Three-year field experiments investigated the effectiveness of Sunspray 850 EC mineral oil protection against PVY, PVM, PLRV. Every seven days six to eleven treatments were applied, depending on the year. Regular protective mineral oil treatments reduced the number of aphids, especially over peak aphid infestation periods – almost by 60% when compared with the control plants. Besides the mineral oil treatment reduced the infection of progeny tubers with PVY and PVM considerably; a significant effect was found on PVY infection, especially in Mila, which was susceptible to that virus. With that in mind it seems justifiable to apply mineral oil to protect cultivars highly susceptible to PVY (scoring 5.5 using the 1-9 degree scale).

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