Organic Garden丨2017 Volunteer Training IV


Common Pests and Their Natural Enemies in Local Area:

  • Name: Aphid

Harm: Aphids would cluster and harm the young leaves, shoots and flower buds. They drink the sap from these parts of the plants, causing the plants to grow abnormally, become dwarfed, or even wither to death.

Natural Enemy: Ladybug, hoverfly, parasitoid wasp, aphidoletes aphidimyza, crab spider, lacewing fly, etc.

  • Name: Cabbage Looper

Harm: Cabbage loopers would bite the leaves of the hose plants. In the most serious case, all the leaves would be eaten up by them and only the veins and stems would be left, causing the total loss of the plants. Such insects could easily cause soft rot of the cabbage. They could also dive into the leaves of cabbages and their stool would pollute the heart of the cabbage.

Natural Enemy: Parasite enemies include apanteles glomeratus, cotesia rubecula, etc. Predators include kissing bug, wasp, spiders, etc.

  • Name: Snail

Harm: Snails parasitize lawns and garden plants. The leaves become incised and the cortex of the branches could also be eaten. Fruits would become cavernous after being bitten.

Natural Enemy: Chickens, ducks, birds, toads, turtles, hedgehogs feed on snails. Fireflies mainly feed on snails.

  • Name: Slug

Harm: Slugs have complex feeding habits and a huge amount of food intake. They mainly cause damage to various kinds of vegetables and they feed on the leaves, causing the leaves to be full of holes. Their excretion would pollute the fruits and decrease the value of them.

Natural Enemy: Ground beetles, birds, toads, etc.We can also sprinkle salt on the slugs so that they would die of dehydration.

  • Name: Red Spider Mite

Harm: Red spider mites prefer hot and dry environment and they usually cluster at the back the leaves, spinning webs and causing damage to the leaves. On the damaged leaves, there appear grey and yellow spots or patches. The leaves would turn orange and fall off until no leaves are left.

Natural Enemy: Many types of ladybugs, predatory mites, lacewing flies, flower bugs, rove beetles, cladosporium cladosporioides, etc.

  • Name: Grub

Harm: Grubs are the larvae of scarabs. They harm the roots and rhizomes of nursery stock. The adults would harm the leaves of apples, causing the plants losing all their leaves. This kind of insects is considered as hard to be controlled both at home and abroad.

Natural Enemy: Many birds, amphibians and reptiles are the enemies of grubs, including turtle doves, cuckoos, hoopoes, magpies, crows, frogs, toads, and lizards. We can also take advantage of their phototaxis and use light traps to eliminate them.

  • Name: Mole Cricket

Harm: Mole crickets in the soil would bite the seeds and seedlings that are newly planted, or they would cut off the roots and stems, causing the deaths of the plants. The damaged roots would be a muddle. When these mole crickets move underground, they would create tunnels in the topsoil, resulting in the roots exposed to the air and losing touch with the soil, and the plants would die of dehydration.

Natural Enemy: Large predatory insects including beauveria bassiana, birds, mantis, tiger beetles, etc.

 Companion Plants to Prevent Pests:

Choose proper associated plants and plant them with the vegetables. This method can help us disinfest and attract beneficial insects. Some common combinations are as follows:

  • Basil: It can repel flies, mosquitos and thrips. It can also promote the growth and improve the taste of tomatoes. Note that it cannot be planted with roe.
  • Sage: It repels pests including cabbage moths, beetles, flea beetles and carrot flies; and it attracts helpful insects as well. It can promote the growth of broccoli, cauliflower, rosemary, cabbage, carrot and strawberry. But it should not be planted with cucumber, the onion family and roe.
  • Onion: It repels carrot flies. It can strengthen the disease resistance of strawberry. It is a wonderful companion of carrot, beet, cruciferous vegetables, lettuce, tomato and strawberry. But it must not be planted with summer savory or beans.
  • Rosemary: it repels cabbage moths, been beetles and carrot flies. We can put the leaves of rosemary on the roots of vegetables. It is a great companion of cabbage, beans, carrots and sage.
  • Garlic: It repels Anomala corpulenta Mots, aphids, root maggots, snails, carrot flies, codling moths, white flies and Neoempheriasinica. It is a great companion of rose, raspberry and fruit trees.
  • Mint: it repels cabbage moths, ants, mice, flea beetles, fleas, aphids, and sciniph. It attracts helpful insects such as bees, hoverflies and earthworms. It is a good companion of cruciferous vegetables. It also promotes the health of cabbage and tomato.
  • Coriander: It repels asparagus beetles. When it flowers, it attracts parasitic wasps and hoverflies. It is a great companion of tomato and asparagus. If planted together with rose, the coriander will make the fragrance of rose even richer.
  • Scallion: it repels carrot flies, and promotes the growth of carrot, celery and other vegetables from the onion family. But it must not be planted with beans.

Ecological Pest Management

  • Besides companion plants, we can also use the natural enemies of pests to control them.
  • Make sure that the vegetables are planted neatly and trimmed on a regular basis to maintain ventilation. This can help us prevent some pests such as red spiders.
  • We can also take advantage of the phototropism of some pests and use light traps to kill them.

Low Toxicity Natural Pesticide DIY

Ingredients of natural pesticide for 350ml:

  • Water:300ml
  • Dish soup:1/2 tbsp
  • Dried chili pepper:5, cut to pieces
  • Garlic:2 cloves, cut to small chunks
  • Orange zest: from one orange (optional), cut to pieces


  • Mix water, dish soap, chili pepper, garlic and orange zest in a bowl
  • Steep overnight
  • Run through a fine strainer
  • Transfer the solution into a spray bottle


  • The orange zest refers to the orange tissue at the outermost layer of an orange.
  • Cut all the ingredients into small pieces before mixing them, in order to prevent the spray head from blockage after running through the strainer.
  • The purpose of using dish soup is not to kill the pests directly with it but to keep the pesticide attached to the pests. So try to use organic and harmless dish soup to reduce the negative influence on the soil and plants.
  • The pesticide is irritant and should not enter one’s eyes. So be cautious when use them during class. It is recommended that each class use one or two final products. And the teacher should control the use of these bottles of pesticides.

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