The damage caused by wireworms on potato tubers seems to be getting bigger and worse. Their causes are not fully known, and chemical prevention and control are very difficult.
Worm-worms are golden-copper to copper-colored larvae of some species of beetle-cracker (Agriotus lineatus, A. Obscures, A. Spectator). Potato tubers will be affected, especially during the summer, in conditions of heat and drought. Usually, potato tubers do not feed on worms, but they attack them because they need lower temperatures and humidity. Therefore, the risk of damage is very high in the potato crop where, due to ripening and desiccation, the potatoes are directly exposed to the sun. One way to reduce this risk is to harvest very early.
In general, wireworms can only be sufficiently controlled by integrated pest control measures; whenever possible – during crop rotation – all available measures should be applied to reduce inoculation (plowing the soil, applying insecticides in seed treatment, etc.).
Chemical control of wireworms in potato production is very difficult due to the lack of adequate products. In the past, soil burning was effective for controlling wireworms, but today it is banned in most countries.
However, certain insecticides and nematocides have partial effects on wireworms. Seed treatment with Prestige®, Monceren® G, Gaucho® (with the active ingredient Imidaclopride); Dantop®, Apacz® (i.e. Chlothianidine); Actara® (i.e. Thiamethoxam) has side effects on wireworms (reduction of symptoms by approx. 10 – 25%).
In some countries, Fipronil (i.a.) is or will be registered for the control of wireworms and other pests. As far as is known, Fipronil-containing products will reduce symptoms by approximately 20-50% if applied using optimal techniques (placement in a row of granules at planting, close to seed, etc.).
Side effects of approx. 30-75% are also obtained from insecticides such as Nemathorin® (i.a. Fosthiazate), Vydate® (i.a. Oxamyl). But these products are expensive, and the cost-benefit ratio must be carefully considered. Also, a side effect of low and insufficient importance is expected from fertilization with mineral fertilizers (calcium cyanamide).
N.B. In the case of chemical control, consider the approval of the registration and the instructions for use indicated by the manufacturer.