Garden Pests and Diseases - Insects
Most insects in the garden are harmless, in fact quite a lot of them are beneficial, pollinating flowers and preying on other damaging insects.
| Insect | Symptoms | Suggestion |
| Ants | They herd and milk greenfly. There nests can damage a lawn. | Use an ant powder or Nippon ant killer. Instant coffee also seems to repel them, particularly in the kitchen. But using this is probably more expensive than using ant powerder |
| Cabbage-root fly | Place collars at soil level around the stem of the brassica. | |
| Carrot fly | Damage to the crop. | Carrot fly can be confused into not laying eggs on carrots by inter planting your rows with onions or pungent herbs such as sage, chive, rosemary or parsley. |
| Leaf cutter bee | Near perfect circular / semi circular holes cut in rose leaves. | These bees cut the leaf to use in building their hollow cigar shaped nests. It's difficult to catch these bees at work and there is little that you can do to prevent the damage. |
| Leaf miner | Erratic lines on the leaves of current bushes and fruit trees. The leaf miner burrows between the layers of leaves, but doesn't do any lasting harm to the plant. | Pull off the infected leaves and burn. There is no need to spray with an insecticide. On decidous plants the leaves will fall and it is unlikley that the problem will reoccur. |
| Mealybug | For a biological control in an enclosed space, at the first sign of attack introduce the predator Cryptolaemus montrouzieri. | |
| Millipedes | Usually eat dead plant material but can also eat the roots of plants and seedlings. | It's not worth chemically treating, although slug pellets will kill them. Clear garden rubbish to reduce hiding places enabling birds to eat them. |
| Red spider mite | For a biological control in an enclosed space, at the first sign of attack introduce the predator Phytoseiulus persimilis mite. | |
| Root aphid | Bugs around the roots of house plants. | Use plant pins that contain a systemic insecticide |
| Scale insect | Brown scale on stems and leaves of fruit bushes, left untreated this can kill the plant. | Spray with a winter tar wash. Tar wash applied other than in winter will damage foliage and fruit. |
| Slugs | General damage to new shoots and plants. Fleshly leaved plants disappearing overnight. | Slugs don't like travelling over sand, gravel or egg shells. Salt and slug pellets will kill slugs. Add shreaded oak leaves to the compost mix, slugs don't like the tanin they contain. Encourage birds, frogs or a hedgehog to your garden, they eat slugs. Create a slug pub - pour beer into a bowl, put a small jar in the middle of the bowl and place a saucer on top of the jar (this will keep animals from drinking the beer and the rain from diluting it). Slugs are attracted to the smell of the beer, they drink it become intoxicated and drown - shame :-). Copper wire carries a mild electrical charge, which deters slugs. |
| Whitefly | Damage to the crop. | French Marigold (Tagetes) and basil (Ocimum basilicum) discourage whitefly from attacking plants by masking their smell. This is particularly effective in the greenhouse. |
| Woodlice | They normally feed on dead plant material but they will also eat seedlings. | Dust them with a contact insecticide or use slug pellets. |
