Weed-Control Indices Calculator

Compute Weed Control Efficiency, Weed Index, Crop Resistance Efficiency and Weed Persistence Efficiency online for free.

Open the Weed-Control Indices (WCE / WI / CRE / WPE) calculator

When to use it

Use to evaluate herbicide treatments and integrated weed-management practices in agronomy field trials. Reports the four most cited indices in weed-science literature: Weed Control Efficiency (WCE), Weed Index (WI), Crop Resistance Efficiency (CRE), and Weed Persistence Efficiency (WPE).

When NOT to use it

Do not use without a weedy check (untreated control); the indices are defined as relative to that baseline. Do not use single-replicate plots; weed populations are heterogeneous and replication is essential.

What you get

Per-treatment table of WCE percent, WI percent, CRE percent and WPE percent, plus the input weed counts or biomass and crop yield. Best-treatment ranking by each index. Treatments are compared against the user-specified weedy check.

Worked example

Four treatments: unweeded check, two herbicides, hand-weeding. Weed weight (g/m^2) and crop yield (kg/ha).

T1_check: 120, 1500
T2_herbA: 20, 2700
T3_herbB: 40, 2400
T4_handweed: 5, 3000

Expected output: Hand-weeding (T4) tops WCE and yield; herbicide A (T2) is the best chemical option by WCE and yield combined.

Source: StatVeda built-in example, paired with the analyse page sample for toolId 'weedindices'.

How to interpret the output

WCE percent quantifies how much of the weedy-check weed mass the treatment removed; higher is better. WI percent is the relative yield loss compared to a weed-free check; lower is better. CRE captures the crop's competitiveness. WPE indicates how persistently weeds resist the treatment. Pick the index whose definition matches your trial question.

Common pitfalls

Computing the indices without a clear weedy-check or weed-free-check reference.
Reporting one index in isolation when the four can disagree on ranking.
Treating early-season counts as comparable to late-season biomass without standardising.

Try it in StatVeda

The Weed-Control Indices (WCE / WI / CRE / WPE) engine runs entirely in the browser. No signup, no install, no data sent to a server. Paste your data, hit Run, copy the output.

Open Weed-Control Indices (WCE / WI / CRE / WPE)

References

Mani, V. S., Malla, M. L., Gautam, K. C. and Bhagavandas (1973). Weed-killing chemicals in potato cultivation. Indian Farming, 23(8), 17 to 18.
Walia, U. S. (2002). Weed Management. Kalyani Publishers, Ludhiana.
Rao, V. S. (2000). Principles of Weed Science, 2nd edition. Science Publishers, Enfield.