Laboratory evaluation of a new strain CCM 8367 ofIsaria fumosorosea(syn.Paecilomyces fumosoroseus) onSpodoptera littoralis(Boisd.)

Abstract

Laboratory experiments were conducted to assess the efficiency of the new strain CCM 8367 of Isaria fumosorosea on different stages of the Egyptian cotton leafworm, Spodoptera littoralis (Boisd.), including soil treatments with pre-pupal and pupal stages. Treatments of larval instars showed a high susceptibility with 3rd, 5th and last instars to suspension of this fungus with concentration 5 Â 10 7 spores/ml. Larval mortality was over 90%. There were no significant differences (P = 0.7929, F = 0.2346) between instar treatments. The commercial fungus, PreFeRal® strain Apopka 97 of I. fumosorosea, which was used in comparison with this new strain caused mortality rates of between 63.33 and 90%. Statistically, differences between the effects of CCM 8367 strain and Apopka 97 were highly significant on the last instar (P = 0.0064, F = 6.479) and extremely significant on the 3rd instar (P < 0.0001, F = 13.29). No significant differences were recorded between the two strains on the 5th instar (P = 0.0597, F = 3.233). Fungal treatments with the late stage insects (end of the last instar or pupal stage) in soil yielded interesting results: the mortality rate on end of final instar larvae was 16.66% when treated with Apopka 97 and 83.33% when treated with CCM 8367. Soil containing pupae of S. littoralis that were inoculated with CCM8367 resulted in a high number of malformed adults, and the mortality rate was 64.52% (32.27% of malformed adults died and 32.25% of pupae fully infected by fungus). Only 3.23% of samples produced morphologically normal adults in this test. The results conclude that the strain of I. fumosorosea CCM 8367 has strong insecticidal effects on S. littoralis and has the potential to be implemented as a novel biocontrol agent.

Soil drenching with entomopathogenic fungi for control of the soil-dwelling life stages and adults of the same generation ofSpodoptera littoralis(Boisd.) (Lepidoptera: Noctuidae)

“…This figure is similar to that obtained in the aforementioned study by Hussein et al . (2013) who achieved 83.3 and 64.5% mortality using C. fumosorosea against prepupae and pupae of S. littoralis , respectively. However, our results are in contrast with the results of Ahmed and El-Katatny (2007) and El-Katatny (2010) who reported low/no mortality in pupae (10%) and prepupae (0%) of S. littoralis larvae treated with B. bassiana isolate IMI 386701, although they did observe higher larval (90%) and pupal mortality (80%) when spraying B. bassiana isolate IMI 382302 at 10 8 conidia ml −1 .…”

“…This is the first study to report the successful use of soil drenching with EPFs for control of the soil-dwelling stages of S. littoralis (prepupae, pupae and adults emerging from surviving prepupae/pupae). There has been only one other study on pathogenicity of EPF against S. littoralis in the soil, but in this case the prepupae and pupae were inoculated by immersion in the EPF ( Cordyceps fumosorosea ) before being placed on the soil (Hussein et al ., 2013). The results of our current study indicate variation in susceptibility of S. littoralis prepupae to the EPFs we evaluated and that this was independent of fungal genera.…”

Potential of endophytic fungi as biocontrol agents of Duponchelia fovealis (Zeller) (Lepidoptera:Crambidae)

“…Other studies have found significant results for isolates of this genus, as observed in our study. Hussein et al (2013) treated third instar larvae of Spodoptera littoralis (Noctuide: Lepidoptera) with a new lineage of Paecilomyces sp (CCM 8367) in a suspension at a concentration of 5.0 × 10 7 conidia/mL and reported a mortality rate above 90%.…”

Laboratory Evaluation of Isaria fumosorosea CCM 8367 and Steinernema feltiae Ustinov against Immature Stages of the Colorado Potato Beetle

“…Because this strain showed high virulence against C . ohridella and other pests [ 60 – 62 ], it was considered to have an application potential and therefore patented [ 39 ].…”