Field Efficacy of Steinernema sp. (Rhabditida: Steinernematidae) on the Colorado Potato Beetle Overwintering Generation.

Maja Čačija,Zrinka Drmić,Renata Bažok,Majda Kolenc,Martina Kadoić Balaško,Tena Bujas

doi:10.3390/plants10071464

Maja Čačija, Zrinka Drmić + Show 4 more

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https://doi.org/10.3390/plants10071464

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Abstract

Colorado potato beetle (CPB) is an economic pest of potato that has developed resistance to all classes of chemical insecticides, thus requiring alternative control measures. As a potential solution, entomopathogenic nematodes (EPNs) have proven effective in suppressing this pest, but their efficacy against overwintering generations of CPB in Croatia has not been sufficiently researched. The aim of this two-year (2018–2019) field study was to determine the efficacy of Steinernema feltiae and Steinernema carpocapsae applied to overwintering CPB adults. EPNs were applied at three doses (7.5 mil./10 m2, 5.0 mil./10 m2 (the recommended dose) and 2.5 mil./10 m2) by watering the soil where the adults were overwintering. The first-year results were satisfactory for both EPNs: the efficacy of S. feltiae ranged from 79.03% to 100.00%, while the efficacy of S. carpocapsae ranged from 77.32% to 96.22%. In the second year, the highest efficacy (69.57%) was obtained using the recommended dose of S. feltiae. Although the results are not consistent across the two years of our study and suggest further research, they indicate that EPNs have great potential in controlling overwintering CPB generations to reduce first generation abundance and damage, and also to prevent the spread of new generations to surrounding potato growing areas.

Highlights

The Colorado potato beetle (Leptinotarsa decemlineata (Say); CPB) is the most important defoliating pest of potatoes [1]
In spring 2018 and 2019, emergence of overwintered CPB adults was monitored in entomological cages for treatments with different doses of S. feltiae and S. carpocapsae and entomological cages for treatments with different doses of S. feltiae and S. carpocapsae and for the untreated control in fields where potatoes were grown in the previous for the untreated control in fields where potatoes were grown in the previous year
Prishchepa et al [26] studied the efficacy of S. feltiae and S. carpocapsae species on CPB and the results showed high efficacy of S. feltiae species while S. carpocapsae gave poorer results

Summary

Introduction

The Colorado potato beetle (Leptinotarsa decemlineata (Say); CPB) is the most important defoliating pest of potatoes [1]. It is widely distributed in North America, Europe, and Asia, covering an area of about 16 million km , and continues to spread [2]. In the 20th century, this pest has become a major problem throughout Europe, Asia, and China [3]. The first recorded case of resistance was in the 1950s, against DDT [2]

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