Microsoft word - problem solving.doc

A year in the vegetable garden

Problem Solving
Every season brings its own problems and each year can be different from another.
This is part of the joy of gardening. However there are several problems which can
occur each year but with careful propagation and planting these can be avoided.
As vegetables are to be eaten it is advisable to use as few chemical sprays as possible.
There are products available which can be used up to harvest and will kill pests such
as aphids and whitefly with no ill effects. It is worth watching out for these in the
garden centres.

Onions
For control of Onion Fly remove onion as soon as symptoms occur and destroy before
the maggots go into the soil to pupate.
To control Downy Mildew on onions. Increase the spacing of onions to improve air
circulation around the plants and keep them weed free. Thrips can be controlled by a
spray with permethrin or garlic concentrate spray.
White rot is perhaps the most serious of the problems as there is no chemical control
available. The infected onions must be lifted and destroyed. Remove the soil that the
onion was growing in. Do not store or re-use this soil but dispose of it. The ground
can then be given a thorough cleaning by using a soil sterilant.
When onions run to seed it is usually due to climatic conditions causing a check in
growth.

Leeks
Leek rust is perhaps the number one problem on any leek bed. Keep the ground weed
free and spray with Dithane 945. When spraying leeks always use a spreading agent
to make sure the spray stays in contact with the leaves. It may be necessary to spray
every two weeks.
For Thrips on leeks spray as for onions but using a spreading agent.
N.B. Soft Soap works as a spreading agent.

Celery
Slugs can be a major problem especially when growing for exhibition as the celery
blanching paper makes an ideal home. Clean and remove the slugs every time a new
blanching band is added and keep a regular supply of slug pellets around the plant. If
pellets are not your preferred choice use one of the many alternative methods
available.
To reduce Heart Rot we have found a dressing of calcified seaweed in March or a
drench spray with a weak solution of calcium nitrate can help.
For Celery Rust spray with a copper-based fungicide and remove any infected leaves.
Celery is also prone to carrot fly, so here again companion planting does help.

Beans
Root Rot is caused by bad drainage so choose the site carefully and rotate the crop. If
there are no or very few flowers there is too high a nitrogen presence in the soil, use a
well-balanced feed. This also applies to flowers that drop. Under watering also affect
flower drop. To help the beans to set, water well when the flowers are in bud.
A problem we have not experienced but is increasing in some areas is Bean Rust. This
is worst in a warm damp summer. We cannot recommend a spray but would suggest
that the leaves be removed promptly.

Peas
Spray at the first signs of Downy Mildew, with Dithane 945. To avoid the problem,
practise good rotation. As Powdery Mildew usually only attacks late in the season it is
often not worth bothering to control.
For Foot Rot on peas spray with a fungicide spray at the first sign.

Brassica
The major problem with growing all types of Brassica in a small garden is Club Root.
To avoid Club Root we suggest using a good crop rotation. Keeping the lime content
high can also help.
Caterpillars can be either sprayed with an insecticide such as permethrin or removed
by hand. If left, they can devastate the crop.
Cabbage Root Fly Maggot can be deterred by a ring of carpet or roofing felt to deter
the fly from laying the eggs in the base of the stem.
White Blister is encouraged by warm humid weather. Avoid growing brassica on
infected soil as it can persist in the ground. As there is no effective control available
we suggest any leaves be removed and destroyed at the first sign of the blister.

Tomato
Diseases are far more important than insect pests on tomatoes. Tomatoes grown
outdoors are much less susceptible to disease than ones grown indoors. Keep a careful
watch on indoor crops and treat plants immediately.
Poor drainage will cause Root Rot. The roots below ground are brown and corky; the
top will wilt in hot weather. The root rot cannot be stopped once its taken hold. A
mulch on top of the ground will help the formation of new roots.
Root rot can be treated if the plant is slightly affected. Treat the affected area with
Cheshunt Compound. This is usually a disease of seedlings or young plants.
Stem Rot or Didymella is a disease of mature plants of which there is no effective
treatment. This can be spread from plant to plant by watering or by handling. The
fungus can over winter on debris or in the soil. It is essential the soil be well cleaned
or sterilised before tomatoes are grown on the same area.
Tomato Blight is a devastating disease of tomatoes and is an increasing problem in
some areas of the country. A spray with Dithane 945 will control the fungus but care
must be taken to destroy all green matter to prevent a follow on infection.
Unlike potatoes rolled leaves on tomatoes do not indicate disease. The curling of
young leaves is usually taken as a good sign if they are dark green. The rolling of
older leaves is usually due to a wide variation between day and night temperatures.
Providing no pests are present no action need be taken.
Either too much heat or too little potash can cause blotchy fruit. The glasshouse can
be shaded to reduce the heat, use a high potash feed. Blossom end rot, which causes
the end of the tomato to turn black, is due to irregular watering when the fruit is
setting and can be problem when using grow bags. To avoid this ensure a regular
water supply to each plant.
Two of the main pests that attack tomatoes are Whitefly and Aphids. Both can be
treated effectively either by predators or an insecticide spray. We have found
predators work extremely well; they work continuously throughout the season.

Pepper/ Aubergine
Peppers, both sweet and hot, and Aubergines can suffer the same type of problems as
tomatoes. The same solutions apply. Always allow sufficient ventilation for the plants
and check regularly for aphids, whitefly or glasshouse spider mite. If found, as with
tomatoes use either an insecticide spray or predators.

Marrow/ Squash/ Pumpkin
Very few pests will attack these. Any Aphids can be removed in the usual way.
Mildew can be controlled by a spray of Dithane 945. Although does not usually
become a problem till late in the season.

Cucumber
Root Rot is when the plants appear to be growing well then collapse. This can be
caused by over watering on cool damp days, or the more common reason, not using
new clean compost. Once the plants have collapsed nothing can be done to restore
them.
Botrytis is caused by to high humidity for the heat in the greenhouse, increase
ventilation on these days.
Bitter fruits can be caused by slow growth; we suggest an increase in feeding. Open
pollinated varieties, such as King George, can be bitter if the fruits have been
pollinated. To prevent this all the male flowers should be removed.
To prevent Mildew on cucumbers ventilate on all possible occasions. Keeping the
floor of the greenhouse moist also helps.

Parsnip
Canker is the main problem when growing parsnips. This however can be caused by
several factors, soil acidity, irregular watering or the presence of too fresh organic
matter in the soil. As there is no spray to counteract Canker careful ground
preparation is a must. Lime the soil regularly and pay careful attention to watering,
particularly when growing long parsnips for exhibition on raised beds or in tubs.

Beetroot
Very few pests attack this vegetable. However they can be prone to the usual attacks
of Aphids so a careful watch should be kept for any infestation. Long beetroot are
usually sown in raised beds therefore there is little chance the seedlings will get Black
Leg, this is a problem usually associated with wet ground.

Lettuce
Aphids can be a serious pest as not only do they make the plant sticky they can also
spread mosaic virus. Spray with insecticide at the first sign, taking care to observe
harvest dates.
Like most other vegetables lettuce can bolt if they receive a check in growth.
However if they reach maturity without being used they will bolt, so it is advisable to
sow or plant only a few at a time.


Carrots
Carrot fly is the main pest for carrots. The fly is attracted to the carrot by the scent. A
good method to prevent an attack is to spray with garlic concentrate this works well to
disguise the smell of carrots. Use companion planting to hide the carrots. Avoid
disturbing the carrots during growth, sow thinly to avoid any thinning out, leave the
weed to hide the crop. Cover the carrots with horticultural fleece or grow them in a
raised bed. When growing long carrots for exhibition in a raised bed there is less
chance of them being spoilt by carrot fly.
Stony soil or ground that has had fresh manure applied can cause forked roots.

Potatoes
One of the main problems with potatoes is blight. It is a devastating condition. Spray
with Dithane 945 at the first sight of brown on the leaves. Plant hygiene is of great
importance. Do not compost or store any tops with blight on. Take them of site
completely or burn as soon as possible to prevent a follow on infection.

Source: http://www.masonette.co.uk/planting/problem%20solving.pdf