Comparative assessment of the efficacy of entomopathogenic nematode species at reducing western corn rootworm larvae and root damage in maize

Abstract

The western corn rootworm (Diabrotica virgifera virgifera LeConte, Coleoptera: Chrysomelidae) is an invasive maize (Zea mays L.) pest in Europe. Crop yield is significantly impacted by the feeding of all three larval instars on maize roots, making them prime targets for control measures. Therefore, the control efficacy of three entomopathogenic nematodes (EPNs), Steinernema feltiae (Filipjev), Heterorhabditis bacteriophora Poinar, and H. megidis Poinar, Jackson and Klein (Nematoda: Rhabditida), was studied in four field plot experiments in southern Hungary in 2005 and 2006. All EPN species significantly reduced D. v. virgifera independently, whether applied as a row spray with a solid stream into the soil at sowing or onto the soil along maize rows in June. When applied at maize sowing, H. bacteriophora was more effective at reducing D. v. virgifera (81%) than H. megidis (49%) and S. feltiae (36%). When applied in June, H. bacteriophora and H. megidis were more effective at reducing D. v. virgifera (around 70%) than S. feltiae (32%). All tested EPN species significantly reduced damage on maize roots independently, whether they were applied at sowing or in June. Damage, however, was not totally prevented. The use of H. bacteriophora for the development of a biological control product for inundative releases against D. v. virgifera larvae is suggested.

Restoring a maize root signal that attracts insect-killing nematodes to control a major pest

“…To ''restore'' E␤C emission and test its importance for root protection under realistic field conditions, a maize variety that normally does not emit this compound was transformed with a gene from oregano (Origanum vulgare). We then compared WCR-inflicted root damage and beetle survival on transformed and nontransformed lines in the presence and absence of EPNs (25,30).…”

Interactions Among Bt Maize, Entomopathogens, and Rootworm Species (Coleoptera: Chrysomelidae) in the Field: Effects on Survival, Yield, and Root Injury

“…A number of Þeld studies have found that soilapplied entomopathogenic nematodes in the genera Steinernema and Heterorhabditis, and entomopathogenic fungi in the genus Metarhizium, reduce rootworm survival and root injury (Wright et al 1993, Krueger and Roberts 1997, Toepfer et al 2008). In 2010, when rootworm abundance was high, the community of entomopathogens reduced April 2013 PETZOLDÐMAXWELL ET AL.…”

“…Field trials have shown that entomopathogens can reduce rootworm survival and injury to maize roots, and in some cases, increase yield (Wright et al 1993, Krueger and Roberts 1997, Journey and Ostlie 2000, Toepfer et al 2008). For example, the nematode Heterorhabditis bacteriophora Poinar significantly reduced root injury caused by western corn rootworm in a Þeld study by 14 Ð54% (Toepfer et al 2010).…”

“…For example, the nematode Heterorhabditis bacteriophora Poinar significantly reduced root injury caused by western corn rootworm in a Þeld study by 14 Ð54% (Toepfer et al 2010). In another Þeld experiment, H. bacteriophora, Heterorhabditis megidis Poinar and Steinernema feltiae Filipjev decreased rootworm survival and root injury (Toepfer et al 2008). The nematode Steinernema carpocapsae Weiser also has been shown to decrease western corn rootworm survival and root injury to maize in the Þeld (Wright et al 1993, Journey andOstlie 2000).…”

Virulence of entomopathogenic nematodes (Rhabditida: Steinernematidae and Heterorhabditidae) for the control of Diabrotica speciosa germar (coleoptera: chrysomelidae)

“…Likewise, Thurston and Yule (1990), testing the nematodes S. feltiae All and S. bibionis Sn against D. barberi larvae in the field, in corn culture, observed that both species of EPNs tested reduced the number of larvae in the soil compared to the control, at concentrations of 1.3 x 10 8 Survival of larval (%) Virulence of entomopathogenic nematodes... 1155 and 1.3 x 10 9 IJ/ha, not verifying a difference among the species or the tested concentrations. Toepfer et al (2008), working with EPNs for the control of D. v. virgifera larvae under field conditions in the corn culture, verified that all of the species of nematodes (H. bacteriophora, S. feltiae and H. megidis) tested caused reduction of the insect population in the soil. However, the most virulent species was H. bacteriophora, that caused an 81% reduction.…”