Virulence of Metarhizium anisopliae (Deuteromycotina: Hyphomycetes) on Anastrepha ludens (Diptera: Tephritidae): Laboratory and Field Trials
Facultad de Ciencias Biológicas y Agropecuarias de la Universidad de Colima, Tecomán, Mexico. Journal of Economic Entomology
(Impact Factor: 1.51).
08/2000; 93(4):1080-4. DOI: 10.1603/0022-0493-93.4.1080
Twenty isolates of the fungus Metarhizium anisopliae (Metsch). Sorkin (Ma) were evaluated to determine their virulence against last instar and adult emergence of Mexican fruit fly, Anastrepha ludens (Loew). Larvae were exposed by immersion in a conidial suspension at a concentration of 10(8) UFC/ml under laboratory conditions. Larvae and pupae cumulative mortality rates ranged from 37.9 to 98.75%. Thirteen isolates caused mortality rates > 83.7%, and their LT50 values ranged from 1.8 to 6.2 d. The Ma2, Ma8, and Ma16 isolates were evaluated at seven different concentrations ranging from 10(1) to 10(7) UFC/ml, showing LC50 values from 3.7 to 4.8 x 10(5) UFC/ml. In a field-cage experiment, 200 ml of a conidial suspension of Ma2, at a concentration of 2.5 x 10(6) UFC/ml, was applied on 2,500 cm2 soil surface (2 x 10(5) UFC/cm2). The fungus reduced adult emergence, 22% fewer adults emerging in a sandy loam soil, and 43% fewer in loam soil, compared with the controls. M. anisopliae may offer a preferable alternative to chemicals as a biological control agent against A. ludens.
Available from: Abdessamad Imoulan
- "Because, it is considered as considerable reservoir of entomopathogenic fungi and as an important favorable environment to target soil-dwelling life stages of fruit fly pest (Jackson et al. 2000; Ekesi et al. 2007), it was suggested that the introduction of conidia to the soil surface could be a useful strategy for fruit fly insects control (Lezama-Gutiérrez et al. 2000; Ekesi et al. 2002; Dimbi et al. 2003). This method seems to be logical, since the larvae at end of the third instar leave the fruits and fall on the ground and become immediately vulnerable to pathogens occurring in the soil (Gutiérrez et al. 2000). Moreover, entomopathogenic fungi have been shown to be effective against soilinhabiting life stages of pests (Rath et al. 1995; Jackson et al. 2000; Lacey et al. 2003), since the persistence of conidia is less affected by the environmental of soil (Garrido-Jurado et al. 2011; Coombes et al. 2013). "
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ABSTRACT: The Mediterranean fruit fly, Ceratitis capitata Wiedemann (Diptera: Tephritidae), is the major tephritid pest in Morocco. This pest survives in Moroccan forests Argania spinosa and continually invades the nearest agricultural areas. Entomopathogenic fungi are an interesting tool for fruit fly control and hold a useful alternative to conventional insecticides. However, primary selection of effective pathogens should be taken in laboratory condition prior to applying them in the field. Here, we used third late instar larvae of C. capitata to investigate the effectiveness of 15 local Beauveria bassiana isolates. Results showed that all isolates were able to infect the larval stage, producing a large mortality rate in puparia ranging from 65 to 95 % and caused significant reduction in adult emergence. The fungal treatments revealed that the mycosis occurred also in adults escaping infection as pupariating larvae. The percentage of mycosed puparia was highest in strain TAM6.2 (95 %) followed by ERS4.16 (90 %), therefore they were the most virulent. Median lethal concentration (LC50) was studied for five isolates at four concentrations ranging from 10(5) to 10(8) conidia ml(-1). The results showed that the slopes of regression lines for B. bassiana ERS4.16 (slope = 0.386) and TAM6.2 (slope = 0.41) were the most important and had the lowest LC50 values (2.85 × 10(3) and 3.16 × 10(3) conidia ml(-1) respectively). This investigation suggests that the soil of Argan forests contains pathogenic B. bassiana isolates and highlights for the first time their potential as biological control toward C. capitata larval stage in Morocco.
Available from: PubMed Central
- "The dead of larvae was counted and recorded everyday till 7 days, then calculated for percent of dead larvae and cultured in water agar plates to confirm the mycosis. This method was described by Lezama-Gutiérrez et al. . "
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ABSTRACT: Ten strains of the entomopathogenic fungi Metarhizium anisopliae and Beauveria bassiana were evaluated to find the most effective strain for optimization studies. The first criterion tested for strain selection was the mortality (> 50%) of Spodoptera litura larvae after inoculation of the fungus for 4 days. Results on several bioassays revealed that B. bassiana BNBCRC showed the most virulence on mortality S. litura larvae (80% mortality). B. bassiana BNBCRC also showed the highest germination rate (72.22%). However, its conidia yield (7.2 × 10(8) conidia/mL) was lower than those of B. bassiana B 14841 (8.3 × 10(8) conidia/mL) and M. anisopliae M6 (8.2 × 10(8) conidia/mL). The highest accumulative radial growth was obtained from the strain B14841 (37.10 mm/day) while the strain BNBCRC showed moderate radial growth (24.40 mm/day). M. anisopliae M6 possessed the highest protease activity (145.00 mU/mL) while M. anisopliae M8 possessed the highest chitinase activity (20.00 mU/mL) during 96~144 hr cultivation. Amongst these criteria, selection based on virulence and germination rate lead to the selection of B. bassiana BNBCRC. B. bassiana B14841 would be selected if based on growth rate while M. anisopliae M6 and M8 possessed the highest enzyme activities.
Available from: Sergio A De Bortoli
- "Laboratory studies showed that M. anisopliae is pathogenic for C. capitata eggs (Castilho 2000), larvae (Gutiérrez et al. 2000), and adults (Garcia et al. 1984, 1985). "
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ABSTRACT: This research intended to investigate if the presence of pesticides in the soil could affect the pathogenicity of Metarhizium anisopliae Metsch. (Sorokin) for Ceratitis capitata (Wied.) and assess the effect of conidia application as suspension or dry conidia. The fungicides chlorothalonyl and tebuconazol, the acaricide abamectin, the insecticide trichlorfon, and the herbicide ametrin were applied at the manufacturer-recommended doses. Soil samples were placed in glass flasks and were given the fungus as conidial suspension or dry. After pesticide application, 20 3rd-instar larvae were placed in the soil. The flasks were sealed with voile fabric and incubated at 27 +/- 0.5 masculineC for nine days, until adult emergence; incubation continued for four more days at room temperature. The total insect survival was significantly affected and pathogenic activity was detected from the pupa stage on. Pupa survival was reduced (P<0.05); the same occurred during the adult phase. No effect was observed at the larval stage. The pesticides applied to the soil affected the activity of M. anisopliae slightly: only in the dry conidia assay the fungicides chlorothalonyl and tebuconazole reduced (86.2% and 82.5%, respectively) the survival period of C. capitata compared to the control (95.0%). The techniques used for conidia application did not influence the total insect survival rate, but conidial suspension applied on soil surface reduced survival during the pupae and adult phases.
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