Entomopathogenic fungi disturbed the larval growth and feeding performance of Ocinara varians (Lepidoptera: Bombycidae) larvae

Abstract

Feeding experiments using three strains of entomopathogenic fungi, Beauveria bassiana, Metarhizium anisopliae and Isaria fumosorosea were conducted with newly moulted 3rd-5th instar Ocinara varians Walker larvae in the laboratory. The mortality of larvae immersed individually in spore suspension (1 × 10 7 spores/mL) of all the strains was ≥ 80% except 5th instar larvae treated with M. anisopliae which transformed into pupae, but did not result in adult emergence. The growth (total body mass), consumption, relative consumption rate and relative growth rate, were reduced at all three larval stages, while developmental time was extended in infected larvae with concurrent significant increase in approximate digestibility in infected larvae. Conversion of digested food (ECD) and ingested food (ECI) values declined in infected larvae as compared to the healthy larvae (control). The 5th instar larvae treated with M. anisopliae showed higher ECD and ECI values than control. Based on mortality and growth inhibition it can be suggested that all the studied fungal strains have a high potential for biocontrol and could be developed into biocontrol agents against O. varians.

Effect of Beauveria bassiana infection on the feeding performance and antioxidant defence of red palm weevil, Rhynchophorus ferrugineus

“…However, B8463 infection, along with enhanced antioxidant defence gene expression, significantly reduced the ECI relative to uninfected larvae. These results are in agreement with those of Hussain et al (2009b), who reported that the most virulent conidia tremendously reduced the ECI of Ocinara varians Walker larvae that were immersed in the suspension of different entomopathogenic fungi, when compared to uninfected control O. varians Walker larvae. Growth retardation of red palm weevil larvae was further confirmed by ECD, which is the index of digested food actually converted into insect biomass.…”

“…The tremendous increase in AD values enables infected, nutrient-deficient larvae to meet their emerging energy demands, and compensate for food deficiency. The reductions in the ECD index reported here are in line with the findings of numerous previous investigations (Farrar et al 1989;Weeler and Isman 2001;Hussain et al 2009b) which illustrate that most of the digested food is metabolized for energy production, resulting in lower ECD values in infected larvae, relative to control larvae. The major portion of this energy is utilized to defend the larvae against invading pathogens as borne out by the up-regulation of antioxidant genes, including catalase 1 and 2 and peroxidase, as observed in our study.…”

“…Their potential in the control of populations of various pests belonging to different orders including Blattodea (Mohan et al 1999), Coleoptera (Dembilio et al 2010b), Hemiptera (James et al 2003), Isoptera (Hussain et al 2009a(Hussain et al , 2010a, Lepidoptera (Hussain et al 2009b), and Orthoptera (Inglis et al 1996), have been successfully exploited.…”

Status of Insecticide Resistance in Field-collected Populations of Rhynchophorus ferrugineus (Olivier) (Coleoptera: Curculionidae)

“…The whole study was repeated over time. The insect, diet and frass weights were used to determine the feeding performance by calculating the efficacy of conversion of ingested food [ECI = 100 × dry weight gained by the larva/dry weight of food consumed] and the efficacy of conversion of digested food [ECD = weight gained by the larva/(food ingested -dry weight of frass)] (Hussain et al, 2009;Hussain et al, 2015). The data on the growth indices were analysed by one-way ANOVA.…”

The fauna of the family Bombycidae sensu lato (Insecta, Lepidoptera, Bombycoidea) from Mainland China, Taiwan and Hainan Islands<p class="HeadingRunIn" style="margin-top: 0cm; text-align: center; line-height: 17.0pt; mso-pagination: none; page-break-after: auto; mso-hyphenate: none; tab-stops: 35.0pt 70.0pt 105.0pt 141.0pt 176.0pt 212.0pt 247.0pt 282.0pt 318.0pt 353.0pt 388.0pt 424.0pt 460.0pt;" align="center"><span style="font-size: 14.0pt; mso-font-width: 100%; mso-ansi-language: EN-US;">The

“…Holloway (1987) reported that this species was widely distributed in the Oriental Region. It is an important pest of ornamental plants (Huang et al, 2002;Rajavel & Shanthi, 2007), and so its biological characters and control have been the subject of several recent works (Ou et al, 2006;Hussain et al, 2009). Diagnosis.…”