Effects of single and combined applications of entomopathogenic fungi and nematodes against Rhynchophorus ferrugineus (Olivier)

Abstract

This study was carried out to investigate the insecticidal properties of Beauveria bassiana, Metarhizium anisopliae and Heterorhabditis bacteriophora for their virulence against different larval instars of Rhynchophorus ferrugineus (Olivier). Both fungi were either applied alone or in combination, with H. bacteriophora simultaneously or 1 and 2 weeks after fungal application; EPN were also applied alone. Moreover, assessment of host development, diet consumption, frass production and weight gain were observed at sub-lethal dose rates. In combined treatments, additive and synergistic interactions were observed. Synergism was observed more frequently in H. bacteriophora + B. bassiana combinations than in H. bacteriophora + M. anisopliae combinations, and was higher in early instars than old instars. In 2nd and 4th instars, synergy was noted in H. bacteriophora + B. bassiana combinations at 0, 7 and 14 d intervals and in 6th instar synergy was observed only in H. bacteriophora + B. bassiana combinations (at 0 and 7 d intervals). A decrease in pupation, adult emergence and egg hatching was enhanced in the combined treatments. Furthermore, reduced weights and variation in duration of insect developmental stages were observed among entomopathogens and enhanced in H. bacteriophora + B. bassiana combinations. Larvae treated with sub-lethal concentrations exhibited reductions in food consumption, growth and frass production and weight gain.

The symbiotic bacteria Alcaligenes faecalis of the entomopathogenic nematodes Oscheius spp. exhibit potential biocontrol of plant‐ and entomopathogenic fungi

“…Different combinations of EPNs and commercial EPF for increasing plant growth and protection have already been attempted in several greenhouse and field trials. Generally, however, they did not show clear additive or synergistic effect of both biocontrol agents and even find negative interactive effects (Wu et al ., ; Imperiali et al ., ; Wakil et al ., ). EPNs were detected in larvae only in a few cases (11%) in the EPF and EPNs combination treatments (Tarasco et al ., ).…”

The invasive moth Paysandisia archon in Europe: Biology and control options

“…The combined use of biocontrol agents may be highly desirable. Wakil, Yasin, and Shapiro‐Ilan (2017) reported additive and synergistic effects of B. bassiana and the nematode Heterorhabditis bacteriophora Poinar when larvae of R. ferrugineus were treated with both organisms (doses: 1 × 10 6 spores/ml and 100 juveniles/ml, respectively). The synergistic effect was most pronounced when nematode treatment was delayed for 2 weeks after fungal inoculation (highest mortality rate: 88.65%).…”

“…In addition, the combined application of H. bacteriophora and the fungus Metarhizium anisopliae sensu lato (Metschn.) Sorokin also provided synergistic effects on host mortality (Wakil et al, 2017). Those biocontrol results, using both B. bassiana and S. carpocapsae, indicate that further preventive and curative trials are needed to evaluate the existence of synergy or antagonistic (Shapiro‐Ilan, Jackson, Reilly, & Hotchkiss, 2004) effects of these or other organisms against P. archon .…”

Compartive Efficiency of Egyptian Entomopathogenic Nematodes and Imidacloprid on the Red Palm Weevil, Rhynchophorus ferrugineus Oliv

“…often infect at lower rates than Steinernema sp. (Wakil et al 2017) but comparative mortality is often similar or higher (Shapiro-Ilan et al 2002). The low infectivity and insect mortality by Heterorhabiditis sp.…”