapigerous sheaths and seed from plants with plants. green bulblets produced plants with green leaf sheaths.

Structure of the Wild Garlic Plant

Wild garlic looks much like the cultivated onion. Figure 2 shows a clump of wild garlic as seen in spring. The leaves are two-ranked and have sheathing bases. The leaf blades are circular in cross section and hollow. The outer layers of a bulb of a growing wild garlic plant are formed from the sheathing bases of the foliage leaves.

Plant Types

Wild garlic consists of two plant types—scapigerous and nonscapig- erous. The larger, scapigerous Figure 2.—A typical dump of wild garlic in the plant bears a scape, which produces spring, showing growth habit and plants of various sizes. The larger upright plants are aerial bulblets (fig. 3) and some- «capigerous and the smaller plants are non- times flowers (fig. 4). scapigerous. Nonscapigerous plants have slen- clature suggested by Davis and der foliage and fewer leaves, and Peters (7) will be used in this do not produce a scape at the end publication. of the growmg season. Aerial Bulblets Bulb Types As many as 300 aerial bulblets (fig. 6, Ä) may be formed on the Four types of bulbs can be found scape of a scapigerous plant (fig. on wild garlic at the end of a sea- 3). son's growth in late spring. Vari- The bulblets develop within a ous names have been given to the spathe (a large, dry, thin, mem- bulb types. The system of nomen- branous ) at the top of the scape. The spathe contains no green color and it remains closed imtil near maturity in late spring- when it bursts, exposing aerial bulblets and flowers. The aerial bulblet consists of a fleshy, cone-shaped scale containing a growing point at its base. The fleshy scale is a bladeless storage leaf. Surrounding the storage leaf is a protective scale consisting of two or three cell layers. The pro- tective scale is a bladeless leaf in most cases, but it may include a blade, which was referred to by Iltis (15) as an appendage. Iltis (15) describes three forms of aerial bulblets found in Virginia, each form appearing in a separate head. One form of bulblet is whit- ish or yellowish with pointed, greenish, or purple tips that are bent slightly to one side. The sec- ond form is dark purple without appendages. The third form of bulblet has green appendages, which are 2 to 3 inches long. The append- ages, or leaf blades, are usually fully developed within the spathe before it bursts. We have observed appendages on aerial bulblets of wild garlic in Missouri, and the bulblets appear much like bulblets that have germi- nated. However, close observation shows that the appendage is the leaf blade of the outer protective leaf figure 3.- -Scapigerous garlic plant as seen at maturity in June. of the aerial bulblet. v**» ♦ *^^ ^

figun 4.—Umbels on scapes of wild garlic. The umbel on the left is a double umbel (single umbels are more common but plants may have as many as three or four) with aerial bulblels only. Umbel on the right contains bulblets and flowers (less common).

Hardshell Bulbs in cross section (fig. 6, C) and varies from the size of an aerial bulblet up The second most numerous type to that of a soft offset bulb. of bulb is the hardshell bulb (fig. 6, Its structure is similar to that of B). These bulbs are larger than other bulb types. However, it aerial bulblets. Hardshell bulbs sometimes does not have an outer have a single bladeless storage leaf, protective scale and is surrounded which contains a growing point at only by the withered bases of foli- its base. The storage leaf is sur- age leaves. If the outer scale is rounded by a bladeless leaf, which present, it is prolonged into a sharp forms a hard protective shell. terminal point. Hardshell bulbs are formed un- derground in the axils of the outer Soff Offsef Bulb leaves of scapigerous and non- scapigerous plants (fig. 7). The soft offset bulb (fig. 7, Z>) is The hardshell bulb is the only formed undergroimd in the axil of bulb type that is produced by both the innermost leaf of the scapig- the scapigerous and the nonscapig- erous plant. It is similar in struc- erous plants. ture to the other bulb types and usually is the largest of the four Central Bulb types. It is ovate in longitudinal section and has a convex abaxial The central bulb (fig. 7, B) is face and a flat adaxial face, which formed underground by nonscapig- form two distinct ridges where the erous plants and is conspicuous at faces meet (fig. 6, Z>). The ridges the end of a season's growth. It is tend to clasp the sides of the flat- formed aromid the main axis of the tened scape to which they are plant. The central bulb is circular attached. Figure 5.—The nonscapigerous plant as seen af maturity in May. These p|ants usually mature about a month earlier than the scapigerous plants.

784-31» 0^-65-

^ figure 6.—The four bulb types of wild garlic: A, aerial bulblet; B, hardshell bulb; C, central bulb; and D, soft offset bulb.

figure 7.—Left: Longitudinal section of the base of a mature nonscapigerous plant showing lA) the hardshell bulbs and IB) the central bulb. Right: Longitudinal section of the base of a mature scapigerous plant showing the positions of IC) hardshell bulbs and (0) a soft offset bulb.

REPRODUCTIVE CYCLES

Figure 8 shows the reproductive scapigerous plant produces one cen- cycles of wild garlic. tral bulb and sometimes one or two Each type of bulb is capable of hardshell bulbs at maturity. The producing either a scapigerous or scapigerous plant produces both a nonscapigerous plant. The non- seed and aerial bulblets above

10 ground plus one soft offset bulb lowing fall. Seedlings evidently and one to six hardshell bulbs below are uonscapigerous; they develop ground. only one small bulb during the first Production of seed is insignificant year (Í5). in most garlic habitats, except near Wild garlic is usually spread by the southern limits of its range in bulbs rather than by seeds. Aerial the United States, where wild garlic bulblets are more numerous than may produce abundant viable seed other bulb types and, therefore, are {15, 32). In Virginia and Dela- responsible for most of the disper- ware, for example, seed production sion of wild garlic. is common (7,15). When seeds are Aerial bulblets that complete produced they usually are viable growth in spring (May and June) (13,15). Garlic seeds are produced sprout the following fall. Plants in the spring and germinate the fol- developing from aerial bulblets may

Seed Seeds in NONSCAPIGEROUS SCAPIGEROUS certain oreas PLANT PLANT J

20 to 300 aerial bulblets

1 central 1 to 2 1 to 6 I soft bulb hardshell hardshel I offset bulbs bulbs bulb

Figure B.—Relation between bulb types, seed, and plant types in the reproductive cycles of wild garlic. The bulb types will give rise to either a scapigerous or a nonscapigerous plant. These plants grow during the winter and terminate their growth in late spring or early summer. Reproductive structures formed by each type of plant are indicated by arrows from each plant. The number of structures formed on each plant is indicated above the name of the structure. 11 produce scapes {19), but they usu- ally produce nonscapigerous plants, which develop only leaves above ground. The growth of the nonscapiger- ous plant is unique because it ter- minates a season's growth with the formation of one central bulb con- taining a stem apex and sometimes two hardshell bulbs in the axils of the foliage leaves (fig. 7). In Missouri, development of central bulbs first becomes apparent in early winter and development of hard- shell bulbs usually becomes appar- ent in February or March. Figure 9 shows a longitudinal section of the basal portion of a nonscapiger- ous plant as seen in April. Plants developing from aerial bulblets may, in some instances, pro- duce a scape, a soft offset bulb, and hardshell bulbs in one season. Freeman (11), in Kentucky, found that about 33 percent of the plants from aerial bulblets produced scapes the first year. Iltis {16), in Virginia, and Pipal {28), in Indiana, have reported that plants growing from aerial bulblets develop secondary bulblets at the figure 9.—Longitudinal section of the base of a nonscapigerous garlic plant on April 15 base of primary bulblets in the fall, showing the origin of the central bulb lA) and the secondary bulblets grow and the hardshell bulb (B). into separate plants during the winter. A development similar to this was the scapigerous plant is terminated described, but was shown to be with the formation of the spathe growth from two bulblets located on the plant axis and the formation close together within the same of one soft offset bulb in the axil of the innermost foliage leaf (fig. covering leaf (^5). Observation in 10, B). Missouri has shown that frequently Central bulbs and soft offset two bulblets can be found within bulbs start sprouting in early fall. the same covering leaf, giving the These bulbs usually produce large impression that only one bulblet is plants, three-fourths of which pro- present. duce scapes {11)- Figure 10 shows the develop- Central bulbs, soft offset bulbs, mental stage of the scapigerous and aerial bulblets sprout during plant in April. the fall of the year in which they The first bulbs developed in the are formed. But only 25 to 40 per- scapigerous plant are the hardshell cent of the newly formed hardshell bulbs, which form in the axils of bulbs sprout in the fall of their the outer foliage leaves. Growth of first year. The rest of them are

12 figure 10.—Longitudinal section of the base of a scapigerous garlic plant on April 15 showing the origin o< the scape (»), soft offset bulb (B), and hardshell bulbs (C).

controlled by a dormancy mecha- (12) and Mitchell and Sherwood nism that releases them m the fall (^) reported that wild garlic was of subsequent years; some may re- observed emerging from the soil in main dormant for 6 years (33). March and April. Sprouting of hardshell bulbs Freeman (11) found that about starts in mid-August or early Sep- two-thirds of the plants produced tember and nearly ceases by Octo- from hardshell bulbs were nonsca- ber or November. Our studies in pigerous their first year. Missouri showed essentially no The mechanism that determines sprouting after November. How- whether a bulb produces a scapiger- ever, many shoots of sprouted bulbs ous or a nonscapigerous plant is did not emerge from the soil until not known. It is thought that plant spring. Freeman and Kavanaugh type is determined in the early

13 development of the plant {31)^ and inches deep produced scapes. In- that it is associated with food re- creasing the depth of planting to serve in the bulb. Planting of soft 8 inches decreased the percentage offset and central bulbs at depths of scape-producing plants to 52 per- of 4 inches or more reduces the cent. This indicates that food re- number of scapes formed from serves are consumed in emergence, these bulbs {21), All plants from and plants growing from great bulbs planted 2 inches deep pro- depths cannot replenish their food duced scapes, but only 76 percent reserves and produce scapes. of the plants from bulbs planted 4

WILD GARLIC: A PEST

Wild garlic contains allyl sulfide, Aerial bulblets also have a high which has a disagreeable odor and moisture content; when they are imparts a garlicy flavor to agricul- harvested with wheat their moisture tural products tainted with it. adds to the problems of milling the Wild garlic is a poor competitor wheat. and, therefore, generally does not Because wheat kernels and aerial reduce crop yields, but it often per- bulblets are similar in size (fig. 11), sists under row-crop culture. Because wild garlic is drought the fresh bulblets cannot be removed hardy, cold hardy, and tolerant to from the wheat with conventional wet soils, it is found on poorly grain-cleaning equipment. drained land along rivers and A garlicy odor often remains in creeks, as well as on hillsides (25, wheat even when the bulblets are 31), Wild garlic grows in many removed from it. types of soil (Í7), but it is best However, if wheat containing adapted to heavy soil (31). aerial bulblets is stored for 6 months, the bulblets generally will Pest in Small Grains be dry enough to remove with a fanning mill {27). Wild garlic is a pest of fall- Artificial heat also has been used planted crops and is especially with some success for drying bulb- troublesome in small grains, which lets in wheat {28). have a growing season similar to Aerial bulblets float when wheat that of wild garlic. containing them is immersed in Aerial bulblets are present when water, but the wheat then has to be small grains ripen and often are dried. Drying makes the large- harvested with the grain. Harvest- scale use of the immersion technique ing bulblets with wheat that is used of removal impractical {27). for flour is particularly objection- Investigations have been made to able because the bulblets taint the determine the effects of storage on flour. Products made from garlicy germination of wheat containing flour usually have a garlicy flavor. aerial bulblets {16). It was found Wheat is graded garlicy when that germination of wheat is not ad- two or more green aerial bulblets, or versely affected by 7 months of stor- an equivalent of dry or partially age, and that most aerial bulblets dry bulblets, are present in 1,000 are no longer viable after 7 months grams of wheat {35). of storage. In one test, however,

14 some aerial bulblets remained viable in milk for several days after dairy for about 2 years {16). cows were removed from garlic- Attempts to destroy the viability infested pastures. lie also rei)orted of aerial bulblets in wheat by rollinj^ that cattle grazed on wild garlic (crushing) also have been made had garlic-flavored meat. In one {16). One rolling did not afl'ect case, the garlic flavor persisted in sprouting and two rollings only the meat of a cow that had been re- slightly reduced sprouting of aerial moved from a garlic-infested pas- bulblets. ture 10 days before slaughter. Be- cause of garlic infestations, many Pest of Pastures and Hay pastures cannot be used in fall or Fields spring when the garlic is growing. Losses due to wild garlic prob- Pest Around Homes and in ably are greatest in the dairy in- Noncrop Areas dustry. Milk from cows grazed on garlic-infested pastures has off- Wild garlic is unsightly around flavors. A small amount of garlic homes and gardens, on roadsides, in the ration of dairy cows taints and in noncrop areas. dairy products made from their It also gives lawns a disagreeable milk. odor. When heavily infested Arbuckle (.|) stated that garlic lawns are mowed, garlic odor be- was the main cause of off-flavor in comes intense in the general area milk in Maryland. of the lawn, on the mower, and on Many authorities believe that re- the clothes of the person mowing moving cattle from garlic-infested the lawn. pastures for 3 or 4 hours before Populations of wild garlic build milking reduces or eliminates the up in lawns, gardens, and waste flavor in milk {4,6,27). But Pipal areas where they serve as sources of {28) stated that off-flavor persisted infestations to adjoining areas.

Figure M.—A, Grains of wheat. B, Aerial bulblets of wild garlic showing the similarity in size. 15 HOW WILD GARLIC SPREADS

Wild garlic spreads from one also result when infested soil is used place to another mainly through for fill or when building is done on movement of bulblet-infested small a garlic-contaminated site. grains, hay, straw, and manure. Spread of wild garlic seed and But all types of bulbs can be aerial bulblets by wind is of minor spread in soil moved during con- significance. Spread of aerial struction of buildings, ponds, ter- bulblets by water, on the other races, and roads. hand, probably accounts for wide- Garlic infestations in lawns most spread infestations on lands subject often are the result of planting in- to flooding. fested sod, but infestations may

CONTROL AND ERADICATION

Where a few plants of wild gar- {23) evaluated the effects of tillage lic are found, eradication can be ob- and disturbance on wild garlic tained by removing the plants and growing in England. He found all underground bulbs. Because that plants with large bulbs re- garlic bulbs are not killed by up- mained green for 7 weeks when al- rooting, they should be burned or lowed to lie on dry soil exposed to destroyed by some other method that will kill the growing points. high temperatures. The more fre- Where wild garlic infestations quently the plant was disturbed, so are extensive, eradication is diffi- that it broke contact with the soil, cult. Central bulbs, soft offset the more the size of the plant was bulbs, and aerial bulblets will ger- reduced. minate during the fall of the year in Eepeated pulling and replanting which they are formed, and most of growing plants reduced the num- of these plants can be killed by re- ber and size of underground bulbs peated tillage or with several appli- {23). Plants that had originated cations of herbicides. However, from aerial bulblets were stimu- hardshell bulbs that remain dor- lated by one pulling in mid-March mant in the soil for as long as 5 or and increased in size. Uprooting 6 years will continue to reestablish the plants every 2 weeks and imme- the garlic stand (5). diately replanting them over a This means that tillage and her- 4-month period did not kill the bicide treatments would have to be plants, but yields of the under- continued for at least 6 years to ground structures were reduced. eradicate wild garlic. The date on which a disturbance took place influenced the ability of Cultural Control the plant to recover {23). When disturbed on March 15, plants origi- Wild garlic is not easily killed by nating from aerial bulblets re- tillage because it possesses a great mained green for 4 to 5 weeks be- deal of food reserves and is able to fore death; but during this time reestablish itself and resume food reserves were exhausted in the growth after tillage. Lazenby production of new bulbs. Plants 16 disturbed in April or June imme- to translocate material to new bulbs. diately transferred their food re- Deep plowing is only partially effec- serves into a small bulb varying tive because wild garlic can sprout from one-half to three-fourths of and grow from great depths. the size of the original bulblet. Tillage should be done after Soft offset bulbs and central emergence because tillage before bulbs lying on the soil surface for plant emergence merely redistrib- 2 weeks began to shrivel, but some utes bulbs and does nothing toward of these bulbs ^yere still viable after control. This principle was recog- 2 months {23). Hardshell bulbs nized by Tinney (33), who recom- attached to the dried soft offset or mended an annual plowing in central bulbs seemed to persist. November for 6 years followed by Wild garlic bulbs are also able to frequent cultivations in spring. tolerate deep planting; and soft Frequent tillage gradually exhausts offsets and central bulbs often food reserves and if continued long emerge from a depth of 16 inches enough eventually prevents repro- (21). Deep planting, however, re- duction of underground bulbs. duced the number of offsets and An immediate effect of tillage is scapes produced on all bulbs. All to prevent the production of scapes plants from soft offsets and central bearing aerial bulbs. bulbs planted at a depth of 2 inches Deep plowing in fall to com- or less produced scapes, but the per- pletely bury garlic plants followed centage of scapigerous plants that by shallow plowing in the spring were produced decreased as depth has been recommended in Illinois of planting increased. Deep- and Indiana (^7,^5). Clean tillage planted hardshell bulbs had fewer during spring and summer follow- scapes and offsets than shallow- ing plowing was then recommended. planted bulbs, but, in addition, Talbot (32) recommended the length of dormancy of hardshell growing of row crops that could be bulbs increased as the depth of tilled to cut off the garlic plants. planting increased. Nearly all Lazenby (22) showed that time hardshell bulbs left on the soil sur- of tillage for planting cereals had face or planted V2 ^'^^^ deep important effects on garlic. Tillage sprouted after 2 years, but when for spring cereals reduced the num- planted at depths of 8 and 16 ber of plants, the number of hard- inches, half of them remained dor- shells, the number of plants bear- mant (^i). ing scapes, and the size of central Because aerial bulblets are smaller bulbs and soft offset bulbs compared than other bulbs they do not have with tillage for fall-planted grains. the food reserve to emerge from Wild garlic apparently had not great depths. There was a large re- used much of its food reserves at duction in the number and weight the time of fall tillage and was thus of reproductive structures on plants able to recover. developed from aerial bulblets The effects of competition on wild planted at a depth of 4 inches or garlic was studied by Lazenby {19^ more (21). 20). 'Ryegrsiss (LolmmmuUiflorum Experiments show that time of and L. perenne) sown with aerial tillage is important and that tillage bulblets did not affect the establish- should be repeated each time new ment of wild garlic, but competitive growth appears. Eepeated tillage effects of the ryegrass later reduced is necessary to reduce reproduction the growth rate of wild garlic and of bulbs because the wild garlic reduced the weight of its under- plant, even when disturbed, is able ground parts to one-fifth of those

17 grown alone {19), Competition plants to the underground repro- from wheat reduced the size of ductiv^e parts. garlic plants and the weight of Many herbicides have been eval- their underground parts {20). uated for use on wild garlic. Dala- After 7 years of competition from pon (2,2-dichloropropionic acid), Phalaris tuberosa, wild garlic lost TCA (trichloroacetic acid), MCPA its vigor, and the plants grew only (2 - methyl - 4 - chlorophenoxyacetic 3 inches tall and failed to produce acid), amitrole (3-amino-l,2,4-tri- scapes {3), azole), 2,4,5-T (2,4,5-trichlorophe- Frequent mowing, beginning in noxyacetic acid), MH (maleic hy- April, reduced the size of garlic drazide), 2,4-DB [4- (2,4-dichloro- plants and the weight of their un- phenoxy) butyric acid], and dicam- derground parts {2It). Close cut- ba (2-methoxy-3-6-dichlorobenzoic ting was more injurious to garlic acid) have given some control. The than high cutting. Cutting in April suggested rates and effectiveness of was more effective than cutting in herbicides vary from location to lo- June. cation. None of the herbicides available in 1965 will eliminate wild garlic in a single application. Even Chemical Control when tops of garlic plants are killed complettíy, viable hardshell or soft Because of the difficulty of con- offset bulbs often remain in the soil trolling wild garlic with cultural and the garlic stand is not eradi- methods, much attention has been cated {8\. Raleigh {29) reported germination of soft offset bulbs given to the possibility of chemical after 3 successive years of top kill control. Control of wild garlic with 2,4-D. with chemicals has been attempted Davis et al, {9) evaluated a num- for at least 60 years. In the early ber of herbicides and showed that 1900's crankcase oil, carbolic acid, 15 pounds per acre of dalapon, 6 sulfuric acid, fuel oil, orchard heat- pounds per acre of MH, 6 pounds ing oil, sodium chloride, and sodium per acre of amitrole, 4 pounds per aresenite were tried on wild garlic acre of 2,3,6-TBA, and 2 pounds per {28), These materials were un- acre of 2,4-D gave reasonable con- satisfactory because they killed the trol of wild garlic. In this study, associated crop. the ester of 2,4-DB at 4 pounds per Although the effects of tillage acre gave fair control of wild garlic. have not been directly compared Because of low rates of applica- with the effects of modern-day tion needed for control (1 to 2 herbicides, the nature of herbicide pounds per acre) and relatively low activity indicates that herbicides are cost, 2,4-D has been investigated more effective than tillage {9), extensively. The esters of 2,4-D Plants of wild garlic treated with have been more effective than the 2,3,6-TBA (2,3,6-trichlorobenzoic amines, perhaps because the esters acid) or 2,4-D (2,4-dichlorophen- penetrate the wax on wild garlic oxyacetic acid) were killed, and the leaves better than do the amines. hardshell and soft offset bulbs at- Time of herbicide treatment in- tached to the plants usually showed fluences the amount of kill obtained growth modifications and often on wild garlic. More garlic plants were killed {9), Central bulbs were receive treatment when herbicide is more frequently killed than other applied after March 15 than when bulb types. Herbicides evidently applied earlier, because wild garlic were translocated through the begins to emerge in late summer

18 and continues to emerge until ber or early December and repeated March 15 (ü). However, early in Februaiy or March. Sprayings treatments will kill wild garlic will have to be repeated twice plants before new bulbs have been yearly for at least 2 years to give developed in the axils of the lower control and for 5 years or longer to leaves. Formation of new bulbs approach eradication. Where leg- usually becomes apparent sometime umes such as white clover are pres- in February. Well-developed ent in the turf, 2,4-DB may be sub- bulbs often survive when the old stituted for 2,4-D to avoid killing plant to which they are attached the legume. However, 2,4-D is has been killed by herbicides (5). more effective on garlic. Growth modifications of new bulbs If trees or shrubs are present on that occur after 2,4-D or 2,3,6- garlic-infested lawns, herbicides TBA has been applied indicated should be carefully applied so that that these herbicides are trans- they do not come in contact with located from the old plant to the the trees and shrubs. Spraying on new bulbs. Many of these bulbs windy days may cause particles of with growth modifications will spray to drift where it is not grow and reproduce (8). In the wanted. Use of amine or low-vola- case of 2,3,6-TBA, time of applica- tile ester formulations will reduce tion may not be as critical as with the amount of vapors and lessen 2,4-D because 2,3,6-TBA remains the hazard from this source. in the soil for some time and is D i c a m b a and 2,3,6-TBA are probably absorbed over a period of equal to, and often are more effec- time by the root system of the garlic tive than, 2,4-D for controlling- plants; thus plants that are not up wild garlic. Both of these herbi- at the time of a fall application of cides persist in the soil and may 2,3,6-TBA will not receive a foliage leach to the roots of woody orna- application, but the herbicide may mentals and injure or kill them. be absorbed by the roots of the For this reason, dicamba or 2,3,6- garlic plant. TBA should be sprayed only on areas beyond the root zone of Chemical Control ¡n Turf shrubs and trees. These herbicides will also kill legumes. Of the herbicides available in 1965 only 2,4-D, 2,4-DB, 2,3,6- Cheniical Confro/ m Pastures TBA, and dicamba should be con- sidered for use on turf. Dalapon On garlic-infested pastures, low- and TCA are general grass killers volatile esters or amine salts of that will kill turf grasses. Ami- 2,4-D in repeated annual applica- trol discolors grasses, and MH has tions give good control. Time and an inhibitory effect on growth of frequency of 2,4-D application are grasses. similar to the suggestions for turf. Annually repeated applications If the pastures are grazed before of low-volatile esters of 2,4-D or spraying, the garlic tops may be amine salts of 2,4-D at 1 to 2 eaten or damaged so that little or pounds per acre will control wild none of the garlic leaf surface will garlic. The addition of a detergent remain. In these cases, the herbi- or wetting agent to the spray solu- cide will not be received by the tion may improve the wetting of leaves of the garlic plants and garlic leaves and cause more her- translocated in maximum amounts bicide to enter the plants and give for good control. better control. For best results, If legumes are present in a garlic- spraying should be done in Novem- infested pasture, 2,4-DB can be 19 Precautions

Some herbicides are poisonous to skin and change clothing imme- man and animals. Read and follow diately. the directions on all herbicide labels To protect fish and wildlife, do and heed all precautions. not contaminate lakes, streams, or Keep herbicides in closed, well- ponds with herbicide. Do not clean labeled containers in a dry place. spraying equipment or dump excess Store them where they will not con- spray material near such water. taminate food or feed, and where Avoid drift of herbicide sprays children and pets cannot reach to nearby crops and other desirable them. plants. AA^oid repeated or prolonged con- Empty containers of poisonous tact of herbicides with the skin. chemicals are particularly hazard- Avoid spilling herbicides on your ous. Burn empty bags and card- skm, and keep them out of the eyes, board containers in the open or bury nose, and mouth. If any is spilled them. Crush and bury bottles or on skin or clothing, wash it off the cans. substituted for 2,4-D, but the pas- grain yields are reduced if herbi- ture should not be grazed for 30 cides are applied before tillering or days after spraying. 2",4-DB is less when the grain is in the boot stage. effective than 2,4-D. Dicamba and Oats are most susceptible to 2,4-D 2,3,6-TBA are effective for control damage ; barley is moderately toler- of wild garlic in pastures, but pes- ant ; wheat is most tolerant. ticide regulations presently (1965) do not allow the use of these mate- Chemical Control in Waste rials in pastures. Areas Chemical Control in Small- The proper herbicide to use ior Grain Fields wild garlic control in waste areas such as ditchbanks, drainageways, When wild garlic is present in and other noncrop areas is deter- small-grain fields, 2,4-D ester at 1/2 mined by the vegetation that is to or ^ pound per acre will usually be maintained on the site. If prevent grain from being graded grasses are to be maintained on the garlicy. This amount of herbicide site, 2,3,6-TBA or dicamba at 2 to will not effectively kill wild garlic 4 pounds per acre, and 2,4-D ester plants, but the production of aerial at 2 pounds per acre should be con- bulblets will be greatly reduced, sidered. Dicamba and 2,3,6-TBA and the tops of the garlic plants are more effective than 2,4-D, but will be knocked down so that a dicamba may slightly injure grain combine will pass over them grasses. MH or amitrole at 3 to without picking up bulblets. 6 pounds per acre may also be used, Fall-planted small gi^ain will be but slight to moderate injury to injured if herbicide is applied in grass can be expected. If the roots the fall. Herbicides should be ap- of desirable trees or shrubs are plied in the spring after the grain under the area to be treated, di- has tillered but before rapid elon- camba and 2,3,6-TBA should not be gation or jointing of the stems oc- used. The possibility of injury curs. Small grains are injured and from drift of herbicide sprays

20 should be considered when using no grass is present or where retain- 2,1-D. Dahipon at 4 to 8 pounds ing the existing grass is not per acre may be used in areas where important.

PARASITES AND DISEASES

Although Avild garlic is grazed also reports Botrytis present in the readily, it is not seriously injured British Isles. The disease causes by animals. We have found that deterioration and decay of the cen- aerial bulblets on the soil surface or tral and soft offset bulbs, and some- other bulbs growing near the soil times may^ attack immature hard- surface may be eaten by field mice shell bulbs. The hard coat of the when this rodent population is high. hardshell bulb may be a factor in Richens {31 ) reports that bulb tis- preventing invasion of the fungus. sue may be eaten by slugs {Agrio- The disease is distinguished by the llmonx agrestis L.), millipedes, and dark bluish color apparent at the nemat odes ( AnguiUulina dipsaci points of infection. Kuhn). Widespread damage from Richens {31) states that rotting insect pests has not been reported of young bulbs can sometimes be on wild garlic, but Freeman^ re- caused by Pénicillium, and Fnsar- ported damage to soft offset bulbs ium species. Sclerotium cepivorum from the cabbage maggot. Berk also attacks the central and At the Missouri Agricultural Ex- soft offset bulbs of garlic as well as immature hardshells {31), The in- perhnent Station, much damage to fection is characterized by fine white soft offset bulbs was found during mycelium covering the surface of the summer of 196-1: from insects the bulb. Later in the season, black tentatively identified as the cabbage sclerotia fill th^ cavity left by the maggot {Hylemya hrassicae rotting bulbs. Both Botrytis and Bouche) and onion maggot {H. Sclerotium may attack the plant at Antiqua Meigen). the same time. Leaf spot {Hetero- Several fungi have been reported sporvuin allii Ell. and Mart.) has to attack wild garlic. Infestations been reported on wild garlic in of Botrytis allii Munn. have been Delaware, Illinois, and New Jersey observed in Missouri. Richens {31 ) The diseases cause serious damage to garlic plants in small localized ^Personal communication from J. F. Freeman, Kentucky Agricultural Exper- areas, but the diseases do not be- iment Station. come epiphytotic.

POCUOWTNB VMÊMK.

21 LITERATURE CITED

(13) HAKANssoN, SIGURD (1) ALLMOND, C. M. 1957. PROGRESS REFORT ON WILD GAR- 1963. Allium vineale L. AS A WEED. LIC {Alliuni vineale L.) IN- Plant Husbandry. 19. 208 pp. VESTIGATIONS. Northeast Almavist and Wiksells Bok- Weed Ck)ntrol Conf. 11th trycken AB Uppsala. Proc, pp. 173-176. (14) HUTCHINSON, J. 1934. THE FAMILIES OF FLOWERING (2) ANDERSON, R. H. 1930. WILD GARLIC OR CROW GARLIC PLANTS. II. . {Alliuin vineale L.) N. S. (15) ILTIS, H. Wales. Agr. Gaz. 41: 322. 1949. AN IMMIGRANT CONQUERS A CONTINENT : THE STORY 0!F (3) ANGOVE, P. C. 1946. THE A POTENTIAL WILD GARLIC. Scientific WEED MENACE. So. Austral. Monthly. 68: 122-128. Dept. Agr. Jour. 49: 382-390. (16) KROCHMAL, A, (4) ARBUCKLE, W. S. 1960. GERMINATION STUDIES OF 1953. OFF-FLAVORS IN MILK CAN BE AERIAL BULBLETS OF AlUum PREVENTED. Hoard's Dairy- vineale L. and A. canadense man. 98(8) : 381. L. Amer. Midland Naturalist (5) BAILY, L. H. 63: 497-508. 1949. MANUAL OF CULTIVATED (17) LAZENBY, ALEC. PLANTS. Macmillan Co. New 1956. THE ESTABLISHMENT AND York. 1,116 pp., illus. GROWTH OF WILD ONION {Al- (6) BOHMONT, D. W., AND SLATER, I. W. lium vineale L.) FROM AF.RTAL 1954. WEED FLAVORS IN MILK DE- BULBILS. Third British Weed STROY QUALITY. Univ. Wyo. Control Conf. Proc. 1: 211- Agr. Ext. Serv. Cir. 135. 219. 4 pp. (18) (7) DAVIS, F. S., AND PETERS, E. J. 1960. ADAPTABILITY IN AlUum Vine- 1965. NOMENCLATURE AND REPRODUC- ale L. THE BIOLOGY OF . TIVE CYCLES OF WILD GARLIC Blaekwell Scientific Pub. Ox- PLANT AND BULB TYPES. ford, pp. 223-235. Weeds 13(2) : 84-87, (19) (8) ', PETERS, B. J., AND FLETCH- 1961. STUDIES ON Allium vineale ALL, O. H. L. I. THE EFFECTS OF SOILS, 1965. EFFECTS OF 2,4-DICHLOROPHE- FERTILIZERS AND COMPETITION NOXYACETIC ACID AND 2,3,6-TRI- ON ESTABLISHMENT AND CHLOROBENZOIC ACID ON BULBS GROWTH OF PLANTS FROM OF WILD GARLIC. Weeds 13 AERIAL BULBILS. JOUr. Ecol. (3) : 210-214. 49: 519-541, , PETERS, E. J., KLINGMAN, (20) (9) 1961. STUDIES ON Allium vineale L. D. L., and others II. ESTABLISHMENT AND 1962. CHEMICAL CONTROL OF WILD GROWTH IN DIFFERENT INTEN- GARLIC. Weeds 10(4) : 281- SITIES OF COMPETITION. JOUT. 284. Ecol. 49: 543-558, (10) FERNALD, M. L. (21) 1950. GRAY'S MANUAL OF BOTANY. 1962. STUDIES ON Allium vineale L. 8th ed. Amer. Bk. Co, New III. EFFECT OF DEPTH OF York. 1,632 pp., illus. PLANTING. Jour. Ecol, 50: (11) FREEMAN, J. F. 97-109. 1958. YIELD AND SEASONAL ACTIVITY (22) OF THE REPRODUCTIVE BULBS OF 1962. STUDIES ON Allium vineale L. WILD GARLIC (Allium vineole IV. EFFECT OF CULTIVATIONS. L.) IN CENTRAL KENTUCKY. Jour. Ecol. 50: 411^28. (Abstract.) Weed Soc. of (23) Amer. Mtgs., pp. 34^35. 1962. STUDIES ON Allium vineale L. (12) AND KAVANAUGH, J. M, V. EFFECTS OF PLANT DISTURB- 1958. SEASONAL ACTIVITY OF THE ANCE. Jour. Ecol. 50: 429- REPRODUCTIVE BULBS OF WILD 438, GARLIC IN A NATURAL POPULA- (24) TION. 15th Ann. Proc. No. 1963. STUDIES ON Allium vineale L. Cent Weed Control Conf. VI. EFFECTS OF CUTTING. JoUr, p. 18, Ecol, 51: 55-73, 22 (25) MITCHELL, J. S. AND SHERWOOD, (31) RICHENS, R. H. L. V. 1947. BIOLOGICAL FLORA OF THE BRIT- 1961. LIFE CYCLE STUDIES OF WILD ISH ISLES—Allium vhieale L. GARLIC AÄllimn vineale L.). Jour. Ecol. 34: 209-226. (Abstract.) Weed Soc. of (32) TALBOT, M. W. Amer. Mtgs. pp. 33-34. 1929. WILD GARLIC AND ITS CONTROL. (26) MuNz, A. AND KEOK, D. D. U.S. Dept. Agr. Leaflet 43. 1959. A CALIFORNIA FLORA. Univ. 8 pp. Calif. Press. Berkeley and (33) TiNNBY, J. R. Los Angeles. 1,681 pp., illus. 1942. ERADICATION OF WILD . (27) PIEPER, J. J. AND RICKEY, L. F. Jour. Min. Agr. 44: 155-157. 1930. WILD GARLIC CONTROL IN ILLI- (34) UNITED STATè:S AGRICULTURAL RE- NOIS. 111. Agr. Exp. Sta. Cir. SE^ARCH SERVICE. Crop Research 353. 16 pp. Division. (28) PiPAL, F. J. 1960. INDEX OF PLANT DISEASES IN 1914. WILD GARLIC AND ITS ERADICA- THE UNITED STATES. U.S. TION. Ind. Agr. Exp. Sta. Dept. Agr. Hanb. 165. 531 Bui. 176. 43 pp. pp., illus. (29) RALEIGH, S. M. (35) UNITED STATES AGRICULTURAL MAR- 1951. CHEMICAL CONTROL OF WILD KETING SERVICE. Grain Division. GARLIC. Northeast Weed Con- 1964. OFFICIAL GRAIN STANDARDS OF trol Conf. 5th Proc. p. 38. THE UNITED STATES. SRA- (30) REGIONAL TECHNICAL COMMITTEE AMS-177. p. 119. OP PROJECT MC-10. Editorial Subcommittee. (36) WILD, G. W. 1954. WEEDS OF THE NORTH CENTRAL 1928. CROW GARLIC AND ITS CONTROL. STATES. 111. Agr. Exp. Sta. New Zeal. Jour. Agr. 37: Cir. 718. 262 pp., illus. 93-96.

23

U.S. GOVERNMENT PRINTING OFFICE: 1965 O—784-319