First Report on the Effect of Aqueous Extracts of Hungarian Organic Mulch Materials on Entomopathogenic and Slug-Parasitic Nematodes

Renáta Petrikovszki,Franciska Tóthné Bogdányi,P Nagy,F Tóth

doi:10.1556/038.54.2019.024

Renáta Petrikovszki, Franciska Tóthné Bogdányi + Show 2 more

Open Access

https://doi.org/10.1556/038.54.2019.024

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Abstract

Few researches address the compatibility of organic mulching and entomopathogenic (EPN) and slug-parasitic (SPN) nematodes, although organic mulching may provide favourable conditions for these beneficial organisms. Our aim was to examine the effect of different concentrations (0.1, 0.5, 1 and 5%) of aqueous extracts of green waste compost, the dry leaf litters of the common walnut (Juglans regia) and Norway maple (Acer platanoides) on EPN (Heterorhabditis bacteriophora, Steinernema carpocapsae, Steinernema feltiae, Steinernema kraussei) and SPN (Phasmarhabditis hermaphrodita) species. Experiments were set up in 96-well, flat-bottom microplates. After a 24-hour exposure time, the number of dead animals was counted under a transmission microscope. Green waste compost extracts caused quite low or no mortality in case of all examined species. Mortality caused by the 5% Norway maple leaf litter extract was moderate (34.6%) in the case of S. carpocapsae juveniles, while 100% of juveniles of other species died. The highest (5%) concentration of the common walnut leaf litter extract caused 100% mortality in all species. As a conclusion, green waste compost mulch seems to be more compatible with EPN and SPN species than common walnut or Norway maple leaf litter mulch.

Highlights

EPNs (Rhabditida: Heterorhabditidae and Steinernematidae) have a wide range of pest insect hosts (Askary and Abd-Elgawad, 2017)
A different sensitivity was noticed with the treatment of 1% common walnut leaf litter extract: 72.5% of S. feltiae, 83.3% of S. carpocapsae, 93.8% of Ph. hermaphrodita was dead, while all individuals of H. bacteriophora and S. kraussei (Steiner) died
The lethal effect of lower (0.1 and 0.5%) concentrations of Norway maple leaf litter extract was under 10% in all cases

Summary

Introduction

EPNs (Rhabditida: Heterorhabditidae and Steinernematidae) have a wide range of pest insect hosts (Askary and Abd-Elgawad, 2017). Application and effectiveness of EPNs depend on various abiotic factors including soil moisture, soil temperature and UV-radiation (Shapiro-Ilan et al, 2006, 2012) These factors can be influenced using organic mulching simultaneously with EPN and SPN species because mulch materials increase soil moisture, do not allow soil overheating (Sinkevičiené et al, 2009), and prevent light from reaching the soil surface (Bond and Grundy, 2001). Both wheat straw and apple wood chips enhanced the effectiveness of Heterorhabditis zealandica (Poinar) against codling moth (Cydia pomonella L.) larvae (de Waal et al, 2011). Different types of compost at different maturity stages could be appropriate as a carrier medium for S. feltiae (Herren et al, 2018)

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