Tips for increased effectiveness of Aphidoletes in the winter
In winter it is more difficult to achieve a good result with the gall midge Aphidoletes aphidimyza. This is due to the cold weather often in combination with the start of the new cultivation. Taking into account a number of points you can increase the effectiveness of Aphidoletes in winter. Our specialist can give you tips.
When starting a crop there are generally few spiders present in the greenhouse but the adult Aphidoletes need a spider web to mate. If they cannot find a web then they will not mate. The solution is to apply a spider web yourself on the bucket in which they are deployed or to apply spiders in the crop.
Aphidoletes is active at night and sets its eggs at a minimum temperature of 12°C. The higher the temperature the better the egg deposits. During the daytime larvae develop best at a temperature of around 23°C.
When a plant is attacked by aphid it separates out signal substances that attract natural enemies of the aphid. These signal substances are better dispersed through the greenhouse in warm air. At a lower temperature Aphidoletes has much more difficulty in detecting aphids and detecting their prey.
The humidity in this period of the year is generally low due to a young and open crop meaning dewdrops are present in the crop to a lesser extent. These dewdrops are essential for hatching gall midges because they drink from them. If the gall midges do not drink they can die within a few hours. Solution: Place a wet cloth in a bucket or place a piece of moist oasis with 10% sugar water in the place where you expand the material.
Air humidity is also important for egg deposits. Aphidoletes prefers the leaves at the bottom of the plant because the conditions are the most moist and dark here.
Polythene and soil temperature
In many new crops Polythene is placed on the ground for hygiene reasons. However, this has a negative impact on the development of Aphidoletes. The larvae can only pupate in the ground. If the larvae end up on the polythene and cannot reach the ground they will die. As a grower you can do little about this but be aware of it. Soil temperature is also low during this period of the year. Keep in mind that the pupation process takes longer, so it takes longer for a new generation of gall midges to emerge.
The final point of attention is not related to the weather but is therefore no less important: disperse the material. APHIDOcontrol from the supplier Agrobio is supplied in bottles with vermiculite as a carrier. For some products, you only have to turn the cap of the bottle and then put it in the crop but with APHIDOcontrol this is not the case. This material must be scattered. If you don't do that some of the gall midges won't get through the vermiculite and will therefore stay behind in the bottle.
Questions about the effectiveness of Aphidoletes in the winter
Do you have questions about the effectiveness and use of Aphidoletes in the winter or would you like tailor-made advice? Then contact Quality Controller Kevin van Kester or ask your question using the form below.