I'm new to veg growing as I've only had my allotment (organic site) for a year. I pulled up my shallots and garlic today as the leaves were all yellow and dead, and discovered that they all had a powder on them and were damp looking, which I'm guessing is onion powdery mildew, but may be wrong. I took them all off site to destroy. Do I need to also pull up all the onions (Red Baron) - nowhere near fully grown - growing adjacent to where the shallots were and destroy them, too, and what do I do about the carrots I planted beside the onions (to try to fool carrot fly)?
All guidance appreciated : )