engleski

Could entomopathogenic nematodes be used as an effective tool in overwintering Colorado potato beetle control in Croatia?

Colorado potato beetle (CPB) is the most important pest of potato. During the long period of its control, this pest developed resistance to all major classes of chemical insecticides, so other control measures need to be found. One of the solutions is to reduce the adult population during the overwintering. Entomopathogenic nematodes (EPN) have been proven effective in suppressing insects of order Coleoptera but their efficacy on Colorado potato beetle in Croatia has not been sufficiently explored. In a two-year (2018-2019) field study, we investigated the efficacy of EPNs Steinernema feltiae and Steinernema carpocapsae on overwintering CPB adults. In both years, EPNs were applied in three doses (4.5 mil./6 m2, 3.0 mil./6 m2, 1.5 mil./6 m2) by watering the field on which potatoes were grown in the previous year. To monitor CPB emergence from the soil, entomological cages were set up in a treated field from mid April till mid May 2018. In 2019, the EPNs were applied in the same dosages but on a different field and were monitored in entomological cages as well. Results (2018) have shown that in the plots treated with S. feltiae, the emergence of adults occurred from 19 April until 10 May. In the plots treated with S. carpocapsae, the emergence of beetles was somewhat earlier (16 April) and lasted ten days shorter (until 30 April) than in plots treated with S. feltiae. On untreated plots, the emergence was recorded from 13 April till 7 May. The results of efficacy were satisfactory for both species: S. feltiae had an efficacy from 79.03% to 100.00%, while S. carpocapsae efficacy was between 77.32% and 96.22%. Both nematodes were most effective in highest doses administered. The efficacy at recommended doses was also satisfactory (96.22% for S. feltiae ; 77.32% for S. carpocapsae). These results indicate that EPNs have a good potential in being used as an effective tool for overwintering Colorado potato beetle control.

Leptinotarsa decemlineata ; entomopathogenic nematodes ; biological control

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