Effectiveness of insecticide protection of very early edible potato cultivars against potato beetle was assessed in the years 2005-2006. The research used Prestige 290 FS, Regent 200 SC and Spruzit 04 preparations, as well as Beauveria bassiana entomopathogenic fungus spore suspension. The selection of preparations for potato beetle control significantly diversified the amount and structure of potato tuber yield. Average total tuber yield on the control, without insecticide protection, was 30.3 t∙ha^-1, whereas on the treatments where Spruzit 04E C and B. bassiana spore suspension were applied the yield was on the level of 36 t∙ha^-1, whereas potatoes protected by chemical preparations Regent 200 SC and Prestige 290 FS produced the largest yields, respectively on the level 41.0 and 41.8 t∙ha^-1. Potato beetle control in potato cultivation contributed to an increase in average tuber weight and the share of big tuber fractions in the yield. A significant rise in the marketable tuber fraction was registered only on treatments protected with B. bassiana spore suspension and by Prestige 290 FS preparation.

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