scholarly journals External development of the entomopathogenic fungi Beauveria bassiana and Metarhizium anisopliae in the subterranean termite Heterotermes tenuis

2002 ◽  
Vol 59 (2) ◽  
pp. 267-273 ◽  
Author(s):  
Alcides Moino Jr. ◽  
Sérgio Batista Alves ◽  
Rogério Biaggioni Lopes ◽  
Pedro Manuel Oliveira Janeiro Neves ◽  
Roberto Manoel Pereira ◽  
...  

The subterranean termite Heterotermes tenuis is one of the main pests of sugarcane and eucalyptus in Brazil, and the use of entomopathogenic fungi, alone or associated to chemicals, is an efficient and environmentally favorable method for its control. Studies related to the fungal development on these insects are important due to the effect of insect behavior on entomopathogens. The objective of this work was to describe the external development of Beauveria bassiana and Metarhizium anisopliae on H. tenuis using Scanning Electron Microscopy (SEM), determining the duration of the different phases of fungal infection. Two fixation techniques for preparing SEM samples were also evaluated. Worker specimens of H. tenuis were inoculated with a 1 x 10(9) conidia mL-1 suspension of the fungi and maintained at 25±1ºC and 70±10% relative humidity. Insects were collected from 0 to 144 hours after inoculation and prepared on SEM stubs for each of the two fixation techniques. The results obtained with the two techniques were compared and duration of the different phases of the infection process were estimated from SEM observations and compared for three fungal isolates. B. bassiana and M. anisopliae have similar development cycles on the termite, but some important differences exist. The penetration, colonization and conidiogenesis phases are relatively faster for M. anisopliae than for B. bassiana, which results in a faster rate of insect mortality. The fixation technique with OsO4 vapor is suitable for preparation of insects to be used in SEM observation of the developmental stages of entomopathogenic fungi.

2000 ◽  
Vol 43 (4) ◽  
pp. 373-378 ◽  
Author(s):  
Pedro J. Neves ◽  
Sérgio Batista Alves

Fifty strains of the entomopathogenic fungi Beauveria bassiana (Bals.) Vuill. and Metarhizium anisopliae (Metsch.) Sorok. were tested against the termite Cornitermes cumulans. In the first phase of the experiments, several bioassays were conducted and the five best strains were selected. The criterion for strain selection during this phase was the confirmed mortality above 50% five days after application of the fungus. Three M. anisopliae and two B. bassiana strains were the most virulent. The second phase of the experiments consisted of a bioassay and a conidial production test using a rice medium. The best M. anisopliae and B. bassiana strains were selected using both the confirmed insect mortality nine days after application of the fungus and the yield of conidia. Considering results from the bioassay, M. anisopliae 1037 showed the highest confirmed (57.8%) and total (89.2%) mortalities after nine days. Among the B. bassiana strains, 447 was the most virulent with confirmed and total mortalities of 45.9% and 89.8%, respectively. M. anisopliae 1037 had the highest conidial yield with mean of 3.37 x 10(12) conidia/kg of rice, followed by B. bassiana strain 447 with 2.66 x 10(12) conidia/kg of rice. The M. anisopliae strain 1037 was the highest virulent followed by B. bassiana strain 447. This strains showed the greatest potential as agents to be used in biological control programs against C. cumulans.


2017 ◽  
Vol 15 (4) ◽  
pp. 31-39
Author(s):  
Elżbieta Popowska-Nowak ◽  
Dorota Tumialis ◽  
Elżbieta Pezowicz

The lesser mealworm Alphitobius diaperinus is present in great numbers in poultry houses. These insects are especially dangerous as a potential carriers of pathogens such as bacteria, viruses and parasites. We explored the possibility of using local strains of entomopathogenic fungi isolated from litter and from soil to control lesser mealworm populations. Isolated fungi showed low pathogenicity to lesser mealworm beetles. Infection with a suspension at a concentration of 1 × 108 spores/ml resulted in only 4 Metarhizium anisopliae sensu lato isolates showing the highest insect mortality in the range of 30–36%. Still lower pathogenicity was found in isolates of Beauveria bassiana, with only 4 isolates of B. bassiana causing a mortality of 17–26%. Isolates of Isaria fumosorosea and I. farinosa did not cause mortality in beetles that differed significantly from that in the control variant. The larvae were more susceptible to infection. Except for I. fumosorosea, all species caused 100% mortality in larvae. For further studies, the B. bassiana 3K isolate (from the litter) could be selected because of its high mortality (100%) and high larval infectivity (50% overgrown with mycelium).


The current study examined the potential use of entomopathogenic fungi to control infestation of Rhipicephalus sanguineus. Examination of 514 dogs admitted to veterinary clinics in Egypt revealed that 67.5% were infested with R. sanguineus. Two hundred and sixty adult ticks were collected. Beauveria bassiana and Metarhizium anisopliae were then tested for their effect on these ticks. The in vitro effect of different concentrations of B. bassiana on engorged females, unfed females, fed males, eggs, larvae, and nymphs was strong for all three concentrations of B. bassiana compared with controls (P<0.05) and white fungal colonies grew on the surface of the ticks. The B1 of B. bassiana (108 conidia/ ml) was the most pathogenic on adult and developmental stages of ticks. The impact of different concentrations of M. anisopliae on adult and developmental stages in comparison with controls was similar, with the growth of green hyphae around eggs and adult ticks which prevented hatching and resulted in tick death. The M2 suspension (107 conidia/ml) had the most potent effect on adult ticks and developmental stages. The efficacy of this suspension was higher than that of the B1 concentration of B. bassiana (98 and 100% respectively). Therefore, 107conidia/ml of M. anisopliae seems to be the most effective fungus to use as bio-pesticide to control different developmental stages of R. sanguineus and may be a reasonable alternative to chemical treatment.


2017 ◽  
Vol 4 (4) ◽  
pp. 273 ◽  
Author(s):  
Azhar Faturohman Abidin ◽  
Nuraeni Ekowati ◽  
Nuniek Ina Ratnaningtyas

Insecticide use has produced negative impact by affecting the non-target predatory organisms in nature, one of which is the entomopathogenic fungi, Beauveria bassiana and Metarhizium anisopliae. Interactions occur, however, between insecticides and the entomopathogens. The combination of insecticides at a low dose and an entomopathogenic fungus can work synergistically to increase pest insect mortality. This combination is particularly advantageous because it decreases the insecticide dose applied, reduces environmental contamination, and decreases pest resistance. The study purpose was to determine the compatible working insecticide dose and the entomopathogenic fungi B. basiana and M. anisopliae. The experimental design applied completely randomized design consisting of 15 treatments and four replicates. There were five types of insecticides with three different doses each (0.5 × Dose of Field (DF), 1 × DF, and 2 × DF), whereas the fungal isolates included B. basiana and M. anisopliae. The parameters observed were the germination percentage of conidia, the percentage of inhibition, and the number of conidia.ml-1. Data were analyzed using ANOVA (5% error rate). The mean values were analyzed by DMRT p < 0.05. Deltamethrin 0.5 x DF, and imidacloprid 0.5 x DF demonstrated the highest conidial germination in B. basiana and M. anisopli, respectively. Insecticides showing the highest vegetative growth on B. basiana and M. anisopliae at 7 DAI was imidacloprid 0.5 x DF, while at 14 DAI was imidacloprid 0.5 x DF and chlorphyrifos 2 x DF, respectively. The highest conidial production of the fungi was triggered by imidacloprid 0.5 x DF. Based on compatibility calculation, imidacloprid 0,5 x DF worked with B. basiana (BI: 67.77) and M. anisopliae (BI: 67.16).


2021 ◽  
Vol 31 (1) ◽  
Author(s):  
Muhammad Shehzad ◽  
Muhammad Tariq ◽  
Tariq Mukhtar ◽  
Asim Gulzar

Abstract Background The diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), is a noxious pest of cruciferous crops all over the world causing serious economic damage. Management of insect pest generally depends on chemical control; however, due to development of resistance against all types of insecticides, alternative approaches especially utilization of a microbial agent is inevitable. Results Potential of 2 entomopathogenic fungi (EPF), viz., Beauveria bassiana and Metarhizium anisopliae, was evaluated against 2nd and 3rd larval instars of P. xylostella by adopting leaf dip and direct spraying methods under laboratory conditions. Significant mortality rate was achieved by each fungus under adopted methodologies. However, B. bassiana was found to be more effective in both conditions than M. anisopliae. Highest mean corrected mortality (77.80%) was recorded, when spores of B. bassiana were sprayed on the 2nd instar larvae (LC50=1.78×104/ml) after the 6th day of treatment. Similarly, incase of M. anisopliae LC50 for the 2nd instar at the same methodology was 2.78×104/ml with a mortality percentage of 70.0%. Offspring sex ratio was non-significantly related to treatment concentration and methodology, except for the control. Conclusion Beauveria bassiana and M. anisopliae had potential to suppress P. xylostella infestations when applied appropriately. Present findings suggested that B. bassiana and M. anisopliae when sprayed on immatures of host insect had more effect as compared to leaf dip procedure. Furthermore, no significant effect of concentrations was observed on sex ratio.


2015 ◽  
Vol 47 (3) ◽  
pp. 117 ◽  
Author(s):  
M.W. Khudhair ◽  
M.Z. Khalaf ◽  
H.F. Alrubeai ◽  
A.K. Shbar ◽  
B.S. Hamad ◽  
...  

Virulence of entomopathogenic fungi <em>Metarhizium anisopliae</em> and <em>Beauveria bassiana</em> were tested against Arabian Rhinoceros Beetle, <em>Oryctes agamemnon arabicus</em> larvae. Four concentrations (1×10<sup>5</sup>, 1×10<sup>7</sup>, 1×10<sup>9</sup> and 1×10<sup>11</sup> conidia/mL<sup>–1</sup>) of two locally isolated entomopathogenic fungi spore suspensions were used in this study via larval direct spraying. Results revealed that both isolates can cause high mortality rate reaching 100% after 29 days. However, <em>Beauveria bassiana</em> scored higher mortality rate in short time especially at the concentration of 1×10<sup>11</sup> conidia/ mL<sup>–1</sup> with lethal time (LT)<sub>50</sub> 12.75 and LT<sub>90</sub> 20.00; while, <em>Metarhizium anisopliae</em> caused the higher percentage of malformed adults. Moreover, both isolates affected insect’s life cycle particularly in the pupal stage which was reduced remarkably by almost 50% in comparison with the control treatment.


2001 ◽  
Vol 44 (4) ◽  
pp. 419-423 ◽  
Author(s):  
Edson Hirose ◽  
Pedro M. O. J. Neves ◽  
João A. C. Zequi ◽  
Luís H. Martins ◽  
Cristiane H. Peralta ◽  
...  

The in vitro fungitoxic effect of three biofertilizers, E.M.-4, Multibion <FONT FACE=Symbol>Ô</FONT> and Supermagro used in organic agriculture and the neem oil (Azadirachta indica A. Juss) on the entomopathogenic fungi Metarhizium anisopliae and Beauveria bassiana was studied. These products were mixed in a medium where the two fungi were inoculated, and germination, vegetative growth and conidiogenesis were assessed. The biofertilizers Supermagro and E.M.- 4 showed to be less toxic for the two fungi whereas Multibion<FONT FACE=Symbol>Ô</FONT> caused major inhibition on M. anisopliae, with reductions in germination (-37.74%), colony diameter (-30.26%) and conidiogenesis (-42.62%). Neem oil promoted a larger negative effect on B. bassiana, inhibiting germination (-45.27%), colony diameter (-36.62%) and conidiogenesis (-84.93%).


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