Larvae in the grass

With the approach of spring, life under the ground starts up again. Insect larvae of different types and shapes can be seen. In this greenkeepedia entry we will review them.

Insect larvae are only one stage of insect development, during which they feed intensively and grow in order to mate and reproduce.

In order to act in time, it is important to know the different types of larvae, which are differentiated by their colour, the shape of the head, jaw and the pattern on the abdomen.

Root damage is severe and water stress should be avoided as far as possible.

The larvae are 2 to 7 cm long and normally live below the surface of the turf in the first few centimetres, moving to deeper areas during the winter. The most damaging pests to turfgrasses are usually annuals. These pests during the larval period affect the roots and during the adult period they affect the leaves, so the damage is enormous.

Normal damage tends to be dry or withered patches, where the soil is well watered and salinity is not high; these patches are common in spring, when the insects emerge from their winter dormancy. Another good indicator of the presence of pests is damage to the canopy by birds or small mammals looking for these larvae to eat.

Each field must have its own Integrated Pest Managementand even see if your countries have legislation determining this aspect, but we are going to make some favourable recommendations on larval management.

Action should be taken if:

• 5 to 10 larvae per square metre are found in non-irrigated areas.
• 15-20 larvae per square metre are found in irrigated areas.

Insecticides are traditionally used, but biological solutions such as the use of Bacillus popilliae or Bacillus thurengiensis are also being explored.

Mature larvae are more resistant to insecticides, so rapid action is the key to avoiding major damage. In order for damaged turf to recover from root damage, it is necessary to act and avoid water stress as much as possible. And actively promote growth in these areas.