Abstract
Entomopathogenic nematodes (EPNs) can be used efficiently as biological control agents against specific insects. Galleria mellonella (Gm) and Spodoptera littoralis (Sl) are considered important agricultural pests. The aim of this study was to evaluate the susceptibility of their larvae to ascending levels of four species of EPNs, Steinernema carpocapsae (Sc), S. arenarium (Sa), Heterorhabditis bacteriophora (Hb) and H. indica (Hi) as well as the ability of nematodes to penetrate and reproduce within their hosts. Fifth larval instar of Gm and Slwere used to evaluate the effect of four inoculum doses [200,400,800, and 1600 infective juveniles (IJs)] of each nematode species. Percentage of insect mortality (% M) and the nematode-rate of reproduction (Rr) were calculated after 24 and 48 hrs. The data confirmed that H. bacteriophora was the highest effective species on both insects. The % M was 75.7, 79.7, 82.3, and 83% after 24 hrs and 98.0, 99.3,100 and 100% after 48 hrs in Gm for these doses, respectively. On the other hand, the corresponding mortalities were 75.0, 78.3, 81.7, and 83.8% after 24 hrs and 97.3, 98.3, 100 and 100% after 48 hrs in Sl. The highest initial EPN population that could penetrate the insect (pi) was achieved by HbinGm (295 IJs) at 1600 IJs, while it was 221.7 IJs in Sl larvae at the same inoculum. The highest final population and Rr were obtained at the inoculum level of 200 and 400 IJs. in Gm and Sl, respectively.The study documented that Heterorhabditis and Steinernema can be used effectively in Gmand Sl management. Moreover, Hb is the most suppressive species tested against the two lepidopteran hosts.
Highlights
The Egyptian cotton leaf worm Spodoptera littorales (Lepidoptera: Noctuidae) is one of the most economically important insects (Zhou et al, 2010)
G. mellonella was more sensitive to the Entomopathogenic nematodes (EPNs) than S. littoralis larvae
Data indicated that the highest percentage mortality was caused by H. bacteriophora, followed by H. indica, S. carpocapsae and S. arinarium in G. mellonella and S. littoralis
Summary
The Egyptian cotton leaf worm Spodoptera littorales (Lepidoptera: Noctuidae) is one of the most economically important insects (Zhou et al, 2010). It is a polyphagous insect pest, feeding on most vegetables in addition to other many horticultural and field crops. It causes considerable loss in their production all over the world (Abd El-Razik & Mostafa, 2013) especially in the Middle East and Africa (Pineda et al, 2007; Shairra and Nouh, 2014). Some insect races could develop resistance to the chemical insecticides
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
