Mushrooms growing in your garden are usually a good sign, as it means that your soil is healthy and rich in organic matter. However, there is one little-known benefit that comes with growing fungi in your garden - that it can deter pests, including slugs, snails, and aphids, all without the need for harmful chemicals.

Mushroom expert Waine Delaney at SporeBuddies has shared the secret to using mushrooms as pest control, including how to make your own mushroom pest repellent to promote a healthier and more resilient garden ecosystem free from chemicals. He explains that entomopathogenic mushrooms are the best at deterring pests. This fungus produces microscopic spores that land on the insect, germinate, grow, and consume the insect from within.

Although they can control pests, they do not harm beneficial insects such as bees, butterflies, or ladybirds, and they are completely safe for humans, pets, and birds. Entomopathogenic mushrooms, in liquid and powder form, can be purchased from garden centres.

Edible mushrooms

However, it isn't just entomopathogenic mushrooms that can help with pest control; any edible mushrooms you currently have in your fridge can also be used. These mushrooms often contain certain bioactive compounds that are antifungal, antimicrobial, and insect-repelling.

Different types of edible mushrooms help deter different pests, so ensure you have picked the right type before using fungi for pest control.

What mushrooms should you use?

• Oyster mushrooms are good for deterring slugs, snails, aphids, and greenflies.
• Shiitake mushrooms will deter caterpillars, aphids, and greenflies.
• Button or white mushrooms can protect your plants from greenflies and aphids.
• King oyster mushrooms will deter slugs and snails.

How to make your own mushroom pest repellent

Waine has shared some tips for making your own pest repellent from any mushrooms you may have in your fridge. Start by placing the mushrooms in a blender or food processor with water, and blend until you get a smooth mixture.

Then, strain the mixture through cheesecloth or a fine mesh strainer into a jug. This will help remove any remaining large chunks that could block the spray from working effectively.

Waine adds that there are a number of essential oils that you can add to the spray: "You can also increase the pest-repelling by adding things like peppermint oil, rosemary, garlic extract (good for slugs and snails), or neem oil (good against caterpillars, greenfly, and aphids)."

Carefully pour the mixture into a spray bottle, adding more water if required.

Shake well before each use and spray directly onto the leaves, not forgetting the underside, stems, and around the base of your plants. Reapply every few days, especially after it rains.