Risk factors and assessment

Tuber damage (holes or galleries) caused by wireworms is intensified when the previous crop has favoured the development of larva populations; for example, permanent pastures or grassland, fallow land, irrigated corn, which are suitable for egg laying.

The damage is exacerbated in wet soils (rain, irrigation), which are favourable to the presence of larvae near the soil surface.

Tests have shown that damage thresholds of 20 to 40 larvae/m² (evaluated before planting by boring with an auger) represent a significant risk to the potato crop, either to the root system or to the yield.

It is easier to evaluate the size of the population in a field by means of either larva traps containing a bait (pots filled with vermiculite containing a mixture of wheat and corn), or by means of a pheromone trap that captures adults. Pheromone traps are commercially available with species specific pheromones for A. lineatus, A. sputator, A. obscurus and A. sordidus.