# Tank mix compatibility: the evidence to collect before mixing pesticides URL: https://leafwrit.com/ie/tank-mix-compatibility/ Reviewed: 2026-10-29 **Mixing products that are chemically or physically incompatible, or whose individual efficacy or safety is compromised, is not good plant protection practice (GPPP).** A tank mix is GPPP only if the timing and rate of application match the conditions of use of each product applied separately. Where a label is silent, a tank mix is GPPP when the approval holder's historic field use or field trial evidence, or an advisor's advice, has established compatibility and continued efficacy. ## Write down the full list before you ask anyone Before you ask a supplier or adviser about a mix, write down every component: marketed name, PCS number, formulation, and the label or SDS you are using. Include growth regulators, trace elements and adjuvants, not only the pesticides. Send the whole list and the crop, and save the adviser's answer with it. If the supplier offers another brand instead, treat it as a new list. Get the documents for the replacement and ask whether the compatibility evidence covers it. Do not record the substitute under the name you first discussed. ## Which products can be mixed in Ireland Irish product labels are listed in [DAFM's label directory](https://www.pcs.agriculture.gov.ie/products/labels/), which can be searched by product name, active substance or function/crop. The [Irish register guide](/ie/pesticide-register-ireland/) explains the Plant Protection Products Database. ## Roundup and MCPA: what the labels say For glyphosate herbicide application, the label of the exact product decides what may go in the tank. Roundup Flex Plus (PCS 07261) is a soluble concentrate containing 500 g/L glyphosate. Do not tank-mix Roundup Flex Plus with adjuvants, pesticides or fertilisers, except as advised by the manufacturer. A glyphosate mix with another herbicide is therefore allowed only where the manufacturer advises it. For the tank: half fill the spray tank with clean water, start gentle agitation, add the correct amount of Roundup Flex Plus, then top up with water. To avoid foaming do not use top tank agitation; a defoamer may be necessary. In a tank mixture, hydraulic sprayers need continuous agitation, and knapsack sprayers need thorough mixing and immediate use. Agritox 500 (PCS 05499) is a soluble concentrate with 500 g/l MCPA as the dimethylamine salt. It can be tank-mixed with other pesticides; questions go to the Nufarm distributor or Nufarm UK Limited. ## Compatibility, crop safety and efficacy are separate questions DAFM's GPPP guidance treats physical and chemical incompatibility, and compromised efficacy or safety, as separate grounds for not mixing. Ask the question separately for the whole planned mix, and keep the answer to each one: | Question | What to ask for | | --- | --- | | Will the formulations mix physically? | The manufacturer's evidence for this named combination | | Is chemical compatibility established? | Product information or technical advice from the supplier | | Is crop safety covered? | Evidence for your actual crop and use | | Is performance covered? | Evidence for your target and conditions | | Do the conditions of use of each product fit together? | Each product's label for crop, timing and rate | A good result on one line does not answer the others. A jar that mixes well says nothing about how the crop reacts or whether the mix works in the field. Do not read one answer as "the whole job is fine". Syngenta Ireland's Elatus Era tank mix list is dated 15 February 2022. It states that the listed mixes were tested for physical compatibility and that no tests have been undertaken on crop safety or product performance. Two combinations were tested both physically and biologically. ## Elatus Era tank mix list Syngenta supports the physical compatibility of 2 or 3-way tank mixes of Elatus Era with the products listed in the document. The fungicides are Amistar, Helix, Proline, Arizona, Kayak, Prosaro, Caramba 90, Lamast, Talius, Comet, Mancozeb, Folicur and Phoenix. The herbicides are Ally Max SX, Galaxy, Presite SX, Axial Pro, Harmony M SX, Quantum SX, Broadway Star with oil, MCPA, Spitfire, Compitox Plus, Optica, Starane XL, Croupier, Pacifica with Biopower, Topik with oil, Duplosan KV, Pixxaro and Foxtrot with oil. The insecticides are Decis Protech, Karate Zeon and Teppeki. The growth regulators are Canopy, Medax Max (alone or with chlormequat), Moddus (alone or with chlormequat), Cerone, K2, Stabilan and Terpal. The adjuvants are Adigor, Biopower and Toil. The two combinations tested both physically and biologically are Elatus Era with 3C, Moddus, Ally Max SX and Starane XL, and Elatus Era with Harmony M SX and Starane XL. Trace elements named in the list are Epso Top, Epso Micro Top, Headland Manganese 15%, Headland Promise, Headland Maple DF, Headland Zinc 700 and Headland Copper. Before using any tank mixture, consult and comply with the recommendations of the partner products. The list gives the Elatus Era buffer zone as 10 metres and rainfastness as 1 hour after application. ## How to read a supplier's compatibility list Read the introduction and the notes before you look for a name you know. Check which combinations the evidence actually describes, and whether a third or fourth partner takes the mix outside that. Keep any colours or legend in the original document, because a plain-text copy can lose the difference between kinds of evidence. Keep the original file next to your notes, and ask the supplier to explain any entry that is unclear. Write down two dates: the edition printed in the PDF and the day you opened the page. A supplier page can link a document with an earlier date. Do not call it a new edition because you downloaded it this season. For a job now, send the supplier your list and ask whether their present advice covers it, naming the edition you used. Keep any written reply or replacement list. If the answer is about another country, formulation or crop, send it back and ask for the right one. Do not assume the products are equivalent. ## Mixing order for Elatus Era Half-fill the tank with the required water and begin agitation. Add the required amount of Elatus Era and allow it to disperse before adding any other product. Syngenta's list adds that each product is added separately to the bulk of the water in the spray tank and thoroughly mixed before the next one, and that the trace element part of the tank mix is added to the sprayer last. For any other combination, get its own instructions and ask the manufacturer about the order. Do not copy an order from an unrelated website. Put every planned addition in the enquiry (trace elements, adjuvants, a defoamer), because a late addition changes the mix you asked about. Give the operator the agreed order in writing before measuring starts, and if the products in front of them do not match it, stop and sort it out first. ## Foam in the spray tank and the spray tank defoamer Foam in the tank is a risk the label names: for Roundup Flex Plus, avoid top-tank agitation to avoid foaming, and a defoamer may be necessary. Follow the product's own agitation advice while filling. A defoamer is one more product in the tank: ask the manufacturer or adviser whether one suits this mix and how much to use, put it on the mix list, and write it into the spray record with the other additions. ## Water and small-scale tests If water quality worries you, tell the product adviser the real source, the pH and hardness results and who took them, and which products you plan to mix. Ask for any water-conditioner advice for that exact mix; advice for one formulation does not carry over to every herbicide with the same active substance. Add any conditioner you use to the final list. A test of one water supply does not describe water taken from another place. Ask the manufacturer or adviser, with the full product list, what a jar test would show and what it cannot show. Do the test only as they describe it, and get the quantities, handling precautions and waste instructions first. If something goes wrong, keep the product names and order, report it back to the adviser, and do not add more ingredients to make an odd mix look acceptable. ## Elatus Era label conditions Elatus Era is an emulsifiable concentrate with 75 g/l benzovindiflupyr and 150 g/l prothioconazole. For yellow rust the label allows a maximum individual dose of 1.0 l/ha and 1 application, from GS31 up to and including anthesis complete (GS69), with a 10 metre aquatic buffer zone. A maximum of 2 foliar applications of products containing SDHIs can be applied to any cereal crop. The water volume is 100-400 l/ha. Apply it with a three star drift reducing nozzle producing a coarse spray quality at 2-3 bars. The higher volumes are recommended where the crop is dense or disease pressure is high. After spraying, wash the sprayer out three times according to the manufacturer's guidelines. Read the crop row, timing, equipment limits and mixing directions of all the labels together. Have the crop, target, timing, method and water volume ready before you start. If the labels conflict on mixing, spraying or cleaning, settle that before preparing the batch, and note the line that causes the question. Do not change a dose just to fit several products into a recipe you have in mind. Agree the use and the purpose with your adviser first, then work out the quantities. ## What DAFM's good plant protection practice says about tank mixing Using products in a tank mix is GPPP if the timing and rate of application match the conditions of use for each product applied separately. Fewer spray passes reduce operator exposure, fuel use and trips through the crop. Some labels give specific tank mix recommendations, for example to control a named pest with a named partner product, and others give general ones for resistance management. An adjuvant is GPPP with particular products or in particular use scenarios, as long as the use is not counter to the authorisations. It is not GPPP where it leaves unacceptable residues at harvest or after storage, or where the label explicitly precludes it. Equipment and application conditions must ensure that a high proportion of the product reaches its target, taking into account nozzle type, pressure, spray volume, droplet size and speed. The equipment must be properly calibrated, and the calibration regularly checked, so the correct dosage is applied. The maximum individual dose is on each label, and a reduced dose is permitted if the agronomic conditions allow. Higher doses are not authorised and are illegal. For all crops, it is important to apply sprays with the correct water volume; applying a concentration that the label considers too high or too low is not GPPP. ## Work out quantities last Calculate only after the compatibility and rate questions are settled. Use the real area, water volume and tank size, one line per product, with the units written in both the plan and the operator's instruction. Do not mix up a concentration with a rate per hectare. Say whether the figure is for a full tank or a part load. If the area changes, recalculate rather than keeping the old quantities. Keep the plan apart from the record of what was actually used, and fill in the treatment record after the work. ## Operator risk from a tank mixture Where there is exposure to several chemical agents, the risk shall be assessed on the basis of the risk presented by all such chemical agents in combination. Decide who measures each product, who runs the agitation and who cleans the equipment, and give whoever does the risk assessment the SDSs and the planned order. For protective equipment, see the [PPE guide](/ie/pesticide-ppe-risk-assessment/); different tasks (handling concentrate, spraying, cleaning) may need different items. Before work, keep the names of all components where anyone talking to a supplier or emergency services can find them, and see the [spill guide](/ie/pesticide-incidents-spills/). ## If the plan changes or the work stops Tell the adviser about any change of product, water, order or job, and keep the new decision with the old plan so the operator has one current instruction. If something unexpected happens in the tank, describe what you saw without guessing the cause, and pass the products and order to the technical contact. Follow the product and machine instructions rather than improvising a cleaning or dilution fix. Note what was returned, kept or disposed of (see the [waste guide](/ie/pesticide-container-waste-disposal/)), and record unused product as unused. ## Tank mix with Yara and BASF products: the Yara tank mix app and BASF tank mix lists A BASF tank mix, a Yara tank mix and the Yara tank mix app are supplier tools. Ask the maker of each product for its own compatibility list and compare it with both labels, as the section on reading a compatibility list explains. Write down the full list of products before you ask. ## Next step Check the product in the [Irish register](/ie/pesticide-register-ireland/), then read the [label and SDS guide](/ie/pesticide-label-sds/) before mixing.