Why August is peak pest season – expert explains why infestations suddenly explode

If it feels like your garden has suddenly become overrun with pests, you’re not imagining it. August can be one of the busiest times of year for garden pests, with weeks of warm weather allowing populations to build before gardeners begin noticing the damage they leave behind.

By late summer, many pests have had plenty of time to reproduce, while warm soil, established plants and an abundance of food can create ideal conditions for populations to thrive. Add periods of summer rain to the mix and some pests can seemingly appear almost overnight.

But while slugs and damaged leaves might be easy to spot, some of the biggest problems are happening completely out of sight.

The experts at Nemasys beneficial nematodes explain why pest problems can suddenly escalate in August and late summer, which garden pests to look out for, and what gardeners can do now to bring them under control.

Why are there so many garden pests in August?

The sudden appearance of pests at this time of year is often the result of something that has been building for weeks.

Warmer temperatures speed up the lifecycle of many garden pests, while the abundance of actively growing plants provides a plentiful food source. By August, several generations may have developed and numbers can be considerably higher than they were at the beginning of summer.

Rain following a prolonged spell of hot, dry weather can make the change feel even more dramatic. Moist conditions encourage pests such as slugs to become more active above ground, while warm, damp soil can provide favourable conditions for pests developing beneath the surface.

It means gardeners may only become aware of an infestation once populations are already well established.

Slugs

A few wet August days can be enough to bring slugs back out in force after periods of hot, dry weather.

Slugs need moisture to move around effectively, so they tend to retreat into cool, damp hiding places when conditions are particularly dry. Once rain returns, their activity can increase dramatically, particularly overnight.

Young plants, leafy vegetables and late-summer crops can quickly become targets. Look for irregular holes in leaves, seedlings disappearing altogether and the characteristic silvery trails left across plants, pots and paving.

Rather than only tackling the slugs visible above ground, Nemaslug contains naturally occurring beneficial nematodes that seek out slugs beneath the soil surface, targeting them where they spend much of their time.

Vine weevil

Vine weevil is particularly troublesome because gardeners may not realise there is a problem until a plant begins to struggle.

Adult vine weevils leave distinctive notches around the edges of leaves, but the larvae beneath the soil can cause much more serious damage by feeding on plant roots.

Container plants can be particularly vulnerable. If an otherwise healthy plant begins to wilt or decline despite being adequately watered, it is worth checking the roots and compost for the characteristic creamy-white, C-shaped grubs.

Late summer is an important period to be vigilant, as eggs laid by adult vine weevils develop into root-feeding larvae.

Beneficial nematodes can be applied to the soil to seek out and control the larvae, tackling the pest below ground before extensive root damage occurs.

Chafer grubs

August is also an important month for gardeners keeping an eye on their lawns.

Chafer beetles lay their eggs in grass during the summer, with young grubs beginning to feed on grass roots beneath the surface. Because the damage happens underground, there can be little indication that anything is wrong initially.

Yellowing or thinning patches of grass can be a sign of an infestation, while birds and other wildlife digging into the lawn in search of the grubs can cause additional damage.

Timing is particularly important when controlling chafer grubs. Young larvae are more susceptible to treatment than older, established grubs, making late summer an important opportunity to act.

Nemasys Chafer Grub Killer contains beneficial nematodes that move through moist soil in search of chafer grubs, providing targeted biological control beneath the lawn.

Don't wait for the damage to get worse

One of the reasons August pest problems can catch gardeners by surprise is that visible damage often comes after a population has already become established.

Checking plants regularly is therefore particularly important at this time of year. Look underneath leaves, inspect the edges of foliage and pay attention to plants that suddenly wilt or stop thriving. Lawns should also be monitored for unexplained yellowing, thinning or increased bird activity.

Where pests are living below ground, beneficial nematodes offer gardeners a way to target them directly. These microscopic organisms occur naturally in soil, with different nematode species targeting specific garden pests.

The key is identifying the pest correctly and treating it at the appropriate stage of its lifecycle rather than waiting until extensive damage is visible.

How to apply nematodes to the garden

Applying beneficial nematodes is no more difficult than watering the garden.

Simply mix the nematodes with water according to the pack instructions before applying them evenly across the affected area using a watering can fitted with a coarse rose or a suitable hose-end applicator.

For the best results:

• Apply when soil conditions and temperatures are suitable for the particular nematode product being used.
• Water beforehand if the soil is dry.
• Keep the treated area moist after application to allow the nematodes to move through the soil.
• Apply during the evening or on an overcast day where possible, as nematodes are sensitive to UV light.
• Always follow the individual product instructions, as application windows and temperature requirements vary depending on the pest being targeted.

Once applied in the right conditions, the nematodes move through the soil in search of their target pest, allowing gardeners to tackle infestations where much of the damage is actually taking place.

Ends

Editors notes

Nematodes are naturally occurring microscopic worms, already present in our soil. Beneficial nematodes attack and kill targeted garden pests. They are compatible with organic farming, easy to use and can even be kept in your fridge!

Research scientists have isolated the nematodes that kill specific garden pests including Slugs, Vine weevils, Leatherjackets, Caterpillars, Codling moth and much more.

BASF’s state of the art production facility in the UK produces billions of nematodes in a form that is easily applied by gardeners. Over 20,000 different species of nematodes have been classified, although some estimates put the total figure closer to one million! BASF has the largest specialist nematode production facility in the world, growing trillions of beneficial nematodes for use in their Nemasys range of pest control products.

BASF experts are available for interviews, features and expert comment on biological pest control management, and product is available for reviews, competitions and product trials.