Foliar Application of Entomopathogenic Nematodes against Cereal Leaf Beetle Oulema melanopus L. (Coleoptera: Chrysomelidae) on Wheat

Anna Mazurkiewicz,Jan Bocianowski,Magdalena Jakubowska,Kamila Roik,Dorota Tumialis

doi:10.3390/agronomy11081662

Abstract

Cereal monocultures are very susceptible to many pests, especially to those living on leaves, which largely affects yield by decreasing its quality. The most dangerous of them is the cereal leaf beetle (Oulema melanopus L.). In cases of heavy infestation by its larvae, the surface of plants may be reduced by 50%, and sometimes even by 80%, with a main yield loss of 10–25%. The aim of the presented study was to assess the efficiency of a native isolate of Steinernema feltiae (Filipjev, 1934) and commercial preparation Larvanem (Heterorhabditis bacteriophora (Poinar, 1975)) in controlling the larvae of O. melanopus, and to reduce crops damage in the field. Nematodes were applied in a dosage of 2 million IJs/m2 as a suspension of 11 litres per square metre. A hand sprinkler with field lance and flat-stream nozzles was used for applications at the lowest working pressure of 3000 hPa. The effectiveness of both nematode species was moderate: 47.8% for S. feltiae isolate and 49.5% for H. bacteriophora. The biggest reduction in leaf damage was found in crops treated with the commercial preparation, where the index of leaf infection was 32%, being more than twofold smaller than that for the control.

Highlights

Cereal production is one of the main branches of agriculture in Poland
Commercial preparation Larvanem produced by Koppert/Holland with infective juveniles (IJs) of H. bacteriophora (1 pack contains 50 million IJs)
Our study has shown that both native isolate of S. feltiae and a commercial preparation Larvanem had a significant effect on reducing the leaf damage with IP of 44.7% and 32%, respectively

Summary

Introduction

Poland is the second-largest country in the EU with respect to the surface area of cereal crops Cereal monocultures are very susceptible to many pests, especially those feeding on leaves, which substantially affect the yield and quality of the harvest. There are two species of cereal leaf beetles in Poland: Oulema melanopus (L.) and Oulema gallaeciana Heyden both belonging to the Chrysomelidae family. The first is more common in the central and northern parts of the country, while the second dominates in south-eastern Poland [2]. O. melanopus is the most important wheat pest in many other countries [3,4], ranging from central Siberia through Sweden, Great Britain, Spain, western Africa [5,6] to the United States and Canada [5,7]

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