Holistic approach to control Melolontha spp. in organic strawberry plantations

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.

Biocontrol of Melolontha spp. Grubs in Organic Strawberry Plantations by Entomopathogenic Fungi as Affected by Environmental and Metabolic Factors and the Interaction with Soil Microbial Biodiversity

“…However, the high variability in the belowground infestation levels on the local scale, somehow related to the soil characteristics, have also been proposed as an explanation for the different efficacy observed in the field in controlling soil-borne pests [ 50 ]. It is also possible that the pathogenicity of the tested strains was lower than that of strains used in other reports or that the production and formulation process negatively affected their virulence [ 10 , 18 ] since the same BR strain formulated as kernels was found to be more effective in other trials [ 51 ].…”

Application of Entomopathogenic Nematodes to Control Larvae of Temnorhynchus baal (Reiche and Saulcy) Under Laboratory Conditions and In Strawberry Fields

“…The application's effectiveness in the field was estimated by the weekly counting of wilted plants caused by the feeding of natural infestation by the larvae of T. baal on their roots (Tartanus et al,2016;Malusa et al,2020). Moreover, 20 larvae of T. baal were collected 7 days after each application to estimate the mortality rate of the larvae.…”

Current Methods, Common Practices, and Perspectives in Tracking and Monitoring Bioinoculants in Soil

“…However, the soil texture and composition should also be taken into consideration in defining the sampling depth due to the possible effect of oxygen (air) availability and organic matter content on bioinoculant persistence (Walstad et al, 1970;Studdert and Kaya, 1990;Vänninen et al, 2000;Weyman-Kaczmarkowa and Pȩdziwilk, 2000;Kessler et al, 2003;Rousk and Bååth, 2007;Fàtu et al, 2015). The frequency of sampling is a variable that can be affected by several factors, including the formulation of the bioinoculum, the crop duration, the strain growth potential, and the pedo-climatic conditions of the site (Horaczek and Viernstein, 2004;Malusá et al, 2020). All of them are quite intuitive to understand; however, a proper sampling strategy cannot disregard them to avoid reducing of the validity of the analytical results.…”

“…The prospect of manipulating crop microbial populations by inoculating beneficial bacteria and fungi to increase plant growth has shown considerable aptitude in laboratory and greenhouse studies; however, responses have been variable in the field (e.g., Arora, 2015 ; Kaminsky et al, 2019 ; Malusá et al, 2020 ). Recent progress in understanding the biological interactions between the practical requirements for microbial inoculant formulation and delivery systems will increase this technology’s evenness in the field and facilitate its commercial development.…”