Potential of the entomopathogenic nematodes Steinernema feltiae, S. weiseri and Heterorhabditis bacteriophora for the biological control of the sugar beet weevil Bothynoderes punctiventris (Coleoptera: Curculionidae)

Abstract

Potential of the entomopathogenic nematodes Steinernema feltiae, S. weiseri and Heterorhabditis bacteriophora for the biological control of the sugar beet weevil Bothynoderes punctiventris (Coleoptera: Curculionidae) Alper SusurlukAbstract The sugar beet weevil, Bothynoderes punctiventris Germ. (Coleoptera: Curculionidae), is one of the most damaging pests of sugar beets in Turkey and has been traditionally controlled by application of large amounts of insecticides. The current study used laboratory microcosms to evaluate the possibility of using entomopathogenic nematodes as an alternative control method. The nematodes Steinernema feltiae (strain TUR-S3), Steinernema weiseri (BEY) and Heterorhabditis bacteriophora (TUR-H2) had previously been isolated from Turkey. Nematode-induced mortality generally increased as soil temperature increased from 15 to 25°C but decreased when larvae were located deeper in soil. Heterorhabditis bacteriophora caused the highest larval mortality at 25°C at all depths (5-20 cm). Steinernema feltiae and S. weiseri were more eVective than H. bacteriophora at 15°C at all depths. Increasing the application rate of infective nematode dauer juveniles (DJs) aVected the number of DJs that penetrated each insect larva and the number of DJs produced per insect. The highest production of DJs per larva occurred at application rates of 50 DJs/larva for S. feltiae and S. weiseri and 100 DJs/larva for H. bacteriophora. Reproduction decreased again at higher application rates. Heterorhabditis bacteriophora had the highest reproductive capability. The results indicate that S. feltiae and S. weiseri might be more eVective against this pest early in the growing season when soil temperature is low and that H. bacteriophora might be more eVective later in the season when temperature increases.

Controlling the sugar beet beetle Cassida vittata with entomopathogenic nematodes

“…Laboratory studies by Akalach and Wright (1995), in Morocco indicated that S. carpocapsae and S. feltiae were effective against the sugar beet weevil Conorhynchus mendicus. Susurluk (2008) obtained encouraging results with S. feltiae and H. bacteriophora against the sugar beet weevil Bothynoderes punctiventris at different temperatures and at different depths in the soil. Laboratory results showed that the most virulent and fastest nematode against larvae of C. vittata was S. feltiae.…”

Ecological characterisation of the Colombian entomopathogenic nematode Heterorhabditis sp. SL0708

“…SL0708, greatest infectivity is presented at 20 °C, diverging from results found by Morton and Garcia-del-Pino (2009) for some species of heterorhabditidae, where 25 °C was the optimum temperature or 30 °C for Heterorhabditis georgiana (Shapiro-Ilan et al, 2009). The inconsistency in results regarding temperature for different species of the Heterorhabditis genus, shows that a single temperature cannot be assigned to the genre and that the infectivity of nematode species may also depend on the size of the larva, the depth of the host in the substrate and search behaviour of the IJs (Boff et al, 2001;Susurluk, 2008).…”

“…It is recognised that temperature is an important factor in the life cycle of entomopathogenic nematodes (Griffin, 1993). Varying temperatures have effects on the viability of the IJs and their ability to reproduce, these effects are observed mainly in extreme temperatures (0 and 40 °C), which are lethal (Rohde et al, 2010;Susurluk, 2008;Morton and Garcia-del-Pino, 2009). As observed in Heterorhabditis sp.…”

Comparative efficacy of classical and biorational insecticides on sugar beet weevil, Bothynoderes punctiventris Germar (Coleoptera: Curculionidae)

“…Cultural and mechanical control measures shall involve spatial isolation and good organisation of the production. Biological control could be effectuated by the use of the nematodes Steinernema and Heterorhabditis (together with symbiotic bacteria Xenorhabdus and photorhabdus) for the suppression of the weevil population (Trdan et al 2006;Susurluk 2008;Hassan 2010). However, the commercial use of products based on the aforementioned organisms has not been reported.…”