Hopen, Herbert John

English

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^Igijj.630.79 Ii6c 11 no.1051m cop. 5Digitized by tine Internet Arciiivein 2011 witii funding fromUniversity of Illinois Urbana-Champaignhttp://www.archive.org/details/controllingweeds1051hopeCIRCULAR 1051uM^VERSlTY OFILLINOISONTROLUNGWEEDSiatRehDmeGARDENniversity of Illinois at Urbana-ChampaignCollege of AgricultureCooperative Extension ServiceThe following publications contain more de-tailed information on weed control and othergardening subjects. These publications can beobtained from your local extension adviser orfrom the listed source.OFFICE OF AGRICULTURAL PUBLICATIONS, 123MUMFORD HALL, URBANA, ILLINOIS 61801:Prevent 2,4-D Injury to Crop and OrnamentalPlants, Circular 808Lawn Weeds: Identification and Control,Circular 873IlUnois Vegetable Garden Guide, Circular 882Soil Disinfection, Circular 893Insecticide Recommendations for the Home-owner, Circular 900 (revised annually)Herbicide Guide for Commercial VegetableGrowers, Circular 907 (revised annually)Growing Small Fruits in the Home Garden,Circular 935Growing Tomatoes at Home, Circular 981Home Orchard Pest Control, Circular 1001Mulching Vegetables, Circular 1009OFFICE OF INFORMATION, EXTENSION SERVICE,U.S. DEPARTMENT OF AGRICULTURE, WASHING-TON, D.C. 20250:Mulches for Your Garden, USDA Home andGarden Bulletin 185Selected Weeds of the United States, Agricul-ture Handbook 366 ($4.00)DEPARTMENT OF HORTICULTURE, 124 MUMFORDHALL, URBANA, ILLINOIS 61801 :Herbicides for Commercial Fruit Crops, H-659(revised annually)This circular was prepared by H. J. Hopen, extension hor-ticulturist, University of Illinois at Urbana-Champaign. Itreplaces VG-4, "Weed Control in the Vegetable Garden."A weed is a plant growing where it is notwanted. Weeds compete with desirable plantsfor water, soil nutrients, sunlight, and gaseouscomponents of the air needed for growth. Manyweeds also harbor diseases and insects that mayattack plants around the home.Three general methods of weed control can beused in the home garden : ( 1 ) cultivation andmechanical removal ( hoeing, pulling, etc. ) ; ( 2)mulching (smothering of weeds) ; and (3) herbi-cides (weedkillers).CULTIVATION AND MECHANICAL REMOVALCultivation and mechanical removal is thesafest and most common method for controllingweeds in small home gardens. Since only thoseweeds that are actually present can be controlled,the process must be repeated several timesthroughout the growing season. It may be diffi-cult to control weeds adequately during vacationsor busy work periods with this method.Hand-hoeing is the most common method for con-trolling weeds in small home gardens.Weeds should be shaved off with a sharp hoewhile gently breaking up the crust. Deep tillagecauses severe injury to many shallow-rootedplants and helps place a fresh supply of weedseeds in position to germinate. Keeping equip-ment sharp and in good condition will help re-duce injury to desirable plants. Hoe carefullyaround your plants and hand pull weeds close tothe plants.Weeds can be controlled by wheel and handhoes in smaller areas or by power equipmentsuch as rototillers and garden-type tractors inlarge gardens. This equipment should be setshallow when used in a garden for weed control.MULCHINGMulching controls weeds by preventing lightfrom reaching the weed seedlings. This methodwill control annual weeds — those that ger-minate from seed each year for several weeks.Perennial weeds (those that sprout each yearfrom below-ground plant parts) usually must beremoved by mechanical means.Organic MulchesThe organic materials most frequently usedfor mulching include plant residues such as strawor hay (free of weed seeds) ; crushed corncobs;\arious nut hulls; leaf and grass composts; peat;wood products such as sawdust, wood chips,shredded bark, and shavings; and well-rottedanimal manures. To function as an effectivemulch, these materials should be applied at adepth of about 4 to 6 inches.Natural mulch materials may require consid-erable hand labor for application. Most organicmaterials are bulky and must be hauled to theplace of use. This is not a serious problem forsmall gardens.Organic mulches return organic matter andsome plant nutrients to the soil and improve soiltilth as they decompose. Added benefits are pre-vention of soil compaction, conservation of soilmoisture, erosion control on slopes, cooler sum-mer soil temperatures, and the added attractive-ness of the garden. Mulches such as coloredstones and decorative l)arks are available forflower and ornamental plantings.When organic materials are used, you mayneed to add nitrogen fertilizer to prevent a de-ficiency of nitrogen in the mulched crop. Withlegume mulches (alfalfa or clover), however,excess nitrogen is released during decomposition.NITROGEN REQUIREDORGANIC MULCH FOR DECOMPOSITIONMATERIAL (pounds per ton of mulch)Cocoa pods 6.0Corncobs, ground 22.5Hay, grass 7.6Peanut hulls 8.5Sawdust, fresh 26.0Wheat straw 17.6Synthetic MulchesCommon synthetic mulches include polyethyl-ene, paper, paper-polyethylene combinations,wax-coated papers, and aluminum and steel foils.Polyethylene film is used in a thickness of 1 toIV2 mils (0.001 inch = 1 mil) and a width of3 to 6 feet. Black polyethylene is preferable forthe home vegetable garden because it preventslight from reaching the weed seedlings. It isgenerally not practical to use transparent poly-ethylene because weed problems develop imderthe polyethylene.Press the edges of the mulch down into fur-rows and cover firmly with soil. Do not throwexcess soil on top of the mulch.A push-type, one-wheel cultivator works wellto open and close furrows. The mulch may alsobe installed simply by covering the edges with arake or shovel. It is better to apply synthethicmulches in crop rows rather than attempting toPolyethylene mulches help control weeds and in-crease early spring temperatures in Illinois.cover the entire area. The area between the rowsof polyethylene mulch must be carefully culti-vated and hoed.The advantages of polyethylene mulching in-clude moisture conservation, increased spring soiltemperatures, and keeping edible abovegroundplant portions clean.HERBICIDESIt is not a good practice to use herbicides insmall ornamental and vegetable gardens contain-ing several crop species because different flowers,vegetables, and weeds vary in their tolerance toherbicides. Some herbicides may remain in thesoil longer than one growing season, and may killor injure some species the following year (espe-cially if excessive rates are used ) . Ideally, a spe-cific herbicide should be used for each cropspecies, but most people have small areas ofseveral species in their gardens, and it wouldoften be impractical and expensive to buy theseveral herbicides that would be needed.Application methods must be carefully con-trolled when a herbicide is used on small areas.The tendency is to apply additional amounts ifthe quantity measured out "looks" as if it is notenough. Check rates of material to use and ap-plication techniques on the container label verycarefully. Applications must be accurate and uni-form. Excessive amounts may cause injury to thepresent or subsequent crops.If a gardener is unwilling to remove weeds byhand in the home garden, Dacthal, Amiben, orTrefian can be used on several species. Theseherbicides may not be the most efTective for alarge planting of the individual fruit or vegetablespecies. Herbicides for large plantings of individ-ual species are listed in the commercial growers'recommendations (see Circular 907 or H-659).Left, weeds in large garden controlled with a "gen-eral" herbicide; no herbicide used on right. Generalherbicides must be applied with extreme care.Herbicides may be sold under several tradenames. If you cannot identify the trade nameson the container, look for the common name orchemical name on the label. The trade nameslisted in this circular are for products commonlyused in Illinois. Products of identical contentmarketed under other trade names may beequally acceptable.TRADE COMMONNAME NAME CHEMICAL NAMEDacthal DCPA dimethyl 2,3,5,6-tetrachloroterephthalateTreflan trifluralln a,a,a-trif)uoro-2,6Preen dinitro-N-N-dipropyl-p-toluidineAmiben chloramben 3-amino-2,5-dichloroVegiben benzoic acidWeedoneGardenWeederDowpon dalapon 2,2 dichloropropionic acidDacthalDacthal is a preemergence (before the weedsemerge) herbicide that must be applied to weed-free soil. It controls very small weed seedlingssoon after the weed seeds germinate. The herbi-cide action is most effective if rainfall occurs orthe soil is irrigated within 2 to 3 days after appli-cation of the herbicide.Dacthal is available as a 75 percent wettablepowder that can be used for large garden areasand as a 5 percent granular material for smallerareas. This material can be used for annual grasscontrol in lawns, on a number of species offlowers, and on strawberries, broccoli, brusselssprouts, cauliflower, cabbage, dry and snapbeans, cucumbers, squash, melons, collards, kale,mustard greens, turnips, garlic, onions, potatoes,sweet potatoes, yams, tomatoes, eggplants, andpeppers.Do not use Dacthal on beets, bugle weed,button pink, carnation, geum, germander, me-sembryanthemum, pansy, phlox, sweet william,and telanthera.A one-time application to all species is notalways possible in a garden of flowers or vege-tables because some plants are susceptible toinjury in early-growth stages. It is preferable touse Dacthal at seeding or transplanting time.When this is not possible, the weeds should beremoved and Dacthal applied to prevent furtherweed development. Consult the container labelfor the appropriate application time.Dacthal is effective in controlling annualgrasses that are a problem in the spring. Thosebroadleaf weeds that escape control should bemechanically removed.Dacthal is the best jnulti-purpose herbicide forhome-garden use.TreflanSince Treflan is used in soybean culture inIllinois, it is widely available. It can be purchasedas a liquid with 4 pounds of active ingredient pergallon for large garden areas or as a 1 .47 percentor 5 percent granular for smaller areas.Treflan can be used for weed control in green,lima, and dry beans, broccoli, brussels sprouts,cabbage, cauliflower, carrots, kale, mustardgreens, okra, peppers, tomatoes, and turnipgreens, or in growing apricots, cherries, grapes,peaches, and plums. Established trees, someornamentals, and many established flowers willtolerate Treflan. Do not use on ground covers,sweetcorn, strawberries, bramble fruits, or blue-berries, since injury may result.Treflan must be mixed with or watered intothe soil to prevent loss of the chemical from thesoil surface. A rototiller or similar equipmentshould be used to mix Treflan with the soil to a3- to 4-inch depth. When it is impractical to mixTreflan with the soil mechanically, all germi-nated and growing weeds should be removedand the herbicide carried into the soil throughrainfall or sprinkle irrigation.The amount of Treflan to use is correlatedvery closely with the type of soil. The appropriateamounts are shown on the container label.Treflan is quite effective on annual grasses,but many broadleaf weeds will need to be me-chanically removed.AmibenAmiben is also available to many farmersbecause it is used in soybean culture. It shouldbe applied to the soil surface before weed seedsgerminate. The herbicide action is most effectiveif rainfall occurs or the soil is irrigated 2 to 3days after application of the herbicide.Amiben is available as a liquid with 2 poundsof active ingredient per gallon for large gardenareas and as a 1 .3 percent or 1 percent granularmaterial. It can be used on seeded asparagus,lima beans, green beans, muskmelons, pumpkinsand squash, cucumbers, sweet potatoes, andtransplanted tomatoes and peppers. Do not useon other vegetable or fruit crops.As indicated on the container label, a numberof annual flowers and established shrubs willtolerate Amiben. Amiben controls a wider rangeof annual grass and broadleaf weeds thanDacthal or Trefian, but it is not as effective onpurslane (often a problem in home gardens).Amiben should not be used on gardens inlight sandy soil.Soil SterilantsHerbicides used to eradicate weeds that volun-teer through cracks in sidewalks, patios, drive-ways, or along fences are known as soil sterilants.Do not use these materials where they can pos-sibly be carried by water or wind movement intolawns or gardens. Most grass weeds will be con-trolled with Dowpon, a relatively safe edgingand border control material.If a garden area becomes contaminated witha persistent herbicide or a soil sterilant, thisarea can be decontaminated by applying acti-vated carbon to inactivate the herbicide.PRECAUTIONSGeneralPhenoxy herbicides (2,4-D, 2,4,5-T, and sil-vex) are used for control of broadleaf weeds.10Most flowers, shrubs, small fruits, tree fruits, andvegetables are susceptible to injury by phenoxyherbicides. When applying these materials tograss, be sure that spray, drifting spray, or fumesdo not reach susceptible plants.Use the forms of the phenoxy herbicides( amine and sodium or lithium salts ) that are lessvolatile and do not drift as easily, and applyunder as calm conditions as possible. A sprayerused to apply phenoxy herbicides on grass shouldnot be used to apply other pesticides on gardens.Never use a phenoxy-contaminated sprayer ondesirable broadleaf plants. Phenoxys cannot becleaned out of sprayers thoroughly enough toavoid injury to broadleaf plants. For further pre-cautions, see Circular 808.Disposal of Pesticide Containersand Surplus PesticidesUse pesticides safely -— read the label. If pesti-cides are handled or applied improperly, or ifunused parts are disposed of improperly, theymay be injurious to humans, domestic animals,desirable plants, pollinating insects, and fish orother wildlife, and they may contaminate watersupplies. Use pesticides only when needed andhandle them with care. Follow the directions andheed all precautions on the container labels.Store all pesticides in a cool, dry, locked stor-age area so that they are not accessible to chil-dren, irresponsible persons, and animals. Do notdispose of pesticides through sewage systems.Haul them or have them hauled to a sanitaryland fill for burial.Never place pressure cans on a stove or heateror near any source of heat that might exceed120°F. Store in a cool place— not in the hotsun. Have empty pressure cans hauled away andburied by experienced disposal crews. Do notincinerate.11Urbana, Illinois March, 1972Issued in furtherance of Cooperative Extension Work, Acts ofMay 8 and June 30, 1914, in cooperation with the U.S. Depart-ment of Agriculture. JOHN B. CLAAR, Director, CooperativeExtension Service, University of Illinois at Urbana-Champaign.12M—3-72—20647I

Controlling weeds in the home garden / 1051

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