The apple sawfly has only one generation per year compared to the codling moth, but destroys 4-5 apples, which then fall. The adult wasps appear in late April / early May and feed on pollen. Their activity is highest when the sun intensity is the strongest, around noon. The females saw into the calyx with their ovipositor and lay one egg per flower. On average, they lay about 30 eggs.
What damage is caused by the apple sawfly?
The first damage is caused by the first larval stage, which eats directly under the skin of the small fruit. The apples grow and with them grows the scar, which is still clearly visible on the apples at harvest time. The second damage is caused by the second larval stage, which bores into several, smaller fruits, thus inhibiting further development of the apples and causing the fruits to drop.
In July, the adult larvae fall to the ground and form a cocoon at a depth of 5 - 10 cm, where they remain for 9 to 21 months.
Controlling apple sawflies with nematodes
The nematode product nemapom® is effective only against adult wasps and is applied to the soil at least one week before flight. The time of flight or application is determined with the help of the temperature sum (consult an advisor). Apply nemapom® (2 billion per hectare) only on well-moistened soil and spray with at least 1,000 liters of water per hectare. If the topsoil is dry, increase water application so that the moisture in the topsoil connects to moist, deeper soil horizons.
If the trunk is also treated up to a height of approx. 1 m, the overwintering larvae (fruit maggots) of codling moth are controlled at the same time.