The fungal disease late blight is a terribly destructive disease of
tomatoes, potatoes and sometimes even peppers and eggplant.
The disease cycle
does have a weak link, so we can take steps to prevent it: free moisture on leaves is
necessary for infection.
Avoid late blight by rotating plantings, using only
healthy starts and seed potatoes, never composting diseased plant material and
keeping the plants dry.
Also, try these tips:
the base of the plant (with soaker hose, if possible).
your tomato cages. They bunch up foliage, so it can't dry quickly. Train vines
up poles and prune off side branches. Well-spaced vines allow maximum air
circulation and dry fast.
building a frame and covering the plants with clear plastic to keep out rain.
Many gardeners are confused about pruning tomatoes. There
is a common belief that pruning leaves from tomato vines will allow sun to get
to the fruit and ripen it faster. Research proves that just the opposite is
true. The leaves produce the sugars and other nutrients that are transported to
the fruit to make them size up and ripen. Direct sunlight on the fruit is not required and,
in fact, it can cause sun scald on the fruit.
So what do you prune? If you are training
the vines up a
wire cage or up stakes, you may want to take out some of the suckers (or new
secondary branches) that start between leaves and stems. This will open the
plant up and provide better air circulation, which helps prevent disease.
Pruning lower leaves (ones touching the ground) of staked plants can also help.
only other pruning recommended is nipping off flowers
and pea-size fruit in late summer. These don't have a chance to ripen anyway, so you
want to direct the plant's energy into ripening the bigger green fruits before