Q&A - Pests

There are all sorts of garden pests that can affect your plants and lawns. You might also like to look at our Q & A's on plant diseases for things such as Apple Scab, Rose Blackspot and replant disease.

Q. I have a plastic compost bin and, to my untrained eye, it looks like it is thriving with plenty of good household waste being worked on by lots of creepy crawlies. But! Every year the bin is always home to ants. When the time comes to empty it I fill bags for use later & douse each bag with ant powder &, when I need compost, the ants are gone. Is this the correct thing to do? Are ants the pests that I perceive them to be? Is there any way to avoid their presence in the first place? I would welcome your advice.

A. There is not much you can do about ants. They really don't do any harm so providing they are not marching into the house they can be left alone and let their natural predators feed on them. Ant powder does work but if you are going to spread the compost on the garden anyway they will move off and many will be eaten by birds and other wildlife.

Q. How do I keep cats out of our front and back gardens?

A. It is almost impossible to keep cats out of the garden. There are some cat repellents available but they are not always successful. Try planting so that there is very little soil exposed. It does however take a few years for the plants to grow sufficiently to achieve this so in the meantime mulch with a 5-7.5cm (2-3") layer of well-rotted manure or bark, which for the most part works. (Don't use peat or potting compost as they love this!)

Q. We have just obtained a pointer puppy, who will normally only wee on the lawn (male dog) and the lawn now has brown patches. How can we eradicate these, and will the problem persist as he gets older?

A. The first thing to do is try and keep the dog off the grass, and if it does wee on the lawn hose the patch down straight away. For the brown patches the best thing to do is to cut them out and either reseed or turf, otherwise weeds will take over. Turfing is the quickest method and under the circumstances probably the most robust.

Q. I suspect I have Eel Worm in my garden in so much that I can never keep any Daffodils, I have to renew the bulbs every year. I've been told the only thing to do is not to plan anything for 3 years but that seems a long time to me. I only have a small garden about 1m x 3 m. Is there anything I can get apart from sterilising the garden.

A. I am afraid there is no effective chemical control for Eelworm and you should certainly not plant bulbs for several years, but other plants should be unaffected. Try planting your bulbs in pots away from the infected areas instead.

Q. Please could you yell me how to get rid of mealy bugs, which I have in my conservatory on an orange tree. I have tried various insecticide sprays and picking them off by hand they still come back.

A. Mealy bugs are difficult to get rid of as they have a waxy coating, which stops chemicals sticking to them. The best way is to rub them off by hand or hose them off with a pressure washer, although you have to be careful not to damage the leaves of your plants.

Q. How do I get rid of a mole that's running rampant under my lawn?

A. There is really no easy way to dissuade moles but you could try a device that emits a high radio frequency and is inserted into their runs or you can buy smoke sticks. You could also buy traps but try other solutions, as moles are generally good for the soil.

Q. I believe that I have just discovered two New Zealand flat worms in my garden. They were grey/black in colour with a red band and about four inches long. I would be grateful if you could confirm physical characteristics and any tips you have to get rid of them.

A. The New Zealand Flatworm grows up to 17cm (7") long and is purplish-brown on its upper surface although the colour fades towards the side of the body. It is mainly found in Scotland and Northern Ireland although it is spreading southwards and has been found in some southern counties. There is no control that is known to be effective apart from squashing the worms when found.

Q. I have small black-like midgets in the soil of a few of the houseplants. Is it possible to kill them without throwing out the plant or soil? They fly around room where the plants are.

A. It sounds as if the problem is sciarid fly (fungus gnat). They are a nuisance rather than a problem and feed off dead leaves so you should make sure leaves are cleaned up. You can also buy sticky yellow traps, which can be hung close to the compost, or a predatory mite is available from some specialists. You can also treat the compost with an insecticide containing permethrin or sprinkle with lindane dust.

Q. Please would you tell me what I can do to make my Garden less attractive to the entire Squirrel population in this area? Not content with stripping my Walnut Tree completely bare they have now turned their attention to my potted bulbs and have dug up and eaten almost half of them already! I've tried covering the pots with a variety of things but these Squirrels are clever chaps and still manage to gain access to the bulb. All I find in the mess and well eaten bulbiIs there any chemical, which they hate, the smell of please that will not harm my plants and/or bulbs?

A. Squirrels can be a real problem and are difficult to discourage or eradicate as they travel across a wide area in search of food. The only thing you can do is to use wire netting over plants and bulbs to stop the squirrels getting access.

Q. For the last two years I have had the problem of wireworms attacking my potatoes. I have cultivated my allotment for 8 years and use rotation exposing the soil for birds to eat them. This year I used chlorophos to no avail. The RHS advises the use of pirimiphos-methyl. Can you please give some advice.

A. Wireworms should be kept under control by continuous cultivation and the damage kept under control by lifting your potato tubers as soon as they have matured. Pirimiphos-methyl is certainly a recommended chemical control and is the active ingredient so you will need to ask at your local garden centre for the product they sell that contains this.

Q. How can I get rid of woolly aphids on my cotoneaster? I have tried everything and although it clears for a few days they return worse than before.

A. Heavy infestations of woolly aphid towards the end of a year are difficult to control and the best thing you can do is to try and rub them off the stems. In spring spray with an insecticide containing any of the following: pirimicarb, dimethoate, heptenophos with permethrin or pirimiphos-methyl.

Q. Last summer I had a new lawn laid. Everything is fine except that I seem to have the biggest worm casts in the world. Do you have any tips to reduce or eliminate this problem?

A. Worms really are good for your soil as they are a sign of good soil and they help improve the drainage of your lawn so if the problem is not too serious you would be best to persevere and keep sweeping the casts away. You can dissuade worms by raising the acidity of your soil by using a fertiliser each spring, which contains sulphate of ammonia (such as lawn sand). Earthworms are generally mostly a problem in spring and autumn during damp mild weather so you should not have a problem for too long a period.