What Pests To Expect During Autumn-Winter

At a Glance:

Autumn and winter increase risks from pests and crop diseases, including rodents, slugs, and fungal infections. Preventive steps, such as clearing residues, tilling soil, rotating crops, and companion planting, help you protect overwintering plants and maintain soil health, ultimately securing strong spring harvests.

Why Autumn-Winter Pest Control Matters

Having your own allotment plot, or garden, is a fulfilling experience, with the reward of fresh produce and beautiful flowers. However, behind that beauty lies a hidden challenge: pests, including slugs and snails, pigeons, bacteria, and viruses - which can all lead to diseases and spoil crops.

Whether it's your first time growing or you’re an experienced gardener, you’ll always need to keep an eye out for diseases affecting crops. 

While garden pests in soil are present throughout the year, their numbers increase significantly during autumn and winter. Disease-causing microbes thrive in damp conditions, feeding on overwintering crops and spreading through compost, mulch, or leftover harvest scraps.

With rain and frost common at this time of year, diseases affecting crops are more likely. But with the right planning, you can still protect your plants and prepare for a strong spring harvest.

At Allotment Online, we offer a vast library of information on fruits and vegetables and the best ways to grow them. Read on to discover exactly which pests pose the biggest risk this winter and how to stop them before they take hold. 

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Common Garden Pests During Autumn and Winter

Before we explore the methods of winter garden pest control, let’s look at some of the pests we need to keep an eye out for:

Rodents

Rats and mice are present throughout the year, especially during winter, when other animals might be hibernating. These rodents can chew through plastics, fleece, cloches, and wires, and young plants are their favourite meal. If you have a garden shed, mice often favour it over open spaces, snacking on seeds and other “food sources”.

To protect your garden from rodents, keep the clutter away. Throw away any plant debris, and keep your mulch and compost bins covered. Regularly inspect your sheds and outhouses for any holes and gaps, and seal these immediately.

Grubs

While grubs hibernate during winter, they remain active from early autumn onwards and throughout spring. If you don’t find and eradicate the pupae during autumn-winter, they’ll be attacking your young seedlings as soon as the weather turns warm.

Finding grubs can be tricky, so it often helps to rely on natural predators of these garden pests in the soil, such as birds.

Squirrels

Squirrels might look cute, but they can be an absolute torment for plants and your gardening shed. They love chewing on wood, plastic, and even electrical wire. Young plants are also a favourite delicacy for squirrels, so if you’re planting new plants in your garden during autumn, make sure to keep an eye out for these furry beasts.

Insects

Insects such as aphids and spider mites often stay dormant in over-wintering plants. In warmer conditions, especially to the south of the country, with its slightly milder climate, these insects can chomp through any vegetation they come across, from broccoli to cabbage and Brussels sprouts.

With the effects of climate change more prevalent and temperatures rising, aphids have become common in the UK, even during the “cooler” months.

Slugs and Snails

Slugs and snails can remain active during the autumn and early winter months, especially in southern coastal areas. They often feed on young plants and seeds. Signs of their presence include holes and slime trails around young plants.

Diseases Affecting Crops

Some common diseases affecting crops during autumn-winter include downy mildew, alternaria, leaf spot and stem canker.

How to Manage Winter Pests

Are pests and diseases affecting crops in your garden, or do you just want to prevent this outcome?

In this next section, we’ll cover some easy hacks to manage the common problems affecting plants during autumn-winter.

Clean Crop Residue

There are plenty of vegetables and fruits to harvest during autumn. Once you’ve plucked the crops, you’ll be left with the uprooted plants and vines. If these are left in the soil, they can rot and attract pests like rodents and insects. 

Weeds are a great hideout for overwintering pests. Cleaning crop residue and weeds is an effective way to minimise the likelihood of a pest or disease outbreak.

Till the Soil

Tilling the soil (digging, turning the soil underneath, and bringing it to the top) should help you avoid several pests and prevent diseases affecting crops. 

Weevils, slugs, beetle grubs and cutworms are just a few of the garden pests in soil that you might spot during the winter. Their larvae, pupae and eggs usually lie dormant during the colder months. By tilling, you expose them to natural predators, like birds, which feed on them and minimise their presence. 

Exposure to cold temperatures and frost also kills the larvae, preventing them from maturing during spring.

Many fungal, bacterial, and viral plant diseases, such as clubroot, onion white rot, and powdery mildew, often remain on crop residue. When you dig the soil, these spores are displaced into the deeper soil layers, where they decompose faster and can’t latch onto any new plants that you sow in spring. Tilling also allows for better aeration and drainage.

Crop Rotation

Another of the best winter garden pest control methods is crop rotation. By alternating plants from different families, you can break the vicious cycle of pest outbreaks. For example, if your cabbage plants have been affected by clubroot disease, and you next sow turnips or Brussels sprouts (which are from the same Brassica family), you’re more likely to see your plants being impacted. 

This can be prevented with crop rotation. Instead of Brassicas, you could plant nightshades (aubergines, potatoes, or tomatoes) or legumes (peas or beans.

Companion Planting

There are many flowers that can be planted for garden pest control. Not only can you use them to control pest outbreaks, but they’ll also attract insects to promote pollination. 

Aromatic herbs are a safe bet for companion plants, as they can mask the scent of crops and deter any pests. Planting legumes, which are known as nitrogen-fixers, helps restore soil balance.

Here are our companion planting combination recommendations for autumn-winter crops:

Trap crops like spinach and radish are often sacrificed for the better harvest of other crops, as they draw pests away from nearby plants.

Share Your Growing Journey with Us on Allotment Online

Pests and diseases affecting crops can dishearten even the most seasoned gardeners, resulting in significant financial loss and leaving you with stunted or dead plants. With proper planning, you can avoid pests and get a good harvest.

Do you have a secret or tried-and-tested winter garden pest control plan? Share it with our community on Allotment Online. 

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