FRAC Rotation & Stay Within Every MoA Budget

It depends on the group's resistance risk. High-risk single-site groups — QoI strobilurins (FRAC 11), SDHI carboxamides (FRAC 7), phenylamides (FRAC 4) and OSBPI (FRAC 49) — are typically capped at 2 solo applications per crop per season, and ideally not back-to-back. Medium-risk groups such as DMI triazoles (FRAC 3) and anilinopyrimidines (FRAC 9) sit around 3, and low-risk multi-site protectants like mancozeb (M03) or chlorothalonil (M05) can be used 6–8 times. The planner enforces each group's cap and the label is always the binding figure.

Enter every spray in your programme with its FRAC group and the budget tracker shows one bar per group: applications used over the season cap. A bar turns amber at 80% of the cap and red once you go over it, with the exact number of applications you need to drop. That is the fastest way to answer 'am I over budget on any one mode of action?' before you ever mix a tank.

Single-site fungicides hit one target in the fungus, so a single mutation can make the whole group fail — and once resistance appears it usually carries across every product in that FRAC group (cross-resistance). Rotating and mixing modes of action means no single resistance mutation is exposed to selection pressure on every spray, which preserves the chemistry. The Fungicide Resistance Action Committee (FRAC) publishes the codes precisely so growers can tell which products share a target site.

Beyond a season cap, FRAC also limits how many sprays of one group you may apply back-to-back before switching. High-risk groups should not be sprayed consecutively at all (limit 1), medium-risk around 2, low-risk multi-sites up to 4–6. Two strobilurin (FRAC 11) sprays in a row is the single biggest resistance driver, so the planner flags any high-risk group used back-to-back as a violation.

A FRAC code is a number or letter assigned by the Fungicide Resistance Action Committee to each fungicide mode-of-action group, published in the annual FRAC Code List. Products with the same code share a biochemical target site and therefore share resistance. Group 11 is the QoI strobilurins, group 3 the DMI triazoles, group 7 the SDHIs, and the M-codes (M01–M09) are the multi-site contact protectants.

FRAC rates QoI strobilurins (11), SDHIs (7), phenylamides (4) and OSBPI (49) as high resistance risk because they are single-site and resistance has appeared rapidly in the field. DMI triazoles (3), anilinopyrimidines (9), CAA (40) and others are medium risk. Multi-site protectants — copper (M01), sulphur (M02), dithiocarbamates such as mancozeb (M03), phthalimides (M04) and chlorothalonil (M05) — are low risk and act as resistance-breaking partners.

Both. Best practice is to alternate modes of action between sprays and, on high-risk single-site products, tank-mix or co-formulate with a multi-site protectant at each application. A multi-site partner means a resistant mutant still has to survive the protectant, which slows selection. When any single-site group in your plan is stressed and no multi-site is present, this planner recommends a partner (FRAC M03, M05 or M01).

Yes. QoI strobilurins (FRAC 11) are high-risk, single-site, and their G143A mutation confers complete resistance — so two FRAC 11 sprays back-to-back is exactly the selection pressure FRAC warns against. The planner caps FRAC 11 at 2 solo applications per season and flags any consecutive pair as a violation; alternate with a triazole or SDHI and add a multi-site.

No. The product label states the legally binding maximum number of applications per crop per season and the minimum interval, and you must follow it. This planner uses the published FRAC general resistance-management guidance as a planning default; where your label is stricter, the label wins. Use the tool to design a resistance-smart sequence, then confirm every figure against the labels you will actually spray.

One where no FRAC group exceeds its season cap, no high-risk group is sprayed consecutively, modes of action alternate spray to spray, and high-risk single-site products are partnered with a multi-site protectant. When all of that holds, the planner shows a green 'resistance-smart programme' verdict; otherwise it lists exactly what to change.

Yes — the FRAC code system is crop-agnostic, so the planner works for any disease programme: vineyard downy and powdery mildew, potato late blight, wheat septoria, or vegetable diseases. The groups, risks and caps are the same; only your product choices and the label maxima change. Enter your actual spray sequence and the budget tracker does the rest.

For every group the tracker computes applications used divided by that group's season cap. The peak utilisation shown in the verdict ribbon is the single highest of those ratios across all groups — so a peak of 100% means at least one group is exactly at its cap with no headroom, and above 100% means a cap is breached.