Effects of Local Entomopathogenic Beauveria Bassiana Isolates Against Sitophilus Granarius (Coleoptera) (original) (raw)
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Egyptian Journal of Biological Pest Control, 2019
Efficacy of the five native entomopathogenic fungi (EPFs), Beauveria bassiana, Isaria fumosorosea, Lecanicillium muscarium, Metarhizium anisopliae, and Simplicillium lamellicola, against adults of the stored-grain insect pests, Sitophilus granarius and Sitophilus oryzae (Coleoptera: Curculionidae), was evaluated under laboratory conditions at two different temperatures. Conidial suspensions (1 × 10 8 conidia ml −1) of the fungi were directly applied to both the pests in Petri dishes (2 ml per dish), using a Potter spray tower. All the dishes were incubated both at 20 and 25°C in 16 h light/8 h dark and in 75 ± 5% relative humidity (RH). Dead individuals were counted daily, following treatments, for 7 days. Lethal time values (LT 50 and LT 90) for EPFs were calculated. The results demonstrated that the mortality rates varied according to both the temperature and the tested EPFs. The highest effect among EPFs at (1 × 10 8 conidia ml −1) concentration on S. granarius at 20°C at the end of day 7 was showed by I. fumosorosea (92.69%) and M. anisopliae (90.35%), followed by the other EPFs. Similarly, M. anisopliae and I. fumosorosea were the most effective ones with 90.48 and 84.21% mortality rates, respectively, at 25°C. However, while M. anisopliae (85.68%) showed the highest effect among all the EPFs applied on S. oryzae at 20°C, B. bassiana with a mortality rate of 93.66% was the most effective one at 25°C. LT 50 values for I. fumosorosea and M. anisopliae were 2.75 and 2.88/days, respectively, and LT 90 values were 4.17 and 4.47/ days, respectively, at 20°C for S. oryzae. However, LT 50 values for M. anisopliae on S. granarius in both temperatures were the lowest. This study indicated that M. anisopliae and I. fumosorosea had a significant potential as a biological control agent against S. granarius and S. oryzae. Further studies are necessary to evaluate the efficacy of the isolate on the pests under storage conditions.
2020
Chemical insecticides have been widely employed for the control of storage grain pests. This has caused such problems as insecticide resistance along with contamination of foodstuffs with chemical residues. Thus, there is a growing interest in using pathogenic control agents as alternative. In this study, the potential of Beauveria bassiana (BbWeevilTM, a commercial product containing 2×10 conidia g) was evaluated against adults of Tribolium castaneum, Sitophilus granarius and Oryzaephilus surinamensis. The experiments were carried out at the rates of 0, 250, 500, 750 and 1,000 mg kg and exposure intervals of 5, 10 and 15 days, in 24±2°C and 50±5% r.h. Fifteen 1 kg lots of grain (one lot for each exposure time-rate) were prepared and treated with the appropriate predetermined doses. Four 50 g samples of each were taken as replications and placed in glass vials. Thirty 1-7 day old adults were introduced into each glass vial. Following mortality count in each exposure time, the adults...
SINET: Ethiopian Journal of Science, 2011
Evaluation of eleven Metarhizium anisopliae and six Beauveria bassiana isolates against the maize weevil Sitophilus zeamais was conducted under laboratory with the objectives of identifying the most virulent locally available fungal isolates, and determining the dose mortality response. The pathogenicity (virulence) of the entomopathogenic fungi was determined using LT 50 and percent mortality at the conidial concentration of 1 x 10 8 ml-1. The most virulent isolates of M. anisopliae (PPRC-2, PPRC-14 and PPRC-51) and B. bassiana (PPRC-GG and PPRC-HH) caused 84.4% to 98.3% mortality to S. zeamais. These isolates had LT 50 ranging from 3.8 to 4.3 days. The dose response study with the isolates PPRC-2, PPRC-14 and PPRC-51 at doses ranging from 1x 10 4 to 1x 10 8 conidia ml-1 revealed susceptibility of the S. zeamais with mortality ranging from 25 to 95.5%. There was an increase in the resulting LT 50 from 4.0 to 11.9 days with a decrease in conidial concentration from 1x 10 8 to 1x 10 4 conidia ml-1. PPRC-2 showed the lowest LC 50 (1.46x 10 conidia ml-1) followed by PPRC-14 and PPRC-51 (3.5x 10 5 and 3.9x 10 5 conidia ml-1 , respectively). In conclusion, the isolates PPRC-2, PPRC-14, PPRC-51, PPRC-GG and PPRC-HH, can be considered as a potential candidates in the development of mycoinsectisdes against S. zeamais.
Agriculture, 2019
The insecticidal virulence of various entomopathogenic fungal isolates retrieved from soil samples was tested on adults of the granary weevil Sitophilus granarius (L.) (Coleoptera: Curculionidae). Bioassays were carried out in the laboratory where experimental adults were sprayed with 1 mL of conidial suspension (108 conidia/mL) from each isolate. Mortality was recorded at 7, 14, and 21 days after exposure. Mean mortality, mean lethal time, survival, and hazard effect were estimated for each isolate. Two isolates of Beauveria bassiana (Balsamo) Vuillemin (Hypocreales: Cordycipitaceae), one isolate of Aspergillus insuetus (Bainier) Thom & Church (Eurotiales: Trichocomaceae) and Metarhizium anisopliae (Metschinkoff) Sorokin (Hypocreales: Clavicipitaceae) resulted in the highest mortality (97–100%). The isolates with both the highest hazard effect and the lowest survival rate were Aspergillus sp. and M. anisopliae. Our results indicate that entomopathogenic fungi have the potential to ...
Egyptian Journal of Biological Pest Control, 2020
The whitefly, Bemisia tabaci (Genn.) (Hemiptera: Aleyrodidae), is one of the most damaging pests in field crops as well as in greenhouses. The present study aimed to evaluate the in vitro pathogenicity of 2 fungus strains of Beauveria bassiana (BB-72 and BB-252) and one strain of Lecanicillium lecanii (V-2) against the whitefly (B. tabaci) at 4 different temperature degrees 20, 24, 28, and 32°C, using a spray method. Three different bioassays were carried out comprised of conidial concentrations and filtrate of fungal strains, BB-72, BB-252 and V-2, and their binary combinations. The 1.5 ml of fungal filtrate was used in filtrate bioassay for each strain of fungus. Three different concentrations (1 × 10 6 , 1 × 10 7 , and 1 × 10 8 conidia ml −1) were used in conidial bioassay for each strain of fungus, whereas in bioassay for binary combination (1 ml conidia + 1 ml filtrate) of BB-72 × BB-72, BB-252 × BB-252, and V2 × V2 were used for these strains of fungus. According to the outcomes, the maximum mortality against whiteflies was observed on 12th day post-treatment. In conidial bioassay, the maximum mortality of B. tabaci was observed in BB-72 isolate (84%), BB-252 isolate (77%), and V-2 isolate (67%) at the highest concentration (1 × 10 8 conidia ml −1) at 24°C, and minimum mortality was recorded in BB-72 isolate (33%), BB-252 isolate (29%), and V-2 isolate (19%) at the lowest concentration 1 × 10 6 conidia ml −1 at 32°C on 12th day post-treatment. Infiltrate bioassay, BB-72 isolate exhibited maximum mortality (92%) at 24°C, and V-2 isolate showed minimum mortality (34%) at 32°C on 12th day post-treatment. Furthermore, in binary combination bioassay, the highest whitefly mortality was recorded in BB-72 × BB-72 isolate (87%), BB-252 × BB-252 isolate (73%), and V2 × V2 isolate (65%) at 24°C and the lowest mortality in BB-72 × BB-72 isolate (57%), BB-252 × BB-252 isolate (50%), and V2 × V2 isolate (39%) at 32°C on 12th day posttreatment. In all bioassays, the BB-72 isolate was the utmost virulent, and application of its filtrate was found to be the most impressive against B. tabaci.
Journal of Stored Products Research, 1996
The virulence of ten isolates of Beauvena bassiana (Balsamo) Vuillemin to the maize weevil, Sitophilus zeamais Motsch., was tested in the laboratory. All isolates tested were capable of infecting S. zeamais but their virulence, determined by adult mortalities and median lethal time, varied. A total of five (I89-481, I90-520, I89-477, I90-533, and I94-907) highly virulent, three (I92-736, I93-906 and I92-761A) intermediate and two (I93-868 and I93-870) weakly virulent isolates were identified for S. zeamais. The growth and sporulation rates and persistency of water formulated conidia of the most virulent isolates were also studied.I90-520 was selected for further work and dose-mortality relationships and the infectivity of dry conidia against Sitophilus zeamais were determined. The lowest dose (104 conidia ml−1) caused about 88% mortality within eight days. To assess the infectivity of a dry formulation of the isolate, conidial doses of 0, 0.1, 0.5 and 1 g of B. bassiana per 25 g of popping maize seeds were compared with pirimiphos-methyl at 10 ppm. This demonstrated the potential of dry conidia of the isolate to infect and cause mycosis to S. zeamais. Adult mortality of S. zeamais and damage to maize seeds treated with different levels of dry conidia were not statistically significantly different from pirimiphos-methyl-treated maize after 14 days of storage period, but the chemical pesticide killed all target insects within 24 h, whereas mortality began at day 3 for the best B. bassiana treatment.
African Entomology
The larger grain borer, Prostephanus truncatus (Horn) and the maize weevil, Sitophilus zeamais Motschulsky continue to cause tremendous losses to stored maize. Research in the UK has identified Beauveria bassiana, IMI 389521 as a suitable control agent for grain storage pests in the UK. The pathogenicity of B. bassiana, IMI 389521 was evaluated against adult P. truncatus, S. zeamais and Teretrius nigrescens in Ghana. Fifty adults of each insect species were treated with 0.5 g dry conidia powder of this isolate at 8.65 × 108 conidia/g for 1 minute and mortality recorded daily for 14 days. The results indicated that B. bassiana, is pathogenic against P. truncatus and S. zeamais, inducing over 90% mortality by day 7. Teretrius nigrescens was, however less susceptible to the fungus with 30% mortality. To determine the most effective concentration of B. bassiana for the control of P. truncatus, a laboratory dose response experiment using four concentrations of B. bassiana (108–1011 cfu/k...
2 Selection of Isolates of Entomopathogenic Fungi
Entomopathogenic fungi are fungi pathogenic to insects and are widely used as biocontrol agents for insect pests. The aim of this research was to study the virulence of Beauveria bassiana and Metarhizium sp. isolates and to evaluate the efficacy of liquid production of those fungi against Leptocorisa oratorius (rice bug). Twelve isolates of B. bassiana and five isolates of Metarhizium sp. were used in this research. Selection result of B. bassiana isolates on third-instar rice bug nymphs showed that the isolate KBC caused the highest mortality rate (93%), while the lowest (46%) was caused by the isolate BBY 725. The shortest time needed to produce 50% mortality (Lethal time, LT 50 ) was 3.52 days (isolate KBC). The longest time (10.36 days) was produced by isolate SLSS. The mortality of rice bug nymphs caused by Metarhizium isolates was only 50-62%. The shortest LT 50 of Metarhizium (5.75 days) was produced by isolate Mtm, while the longest (7.46 days) was produced by isolate Mpx. Bioefficacy tests on six kinds of liquid formations of entomopathogenic fungi indicated that all were effective, mostly with LT 50 d" two days. The mortality rates of rice bug nymphs caused by bioefficacy of fungus liquid production was generally above 85% up to 100%. The liquid media for entomopathogenic fungi performed better compared with solid media (SDA), as indicated by the greater mortality rate and shorter LT 50 .
Bioassays with conidial suspensions (1×10 8 conidia/ml) of isolates of the entomopathogenic fungi Beauveria bassiana (Bals.) Vuill. and Paecilomyces farinosus (Holm.) Brown & Smith have been proved against adults of Ips sexdentatus Boer. and Ips acuminatus Gyll. (Coleoptera: Scolytidae). Lethal effect of each fungal isolate was estimated by values of the cumulative mortality (%) in treated populations during ten days. It has been established that the isolate 426 of B. bassiana caused the highest lethal effect to adults of Ips sexdentatus ≠ 96.67%, following by isolates 412 and 422 of B. bassiana ≠ 90.67% and 89.33%, respectively. The isolate 426 of B. bassiana was obtained into pure culture from imago of Ips sexdentatus. For the first time in Bulgaria the fungal pathogen B. bassiana has been found to occur in natural populations of the pest. Isolates 290 and 290re of P. farinosus showed less lethal effect to the same host ≠ 45.00% and 66.67%. It has been established that adults of Ips acuminatus were not susceptible to the studied fungal isolate 290 of P. farinosus. The isolates 412, 422 and 426 of B. bassiana were highly virulent to adults of Ips sexdentatus. Their values of the median lethal time (LT50) varied within overlapped narrow confidence intervals from 4.374 to 4.867, from 3.659 to 6.112 and from 4.110 to 4.550 days (at p-level < 0.05). Significant differences between virulence of B. bassiana isolates have not been proved. Isolates of B. bassiana could be distinguished from P. farinosus isolates according to their virulence to Ips sexdentatus evaluated as median lethal time.
African Journal of Agricultural Research, 2013
Virulence of ten fungal isolates of entomopathogenic fungi, Beauveria bassiana (Balsamo) Vuillemin and Metarhizium anisopliae (Metcsn.) Sorokin against third instar larvae of Mediterranean flour moth, Ephestia kuehniella Zeller, was tested under laboratory conditions. These isolates were originated from soil by using Galleria mellonella (L.) (Lepidoptera: Pyralidae) as a live insect bait. All isolates were inoculated by immersing the insects in 10 ml of a fungal suspension for 5 s. The experiments carried out with 3 replications and 10 larvae were used for each replication.Cumulative mortality after treatment varied from 11 to 92% in M. anisopliae and in B. bassiana from 17 to 88%. The increase of dose and exposure interval increased mortality. LC 50 values ranged from 8.3 × 10 5 to 6.5 × 10 6 for B. bassiana and from 5.4×10 7 to 3.4×10 8 for M. anisopliae. Among the isolates evaluated in the study, C-IIA7 isolate of B. bassiana had the lowest LC 50 .The LT 50 values for these isolates varied from 107 to 154 h for B. bassiana and from 93 to 162 h for M. anisopliae, whereas, B-VM1 isolate of M. anisopliae, recorded the least LT 50 of 93 h. Our results demonstrated that the entomopathogenic fungi could be used as an alternative for the control of stored products pests in IPM programs.