• Olive Tree Gardens

The pest test!

You may have recently noticed an increased number of critters buzzing and flying about and generally being a nuisance! They disturb your mealtimes and they munch on your plants. But which ones should you get rid of and which should you honour?

This video from Project Diaries is a handy insight into the 10 most beneficial insects that you should encourage to thrive in your garden, and it tells you how to do so as well as outlining some of the pests that these insects help to get rid of. From the humble bee to the striking ladybird, these 10 critters are a gardener's best friends.

Moving onto those that gardeners love to hate! The top 10 most common pests that cause damage to your garden are (drum roll, please)...

1. Birds

Wood pigeons are particularly troublesome, pecking at your leaves and attacking your flowers. Robins are known to snack on garden fruits, vegetables, and even seeds in the ground.

2. Caterpillars

They can destroy a garden overnight, destroying foliage and causing plants to collapse. Many leave their webbing on the plant.

3. Slugs and snails

They eat holes in leaves and they are particularly damaging to seedlings and new growths.

4. Aphids

They feed on sap, inflict viral diseases, encourage the growth of mildew and cause decay in plants. They are recognisable by the sticky substance, honeydew, that they excrete on plants, on which moulds grow.

5. Flea beetles

They can travel quickly by jumping (like a flea) and they chomp holes in your leaves.

6. Codling moths

You can all picture the maggoty worm that everyone fears biting into - if you've ever experienced this, then it would likely have been the larvae of a codling moth, who feast on apples, pears and, occasionally, other fruits.

7. Thrips

Thrips really are quite nasty; distinguishable by the mottled foliage they leave in their wake, they are microscopic and feed on sap.

8. Mealybugs

These small and fluffy bugs also suck the sap from plants and they can breed quickly. Like aphids, they excrete a sticky substance called honeydew, which allows the growth of sooty moulds.

9. Vine weevils

Adult weevils nibble on foliage, leaving it notched, whilst the larvae do the most damage, eating the plant's roots, thereby killing them.

10. Leaf miners

This collective term describes various maggots that leave trails of discolouration on leaves, which is generally harmless to the plant, leaving cosmetic damage only.

Image by Shiraj Pradhanang on Unsplash

It is important to be vigilant and keep on top of these pests, as they can get out of hand quickly. First, diagnose the issues you are facing in your garden, and then research them to find out the most effective way to discourage them from spreading. The RHS has an excellent compendium of pests online, where you will find more detail on all of the above-named critters; https://www.rhs.org.uk/advice/plant-problems/pests.

Biological pesticides

The most organic cure for pests is to squash them between your fingers, but clearly, this can be quite a task if you do not keep on top of it! Introducing predators, such as various species of wasp, mite, and ladybirds, is an effective way to reduce the population of many pests naturally, so research the pest and its predator to know what will be best for your garden.

You can purchase pathogenic nematodes online, which are biological parasites that can be introduced to keep pests under control without damaging the plants themselves. As they are living creatures, they must be used very soon after purchase, and they may need to be reintroduced every year as they can die in the winter. But they need time to establish themselves, so use them before your plants become heavily infested.

Healthy plants are less likely to be susceptible to an attack so mulch new plants after watering to help them retain moisture and slow the rate of evaporation from the ground surface. Keep your garden tidy and weed-free, as weeds can in fact host pests and diseases.


Biological controls are always advised over chemical ones, unless in severe cases, as long-term use of synthetic chemicals can do more harm than good, killing all insects, including the beneficial ones. If using chemicals, spray them late in the evening when there are likely to be fewer beneficial insects present.

Need advice on any of this? Get in touch with us and we can help you to stay in control of your outdoor spaces. We have years of experience in the field, so don't delay! Enlist us to keep those slugs at bay!

Thanks for reading, and please pop back soon.

Olive Tree Gardens

Your local gardening services company, based in St Albans


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Blog cover image by Krzysztof Niewolny on Unsplash


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