Pests and diseases in plants


Find out how to best survive diseases, pests and bugs in your garden. Wherever possible don't use chemical solutions without first trying other methods of eradication. You will find many helpful tips here:

Indoor plant pots should always be spotlessly clean and then be filled with a sterile potting mixture. If you use garden soil you will introduce bugs and pests right from the word go.

Leaves on indoor plants can be washed with a soft cloth and soapy water. Use a magnifying glass to inspect for pests. Especially look underneath the leaves.

Use fish and seaweed emulsions to boost your plants' condition so that bugs and diseases will be less likely to affect them.

Airborne insects such as cabbage butterflies dislike strong bitter aromatic herbs. Plant some Wormwood close by as a deterrent.


Tips and hints on how to rid your garden of diseases, pests and bugs

Recipe for natural insect spray. In your blender place one large garlic clove, an onion, 1 teaspoon cayenne pepper and 1 litre of water. Blend well. Pour into a large plastic juice or cordial bottle. Add another litre of water and a tablespoon of liquid soap. Shake well. Store in the fridge.


Spray the whole plant, including underneath the leaves with a dilute solution of soapy water. Then spray the plant with clean water. Planting marigolds as companion plants is said to deter aphids too. Ladybirds are great consumers of aphids. Plant garlic chives in close proximity to plants that are susceptible to aphids. You can also use onion plants and normal chives but these die off whereas garlic chives last forever. Lavender plants exude a strong aroma that they mask the smell of roses and hence aphids are not tempted to invade the rose bushes.

Black Spot

Black Spot is a fungal disease and it thrives best in warm, humid conditions. It is infamous to rose growers. The disease starts off as a black spot on a rose leaf. Eventually the leaf turns yellow and drops off. some susceptible rose bushes can die from this disease. Fungal diseases thrive on humidity so when watering roses always water them at ground level. Don't water their leaves. Using Sulphate of Potash will decrease the incidence of Black Spot on your roses. Give each rose bush 100 - 150 grams of it about four times per year. Sulphate of Potash increases the thickness of the plant's cell walls making it more difficult for the Black Spot spores to wriggle their way into the plant. A fungicide can be made from common kitchen ingredients. Mix together 2 teaspoons of Bi-Carb, 5 litres of water and a few drops of detergent. This combination will work as a spray-on fungicide.


Manually catch them and squash them. Encourage birds to your garden as they will enjoy eating the caterpillars. If necessary Dipel or Derris Dust can be used to kill them.

Mealy Bugs

These look like there are tiny tufts of fluffy white cotton wool on your plants. They tend to gather underneath leaves and also in the joints where the leaves meet the stems. Mealy bugs have a waxy coating on them and it is sometimes difficult to get through the waxy barrier to kill them. Wherever possible try to kill the mealy bugs with alcohol. Dip a cotton bud in the alcohol and dab it on each mealy bug. You may need to repeat this process over and over to finally get rid of them. If you have to resort to a chemical solution please be careful and observe all warnings when using the product.


The following plants deter mosquitoes: rosemary, catnip, marigolds and ageratum. Rosemary and catnip can be crushed and rubbed onto your skin as well. It is the actual crushing of the plant that releases the odour that mozzies don't like. Don't rub marigolds or ageratum onto your skin.

Slugs and Snails

These slimy creatures each have both female and male reproductive organs. So they can mate very easily and produce lots of problem babies. For removal the best option is to search out all possible snail and slug homes within your garden. Tidy everything up in your yard. Remove any weeds and dead organic matter. They like hiding underneath long grass and weeds. Look beneath any pot plants, check areas that are dark and tucked away. Check around the back of the shed, around your compost heap and especially alongside any any spare bricks and timber you are saving for future projects. At night head outdoors with a torch and follow their shiny trails. Now put out some traps to catch the ones you have missed. Find a shallow bowl and put in some stale beer. They will be attracted and will then drown themselves in the beer. Keep an eye out for their eggs - they look like tiny jelly balls. Destroy them. Spread oat bran around. It kills slugs and snails. They don't like gravel or other rough surface ground coverings such as wood chips. So, spread something similar around your plants and it will deter the them from reaching the plants. If you have to resort to baits please consider what other garden creatures might be killed as well as the slugs and snails. If you use baits then put them in places where pets won't be able to reach them. Possibly put them under a piece of corrugated iron that has a brick or two on top to stop it being moved. There is now an organic certified snail bait available that is safe around pets and children.

Spider Mites

These critters are difficult to see with the naked eye. If your plants are looking yellowish -brown and you have eliminated other causes then spider mites could be the problem. Check out the plants with a magnifying glass to be sure. They are difficult to control without using chemicals. If you are forced to resort to a chemical solution then please read the instructions very carefully. The chemical you purchase must say on the label that it is suitable for spider mites. General insecticides won't work. Dry air seems to encourage spider mites to breed so keep up the moisture wherever possible.


These are hard to see. They are tiny little brown insects and they will want to fly away when you get near them with sprays. This is another pest that Ladybirds enjoy eating. Try using an insecticidal soap to get rid of them.


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