This is a slightly different post. I have been looking at the impact of the 2026 Iran war on agriculture, partly motivated by the Substack post Heads up: food crisis incoming by Sarah Connor.

And, it was Plant Health Week last week.

So, I set Claude Cowork to collect data and produce an interactive dashboard for the major fertiliser and pesticide prices.

The impact is very clear, although in the case of pesticides/herbicides, it is probably indirect – China is a major producer and energy prices going up will affect the outputs.

The point I am making here is about potential synergistic effects. As Sarah points out, plants that do not get enough fertiliser, nitrogen, phosphorus and potassium (NPK) as well as sulfur, are weaker.

But this means that they are also more susceptible to pests and diseases.

If the cost of pesticides also goes up, farmers are hit twice: lower yield, higher losses. For annual plants, like wheat, rice, soya, the hit is confined to this year. For perennial plants, like coffee, this might be irreversible.

I have not verified the data, so the graphs below need to be used with caution, but they do make sense.

Major fertiliser & pesticide prices vs the 2026 Iran war

Weekly benchmark prices, 5 Jan – 18 May 2026. The chart defaults to index (5 Jan 2026 = 100) so very different commodities can be compared on one axis. Vertical dotted lines mark the five key events of the war. Toggle commodities on/off below the chart.

Move since 5 Jan 2026

Weekly database