Duplomb Law: in the Marne, "we monitor tractors passing by, but we never know if they are spraying acetamiprid"

Sunflower yellow, wheat yellow, sunshine, or lemon. If the primary color conjures up images of vibrant nature, it's because you're not planting beets. For producers in the sugar industry—an extract from the root of the vegetable—the first yellow that comes to mind is the pale shade of fields ravaged by jaundice. When the plants take on this hue, it's too late. "There is no curative treatment," explains Jean-Marie Delanery, based in Tilloy-et-Bellay, in the Marne department. Shins buried in leaves, the farmer grimaces: the hilly terrain highlights the "rings" of jaundice, random Dalmatian spots in the green as far as the eye can see. The only solution: "Kill the virus vector." A malefactor a few millimeters long called a green aphid. When it bites stems and leaves to feast on the sap, it contaminates the beets one by one. The equivalent, for plants, of mosquito bites for humans, sometimes harmless, sometimes fatal.

Last year, abundant rain had limited their appearance. The dry spring of 2025, on the other hand, saw them proliferate: in one weekend, the department was "drenched in aphids." Action-reaction, Jean-Marie Delanery immediately applied the treatment: "Three passes spaced two weeks apart, two Teppeki, one Movento" – the two products approved to get rid of the pest. By early August, it had clearly not worked. At first glance