Holistic approach to control Melolontha spp. in organic strawberry plantations

Eligio Malusá,Małgorzata Tartanus,Ewa M Furmanczyk,Barbara H Łabanowska

doi:10.1007/s13165-020-00295-2

Abstract

To achieve an effective reduction of the damage by root feeding grubs of Melolontha spp. in organic strawberry plantations, we have tested an approach targeting different stages of the insect’s biological cycle. Adult beetles were caught by using light traps or by manual shaking off trees associated to the monitoring of cockchafer swarm flights supported by forecasts models. Phytosanitary pre-crops and the application of biological control agents were tested against the larvae. The three predictive models utilized to forecast the period of emergence of the cockchafer were suitable to support the deployment of the light traps before the adults’ swarm flights. Traps positioned at 4-m height were more effective in attracting the beetles than those kept at 2-m height. Buckwheat in mixtures with either a mustard or leguminous species used as pre-crops was able to reduce the population of grubs, and considering also its capacity in solubilizing recalcitrant phosphorous sources should enter in a rotation with strawberry or any other crop susceptible to grubs damage. The distribution of two different strains of entomopathogenic fungi resulted in a reduction of the damage to plants due to the cockchafer grubs’ activity, even though the efficacy resulted to be dependent on environmental and agronomic factors, including the kind of formulation used. It is concluded that to assure a sufficient level of control of Melolontha spp. in organic strawberry plantations, it is necessary to integrate several methods that are targeting the different biological stages of the insect and are based on different kinds of practices.

Highlights

In recent years, an increase in the damage to nurseries and horticultural crops by root feeding grubs from the forest cockchafer (Melolontha hippocastani Fabr.) and the European cockchafer (Melolontha melolontha L.) (Coleoptera: Scarabaeidae) has been recorded in Poland and in other European countries (Dolci et al 2006; Łabanowska and Bednarek 2005; Nageleisen et al 2015)
The increase of the populations of these pests in Poland has likely resulted from the concomitant occurrence of different conditions, including the ban of aerial treatments, to forests and woods, which were used to control the adults of these species, due to the implementation of European Union legal provisions concerned with the sustainable use of pesticides (Directive 2009/128/EC), the lack of chemical products for soil treatments that were previously commonly applied in conventional crops, and the uncultivated afforestation taken over agricultural lands, where grubs have found excellent development conditions (Malinowski 2009)
Agr. (2020) 10 (Suppl 1):S13–S22 associated to the monitoring of cockchafer swarm flights supported by forecasts models, phytosanitary crops preliminary to the planting of the strawberry plants to disturb the growth of grubs in the soil and the application of biological control agents against the larvae

Summary

Introduction

An increase in the damage to nurseries and horticultural crops by root feeding grubs from the forest cockchafer (Melolontha hippocastani Fabr.) and the European cockchafer (Melolontha melolontha L.) (Coleoptera: Scarabaeidae) has been recorded in Poland and in other European countries (Dolci et al 2006; Łabanowska and Bednarek 2005; Nageleisen et al 2015). The increase of the populations of these pests in Poland has likely resulted from the concomitant occurrence of different conditions, including the ban of aerial treatments, to forests and woods, which were used to control the adults of these species, due to the implementation of European Union legal provisions concerned with the sustainable use of pesticides (Directive 2009/128/EC), the lack of chemical products for soil treatments that were previously commonly applied in conventional crops, and the uncultivated afforestation taken over agricultural lands, where grubs have found excellent development conditions (Malinowski 2009). Strawberry is among the plant species that are highly liked by the grubs to feed on (Huiting et al 2006)

Methods

Results

Conclusion