Agriculture Reference
In-Depth Information
condition, avoiding crowded planting, and using a mulch to lock in moisture will
make attacks much less likely. If you suspect an attack, take a good look at the
leaves, as some varieties get silvery patches that are sometimes mistaken for this
disease. If it is mildew, spraying the plant with bicarbonate of soda solution (see
Chapter 7, page 58) or one part milk to ten parts water will help to slow it down
and you will still get plenty of fruit. It's still possible to get fruit from plants
where all the leaves, except perhaps a very few of the youngest, have mildew.
The fruit itself usually remains completely unaffected. However, if you can,
remove affected leaves as mildew develops and spray the plant as often as pos-
sible. Try not to get the leaves of other plants wet in the process.
Rabbits
As mentioned in Chapter 2, the best way to avoid a serious and rapidly growing
rabbit problem is to ensure they never get inside the tunnel in the first place. To
keep them out, all you need are a few screws, a couple of short lengths of batten
and a piece of wire mesh roughly 35-40cm tall, and wide enough to stretch across
the tunnel doorway. Chicken wire is fine, but make sure that it has a neat top or
it will be forever snagging your clothes when you step over it.
Holding one end of the mesh against the inside of the door frame, screw one of
the lengths of batten down on to it to while holding it firmly in place. Repeat on
the opposite side of the door, making sure the mesh is tight enough across the
doorway to prevent rabbits from pushing underneath. You will need to step over
it every time you go in or out, but it's better than rabbits!
If you are worried that rabbits might push underneath the mesh, thread a short
length of bamboo through the bottom edge to hold it rigid.
Red spider mite
Although less likely to be a problem in polytunnels than in greenhouses (because
of the higher humidity in the tunnel), red spider mites can attack almost any
plant. Because they are so small - even the adults are barely visible - they are
often missed until a network of fine webbing appears on affected leaves, by
which time the infestation is severe.
The early sign of attack is a fine, pale mottling on the upper surface of leaves. If
you see this, use a hand lens to check the underside of the leaves for mites
(which are actually a yellowish-green for most of the year), and move any affected
pot-grown plants outside, where predators and the elements will usually kill the
mites within a few days. If this is not possible, nip out the damaged growth or
purchase a biocontrol.
