Laboratory Virulence and Orchard Efficacy of Entomopathogenic Nematodes Against the Lesser Peachtree Borer (Lepidoptera: Sesiidae)

Abstract

The lesser peachtree borer, Synanthedon pictipes (Grote & Robinson) (Lepidoptera: Sesiidae), is indigenous to eastern North America. It is a pest of commercially grown Prunus spp., especially to southeastern peach orchards where earlier regulatory changes affected pesticide use on peach leading to increased S. pictipes damage. Pest management practices are now having a positive effect toward control of this pest, but cost-competitive biological control solutions that promote environmental stewardship are needed. Here, we tested four Steinernema species and five Heterorhabditis species of entomopathogenic nematodes against larval S. pictipes. Included were four strains of S. carpocapsae (All, DD136, Sal, and Hybrid2) and three strains of S. riobrave (3-8b, 7-12, and 355). Larvae treated with any strain of S. carpocapsae always resulted in <20% survival, whereas larval survival was always >50% when treated with any other Steinernema or Heterorhabditis spp. These differences were always significant for the Hybrid2 strain of S. carpocapsae and similarly for other tested S. carpocapsae strains except for when larvae were treated with the 3-8b strain of S. riobrave. In addition, we determined the susceptibility of different size S. pictipes larvae, because they occur simultaneously in orchards, and we found that larvae rated as "medium" and "large" were significantly more susceptible than "small" larvae. Last, we demonstrated that moisture-retaining covers (placed over S. pictipes-infested wounds on peach limbs) increased efficacy of nematode treatments against larval S. pictipes. Even when using highly virulent nematodes against S. pictipes, it is likely that an aboveground application will require an environmental modification to remain efficacious.

Safety evaluation of four entomopathogenic nematode species against two silkworm species

“…In this study, our results showed the safety of S. bicornutum 0311 and S. feltiae 0636 to both A. pernyi and B. mori, S. glaseri 0321 was only safe to A. pernyi and S. carpocapsae A24 was not safe to both A. pernyi and B. mori. It has been shown that S. carpocapsae and S. glaseri had high insecticidal activity to some Lepidopteran pests (Ali et al 2006;Chambers et al 2010;Cottrell et al 2011). Our result showed that these two EPNs had more virulence to the silkworms than the other two EPN species (S. bicornutum 0311and S. feltiae 0636).…”

“…; Cottrell et al . ). Our result showed that these two EPNs had more virulence to the silkworms than the other two EPN species ( S. bicornutum 0311and S. feltiae 0636).…”

Sustainable Horticultural Systems

“…In particular, in vitro liquid production is considered to be most cost efficient process for mass production, and is thus more broadly used for the commercialization of nematode products. Several studies showed reduced quality or efficacy in vitro liquid culture than production in vivo or in vitro solid medium Cottrell et al 2011), whereas some others did not detect any significant difference .…”

A Review of the Potential Use of Entomopathogenic Nematodes to Control Above-Ground Insect Pests in South Africa

“…Cossentine et al (1990) applied H. bacteriophora (heliothidus strain) to control the peach tree borer, Synanthedon exitiosa (Say) (Lepidoptera: Sesiidae), finding that a suspension of EPNs in and around the boreholes failed to reduce the number of adults emerging from the holes significantly. Cottrell et al (2011), in testing several EPN species for efficacy against the lesser peach tree borer, Synanthedon pictipes (Grote & Robinson) (Lepidoptera: Sesiidae), compared two adjuvants (polyacrylamide gel and moistened baby diapers) with the aim of improving moisture retention and UV protection. Both adjuvants were found to improve the control of S. pictipes compared to the control.…”