Pesticide Mixing Calculator

Related Calculators

References

Frequently Asked Questions

How do I calculate the correct amount of pesticide to add to my sprayer?

Pesticide amount = (label rate per acre � GPA � tank capacity) / (GPA � 1). Simplified: pesticide per tank (oz or lbs) = (tank capacity / GPA) � label rate per acre. Always check the label for rate in oz/acre, lbs/acre, or quarts/acre. Measure precisely � under-dosing causes treatment failure, over-dosing wastes money and risks crop injury.

What is the correct order for mixing pesticides?

The W-A-L-E-S order: Wettable powders (WP) first, then Agitate, then Liquid flowables (L/SC), then Emulsifiable concentrates (EC), then Surfactants/adjuvants. Fill the tank 50% with water, add each product with continuous agitation, then top off to final volume. Never mix concentrates together before adding to water. Allow each product to disperse before adding the next.

How do I convert between different pesticide label rates?

Converting label rates: 1 pint/acre = 0.125 gallons/acre � GPA = oz per tank. 1 quart/acre = 32 oz/acre. 1 gallon/acre = 128 oz/acre. For percentage solutions: 1% = 1 gallon per 100 gallons of spray. 0.5% = 1/2 gallon per 100 gallons. Use the formula: product per tank (oz) = (tank gallons / GPA) � (label oz per acre).

What is the difference between EC, WP, SC, and WG formulations?

EC (Emulsifiable Concentrate): liquid, easy to mix, but can cause crop injury in hot weather. WP (Wettable Powder): dry powder, requires good agitation, can settle in tank. SC (Suspension Concentrate): liquid, easy to handle, good stability. WG/WDG (Water-Dispersible Granule): dry granules, low dust, easy to measure, good suspension. SP (Soluble Powder): dissolves completely, no agitation needed.

How do I calculate adjuvants and surfactants?

Adjuvants are typically added at 0.25-1% v/v (volume/volume) or 0.5-2 pints per 100 gallons. NIS (non-ionic surfactant): 0.25-0.5% v/v. COC (crop oil concentrate): 1% v/v (1 gallon per 100 gallons). MSO (methylated seed oil): 1% v/v. Adjuvant amount per tank = tank gallons � (desired % / 100). Always follow the pesticide label for specific adjuvant recommendations.

How do I mix multiple pesticides in one tank?

Compatibility is critical. Conduct a jar test: add 1 pint of water, then add each pesticide at the proportional rate (1 tsp per pint = 1 qt per 100 gal) in the correct order. Shake gently. If gel, flakes, or separation occurs, products are incompatible. Do not mix copper-based products with other pesticides. Do not mix more than 3-4 products. Always use a compatibility agent when in doubt.

What is the maximum number of products I can tank mix?

Most labels specify a maximum of 3-4 products in a single tank mix. Exceeding this increases the risk of antagonism (reduced efficacy), phytotoxicity (crop injury), and physical incompatibility (precipitation, gel formation). Some specific combinations like glyphosate + 2,4-D + dicamba + surfactant are common corn/soybean burndown mixes that require careful attention to mixing order.

How do I calculate the amount of water needed for a specific pesticide dose?

Water volume is determined by your calibrated GPA rate and the label pesticide rate. If the label says apply 2 qts/acre at 20 GPA: mix 2 qts of pesticide per 20 gallons of water. For a 400-gallon tank: (400/20) � 2 qts = 20 qts (5 gallons) of pesticide per tank. Some labels give both low and high volume rates � use the rate that matches your equipment.

What safety precautions are required for pesticide mixing?

Always wear: chemical-resistant gloves (nitrile), long-sleeved shirt and pants, closed-toe shoes with socks, eye protection, and an N95 respirator for dust formulations. Mix in a well-ventilated area or use a mixing pad. Have clean water available for emergency eye/skin wash. Never eat, drink, or smoke while mixing. Triple-rinse empty containers and dispose properly.

How do I handle leftover spray solution?

Never store mixed pesticides � use them within 24 hours. If you have leftover solution, apply it at the labeled rate to a labeled crop or fallow ground, never at a higher concentration. Do not dump near water sources, wells, or drainage areas. Clean the sprayer thoroughly with a triple-rinse procedure. Record the disposal method in your pesticide application records.

What is the cost per acre of a pesticide application?

Cost per acre = (product price per gallon � gallons used per acre) + (adjuvant cost per acre) + (application cost per acre). At $80/gal, 2 qts/acre ($40/acre), plus surfactant $2/acre, plus application $8/acre = $50/acre total. Band spraying can reduce costs 40-60%. Always include water, transportation, and labor costs in your economic analysis.

How do I clean pesticide residues from the sprayer?

Triple-rinse procedure: 1) Drain tank completely. 2) Fill 10% with clean water, add tank cleaner (ammonia 1 qt/100 gal or commercial cleaner). 3) Agitate and circulate through boom for 15 minutes. 4) Spray out rinseate on a labeled crop. 5) Repeat 2-3 times. Remove and clean nozzle screens individually. For sulfonylurea herbicides, use chlorine bleach (1 cup/100 gal) as a special cleanout.

What records must I keep for pesticide applications?

Required records: crop and field ID, date and time of application, product name and EPA registration number, total amount applied (per acre and total), application rate and GPA, target pest and growth stage, weather conditions (wind speed, temperature, humidity), applicator certification number, and any special instructions or restrictions. Keep records for 2-3 years (varies by state and crop).

How do temperature inversions affect pesticide application?

Temperature inversions occur when the ground is cooler than the air above, causing spray particles to suspend and drift. Signs: fog, smoke that hangs in the air, dew on the ground, stable air. Never spray during inversion conditions � drift can travel miles. Check for inversions at dawn and dusk. Use inversion-prone conditions as a strong warning to delay application.