TOTAL VEGETATION CONTROL

EM 3458 Revised April 1978

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COOPERATIVE EXTENSION SERVICE • COLLEGE OF AGRICULTURE • WASHINGTON STATE UNIVERSITY • PULLMAN In cooperation with the United States Department of Agriculture Issued in furtherance of the Acts of May 8 and June 30, 1914, by the Washington State University Cooperative Extension Service, J. 0. Young, Director •

Assistance from Washington State University is available to all persons, without regard to race, color, or national orzgzn. Trade names have been used to simplify the presentation of information. No endorsement of products is intended. INTRODUCTION

The weed control information presented in this publication includes the research developments as well as the practical experience of the following personnel of Washington State University and the Crops Research Division, Agricultural Research Service, United States Department of Agriculture. Moreover, ,information based on work by IIVeed scientists in other states, where applicable, is used.

Contributor

D . E. Bayer Plant Physiologist Davis Univ. of Calif.

N. R. Benson Soil Scientist, Horticulturist Wenatchee Wash. State Univ.

R. D. Comes Plant Physiologist Prosser Agric. Res . Serv.

P. C. Cr:andall Horticulturist, Superintendent Vancouver Wash . State Univ.

J . H. Dawson Research Agronomist Prosser Agric. Res. Serv.

C. C. Doughty Associate Horticulturist Puyallup ~ash. State Univ.

R. L. Goss Agronomist, Extension Agronomist Puyallup Wash. State Univ.

W. A. Haglund Plant Pathologist Mt. Vernon Wash. State Univ.

L. K. Hiller Assistant Horticulturist Pullman Wash. State Univ.

Richard C. Maxweli Associate Agricultural Pullman Wash. State Univ. Chemicals Scientist

T . J. Muzik Professor, Agronomist Pullman Wash. State Univ.

A. G. Ogg Plant Physiologist Prosser Agric. Res. Serv.

D. V . Peabody Associate Agronomist, Mt. Vernon Wash. State Univ. Extension Weed Scientist

W. C. Robocker Research Agronomist Pullman Agric. Res. Serv.

G. F. Ryan Associate Horticulturist Puyallup Wash. State Univ.

R. D. Schirman Research Agronomist Pullman Agric. Res . Serv.

A . Y. Shawa Assistant Horticulturist, Long Beach Wash. State Univ. Area Extension Agent

D. G. Swan Agronomist, Pullman Wash. State Univ. Extension Weed Scientist

There is no guarantee that use of the information in this publication will give satisfactory weed control and not cause plant injury or soil/plant residue problems. However, the research data upon which the information is based indicates that effective, economical control with no illegal residues may be expected. This, of course, occurs only if directions (in the publication and on the herbicide label) are carefully followed. Information on chemical weed control does not include herbicide uses which are not registered with the EPA or State Department of Agrij::ulture. • Before using any weed control method, know what weed species are to be controlled and their growth habits as related to the desired crop. Thorough knowledge of the problems will help in the selection of a weed control method. Always evaluate whether a cultural, mechanical, chemical, or combination of these methods will give the most effective economical weed control.

CA UT/ON: If the decision is to use a herbicide, read, study, and follow the label. It is estimated that 8 to 12 million development dollars are spent to get the information printed on that label.

Check with the Washington State Department of Agriculture on spray orders for the area where the herbicide is to be used. Some herbicides are restricted in many areas of the state. ii

RECOMMENDATIONS

The term "recommendation" is not used. Instead, the accepted use herbicides are presented first under each crop. This information is derived primarily from tests and use experience in Washington in which there is considerable confidence. Other Registered Herbicides lists those herbicides known to be registered but which are not ready for or never will be in the accepted use category for various reasons.

WETTABLE POWDER FORMULATION PRECAUTIONS

Wettable powder formulation precautions should be observed-wettable powders go into suspension, not solution. Therefore, constant agitation is required to keep the powder in suspension for uniform spraying. Mechanical agitation is preferred over hydraulic agitation. line and nozzle strainers should be at least 50 mesh to permit free passage of the wettable powder spray mixture through the spraying system. Since wettable powders are abrasive, sprayers should be recalibrated frequently to assess their delivery.

REGULATORY INFORMATION

\ Federal and state pesticide regulations change frequently. Growers are advised to check with county agents or pest control consultants f or the latest information before applying any chemical. Growers are also advised to check with their buyers, processors, or packers before applying chemicals. In some cases, buyers and processors will not accept crops treated with certain materials, even though these materials are approved for use by federal and state agencies. •

licensing

Pesticide Dealer. Any individual acting as a pesticide dealer must obtain an annual license from the State Department of Agriculture.

Pesticide Dealer Manager. All licensed pesticide dealer outlets must employ a pesticide dealer manager who has passed an examination given by the State Department of Agriculture. ·

Pest Control Consultant. Any individual who offers recommendations, technical advice, or aid on the use of "highly toxic" or "restricted use" pesticides (those which may be sold only by licensed dealers) or on any other pesticides except those packaged only for home and garden use must pass a qualifying examination given by the State Department of Agriculture and the license must be renewed yearly.

Private Pesticide Applicators. Commercial producers (growers) are not as yet required by federal law to be certified (licensed) by the Washington State Department of Agriculture. But to purchase and apply restricted use pesticides, commercial producers must either be certified (licensed) or obtain a special use permit.

Pesticide Use Permits

State re gu lations restrict the use of some pesticides to commercial producers, commercial applicators, and government agencies and these are only to be sold by lice11sed pesticide dealers. Seventeen of these may be sold only to users who obtain an annual permit.

The purpose of the perm it is to make sure that the most dangerous pesticide~ are sold only to persons experienced in their use and aware of their hazards. lmpro!Jer use can result in revocation of the permit .

Any pesticide dealer authorized by the State Department of Agriculture may issue a permit immediately before a sale. A licensed pesticide applicator does not need to obtain a permit.

Pesticides that require a permit include:

Parathion and methyl parathion-1.1 percent and above Phosdrin Systox (demeton) Tordon-for some uses 2,4-D-all volatile formulations used in eastern Washington

T he regulations spell out the responsibilities of every person who handles these and ether highly toxic pesticides. For example, they ca nnot be t ransported in the same vehicle with food, clothing, or any other material intended for human or animal consumption . The pesticides and their containers cannot be discarded or stored in a manner that injures humans, plant life, crops, livestock, wildlife. or pollinating insects or pollutes any water supply or waterway. They cannot be delivered unless the consignee or his agent is present to accept delivery and signs a delivery slip .

Complete state pesticide laws and regulat ions may be obtained from Pesticide Branch, Washington State Department of Agricult ure, 2015 S. First Street, Yakima, Washington 98903, or from 406 General Administration Building, Olympia, Washington 98504. iii

Tank Mixes

The Environmental Protection Agency has provided the following interpretation (PR Notice 73-1) with respect to tank mixes (combinations of two or more pesticides in the spray tank) and serial application of one pesticide immediately or shortly following the application of another.

"Tank mixes and serial applications may fall into one of several categories:

Category 1. Instructions provided for such use on one or more labels of EPA-registered products.

Category 2. Such use may be covered by an intrastate registration .

Category 3. Various tank mixes and serial applications have been tested and recommended by Agricultural Experiment Stations, State Departments of Agriculture, or are common agricultural practices.

"Tank mixes or serial applications recommended on EPA labels (Category 1) are obviously consistent with the label and do not constitute use inconsistent with such label.

"Intrastate registrations remain valid until replaced by EPA registrations under Section 3 of the amended FIFRA. This will occur generally after October 21, 1974, and be completed by October 1976, under the schedule spelled out in the law'; 9r, by special actions taken by the Administrator in the form of orders bringing products under sole EPA registration at some earlier tjme. This latter action will occur primarily with respect to products containing the same active ingredients and registered intrastate for the same kinds of uses as the Administrator has cancelled or suspended in interstate commerce under the 1947 version of the FIFRA.

"Therefore, tank mixes and serial applications registered by a State (Category 2) will not be deemed uses inconsistent with the label.

" ... tank mixes and serial application in Category 3 will not be deemed use inconsistent with the label if: a) the products in the mix are applied at a dosage rate not to exceed the label instructions for use of any product in the mix used singly for the same set of pests on the same crop; and b) the label on one or more of the products does not explicitly instruc against such mixture.

" It must be recognized under Categories 2 and 3 that EPA has not reviewed any efficacy or human and environmental safety data on the combination of products and the user applies them in this manner at his own risk with respect to effects on crops and application eq uipment, applicator safety, environmental effects, and tolerance preharvest intervals. The policy of deeming such use not inconsistent with the label, must not be construed as EPA approval of the use.

" If adverse effects are observed from any particular tank mix or serial application, EPA may take appropriate action to rule the use of such specific mix or serial application to be inconsistent with label instructions on a case-by-case basis. The Agency will be watchful for any adverse effects that might accrue from any of above methods of application.

"This policy will be in effect until modified by further statements or regulations."

PESTICIDE DISPOSAL SITES

This list was prepared with the assistance of the Washington State Pest Control Consultant's Association and the Washington State Department of Social and Health Services.

Please notify your county agent of changes that come to your attention so that this list may be kept as accurate and up to dat e as possible. Your cooperation will be appreciated.

For those counties where official sites are not yet designated, check with the local county health office, Environmental Health Division, for current advice.

ASOTIN COUNTY CHELAN AND DOUGLAS COUNTY LOCATION : Clarkston landfill LOCATION : •By appointment only 4 miles W. of Clarkston South end of Webb Rd., on Evans Rd. E. Wenatchee CONTACT: Clarkston City Government CONTACT: Dependable Disposal Service 758-5541 390 N. Main St. E. Wenatchee, WA 98801 CLARK COUNTY 884-3555 LOCATION : Vancouver Sanitary Service 9411 N .E. 94th Ave. GARFIELD COUNTY Vancouver, WA 98660 LOCATION : 5 miles N.E. of Pomeroy on CONTACT: Dr. Champagne Bell Plain Road . County Health Department Mon.-Sat. 10-4, Sun . 12-4 (closed Thurs.) CONTACT: Asotin-Garfield Co . San itation Officer Clarkston, WA 99402 iv

GRANT COUNTY SKAGIT COUNTY LOCATION: NE 1/4 of SE 1/4 of LOCATION: New Inman dump Sec 19, T 17, R 27 Sec 21, T 35N REW M Royal Slope- (from Chuckanut Drive at open 24 hours daily Allen go 2 1/2 miles W. CONTACT: Dan Dietrich on Allen West Road and County Solid Waste Coordinator 1/2 mileS.) PERMISSION REQUIRED KITSAP COUNTY CONTACT: Engineers Office (Donald Nelson) LOCATION : All licensed landfill sites Mon.-Fri. 8:30-4:30 (small amounts) 336-6147 or 757-2203 CONTACT: Local health department (20 lb or more) SNOHOMISH COUNTY LOCATION: Warm Beach dump KITTITAS COUNTY on Frank Waters Rd., LOCATION: 11 miles E. of Ellensburg beyond Lake Goodwin on Mundy Rd., 1 mile S. CONTACT: Director, Solid Waste Disposal of 1-90, E. Kittitas 3001 Rockefeller CONTACT: County Engineer Everett, WA 98201 Rm 105, Courthouse 259-9488 Ellensburg, WA 98926 925-5317 SPOKANE COUNTY LOCATION: Indian T rails disposal site LINCOLN COUNTY LOCATION: Harrington landfill Marshall disposal site 2 miles S. on old Odessa Hwy ., cross RR, left Mica disposal site CONTACT: Notify attendant of Odessa landfill pesticides and containers 1/3 mile N. of Odessa on Odessa-Wilbur Hwy. WHA TCOM COUNTY LOCATION : VanZandt dump CONTACT: Whatcom County Engineering Dept. OKANOGAN COUNTY 676-6730 or 384-5482 LOCATION : Okanogan landfill Mon. 12-8, Tues.-Sat. 9-5 YAKIMA COUNTY LOCATION: Terrace Heights site Tonasket landfill 5 miles E. of Yakima Tibbs Refuse Service on Terrace Heights Way 3 1/2 miles N. of Ellisforde Mon.-Fri. 94 Mon.12-8, Tues.-Sat. 9-5 Cheyne disposal site Pateros dump 4 miles N. of Zillah on 2 miles S. on Hwy. 97 Cheyne Rd . open 24 hours daily Fridays only, 124

Twisp landfill Snipes Mountain site Mon.-Sat. 104 South end of Dekker Rd. CONTACT: Notify attendant of between Granger and pesticides and containers Sunnyside CONTACT: All sites REQUIRE PERMIT PIERCE COUNTY from attendant LOCATION: Orchard St., Tacoma

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SAFETY CODE FOR HANDLING PESTICIDES

(Published by the National Agricultural Chemicals Association)

1. Always read the label before using sprays or dusts. Note 7. Wash hands and face and change to clean clothing after warnings and cautions each time before opening the spraying or dusting. Also wash clothing each day before container. reuse.

2. Keep sprays and dusts out of the reach of children, pets, 8. Cover food and water containers when treating around and irresponsible people. They should be stored outside of livestock or pet areas. Do not contaminate fish ponds. the home and away from food and feed. 9. Use separate equipment for applying hormone-type 3. Always store sprays and dusts in original containers and herbicides in order to avoid accidental injury to susceptible keep them tightly closed. Never keep them in anything but plants. the original container. 10. Always dispose of empty containers so they cannot harm 4. Never smoke while spraying or dusting. humans, animals, or valuable plants.

5. Avoid inhaling sprays or dusts. When directed on label, 11. Observe label directions and cautions ' o keep residues on wear protective clothing and masks. edible portions of plants within the lill)its permitted by law.

6. Do not spill sprays or dusts on the skin or clothing. If they 12. If symptoms of illness occur during or shortly after are spilled, remove contaminated clothing immediately and spraying or dusting, call a physician or get the patient to a wash thoroughly. hospital immediately.

Where to Get Information on Pesticide Toxicity, Hazards, Treatment, Blood Cholinesterase Tests, Etc.

This information may be obtained from the Washington State Division of Health Services at the address on the- next page or from the Environmental Protection Agency, Field Studies Section, Tree Fruit Research Center, P.O. Box 219, Wenatchee, Washington 98801. Phone (509) 663-0031, Extension 243 or 244. Information can also be obtained from one of the following Poison Control Centers:

ABERDEEN St. Joseph's Hospital, 1006 North H Street (206) 533-0450 Ext. 277 & 278

OLYMPIA St. Peter Hospital, 413 North Lilly Road (206) 491-0222

RICHLAND Kadlec Hospital, 888 Swift Boulevard (509) 943-1283

SEATTLE Children's Orthopedic Hospital (206) 634-5252 4800Sand PointWay, 1\i.E.

SPOKANE Deaconess Hospital, West 800 5th Avenue (509) 747-1077 or 747-4811

TACOMA Mary Bridge Children's Hospital (206) 272-1281 311 South L Street

VANCOUVER St. Joseph's Hospital, 600 Northeast 92 Avenue (206) 256-2064

YAKIMA Yakima Valley Memorial Hospital (509) 575-1800 2811 Tieton Drive

REPORTING PESTICIDE ACCIDENTS

Prompt investigation of pesticide accidents, misuse, or poisonings by appropriate •state or federal agencies is essential to m1n1m1ze harmful effects, to determine causes and responsibilities, and to reduce the possibility of recurrences. These agencies have trained investigative personnel to handle such problems, but to do their job effectively it is important they be informed as soon as possible after an incident occurs. Otherwise valuable information may be lost, or it may be too late to adequately protect public health or property. vi

Accidents Involving Application

(Drift problems, animal poisoning, plant damage, fish kill, etc.)-notify one of the following:

Washington State Department of Agriculture 406 General Administration Bldg. Olympia, Washington 98504 Phone (206) 753-5062

OR

Washington State Department of Agriculture Pesticide Division 2015 S. First Street Yakima, Washington 98903 Phone (509) 575-2746 (Day or Night)

Accidents Involving Storage or Transportation*

If sign ificant pesticide contamination results from fires, floods, spillage, leakage, etc., notify one of the following:

Washington S'tate Division of Health Services Pesticide Laboratory 1719 Springwater P.O. Box 190 Wenatchee, Washington 98801 Phone (509) 662-8161 (Day) (509) 884-3401 (Night) or (509) 663-3819 (509) 662-5792

Environmental Programs State Health Services Division Olympia, Washington 98504 Phone (206) 753-3468 (Day) (206) 943-0430 (Night) or (206) 943-2124

* Washington State regulations, RCW 70.104, require that emergencies relating to pesticides which represent a hazard to the public must be reported by the person having control of the pesticides involved. The report must be made by telephone or fastest available method to the Department of Social and Health Services represented by the two offices listed above .

• SOIL FUMIGATION

Application Problem and Treatment Rate* Time of Application Remarks/Use Restrictions

Weed seeds, roots, stems, tubers, rhizomes, etc., in vegetable plant beds, orna­ mental plantings, green­ house soils, and turf seed- ings Met ham (Vapam, 124 to 130 Expose to fumigant for Apply to thoroughly cultivated soil, free of • VPM) lb/A five to seven days. clods, and with adequate soil moisture for seed Light soil: aerate 14 to germination. Soil temperature should be between 21 days. Wet, heavy, or 60 to 90 degrees F. at 3-i nch depth. high organic content Method of application: watering can, hose soils: aerate 30 days. proportioner, flood, surface application (followed by immediate incorporation), soil injection (horizontal shank spacing 5 inches, depth 3 to 5 inches). Rates will be determined by soil type, method of application, and degree of weed control desired. · f Aerate soil by shallow cultivation (2 to 3 inches) to prevent soil crusting, and allow vapors to escape. Do not apply in greenhouses with growing plants, within 3 feet of drip line of trees, or in areas underlaid by roots of desirable trees or shrubs. 124 to 130 lb/A is equivalent to 40 to 100 gpa. Refer to label for specific rates, methods of application, and handling precautions.

e Methyl bromide 320 to 860 Expose soil to fumigant Apply to thoroughly cultivated soil, free of lb/A for one to two days. clods with adequate soil moisture for seed Aerate two to three germination. Apply chemical as vapor or with knife days before planting injectors. Cover with plastic tarp unless using the seeds. For transplants, gel formulation. aerate seven to ten Effective for the treatment of greenhouse soils days. in benches and planting flats. Care must be taken because vapors are toxic to living plants. When treating greenhouse soils in flats or benches, care must be taken to prevent liquid methyl bromide from coming in direct contact with soil, unless using a knife or similar injector system. Soil temperature of 60 to 90 degrees F. is ideal for fumigation. Methyl bromide with 2% chloro­ picrin as a warning agent is preferable for use in greenhouses and fields, because the vapors of methyl bromide are odorless and toxic to humans. Refer to label for specific rates, methods of application, and handling precautions.

e Methylisothiocyanate 240 to 480 Expose to fumigant Apply to thoroughly cultivated soil, free of (Vorlex) lb/A four to seven days in clods, and with adequate soil moisture for seed warm soil; one to three germination. Inject fumigant 6 to 8 inches deep weeks in cool soil. ~ith shanks at a horizontal spacing of 8 to 10 Aerate two to four inches. weeks before planting. Time of exposure to fumigant should be increased at low temperature (below 60 degrees F.) and aeration increased if soil temperature remains cool. Do not fumigate if soil temperature at 3-inch depth is over 90 degrees F. Fall application should remain undisturbed until spring. Do not apply in greenhouse with living plants or in areas underlaid by roots of desirable shrubs. Refer to label for specific rates, methods of application, and handling precautions. OTHER REGISTERED HERBICIDES

EDB (Soilbrom-85): Limited experience and field testing in Washington.

*acid equivalent or active ingredient EM 3458- Page 2

TOTAL VEGETATION CONTROL

GENERAL WEED CONTROL Four months to two years-semipermanent soil residuals More than two years-permanent soil residuals Foliar Desiccation Remarks: I. Dinoseb: Apply dinoseb (general) at 1.5 to 1.8 lb in 5 to 30 gal of oil made up to 100 gal with water when weeds are 1. Know the weeds which are to be eradicated. This is young and succulent. important to determine which chemicals to use. 2. Know the area where the chemicals are to be used. Adjacent Remarks: vegetation and terrain are important. 3. Plan a program. No single herbicide or other weed control 1. Spray weed growth to wet. practice will solve all weed problems. 2. Provide agitation to keep emulsion in suspension. NOTE: May be used with straigh t oil as a carrier and only moderate Precautions: agitation is required. 3. This treatment gives only top kill of most perennial weeds; 1. Man, animal, or equipment should not move soil from treated thus repeated treatments are necessary. area. 4. Use the higher rate of oil when grasses are the weed problem. 2. Avoid spray drift during application 5. Dinoseb is toxic-do not get in eyes, on skin, or clothing. 3. Avoid applying sterilants where wind. or water might move Avoid breathing spray mist. the treated so il. i 6. This treatment is nonselective-do not apply to desirable 4. Some herbicides vaporize easily. Reduce hazard by applying vegetation. at lower temperatures and use low volatile formulation. 5. Do not apply where roots of desirable vegetation may extend II. Paraquat: Apply paraquat (Paraquat CL) at 0.5 to 1 lb/A into treated area. when weeds are young and succulent. 6. Some herbicides have a human poisoning factor. Avoid applying thes.e to vegetation or fruit that might be eaten. Remarks: AMIZINE 1. Use 0.5% of a nonionic brand surfactant suggested by the manufacturer. Use enough water to obtain thorough coverage Type of Weeds Controlled: Weed control is similar to simazine. of the weeds. This material is a mixture of simazine and amitrole. The amitrole 2. This treatment gives only top kill of most perennial weeds; causes more rapid weed kill, particularly if dry weather follows thus repeated treatments are necessary. treatment. It also kills certain simazine-resistant perennials, such 3. Do not use around homes or other areas contacted by as Canada thistle, horsetail rush, etc. children or pets. 4. Do not breathe spray mist. Time of Application: Same as for simazine. Treatment can be 5. Do not let spray come in contact with skin or clothing. made somewhat later than for simazine alone. 6 . This m aterial is nonselective-do not apply to desirable vegetation. Rate of Chemical to Use: Apply rates of 20 lb/A on areas of mixed vegetation treated for the first time, where more than one Nonselective, Nonresidual growing season of control is desired. For re-treatment or single season control, rates of 15 to 20 lb/A should be used. Use the I. Glyphosate: Apply glyphosate (Roundup) at 0.75 to 1 lb/A higher rate when perennials are present. For maintenance for annual weeds. Apply 1.5 to 3 lb/A for perennial weeds treatments use 10 to 151b/A annually. (all rates are acid equivalent). Remarks: This material can cause drift injury to nearby sensitive Remarks: crops.

1. Use 20 to 30 gpa of water carrier and spray for complete ATLACIDE AND ATLACIDE-2,4-D coverage. 2. Rainf all occurring within six hours after application may Type of Weeds Controlled: These materials are similar to sodium reduce effectiveness. chlorate and when combined with 2,4-D are designed to increase 3. Established perennials may require re-treatment. the efficiency of sodium chlorate on deep-rooted, perennial, 4. Avoid contact with desired vegetation. broadleaf weeds, such as Canada thistle and field bindweed. 5. Glyphosat e is highly translocated and has little or no soil activity. Time of Appli~ation: Application should be made at the same 6. Do not use glyphosate in galvanized or mild steel tanks. time as recommended for sodium chlorate when used alone.

TOTAL VEGETATION CONTROL* Rate of Chemical to Use: The rates of application should be the same or slightly higher than those recommended for sodium Total vegetation control (soil residuals) designates a process chlorate when used alone. where the addition of chemi.cals renders the soil unfit for plant growth. Weed control soil residuals do not kill all animal and Remarks: The same precautions suggested for sodium chlorate microbiological life in the soil as does a plant pathologist's should be observed in the use of Atlacide or the Atlacide-2,4-D soil sterilization. combination even though these materials are less of a fire hazard.

Soil residuals are classed as follows: *Acknowledgement is made to the weed scientists at 0 reg on V egetation control for- State University for permission to use the information in this section. Forty-eight hours-no residual toxicity Four months or less-temporary soil residuals EM 3458- Page 3

ATRAZINE (AAtrex) BROMACIL PLUS DIURON (Krovar II)

Type of Weeds Controlled: Atrazine is highly effective against a Type of Weeds Controlled: This material is a very broad wide variety of both perennial and annual broadleaf species. It is spectrum, soil-residual sterilant that kills most annual and more water soluble than simazine and has some activity through perennial grass and broadleaf species. foliage absorption. There are fewer weed species with resistance to atrazine compared with simazine. It kills most grasses readily. Time of Application: East of the Cascade Mountains, Krovar II can be used throughout the ra iny season. For best results, do not Time of Application: East of the Cascade Mountains, atrazine apply until after the first rain in the fall. Rainfall is necessary should be applied in the fall or early winter. West of the following application for weed control. mountains, applications should be made in March or April. In western Wash ington, treatment should be made in March or Rate of Chemical to Use: Apply 16 to 32 lb/ A (active early April. ingredient) in 40 to 100 gpa of water. Lighter rates may be used for re-treatment or on annual vegetation in lower rainfall areas as Rate of Chemical to Use: Apply at rates of 4 to 20 lb/A (active indicated for simazine. Use lighter rate east of the Cascade ingredient). Use the higher rate where deep-rooted, hard-to-kill Mountains. perennial weeds are dominant. Reduced rates may be used for maintenance re-treatment as needed. Remarks: Atrazine is shorter residual than simazine, especially under higher rainfall conditions. Remarks:

BENZABOR 1. This material has long soil-residual effects. 2. Since this chemical can damage trees or other plants, it Type of Weeds Controlled: Similar to TBA. Especially effective should not be used in areas where the roots of desired on field bindweed, Russian knapweed, and Canada thistle. vegetation may extend.

Time of Application: Apply during the spring in western CHLOREA Washington, or whenever weed patches are evident in eastern Washington. Type of Weeds Controlled: This chemical is a highly effective material for the elimination of annual grass and broadleaf weeds Rate of Chemical to Use: Use 1 to 1.5 lb per square rod. This is a and deep-rooted perennials of both the grass and broadleaf granular formulation for spreading dry by hand or spreader. types. This is an excellent, general purpose, soil sterilant for the control of all vegetation. Remarks: Benzabor is a combination of TBA and borate. It is not effective as a general soil sterilant and should be used only as Time of Application: Application in eastern Washington shoulo a spot treatment on perennials. be made during the fall. In areas west of the Cascade Mountains, application should be made in late March or early April.

BROMACIL (Hyvar X) Rate of Chemical to Use: Chlorea 125 (1.25% monuron) should be applied at the rate of 6 to 9 lb per square rod for the control Type of Weeds Controlled: This material is a very broad of mixed vegetation. If the area has been previously treated to spectrum, soil-residual sterilant that kills most annual and control deep-rooted perennials, a rate of 3 lb per square rod is perennial grass and broadleaf species. Brush and brambles show adequate for maintenance. some resistance. Chlorea 3 (contains 3% monuron for use as spray or dry) and Time of Application: Apply in the fall or winter under Chlorea granular (3% monuron) may be used at half the rate conditions east of the Cascade Mountains. In western indicated for Chlorea 125. Washington, treatment should be made in March or early April. Remarks: Rate of Chemical to Use: Apply at rates of 8 to 16 lb/A (active ingredient). Use the higher rate where deep-rooted, hard-to-kill 1. Chlorea is a combination of sodium chlorate, borate, and perennial weeds are dominant. Reduced rates may be used for monuron. It combines the properties of these three re-treatment as needed. Apply in 40 to 100 gpa of water in a chemicals. This makes it one of the .best sterilants for the sprayer using mechanical agitation. control of both perennial and annual weeds. 2. It is effectiv~ for two or more seasons in areas of low rainfall, Remarks: such as east of the Cascade Mountain range. It will normally give control for one season under western Washington 1. Soil-residual life appears to be equal or superior to diuron, conditions, although control is often obtained the second monuron, simazine, or atrazine. season. 2. Since this chemical can damage trees or other desirable 3. Do not apply this material near the root zone of desirable vegetation, it should not be used in the vicinity of plants. ornamentals. Walnuts are particularly sensitive. 4. Observe precautions listed for monuron. 3. Application on wet soil where heavy rainfall may occur after treatment may reduce effectiveness. EM 3458- Page 4

MONOBORCHLORATE-GRANULAR 2. This material is toxic to livestock and is qften readily consumed because of its salty taste. It is particularly Type of Weeds Controlled: Same weed types as controlled with appealing to livestock that have been without salt. Care sodium chlorate and polybor chlorate. Nonselective weed should be exercised not to let livestock come in contact with control. treated areas until rainfall has leached the chemical into the soil. Time of Application: Needs moisture to leach chemical into root 3. Sodium chlorate is not effective in western Washington as a area of plants to be controlled. sterilant during the winter. It will give control of vegetation through the summer months if applied in the late spring. It is Rate of Chemical to Use: Apply 1 to 4 lb per 100 sq ft. Heavier least effective for the control of grasses. rates for deep-rooted perennial plant control. 4. Do not treat near root zones of desirable plants.

Remarks: Monobor chlorate can be applied as dry granules or as DIURON (Karmex) a spray. Water is needed to leach material into the soil when used under blacktop or similar paving material. Read the label for Type of Weeds Controlled: This material controls about the details. same species of weeds as monuron. It is slightly less effective on deep-rooted perennials due to its lower water solubility. POLYBOR CHLORATE Time of Application: Diuron should be useq in areas east of the Type of Weeds Controlled: The types of weeds controlled with Cascade Mountains in the fall, because conSiderable moisture is polybor chlorate are similar to those controlled by sodium required to carry it into the root zone of weeds. This material is chlorate used alone. not normally recommended east of the Cascade Mountain range for sterilant purposes, because of its low water solubility. Time of Application: Time of application should be the same as Monuron gives about the same weed control and is more for sodium chlorate. efficient in areas of low ra inf all. In areas west of the Cascade Mountains, diuron is recommended for general soil sterilization. Rate of Chemical to Use: Polybor chlorate should be applied at It is most efficient when applied in late winter or early spring. the rate of 8 to 10 lb per square rod. Application may be made Fall applications are effective, but do not last as long. either in water or spread dry. Rate of Chemical to Use: Diuron is used at the same rates as Remarks: monuron. Application rates should be 32 lb/A (active ingredient) where application is made to areas not previously treated for t he 1. Polybor chlorate is a combination of boron and sodium control of perennials, and for general vegetation control. chlorate. The boron acts as a fire retardant and overcomes Maintenance application on areas previously treated with soil most of the fire hazards inherent in sodium chlorate. sterilants should be made at the rate of 8 to 16 lb/A. 2. The material has a toxicity t,o livestock similar to that of sodium chlorate, so the same precautions should be observed. This material should be applied in water at volumes of 40 to 100 gpa of water in a sprayer wit h mechanical ag itation. SODiUM CHLORATE Remarks: This material has long soil-residual effects under Type of Weeds Controlled: Sodium chlorate, when used alone, is western Washington conditions and will normally give relatively an excellent treatment for the control of many deep-rooted good sterilization for two seasons. Since it is not exceptionally perennial broadleafs such as Canada thistle, bindweed, whitetop, efficient for t he control of certain perennial and biennial weeds, and similar types. It is partially effective on perennial grasses such

T ime of Application: Application of sodium chlorate should be made in areas east of the Cascade Mountains during the fall or FENAC early winter. In areas west of the Cascade Mountains, applications should be made in April or early May. Type of Weeds Controlled: Similar to 2,3,6-TBA but much more insoluble and active through the soil only. Rate of Chemical to Use: Sodium chlorate should be used at the rate o f 4 to 6 lb per square rod for control of perennial weeds. It is effective in•controlling numerous perennial weeds, such as Where the material is being used as a semipermanent soil sterilant field bindweed, Canada thistle, and horsetail rush. It is also for seasonal control of all vegetation, rates of 2 to 3 lb per effective for keeping down Russian thistle, puncturevine, and square rod are adequate. similar annual weed species.

Applications may be made either dry or in water solution. Where Time of Application: Apply in the early spring in western application is made in water solution, at least 1 gal of water Washington. It should be used as a fall treatment only under should be used to dissolve each 2 lb of sodium chlorate. eastern Washington conditions. Chi orates are safer when applied dry rather than as a spray. Rate of Chemical to Use: Use 3 to 4 lb/A for the control of Remarks annual weeds, such as Russian thistle, al ong roadsides and similar areas. It may be added to other so il sterilants. Application on 1. Sodium chlorate creates a fire hazard by increasing the perennials should be from 10 to 20 lb/ A. The higher rates should flammability of any combustible material. Extreme care be used on heavier soil types or under arid conditions. should be exercised when using this material, to avoid catching fire as a result of having sodium chlorate saturated Remarks: This treatment is very slow-acting and often shows clothing. It is also extremely hazardous around vegetation very little injury to perennial weeds the first year of treatment. where there is danger of ignition from cigarettes or other As the material leaches into the root zone, the killing action may sources. be exhibited a year or more after treatment. r' EM 3458 - Page 5

FENAMINE Time of Application: Best results are obtained when natural moisture is available. Fall application in eastern Washington and Type of Weeds Controlled: This product is a combination of spring application in western Washington. ' atrazine, amitrole, and fenac. It is designed for broad spectrum weed control. Rate of Chemical to Use: Apply 300 to 500 lb/A or 1 to 1.25 lb per 100 sq ft. Time of Application: This product contains both foliage- and root-absorbed herbicides; for maximum efficiency, weed species Remarks: Can be used as a dry application or as a spray. Sprays should be actively growing at time of treatment. made by using 1.5 to 2 lb in 1 gal of water.

Rate of Chemical to Use: The primary advantage of this material . PROMETONE (Pramitol) is for residual control of Russian thistle and similar fenac­ sensitive species. Suggested rates of treatment are 9 gal of Type of Weeds Controlled: Ouackgrass and similar species fenamine per acre in 100 gal of water. growing in highly orga or alkaline soils.

Remarks: Fenamine requires considerable rainfall to carry it into Time of Application: At emergence or within two to three the soil where it will kill the germinating seed of weed species months after spring growth commences. such as Russian thistle. Treatment should be made after enough rainfall to germinate winter annual weeds but before the end of Rate of Chemical to Use: 10 to 15 lb/A active ingredient (5 to the winter rainfall period in order to have fenamine carried into 7.5 gaiL - the soil prior to spring weed germination. Remarks: Other broader spectrum sterilants will give more FENAVAR lasting control for a broader range of species when used on mineral soils. Prometone has both foliage absorption and root Type of Weeds Controlled: This product is a combination of action. This material has been one of the more effective bromacil, amitrole, and fenac. It is designed for broad spectrum sterilants for organic and alkaline soils. weed control of both annual and perennial grass and broadleaf weeds. RACK GRANULAR

Time of Application: This product contains both foliage- and Type of Weeds Controlled: Rack is a 10% active formula con­ root-absorbed herbicides. For maximum effectiveness, weeds taining atrazine and fenac in a 2 :1 ratio. The combination of should be young and actively growing at the time of application. these two herbicides in a granular form has resulted in broader This product should have a minimum of 8 to 10 inches of spectrum control of a number of weeds over similar rates of rainfall to get the maximum effectiveness out of the soil fenac or atrazine applied alone. Refer to weed species controlled material. Early winter applications are suggested in eastern under both fenac and atrazine. Washington and March and April applications in west&:-;n Washington. Time of Application: Apply in the fall prior to winter rains.

Rate of Chemical to Use: The rate for effective control varies Rate of Chemical to Use: Use 80 to 160 lb/A of Rack for from 3 to 10 gpa depending on weed species present. The higher season-long control. This is a granular formulation for spreading rate is recommended for longer residual and difficult-to-control dry. perennial weeds. Remarks: This treatment is very slow-acting and will be inactive Remarks: The product has similar moisture requirements as until ample rain has fallen to leach the chemical into the root fenamine. The bromacil component in this product makes it zone. more effective on the perennial grass species and other triazine-resistant weed species. · SIMAZINE (Princep)

FENAVAR GRANULAR Type of Weeds Controlled: This material, when used at sterilant rates, is highly effective for the control of most annual grass and Type of Weeds Controlled: This is a combination of fenac and broadleaf · species. It is also efficient for the control of many bromacil designed to control both annual and perennial grass and perennial grasses and most shallow-rooted, broadleaf perennial broadleaf weeds. species. It is least effective on deep-rooted perennial broadleafs such as Canada thistle, bindweed, St. Johnswort, and others with Time of Application: For maximum activity, this product should similar root systems. have a minimum of 8 to 10 inches of rainfall for adequate soil incorporation . February and March applications are Time of AppliCjtion: Since simazine is highly water insoluble, it recommended in the heavier rainfall areas of western Washington is necessary to make applications in the early fall in areas east of and fall application in eastern Washington. the Cascade Mountains.

Rate of Chemical to Use: Apply 75 to 150 lb/A. Lower rates for In areas west of the Cascade Mountains, applications should be annual weeds; higher rates are suggested for ' the 20 inch plus made in late winter or early spring. The most desirable time to rainfall areas, on hard-to-control perennial weeds, or where make application is in late February or March. Applications longer residual is desired. made after April 1 may not receive enough moisture to carry the materials into·the root zone of the weeds. Remarks: This product is very slow-acting and will require ample rainfall to leach the herbicides into the root zone. Rate of Chemical to Use: Simazine, when applied on areas containing a variety of mixed species and not previously treated HIBOR-C with soil sterilants, should be used at rates of 16 to 32 lb/A (active ingredient). Use the lighter rates east of the Cascade Type. of Weeds Controlled: Perennial weeds on noncropland. Mountains. Where simazine is used on areas that have been EM 3458 - Page 6 I L

J t reated to kill perennials or for maintenance where previous Rate of Chemical to Use : For annual weed contrpl, use 1 lb per sterilant treatments have been used to kill perennial vegetation, 100 sq ft; for perennial weed control, use 3 lb per 100 sq ft. rates of 8 to 16 lb/A (active ingredient) may be used. The lower New Improved Ureabor can be applied dry or as a spray appli­ rates may also be used for initial treatment on annual vegetation cation. in areas with less than 20 inches of annual precipitation. UROX Application of simazine should be made in water at volumes of 40 to 100 gpa in a sprayer with mechanical agitation. Type of Weeds Controlled: This material is very similar to monuron in the weed species controlled. However, there are a Remarks: few more species resistant to this material compared with monuron. 1. In areas west of the Cascade Mountains, 2,4-D at the rate of 4 lb/A should be included with all sim~zine applications to help 1 Time of Application: In areas east of the Cascade Mountain control some of the deep-ro.oted perennial weeds not range, Urox should be used as a fall or early winter application. effectively killed by simazine. 1 It requires some moisture to carry it into the root zone of the 2. This material is a long residual soil sterilant that will give weeds. West of the Cascade Mountains, application should be weed control for at least two seasons. made in late March or early April. 3. Applications of 2,4-D may be necessary for maintenance the second year to keep deep-rooted perennial broadleafs under Rate of Chemical to Use: Urox should be used at the rate o f 150 control. to 200 lb/A of 22% material or twice this ~ mount of 11% formu­ 4. This material is not a fire hazard nor poisonous to livestock. lation on areas that have mixed vegetation and have not been 5. Observe the precautions listed for monuron. previously treated with a soil sterilant. For maintenance treat­ ment on areas where perennial weeds have been removed, or T EBUTHIURON (Spike) where sterilants have previously been applied, rates of 50 to 75 lb/A of the 22% material will suffice. Type of Weeds Controlled: This material is a broad spectrum herbicide f or control of herbaceous and woody plants. It is This product is general ly a granular material and is not water readily absorbed by plant roots. soluble, so it must be spread dry, either by hand or with some type of spreader. Time of Application: Tebuthiuron should be applied before or during the period of active plant growth. Initial contro_l is An oil-soluble form is available and should be used at compar­ enhanced by ra infall. able rates of active ingredient.

Rate of Chemical to Use: Apply at rates of 4 to 16 lb/A (active Remarks: ingredient). Use higher rates for more difficult to control weeds. Reduced rates may be used for re-treatment. 1. Urox is somewhat more sol uble than monuron and will give effective weed control for two seasons in eastern Washington, Remarks: Pellet formulations are suggested for control of but will give control for only one season under western individual woody plants. Washington conditions. 2. The same precautions as for monuron sh ould be observed. NEW IMPROVED UREABOR OTHER HERBICIDE MIXTURES Type of Weeds Controlled: New Improved Ureabor is a general sterilant containing 66.5% borate combinations, 30% sodium Several mixtures are being formulated and sold under various chlorate, and 1.5% bromacil. It controls annual grass, broadleaf brand names. Those listed in this manual represent some of the weeds, and deep-rooted perennial plants. common types sold, but many may have been left out. Most of these products are effective when used according to the label. Time of A pplication: New Improved Ureabor should be applied under eastern Washington conditions in the fall, and under Unless they are formulated for control of specific weeds, they western Washington conditions in March or April. should contain one of the broad spectrum herbicides in the phenyl urea, triazine, or uracil group as the basis of the formulation .

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