Organic Pest and Disease Control

From the Community Gardening in SA Resource Kit. Originally written by David Corkill for organic
gardening courses at Fern Ave Community Garden. May be reproduced for use in community

The aim of organic pest control
is to reduce damage to an
acceptable minimum. It is
neither possible nor desirable to
eliminate all pests completely
from the garden.
Natural balance
If the right conditions are
created in the garden, a host of
useful predators and parasites
can be encouraged to move into
the garden and do the pest
control for you. These conditions
are habitat (somewhere to live)
and food (pests or other food
used during different times of
the predators’ life-cycle). The
best way to maintain the
conditions required for a range
of useful organisms in the
garden is to grow a diversity of
plants and to avoid the
temptation to try to eliminate all
pests.
Some commonly found useful
garden predators and parasites
are birds, lizards, frogs, spiders,
ladybirds, hover flies, lacewings,
dragon flies, praying mantis,
centipedes, parasitic wasps, and
predator mites. Small children
with instructions to collect snails
can be useful too.
Soil Conditions
Improving soil quality can reduce the occurrence and impact of pest
and disease in the garden. Plants grown in good healthy soil will be
healthy and healthy plants are disease resistant. Fungi and moulds in
healthy soil produce natural antibiotics, cleansing the soil and aiding
plants’ disease resistance. Unhealthy plants, including plants raised on
artificial fertilisers, attract pests. Healthy plants will resist pest
attack and outgrow pest damage.
Organic sprays and dusts
Materials with natural insecticidal properties, which quickly break
down and do not cause contamination may be used to kill garden
pests. They will also kill many useful organisms so only use as a last
resort.
Pyrethrum - The dried flower heads of the pyrethrum daisy are used
to make an insecticide spray, Though non-residual, the spray is quite
strong and should be used with caution.
Neem - Oil extracted from the Neem tree has insecticidal, fungicidal
and antiseptic properties.
Quassia - The wood and bark of the Quassia tree, from South
America, is a mild insecticide. Quassia chips can be kept in long term
storage with little loss of potency.
Bacillus thuringeinsis - A micro-organism that acts as a stomach
poison for caterpillars. Sold under the name “Dipel”.
Sulphur - A yellow mineral used as a powder. Fungicide and miticide.
May damage tender plants.
White oil - Mineral oil used to control scale. Acceptable for occasional
use.
Repellent sprays
Home-made repellent sprays are prepared as per herb tea then
sprayed to protect vulnerable plants. Some have mild insecticidal
properties. They include garlic, rhubarb, cloves, aniseed, sage,
camphor, chillies, chives, onion, feverfew, wormwood, tansy. Mixing
soap with a spray improves its wetting ability and increases the
insecticidal effect.

How to Grow Your Own Edible Garden Class

Jeff Digging Holes

Helen Watering the No-Dig Garden Bed Planted with Herbs

The Contraversial Compost Bins

April, Jess and Helen fixing up another No-Dig Horseshoe Bed

Karen Digging holes for the grapevine

Sonya planting the grapevine

Sharon planting passionfruit grape

The Plan


Planting Stuff

I think we are into our fifth week in this class and it has grown. (See previous post about compost), this week we designed our 'fantasy' garden for Vines Road, and came up with some interesting ideas. Then we went out into the garden and planted Passionfruit Grape, aquired from Gail Thomas, and Globe Artichokes, generally tidied up the garden watered and weeded. The Garden is growing.

Tomatoes

There are so many varieties of Tomatoes in every shape or colour and every gardener will tell you that home grown are infinitely better tasting than shop bought. Grafted plants can be bought for a higher price and they produce potentially more fruit per plant, so a grafted tomato is a good idea if you are growing them in a pot or container, or have only a small garden. They are one of the easiest plants to grow and very good for a beginner.
The potato is in the same family as tomatoes, Solanaceae but while their fruit while similar to tomatoes it is poisonous. Tomatoes originated from central to South America. Their Latin name means wolf peach as they were commonly eaten by the wild dogs. I have heard of cats eating tomatoes. Apparently they lie under the bush like great empresses and pluck tomatoes from the bush. China produces 31.6 million tones a year!! Last year in Geelong felt like a bumper crop for most people it was ideal tomato conditions, a dry long summer.
Is a tomato a fruit or a vegetable, botanically it is a ‘berry’ as it develops from the ovary of the plant after fertilization. The fruit contains hollow spaces full of seeds and moisture. In America the definition effects the tax paid on it as in 1887, U.S. tariff laws that imposed a duty on vegetables but not on fruits caused the tomato's status to become a matter of legal importance.
Heritage or Heirloom varieties give a variety of shape and colour from the 3 coloured purple to green Paul Robeson to the cream coloured Snow White. In companion planting they like to be with Parsley, Asparagus, Basil, Cabbage, Carrot, Onion, Pea, and Sage and hate Potatoes and Fennel. As a general rule of thumb you should never plant vegetables from the same family after one another, so don’t plant Tomatoes, after other members of the Solanaceae family, such as Capsicum, Chilli’s, Eggplant and Potatoes. In Geelong Tomatoes are best planted September until March, although they can be started earlier in the green house, in August. Don’t be tempted to sow seed any earlier as they will just grow at the same rate as those sown later, so you are just taking up valuable space in the greenhouse. At Geelong Botanic Gardens this year we are planting 15 varieties of Tomato this year. I only hope we have room for them all. Keep an eye out for
Yellow Pear
Pink Ping Pong
Wapsipinion Peach
Hillbilly
Thai Pink Egg
Yellow Perfection
Yellow Sausage
Paul Robeson
Yugoslav ( I personally grow this one every year and it is defiantly a favourite)
Tommy Toe
Cherry Mix
Snow White
Purple Calabash
Buddiah
Seeds germinate in 7-10 days at temperatures above 15oC. Once the seeds have germinated and are up to their second or third set of true leaves, then it is time to pot them up. Tomatoes unlike other plants can be planted deeper in the soil; in fact this gives a healthier and stronger plant. The seedling can be planted with the leaves 5cm above the soil. It is also better to plant out the Tomato when it is slightly pot bound as this plant will produce more fruit. Remember to harden off your seedlings in a sheltered area, maybe even bringing them in at night, until the temperatures are regularly over 15oC.
Tomatoes are relatively pest and disease free if the soil is kept moist; don’t overwater as a slightly dry soil produces better fruit. The simplest tomato to grow is the Cherry type, if your soil is mulched well with straw so that the fruit does not come in direct contact with the soil, then this could be grown without staking and allowed to trail along the ground. Other taller types such as Bush or Climbing need staking, there are several ways.
1. Create a triangle with three stakes around your plant and then make ‘rings’ with wire 20cm apart up the triangle
2. Create a lattice using two stakes and bamboo canes tied vertically across, the tomato plant is then tied into this as it grows and any outward growth trimmed so that it grows almost flat against the ‘lattice’. When it reaches the top, the tips are pinched out.

The lower leaves of the plants are removed to create more airflow
Regular watering and occasionally feeding with liquid seaweed will ensure a disease free crop.
The main problem in Victoria is fruit splitting due to fluctuating soil moisture. Blossom End Rot, brown sunken areas at the base of semi-mature fruit is caused by lack of calcium and fluctuating soil moisture. A sprinkling of Dolomite Lime, watered in around the base of each plant should solve this problem.
Tomatoes are the easiest fruit to save seed from. Choose the best fruit and allow ripening until squishy. Then separate as much of the seed from the fruit, and drop the mass into a jar of warm water and leave to soak for a few days. The flesh will float to the top, decant the water and flesh leaving the seeds; they can then be dried out on paper.