Rice-Wheat Consortium for the Indo-Gangetic Plains

Andrew Miller Robin Bellinderand

Herbicide ApplicationUsing a Knapsack Sprayer

Andrew Miller and Robin Bellinder

Facilitation UnitRice-Wheat Consortium for the Indo-Gangetic Plains

CG Block, National Agricultural Science Centre (NASC) Complex,DPS Marg, Pusa Campus, New Delhi 110 012, India

2001

Contents

1. Introduction .. .. .. 1

2. Nozzles .. .. .. 1

3. Multiple nozzle booms .. .. .. 2

4. Calibration .. .. .. 4

5. Pressure regulation .. .. .. 5

6. Shielded spraying .. .. .. 6

7. Mixing .. .. .. 6

8. Cleaning .. .. .. 7

9. Surfactants .. .. .. 7

10. Spray drift .. .. .. 7

11. Pesticide safety .. .. .. 8

References .. .. .. 8

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Acknowledgements

The Rice-Wheat Consortium for the Indo-Gangetic Plains acknowledges its appreciation to Dr. AndrewLanders (Cornell University), Dr. R.K. Malik (Haryana Agricultural University) and Dr. Peter R. Hobbs(CIMMYT) for their assistance in assembling and reviewing the materials for this publication and theworkshops where it will be distributed, and to Mrs. J. Ranjit for having it translated in Nepalese.

This publication has been put together as a supplemental handout for workshops given in India and Nepalin cooperation with Dr. R.K. Malik (HAU), Dr. L.S. Brar (PAU), Mrs. J. Ranjit (NARC), Mr. G. Sah (AIRC),Mr. Gami (Parwanipur Ag. Research Station) and Dr. Peter R. Hobbs (CIMMYT).

The production of this publication has been supported by the National Agricultural Technology Project(NATP), Indian Council of Agricultural Research through its Special Research Sub-project on “Acceleratingthe Adoption of Resource Conservation Technologies (RCT) for Farm-level Impact on Sustainability ofRice-Wheat Systems of the Indo-Gangetic Plains” in the PSR Mode.

Support for the sprayer-technology workshops was given by Herbicide Resistance Action Committee(HRAC), India.

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Authors

A Miller Department of Fruit and Vegetable Science, 134 Plant Science Building, Cornell University,Ithaca, New York, USA.

R Bellinder Department of Fruit and Vegetable Science, 134 Plant Science Building, Cornell University,Ithaca, New York, USA.

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Citation: Miller, A. and Bellinder, R. 2001. Herbicide application using a knapsack sprayer.New Delhi-110 012, India: Rice-Wheat Consortium for the Indo-Gangetic Plains. pp 12

The designations employed and the presentation of the material in this publication do not imply the expression ofthe opinion whatsoever on the part of the Rice-Wheat Consortium for the Indo-Gangetic Plains concerning the legalstatus of any country, territory, city or area, or of its authorities, or concerning the delimitations of its frontiers orboundaries. Where trade names are used this does not constitute endorsement of or discrimination against any productby the Consortium.

The initial support from the Asian Development Bank and InternationalFund for Agricultural Development provided the groundwork forestablishment of the RWC in 1994 and formalizing the collaborationsbetween the NARS, IARCs and ARIs. The NARS-driven strategicecoregional research initiatives with financial support from theGovernments of the Netherlands, Sweden, Switzerland, Australia andthe US Agency for International Development and the World Bankhave grown over the years into a dynamic agenda of resourceconservation technologies appropriate to different transects of theIndo-Gangetic Plains. The on-going successes in scaling-up resourceconservation technologies for enhancing productivity and sustainabilityof the rice-wheat systems are beginning to create a revolution andfavourably benefit large areas and more numbers of farm families.

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The production of this publication has been supported by the National AgriculturalTechnology Project (NATP), Indian Council of Agricultural Research through its SpecialResearch Sub-project on �Accelerating the Adoption of Resource Conservation Technologies(RCT) for Farm-level Impact on Sustainability of Rice-Wheat Systems of the Indo-Gangetic Plains� in the PSR Mode.

Publications of the Rice-Wheat Consortiumfor the Indo-Gangetic Plains

I. Paper Series

1. Long-term Soil Fertility Experiments in Rice-Wheat Cropping Systems: Proceedings of a Workshopedited by I P Abrol, K F Bronson, J M Duxbury and R K Gupta. 1997.

2. Reduced and Zero Tillage Options for the Establishment of Wheat after Rice in South Asia by PeterR. Hobbs, Ghana Shyam Giri and Peter Grace. 1997.

3. Herbicide Resistance - a Major Issue for Sustaining Wheat Productivity in Rice-Wheat CroppingSystems in the Indo-Gangetic Plains edited by R K Malik, G Gill and P R Hobbs. 1998.

4. Nematode Pests in Rice-Wheat-Legume Cropping Systems – Proceedings of a Regional TrainingCourse edited by S B Sharma, C Johansen and S K Midha. 1998.

5. Sustaining Rice-Wheat Production Systems : Socio-economic and Policy Issues edited by PrabhuL Pingali. 1999.

6. Long-term Soil Fertility Experiments in Rice-Wheat Cropping Systems edited by I P Abrol, K FBronson, J M Duxbury and R K Gupta. 2000.

7. Nematode Pests in Rice-Wheat-Legume Cropping Systems : Proceedings of Review and PlanningMeeting and Training Workshop by S B Sharma, Pankaj, S Pande and C Johansen. 2000.

8. Stagnation in the Productivity of Wheat in the Indo-Gangetic Plains : Zero-till-seed-cum-fertilizer Drillas an Integrated Solution by R S Mehla, J K Verma, R K Gupta and P R Hobbs. 2000.

9. Soil and Crop Management Practices for Enhanced Productivity of the Rice-Wheat Cropping Systemin the Sichuan Province of China edited by P R Hobbs and R K Gupta. 2000.

10. Potential Yields of Rice-Wheat System in the Indo-Gangetic Plains of India by P K Aggarwal, K KTalukdar and R K Mall. 2000.

11. Rice-Wheat Cropping Systems of the Indo-Gangetic Plain of India by R S Narang and S M Virmani.2001.

12. Rice-Wheat Cropping System of Nepal by S P Pandey, S Pande, C Johansen and S M Virmani.2001.

13. Baseline Study on Agricultural Mechanization Needs in Nepal by Madan P Pariyar, Khadga B.Shrestha and Nara Hari Dhakal. 2001.

II. Traveling Seminar Report Series

14. Research and Extension Issues for Farm-Level Impact on the Productivity of the Rice-WheatSystems in the Indo-Gangetic Plains of India and Pakistan edited by R K Gupta, P R Hobbs, MSalim, R K Malik, M R Varma, T P Pokharel, T C Thakur and J Tripathi. 2000.

15. Study of Research and Extension Issues in the Sichuan Province of China for Farm-Level Impacton the Productivity of the Rice-Wheat System edited by R K Gupta, P R Hobbs, M Salim, N HChowdhary and S I Bhuiyan. 2000.

III. Miscellaneous

16. RWC-PRISM User Manual for Data Entry & Updating and Focal Point Management, 2001

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1. IntroductionKnapsack sprayers are indispensable agriculturaltools. Understanding how to use them is essentialfor the successful application of agriculturalchemicals, especially selective postemergenceherbicides. Herbicide efficacy and crop tolerancedepend upon inherent species sensitivity to aherbicide and the size of the weed or crop atapplication. With many new herbicides, the ratedifference between effective weed control and croptolerance is small. In order to successfully useherbicides, their application must be accurate anduniform.

Nozzles, spray tips, multiple nozzle booms,pressure regulation and sprayer calibration are theessential components of the spray-applicationtechnology.

2. NozzlesNozzles are comprised of a spray tip, a strainer,and a nozzle body and a cap (Figure 1).

Spray tip is the most important nozzle component.It determines the flow and distribution of the spray.Tips are made in a variety of kinds each designedfor a certain type of spray application.

Flat fan spray tips are designed specifically formultiple nozzle booms (Section 3). The spraypattern is tapered from the center (full flow) to theedges (lighter flow) and is designed to overlap withadjacent nozzles, creating a uniform pattern acrossa spray boom (Figure 2).

Even fan spray tips are designed for single passsprays over crop rows or between rows of vegetable

or plantation crops. The spray pattern is uniform(full flow) from edge to edge. Even fan spray tipsare not made for use on multiple nozzle booms(Figure 2).

Flood (cut) spray tips are designed to have a widespray pattern at low pressure making them popularwith knapsack sprayer operators. They are bestsuited for defoliants and total weed killers and insituations where multiple nozzle booms are notpractical. The spray pattern is tapered from thecenter to the edge but it is not as uniformly taperedas that of the flat fan. The spray is heavy towardthe very edges and coarse throughout the spraypattern. Using this nozzle in a “swinging” patternacross a field will normally result in poor applicationresults. Overlapping by 50 per cent can helpeliminate the inherent unevenness in the spraypattern (Figure 3).

Variable cone spray tips have a cone-shapedspray pattern that is adjustable from a fine mist toa solid stream. The adjustable pattern makesvariable cone spray tips versatile tools. Calibratingthese nozzles is not easy due to the difficulty ofadjusting the tip to the same pattern and flow timeafter time. While not ideal for most applications,they are useful for many insecticide, fungicide andtotal weed killer herbicide sprays (Figure 4).

Figure 1. Nozzle assembly.

Flat fan tip Even fan tip

Figure 2. Spray patterns of flat fan and even fan spray tips.

Figure 3. Flood (Cut) spray tip and spray pattern.

Flood (cut)spray tip

Spray pattern

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Hollow cone spray tips produce a fine spray thatis concentrated on the outside edge of the pattern.The spray approaches the target from differentangles increasing coverage. They are designed forfungicide and insecticide applications whereexcellent coverage is needed. The fine spray patternincreases spray drift potential (Figure 5).

Strainers are fine mesh screens that are insertedinto the nozzle body to filter out particles that canclog the spray tip. Strainers are needed for all spraysolutions mixed up with any type of unfiltered water.Even with strainers in place, nozzle tips can becomeclogged. The best way to clean a clogged tip is toremove it from the nozzle body and rinse it in water.If necessary, a soft brush can be used to helpremove particles. Never use a wire, or any hardtool, to clean a spray tip. This will damage the tip.

Worn out and damaged spray tips lose theability to properly regulate the spray pattern and

should not be used. Worn out tips have a greateroutput with the spray concentrated beneath the tip.Damaged spray tips have an erratic output, over-applying and under-applying (Figure 6). Inspectspray tips and spray patterns at regular intervalsreplacing worn out and damaged tips as needed.

3. Multiple nozzle booms

Multiple nozzles are used to increase applicationefficiency and accuracy (Figure 7). Hand boomscan be purchased from a manufacturer orconstructed from any type of plumbing materialsuitable in strength and weight. Aluminum, steel,brass, copper and plastic tubing with brass orplastic fittings have all been used to create boomsprayers.

Flat fan nozzles are spaced on the boom sothat the spray pattern of adjacent spray tips willoverlap by 30% (Figure 8). Spacing will depend onboom height and the angle rating of the spray tips.Larger angle tips have a wider spray pattern andare spaced further apart on the boom when theheight remains constant.

Variable conespray tip

Spray pattern

Figure 4. Variable cone spray tip and spray pattern.

Figure 5. Hollow cone spray tip and spray pattern.

New Worn out Damaged

Figure 6. Output patterns of new, worn out and damaged spray tips.

Figure 7. Four nozzle boom attached to a knapsack sprayer.

30% 40% 30%

Figure 8. 30% overlap of adjacent spray patterns. Center 40%of each pattern does not overlap.

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Spraying with a multiple nozzle boom

When a single flat fan nozzle is sprayed, only themiddle third of the spray pattern of the nozzle canbe considered to have a full rate application (Figure9). When two or more are spaced to overlap by30%, the tapered pattern of adjacent nozzles createsa uniform spray distribution. On the boom ends,where there is no adjacent nozzle, the outsideedges of the spray will still have a light application.

The two most common spray tip angles are 80°and 110°. This refers to the size of the angle of thespray pattern from side to side (Figure 10).

In general, 80º nozzles will be spaced 50 cmapart on the boom and 110º nozzles will be spacedat 75 cm when the boom is used 50 cm above thetarget.

Adjacent passes of multiple nozzle boomsmust be overlapped by approximately 30%, similarto the way adjacent nozzles on the same boomshould overlap. This will create a uniform applicationrate from one pass to the next (Figure 11).

Height is important when using a boom sprayer.If the boom is too low to the ground, the nozzleswill not overlap resulting in bands of concentratedspray with little or no spray in between (Figure 12).Boom height depends on nozzle spacing andnozzle angle ratings (Figure 13). Variable pressure,speed and mixing can cause the same applicationproblems with a multiple nozzle boom as they willwith a single nozzle lance.

Nozzle angle 50 cm spacing 75 cm spacing

65º 55-60 cm 83-89 cm

80º 43-48 cm 66-71 cm

110º 41-46 cm 50-55 cm

Figure 13. Minimum spray heights at two nozzle spacings

To determine the spray swath of multiple nozzlebooms, multiply the nozzle spacing by the numberof nozzles. When the boom is used at the appropriateheight, this will give the spray swath width for thatboom when multiple passes are made across afield. For example: 4 nozzles x 50 cm spacing = 200cm swath width.

Spray applications

Herbicide applications need to be applied uniformly.Areas of over- or under-application will result inundesired application results. Potential problemsinclude crop injury, lack of weed control and withresidual herbicides, rotational crop injury.

Herbicide applications can be made using asingle nozzle lance. However, spraying a straightswath with appropriate overlapping is extremelydifficult and time consuming. If the single nozzlelance is swung from side to side while walking, the

Figure 9. Effective spray swath of different booms.

80° 110°

Figure 10. 80° and 110° spray angles.

Figure 11. Uniform application between passes.

Figure 12. Strips from a boom being too low.

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resulting application will have large areas of under-and over-application (Figure 14). Variable pressure,inconsistent speed and poor mixing in the tank canall contribute to non-uniform applications.

Using a boom sprayer, compared to swinginga single flood jet nozzle, will increase the uniformityof spray applications. The width of a pass may besmaller using a three or four nozzle boom, but eachpass will have very uniform herbicide distribution.Spray swaths of three meters or more can beobtained by fitting a knapsack with the appropriatenozzles and adjusting the spray pressure of thesystem to provide adequate output.

4. Calibration

Calibration is necessary in order to achieve accurateand uniform applications. Calibration is simplydetermining sprayer output for a known area.Speed, nozzle capacity and pressure influencesprayer calibration.

Speed is inversely proportional to spray applicationwhen boom output is kept constant. As youwalk faster, less spray is applied to a given area(Figure 15).

Nozzle capacity is a manufacturer’s rating that tellswhat output a nozzle will have at a given pressure.At constant pressure and speed, nozzle capacity isdirectly proportional to sprayer output. Outputbecomes greater as nozzle capacity increases(Figure 16). When multiple nozzle booms are usedon knapsack sprayers it may be necessary to keepthe nozzle capacity ratings low to avoid exceedingthe output capacity of the knapsack pump. Typicalnozzle sizes are 700, 800 or 900 ml/minute. Smallernozzle sizes are manufactured by some companiesbut may not be universally available. A 1000 ml/minute nozzle will have twice the output as a 500ml/minute nozzle at the same pressure. The anglerating of a spray tip is not related to output.

Nozzle Size* Pressure Flow Rate(80º and 110º) (PSI) (BAR) (gpm) (ml/min)

01 30 2.0 0.09 340

40 2.8 0.10 380

50 3.5 0.11 415

02 30 2.0 0.17 640

40 2.8 0.20 760

50 3.5 0.22 830

03 30 2.0 0.26 985

40 2.8 0.30 1135

50 3.5 0.34 1290

Figure 16. Selected TeeJet® flat fan nozzle sizes (*measure in10ths of gallons) and flow rates at various pressures.

Pressure. As pressure increases, sprayer outputincreases. However, this relationship is not direct.Pressure must increase four times in order todouble nozzle output (Figure 17).

Pressure Output per Minute

1 Bar (15 PSI) 1 liter

4 Bar (60 PSI) 2 liter

Figure 17. Pressure and output of a nozzle in one minute withan output rating of 1 liter per minute at 1 BAR.

Variable pressure will cause variable output.Pressure may also affect the spray angle of differentnozzles. The nozzle angle rating is for a specific

Figure 14. Typical spray distribution when an application is madeby swinging a single nozzle lance. Dark areas show over-application and light areas show under-application.

Figure 15. Effect of speed on spray application.

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pressure. The spray angle of a nozzle will decreasewhen pressure drops below the recommendedminimum pressure for that nozzle (Figure 18). Lowpressure nozzles (nozzles that have spray anglesmaintained at low pressures) are manufactured.However, they may not be universally available.

Calibrating a multiple nozzle boom

Calibration is done to determine sprayer output fora given area (i.e. liters per hectare or gallons peracre). The simplest way to calibrate is to measurethe output against a known area (Figure 19).

In this example, a two nozzle boom with 80°nozzles spaced 50 cm apart will be used. An areaof 100 square meters (1/100th of a hectare) will besprayed using a tank filled with a known quantityof water (4 liters). When calibrating, operate thesprayer like it will be done in the field. Walk at acomfortable pace and pump the sprayer in aconsistent manner.

This sprayer has been found to have an outputof 180 liters / hectare. This is only true for the speedand pressure that were used when it was calibrated.

Determining the amount of herbicide to use

Once the sprayer output per area is known, theapplicator can begin to prepare to spray a field.

With a sprayer output of 180 liters/hectare anda herbicide rate of 100 grams/hectare thecalculations for spraying a one hectare field wouldbe:

Put 100 grams of the herbicide into 12 liters ofwater and mix well. Pour one liter into each tank,fill with water, mix and spray at the same speedused for calibration. With this boom sprayer, straightpasses will be made each meter across the field.

5. Pressure regulationMaintaining a constant pressure can be very difficultwith a knapsack sprayer. Without pressureregulation, pressure will tend to fluctuate betweenthe down stroke of the pump and the upstroke -high on the down stroke and low on the upstroke.It will also tend to fluctuate as a person sprayingbecomes tired and finds it more difficult to maintainthe initial pressure.

While it is possible to make adequate herbicideapplications without a pressure regulator, a regulatorwill make sprays simpler and more accurate. Mostknapsack sprayers do not come equipped with apressure regulator. A traditional regulator may befar too expensive to justify purchase. Severalcompanies are now manufacturing regulator valvesthat are intended specifically for knapsack sprayers(Figure 20). They are durable, accurate and relativelyinexpensive.

Automatic pressure relief valves are attachedto a lance or boom line, usually directly before thenozzle. They do not open until their rated pressure

Figure 18. 80º spray tip at 1 BAR and 2 BAR pressure.

Spray swath 1 meter wide

25 meters

(Cross the area up to four times for 100 meters × 1 meter)

Calibration : Used 1.8 liters to cover100 square meters or 1/100th of ahectare. Multiply 1.8 liter by 100 tofind 180 liter/ha sprayer output.

Initial volumein spray tank

End volume inspray tank

4Liter 2.2

Liter

Figure 19. Calibration.

180 liters / ha x 1 ha = 180 liters180 liters / 15 liter per tank = 12 tanks(Spray tank capacity of 15 liters)

Wheat field size:1 hectare

First pass, 1 meter wide. Direction of travel :

Second pass 1 meter wide two meters now sprayed)

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is reached. Once the valve does open, excesspressure is managed down to the preset pressure.If pressure should drop below the preset pressure,the valve will shut off flow to the nozzle. Constantpressure regulator valves will help eliminate incorrectapplication caused by pressure being too high(over-spraying, crop injury) or too low (no weedcontrol) (Figures 21 and 22). When these valvesare correctly matched with nozzles, they will ensureproper nozzle performance. Pressure regulation, ofsome type, is critical in calibrating a sprayer.

6. Shielded sprayingSpraying with a shielded sprayer is done in rowcrops to keep pesticides away from crops thatwould otherwise be injured. A metal or plastic shieldis placed over the end of a spray lance or boom.The shield is open on the bottom and enclosed onall other sides (Figure 23).

Typically, shielded spraying is used to applycomplete weed killers or other herbicides that maydamage a crop. The spray is placed between rowsand is not applied to the crop. Herbicide applicationrates are calculated only for the actual area that willbe sprayed. If a single nozzle is shielded, an evenflat fan or hollow cone nozzle can be used. If morethan one nozzle on a boom is shielded, flat fannozzles should be used (Figure 24).

7. MixingIt is important that the spray remains mixed. If anherbicide is not properly mixed in the spray solution,poor application will result. This will happen if theherbicide has settled to the bottom of the tank.When the application is made, the spray will initiallybe too concentrated, and subsequently too weak.Over- and under-application will result. Mix thesolution when the chemical is first added. Stop atintervals while spraying to keep the solution mixed.Never allow a long time to pass between mixing

Figure 20. Pressure regulation valves.

Sprayer output with regulator valve

Sprayer output without regulator valve

Figure 21. Sprayer output with and without regulator valves

Figure 23. Shielded sprayer and spray pattern inside shield.

Figure 24. Shielded boom with two flat fan nozzles.

Figure 22. Unevenness in hand pumping will be regulated bypressure regulator valve.

Sprayer used withoutregulator. Unevenness inhand pumping results inuneven application

Over-application

Under-application

Sprayer regulated.Unevenness in handpumping does not result inuneven application

Uniform application

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and spraying. It is especially important when usingdry formulations.

8. CleaningAlways clean the sprayer after use or when changingto a new chemical. Rinse the tank with clean water,add fresh water to the tank and spray it through thelance or boom. This should be repeated twice. Withmost herbicides, extra precaution should be takento ensure that no chemical is left in the sprayer.Some may contaminate a future spray mixture andcause unwanted crop injury.

9. SurfactantsSurfactants are materials that may be used withsome herbicides to help them bind to, penetrate orspread uniformly over leaf surfaces. They improve

the weed control of some herbicides, and aretherefore, useful in certain situations (Figures 25and 26). With some herbicides, however, cropinjury can increase to unacceptable levels. FollowUniversity developed guidelines when choosing touse a surfactant.

10. Spray driftDrift is the movement of spray droplets to unintendedtargets. Spray drift can injure or kill crops inadjacent fields and expose nearby people or animalsto harmful pesticides. Causes of drift include dropletsize, wind, nozzle height and temperature.

Droplet Size. Most nozzles spray a wide range ofdroplet sizes (Figure 27). Small spray droplets aremuch more likely to drift than large ones. They aremore easily moved by wind and, if they are verysmall, can move with what might seem like no windat all. Small nozzle sizes and high pressure willcreate more small droplets. To minimize thepercentage of small droplets in a spray “cloud” uselow pressure and large nozzle sizes. In some casesit is not desirable to have only large droplets. Smalldroplets can increase spray coverage and may bewanted with some fungicides, insecticides andcertain contact herbicides. In this case it becomesvery important to avoid other causes of spray drift.

Wind. Drift potential increases with wind speed.Large nozzle sizes and low spray pressure shouldbe considered when wind is likely to cause drift. Asa general rule, the risk of wind-caused drift beginswhen tree leaves begin to move. While sprayapplications can be made in wind up to 6-8kilometers per hour (moderate leaf movement), it

Figure 26. Untreated, sulfosulfuron, and sulfosulfuron plussurfactant treated P. minor. The surfactant increased the efficacyof the herbicide.

Figure 25. Untreated, fenoxaprop, and fenoxaprop plus surfactanttreated P. minor. The surfactant had a minimal effect upon theefficacy of the herbicide.

Figure 27. Average droplet size decreases with increasedpressure.

LargeDroplets

SmallDroplets

Low Pressure High Pressure

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is best to spray at calm times. In many cases, theearly morning and late afternoons are good timesto spray.

Spray Tip Height. Greater spray heights increasethe chance that wind can cause drift.

Temperature. High temperature (25º C), with lowhumidity, makes droplets susceptible to drift due toevaporation. Avoid spraying under these conditions.

11. Pesticide safetyPesticides are chemicals that can cause both short-and long-term health problems with people. Whilenot all pesticides have the same level of health risk,they should all be handled carefully. Keep allpesticides out of the eyes and mouth. Avoid contactwith the skin. If contact occurs with the skin, washwith soap and water immediately. Do not eat, drinkor smoke while handling (mixing, spraying or storing)pesticides. Wear boots, long trousers and rubbergloves when spraying. Change and wash all clothingafter spraying. Never store pesticides where childrenmay accidentally become exposed. Do not re-useempty pesticide containers.

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ReferencesFraser, F., and Burrill, L.C., 1979. KnapsackSprayers. International Plant Protection Center,Oregon State University, Corvallis, Oregon, USA

A Shell Pocket Guide. Knapsack Sprayers. ShellAgriculture, England

Agricultural Spray Products, Catalog 47. 1998.Spraying Systems Co., Wheaton, Illinois

Burrill, L.C., Cardenas, J., and Locatelli, E., 1976.Field Manual for Weed Control Research.International Plant Protection Center, Oregon StateUniversity, Corvallis, Oregon, USA

Agricultural Training Board, 1987. Instructor Manual:Hand Held Pesticide Applicators- Hydraulic NozzlePreparation, Maintenance and Operation.Beckenham, Kent

Rice-Wheat Consortiumfor the Indo-Gangetic Plains

The Consortium is an Ecoregional Program of the Consultative Group onInternational Agricultural Research (CGIAR), managed by CIMMYT, involving theNational Agricultural Research Systems, the International Agricultural ResearchCenters, and the Advanced Research Institutions. Its main objective is to promoteresearch on issues that are fundamental to enhance the productivity andsustainability of rice-wheat cropping systems in South Asia.

These objectives are achieved through:

Setting priorities for focused research on problems affecting many farmers.Promoting linkages among rice-wheat research specialists and other branches ofresearch and extension.Encouraging interdisciplinary team approach to understand field problems and tofind solutions.Fostering quality work and excellence among scientists.Enhancing the transfer of improved technologies to farmers through establishedinstitutional linkages.

Financial support for the Consortium's research agenda currently comes from manysources, including the Governments of Australia, Netherlands, Sweden, Switzerland,and the Department for International Development (DFID), the International Fund forAgricultural Development (IFAD), the United States Agency for InternationalDevelopment (USAID), and the World Bank.

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Facilitation UnitRice-Wheat Consortium for the Indo-Gangetic Plains

C/o CIMMYT-India, CG Block, NASC Complex,DPS Marg, Pusa Campus, New Delhi 110 012, India

Telephone + 91 (11) 5822940, 5827432 Fax + 91 (11) 5822938E-mail: rwc@cgiar.org

Visit our World Wide Web site at http://www.rwc.cgiar.org

ISSN: 0972-2084