This is likely an experiment to find pest RESISTANT grain. There isn't enough growth in those buildings to be a large-scale production deployment to feed millions in the USSR and elsewhere. This is a small subset of the kind of seeds they use. The burnt-out brown dead growth is not intentional sabotage of the harvest, but merely a failed segment of the experiment. The green growth that was in the same area and seemed to be risen to the same height as the dead stuff (implying simultaneous seeding between the two strains) appeared to be more robust to pest attacks. I'm certainly not a bio-chemist, but is a theory that fits the visual facts. This really feels like an experiment to BENEFIT grain recipients to me, not poison them.
If she was smart (which she usually is), she would have clipped off sample pieces of live and dead growth, as well as captured some of the bugs she washed off in the shower, put them all in a couple lunch bags and sent them to Gabriel, up the chain to find out what was REALLY going on there.
My gut instinct tells me that they're really proceeding to a false assumption on this grain business.