Protection of organic strawberry plantations from Melolontha spp. through an integrated approach: results from four-year trials in Poland

Abstract: Integrated strategies including various control methods and agronomical practices have been tested to control Melolontha spp. in organic strawberry plantations. Reduction of the populations was attempted by covering the planted rows with fabric-like mulching during the period of the beetles’ flight, to decrease the number of eggs deposited in the soil. The control of grubs in the soil was pursued with pre-planting soil tillage and sowing of buckwheat (Fagopyrum esculentum) as well as with microbial inocula, applied also after soil steaming. Biocontrol treatments were based on entomopathogenic fungi (Beauveria bassiana and Beauveria brongniartii) and entomopathogenic nematodes (Heterorhabditis bacteriophora and Steinernema kraussei). Different formulations of the inocula (single or co-inocula, granulated or liquid), application methods, doses and timing of treatments were tested in different locations to evaluate their effect on overall efficacy of the treatment. The results indicated some effective action of the different integrated strategies in reducing the number of active grubs and their damage to plants.