The prevention of potato volunteers in organic farming systems by using pigs

In organic agriculture potato volunteers, presenting an important primary inoculum source for late Blight (Phytophthora infestans), are controlled by mechanical meth-ods. These may be partly replaced by ‘foraging’ livestock animals, such as cattle, sheep, horses, ponies or pigs. Most animals eat only the remaining potatoes on the field surface; however, pigs also dig up potatoes. This paper reports on two experi-ments with pigs (sows or finishing pigs), which appear to be very effective in digging up potatoes that are left in the field after the potato harvest within a reasonable time period. However, the workload for the farmer, problems with animal health and meat quality and possible damage to the soil structure seriously limit the applicability of pigs for the control of potato volunteers. Aspects of animal health, animal nutrition and environmental aspects (nutrient excretion) are discussed.