Anticipate and deal with autumn pest risks

Anticipate and deal with autumn pest risks

Autumn, the sowing period for winter cereals, can present major pest risks such as aphids, leafhoppers and slugs. They threaten crop health and thrive in specific weather conditions. This is why it is essential to closely monitor the weather conditions of your crops to anticipate future risks.

What are the risks associated with autumn pests? What weather conditions favour their development? And how can connected weather help you anticipate these threats and protect your crops? Find out more in this article.

Aphid risks

Aphids are small, sap-sucking insects that multiply quickly. They feed on plant sap, thereby weakening crops. These insects also carry diseases from one plant to another. It serves as the primary carrier of the Barley Yellow Dwarf Virus (BYDV).

Winter cereals, such as wheat and barley, are particularly vulnerable to aphid attacks in autumn.

Weather conditions favourable to aphid risks

The ideal conditions for aphid development are between 12°C and 25°C. Indeed, above 12°C, winged individuals can resume their flight and migrate towards healthy crops. The speed and intensity of their reproduction increases with temperature. Once temperatures exceed 30°C, conditions become unfavourable for aphid infestations.

Conversely, when temperatures drop below 3°C, aphids become inactive but can still survive.

An ideal environment for autumn aphids is established when a moderate summer is followed by a gentle autumn.

Assess the aphid risks on your crops

Prior to taking action on your crops, it's crucial to conduct thorough observations and continuously monitor pest activity, starting from the emergence of cereals and continuing until the onset of the first frost.

To most accurately evaluate aphid pressure on your crops, conduct your observations as follows:

  • in high-risk zones like grassy borders or areas adjacent to hedges
  • on a series of 10 plants
  • in bright and warm daylight hours, aphids are easier to spot.

Trigger an intervention

Application is then recommended when 10% of plants carry at least one aphid, or when their presence continues on the crop for at least 10 days (regardless of their number).

Leafhopper risks

Leafhoppers are insects that extract nutrients from plant sap and can also act as disease vectors, specifically transmitting the Wheat Dwarf Virus (WDV).

They are known to attack winter cereals and cause significant damage by weakening crops.

Weather conditions favourable to leafhoppers

As for aphids, the ideal conditions for leafhopper development are mild temperatures above 12°C.

Evaluate the leafhopper risks on your crops

In order to best reduce the leafhopper risk on your farm, you can position adhesive plate traps on the ground at a distance greater than 20 meters from the field's perimeter shortly after sowing. We reccomend you carry out an observation of these traps twice a week.

Piège englué avec pucerons et cicadelles observé en octobre 2023 en Hauts de France
Sticky plate for trapping pests - photo credit: Arvalis

It is also possible to make observations directly on your crops.

Trigger an intervention

It is recommended to trigger an intervention when the number of leafhoppers captured weekly is greater than or equal to 30.

Slug risks

Slugs are plant-damaging organisms that consume leaves and young plants. They are most active during autumn and pose a threat to straw cereals from the emergence stage up to the 3-4 leaf stage.

Weather conditions favourable for slugs

Factors favorable to slug development include:

  • Elevated humidity levels (exceeding 60%) are conducive to their growth.
  • Consequently, frequent rainfall greatly supports their development..
    average temperatures between 10 and 20°C

When the weather is drier and colder, slugs migrate into the soil, waiting for more favorable conditions to return.

The development of slugs is influenced by factors other than the weather such as the type of soil, tillage or rotation for example.

Assess the slug risks on your crops

Trapping can be conducted during periods of high humidity. Vigilant monitoring before and after crop emergence is imperative.

Trigger an intervention

Here is the link to AHDB, this link provides conditions favourable to slugs, damage incurred to plants by slugs, how to monitor slugs in your field and any neccessary information regarding the control of slugs.

Connected weather for your fight against pests

Connected weather allows you to access live readings of the weather data from your crops and anticipate risks thanks to reliable weather forecasts. Enhance the identification of high-risk periods and conduct thorough observations in your fields.


Sencrop application

When pest pressure is identified, connected weather helps you plan your interventions. Thanks to your crop surveys and forecasts, identify the best treatment window in the blink of an eye. Thus ensuring the effectiveness of your interventions.

Discover the Sencrop solution

Create your profile, connect to a station close to your plots and benefit from a free trial, without obligation.

Try the application for 14 days