Field observation on the occurrence of potato aphids in organic potato crops were carried out in three localities of the Opole district in 2002–2004. During the years of conducted research a total number of 12 protection treatments against Colorado potato beetle using nettle and poultry liquid manure (4), basalt powder (3), milk lime (5) were done. Applied insecticides caused on average 50% reduction in the number of aphids and about 25% reduction of their predators. After treatments the average value prey/predator ratio was almost the same for manure treatments, higher for milk lime treatments and lower for basalt powder treatments.