Virulence of 11 native strains of entomopathogenic fungi; Metarhizium anisopliae (three strains), Beauveria bassiana (six strains) and Lecanicillium psalliotae (two strains) collected from different parts of Iran, were studied against different developmental stages of Rhipicephalus (Boophilus) annulatus. After the exposure of ticks to the fungal strains in different concentrations (i.e. 10(3), 10(5), 10(7) conidia/ml), various parameters such as mortality rate and reproductive efficiency of engorged females, mortality of unfed tick larvae and eclosion percentage of infected eggs were evaluated to determine the fungal virulence. Based on the obtained results, five strains including M. anisopliae (IRAN 437 C and DEMI 001), B. bassiana (IRAN 403 C) and L. psalliotae (IRAN 468 C and IRAN 518 C) were found to be virulent to various stages of tick developmental cycle. Mortality rate of engorged females was found to be dose-dependent with regard to the conidial concentration used. Total mortality rates of 90-100%, 70% and 56.6% were observed for M. anisopliae (IRAN 437 C and DEMI 001), B. bassiana (IRAN 403 C) and L. psalliotae (IRAN 468 C), 6-11 days post inoculation (PI) with 10(7) conidia/ml, respectively. Most strains were able to inhibit egg laying by females in the range of 0-26% in different conidial concentrations. The results indicated that the mean egg laying of treated engorged tick females exposed to M. anisopliae (IRAN 437 C) was less than the mean values of those treated with other fungal strains. Results revealed 89.1%, 35.5% and 56.3% decrease in egg hatchability and 88.69%, 78.15% and 59.74% reduction in reproductive efficiency of the ticks using 10(7) conidia/ml of M. anisopliae (IRAN 437 C), B. bassiana (IRAN 403 C) and L. psalliotae (IRAN 468 C), respectively. In general, the entomopathogenic effects of native M. anisopliae and B. bassiana against various developmental stages of R. (B.) annulatus were confirmed in the present work. Likewise, although L. psalliotae, which was introduced for the first time as an entomopathogenic fungus against tick had not more than 13.3% mortality effect against adult females, but its effect on egg hatchability and reproductive efficiency was remarkable.
The Western flower thrips Frankliniella occidentalis, an important greenhouse pest, has acquired rapid resistance to the chemical pesticides. Therefore, biological control is worth consideration as an alternative control method. Among the biological control agents, entomopathogenic fungi showed to be quite successful in some occasions. In this study, three Iranian isolates of Metarhizium anisopliae ('DEMI001', 'DEMI002' and 'DEMI003') were bioassayed for their lethal effects on the adults of the F. occidentalis, in vitro. The 'DEMI002' and 'DEMI003' had the lowest and highest LC 50 at concentrations of 3.06 10 4 and 1.90 10 5 conidia/ml, respectively. Also, the isolate 'DEMI002' had the lowest LT 50 of 4.39 2.13 days at the concentration of 10 6 conidia/ml. The mean comparison showed that there was a significant difference between DEMI002 and DEMI003 in terms of virulence at most of the concentrations. Consequently, the 'DEMI002' can be considered as a promising tool in biological control programs of the F. occidentalis.
The potato tuber moth PTM, Phthorimaea operculella, is one of the most economically important potato pests worldwide. In the present study, the potential of Steinernema feltiae and Steinernema carpocapsae for controlling PTM in potato tubers was evaluated compared to alpha-cypermethrin. Steinernema carpocapsae in both concentrations (12.6×10 6 IJs and 6.2×10 6 IJs) showed a lower number of emerged insects than alpha-cypermethrin (10 mg ai l -1 ).Alpha-cypermethrin (20 mg ai l -1 ) showed the highest efficacy against PTM (81.17%), S.carpocapsae (12.6×10 6 IJs), and alpha-cypermethrin (10 mg ai l -1 ) showed similar efficacy (72.53%) while S. feltiae (6.2×10 6 IJs) showed the lowest efficacy (39.04%). The results showed that S.carpocapsae in both concentrations and S. feltiae (12.6×10 6 IJs) were efficient the same as alpha-cypermethrin (10 mg ai l -1 ) having no environmental and health adverse impacts issued in the chemical insecticides usage. Both concentrations of alpha-cypermethrin and S. carpocapsae showed the least tuber damage with no significant differences, while it was as high as the control (59.26%) in both concentrations of S. feltiae. This promising finding introduces EPNs as a part of the potato tuber protection program in storage. Accordingly, EPNs can be considered as an appropriate alternative to synthetic chemicals for PTM control without any residue and health problems.
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