Posted: 15/09/2012 at 15:55
Hello, I have some tomato plants with the dreaded blight next to sweetcorn which also looks sick. Please could you let me know if it is transferable to the other plants in my garden and if any blight treatments are ok for them, I know it is likely that my potatoes will succumb but am worried about courgettes and the sweetcorn. Thanks very much.
When you say "the dreaded blight" it depends exactly which fungal problem you have on the toms. It might not even be fungal. It could be bacterial. Can you post a photo?
As Geoff says, toms and spuds are both prone to a couple of the same fungal diseases. One is Late Blight. If you have Late Blight, the tomato plant will be wiped out within a week or ten days. If your plants have been coping for that or longer it's probably not Late Blight. Early Blight, another common tomato fungal problem, can also affect spuds, though, as with toms, it's nowhere near as destructive.
I've never heard of any of the tomato/potato fungal diseases affecting sweet corn. Sweet corn only has one fungal threat that I know of. It's called "smut" and you'd know whether your plants are affected. The kernels expand to three or four times their size and are a dark grey/purple colour. It looks hideous, though, in some parts of the world, it's a delicacy. I get it a lot on my sweet corn here in Italy.
In terms of dealing with your disease problem now, it's too late for prevention. Once the spores are in place, you can't kill them, per se. You can only try to minimise the impact by removing affected foliage to try to stop the spread.