Agronomy advice

Better spraying for better yields

Calculation tools, calendars and good practice for effective, economical and safe treatments.

Recording field observations

Tools

Decision-support tools

Work out your product quantities and check the weather before you spray.

Dose calculator

Choose a product and enter the rate, the area and your equipment: the calculator works out the amount of product, the spray volume and the number of tank loads to prepare.

Knapsack sprayers usually hold 15–20 L.

The spray volume measured when calibrating your sprayer.

Result

Total product needed
—
Total spray mix
—
Number of tank loads
—
Product per tank
—

Fill in the form to see the result.

Total product = rate × area; spray mix = volume per hectare × area; product per tank = rate × tank capacity ÷ volume per hectare.

Indicative result: always follow the rate, spray volume and conditions of use on the label. Always read the label before use.

Spray window checker

Enter the wind speed, temperature, humidity and time until the next rain: the tool tells you whether conditions are suitable.

Leave empty if no rain is forecast.

Verdict

    Fill in the form to see the result.

    Reference values

    • Wind: ideal between 3 and 15 km/h; caution between 15 and 20 km/h or below 3 km/h; avoid above 20 km/h.
    • Temperature: ideal up to 30 °C; caution between 30 and 35 °C; avoid above 35 °C.
    • Relative humidity: ideal from 50%; caution between 35 and 50%; avoid below 35%.
    • Rain: avoid if expected within 2 hours or before the product's rainfast period ends; caution between 2 and 6 hours.

    Decision aid only: also check conditions in the field before spraying.

    Calendars

    Crop protection calendars in Tanzania

    The main treatment periods, crop by crop.

    • Herbicides
    • Insecticides
    • Fungicides
    • Growth regulators

    Maize

    South and centre: planting November – December, harvest May – July · North: masika crop March – July

    1. November – DecemberHerbicide Pre-emergence weed control just after planting (unimodal areas)

    2. December – JanuaryHerbicide Post-emergence weed control at the 3–6 leaf stage

    3. December – FebruaryInsecticide Fall armyworm scouting and control

    4. March – AprilHerbicide Pre- and post-emergence weed control (masika crop, north)

    5. April – MayInsecticide Fall armyworm and stem borer control (masika crop)

    Rice

    Rainfed lowland rice: sowing December – January, harvest May – July · irrigated schemes: two crops a year

    1. December – JanuaryHerbicide Pre-emergence weed control of upland and dry-seeded rice

    2. January – FebruaryHerbicide Post-emergence weed control 15–25 days after sowing or transplanting

    3. February – MarchInsecticide Stem borer control from tillering to panicle initiation

    4. March – AprilFungicide Rice blast protection from booting to heading

    Cashew

    Flowering: June – September · harvest: October – January

    1. May – JuneHerbicide Orchard clearing, under-canopy weeding and firebreaks as the rains end

    2. June – SeptemberFungicide Powdery mildew protection from panicle emergence through flowering (sulphur, alternating with a triazole or strobilurin)

    3. July – OctoberInsecticide Helopeltis and coreid bug control at flushing and flowering, outside bee foraging hours

    4. December – JanuaryInsecticide Termite protection of young trees planted with the rains

    Coffee

    Flowering: September – November · harvest: July – December (north), May – September (southern highlands)

    1. October – NovemberHerbicide Weed control and slashing between rows as the rains return

    2. November – DecemberFungicide Leaf rust protection with copper or triazole sprays at the start of the rains

    3. January – MarchInsecticide Coffee berry borer control during the female flight period, 90–120 days after the main flowering

    4. March – AprilHerbicide Second weed control round during the long rains

    5. March – MayFungicide Leaf rust protection during the long rains

    Cotton

    Lake Zone: sowing November – December · harvest: June – August

    1. November – DecemberHerbicide Pre-emergence weed control just after sowing

    2. December – JanuaryHerbicide Post-emergence grass control

    3. December – JanuaryInsecticide Aphid and jassid control on young cotton

    4. January – FebruaryGrowth regulator Growth control of vigorous cotton at early flowering

    5. January – AprilInsecticide Bollworm and sucking pest control from flowering to boll formation, following the spray programme

    Indicative calendar: timing varies with location, variety and the season's rainfall.

    Good practice

    The basics of successful spraying

    A good product applied badly gives poor results. These three points make the difference.

    Calibrate your sprayer

    Calibration tells you how much spray mix you actually apply per hectare, so that you can dose accurately.

    1. Check the equipment

      Check for leaks and inspect the filters, lance and nozzle. Use a flat-fan nozzle for herbicides and a hollow-cone nozzle for insecticides and fungicides.

    2. Mark out a test area

      Measure an area representative of your field, for example 10 m × 10 m, or 100 m².

    3. Spray clean water

      Fill the sprayer with a known volume of water and spray the test area at your usual walking speed and pressure.

    4. Measure the volume used

      Measure how much water is needed to refill the sprayer to the starting level.

    5. Work out the volume per hectare

      Volume per hectare (L/ha) = volume used (L) × 10,000 ÷ test area (m²). Example: 2 L on 100 m² equals 200 L/ha.

    6. Adjust and calculate the dose

      If needed, change your speed, pressure or nozzle to reach the recommended volume, then use the calculator to find the amount of product per tank.

    Follow the mixing order

    When the label allows a tank mix, the order in which products are added prevents lumps and deposits.

    1. Water and agitation

      Half-fill the tank with clean water and keep it agitated throughout.

    2. Dry formulations WP WG

      Add wettable powders (WP) and water-dispersible granules (WG), pre-mixed in a bucket of water.

    3. Suspensions SC OD

      Then add suspension concentrates (SC) and oil dispersions (OD).

    4. Emulsions EC EW

      Add emulsifiable concentrates (EC) and oil-in-water emulsions (EW).

    5. Solutions and adjuvants SL SP

      Finish with soluble concentrates (SL) and soluble powders (SP), then any adjuvants, and top up with water.

    Always do a compatibility test in a clear jar before a new tank mix, and spray the mix the same day.

    Mind the water quality

    Water makes up most of the spray mix: its quality directly affects how well the treatment works.

    • Clean water

      Avoid muddy water or water with debris: clay and organic matter bind some active ingredients, such as glyphosate, and block nozzles.

    • pH

      Very alkaline water can break down some active ingredients in the tank. Neutral to slightly acidic water suits most products.

    • Hardness

      Water rich in calcium and magnesium can reduce the efficacy of some herbicides. Use soft water where possible.

    • Use it promptly

      Prepare only the quantity you need and spray straight away: a mix left in the tank for hours loses efficacy.

    Sustainability

    Managing resistance

    Weeds, pests and fungi adapt to repeated treatments. These principles keep the available solutions effective.

    • Rotate modes of action

      Switch HRAC, IRAC or FRAC groups between treatments and between seasons.

    • Spray only when needed

      Act on the basis of scouting and thresholds, at the most susceptible stage of the pest or weed.

    • Use the right rate

      Neither under- nor overdose: the label rate ensures efficacy and limits selection.

    • Limit the number of applications

      Respect the maximum number of applications per crop cycle, especially for single-site products.

    • Combine methods

      Rotation, suitable varieties, stale seedbeds, field hygiene: chemical control is only one lever among others.

    Read the mode-of-action codes

    HRAC Herbicides: groups defined by the Herbicide Resistance Action Committee. 6
    IRAC Insecticides and acaricides: groups defined by the Insecticide Resistance Action Committee. 11
    FRAC Fungicides: groups defined by the Fungicide Resistance Action Committee. 6

    Always read the label before use. Product information is given for guidance only; the label of the product authorised in your country always prevails.

    Training

    Field training

    Our technical team runs practical sessions for farmers, cooperatives and agro-dealers.

    Safe use of products

    Reading the label, wearing PPE, preparing the spray mix and washing after spraying.

    Sprayer set-up

    Nozzle choice, calibration, maintenance and dose calculation.

    Recognising crop enemies

    Identifying the main weeds, pests and diseases, and scouting methods.

    Resistance and containers

    Rotating modes of action, triple rinsing and empty container management.

    Formats on offer

    • Field demonstrations
    • Sessions for cooperatives and farmer groups
    • In-store training for agro-dealers
    Request a training session

    A project or a technical question?

    Our advisers will answer your questions and prepare a quote tailored to your crops and acreage.