Debilitation in conidia of the entomopathogenic fungi Beauveria bassiana and Metarhizium anisopliae and implication with respect to viability determinations and mycopesticide quality assessments

Faria, Marcos; Hotchkiss, Joseph H.; Hajek, Ann E.; Wraight, Stephen P.

doi:10.1016/j.jip.2010.05.011

Cited by 43 publications

(25 citation statements)

References 56 publications

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“…On average, however, the additional increases in control achieved through evening applications were small (66% vs. 54% and 83% vs. 76%, relative to the AM carrier controls) and might not warrant the inconvenience associated with such a restricted window of time, particularly in large-scale control operations. Conidia are certainly protected from UV radiation at night and generally experience favorable moisture conditions, which enhances activity in the short-term, but Beauveria conidia, especially from prolonged, dry storage generally require at least 16 h incubation at moderate temperatures and 100% RH to fully germinate (Faria et al, 2010). This places the germlings in early stages of producing germ tubes and penetration structures in a vulnerable position at sunrise of the following day.…”

Section: Discussionmentioning

confidence: 99%

Delayed efficacy of Beauveria bassiana foliar spray applications against Colorado potato beetle: Impacts of number and timing of applications on larval and next-generation adult populations

Wraight

Ramos

2015

Biological Control

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Section: Discussionmentioning

confidence: 99%

Delayed efficacy of Beauveria bassiana foliar spray applications against Colorado potato beetle: Impacts of number and timing of applications on larval and next-generation adult populations

Wraight

Ramos

2015

Biological Control

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“…In this regard, Faria et al (2010) determined that the atmosphere modifications are also important during the storage, once conidia were harvested, as conidial viability was prolonged in low-O 2 atmospheres.…”

Section: Discussionmentioning

confidence: 99%

Production and quality of conidia by Metarhizium anisopliae var. lepidiotum: critical oxygen level and period of mycelium competence

García-Ortiz

Tlécuitl-Beristain

Favela‐Torres

et al. 2014

Appl Microbiol Biotechnol

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Mycoinsecticides application within Integral Pest Management requires high quantities of conidia, with the proper quality and resistance against environmental conditions. Metarhizium anisopliae var. lepidiotum conidia were produced in normal atmospheric conditions (21 % O2) and different concentrations of oxygen pulses (16, 26, 30, and 40 %); conidia obtained under hypoxic conditions showed significantly lower viability, hydrophobicity, and virulence against Tenebrio molitor larvae or mealworm, compared with those obtained under normal atmospheric conditions. Higher concentrations of oxygen (26 and 30 %) improved conidial production. However, when a 30 % oxygen concentration was applied, maximal conidial yields were obtained at earlier times (132 h) relative to 26 % oxygen pulses (156 h); additionally, with 30 % oxygen pulses, conidia thermotolerance was improved, maintaining viability, hydrophobicity, and virulence. Although conidial production was not affected when 40 % oxygen pulses were applied, viability and virulence were diminished in those conidia. In order to find a critical time for mycelia competence to respond to these oxidant conditions, oxygen pulses were first applied either at 36, 48, 60, and 72 h. A critical time of 60 h was determined to be the best time for the M. anisopliae var. lepidiotum mycelia to respond to oxygen pulses in order to increase conidial production and also to maintain the quality features. Therefore, oxygen-enriched (30 %) pulses starting at 60 h are recommended for a high production without the impairment of quality of M. anisopliae var. lepidiotum conidia.

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“…In addition, the high and fast germination rate for fungal entomopathogens has a positive relationship with their virulence toward a host (Altre et al, 1999;Hassan et al, 1989;Rangel et al, 2008). Faster conidial germination indicates non-stressed conidia which play an important role for the success of biological control of insects and should be the major concern in quality control protocols for conidia-based mycoinsecticides (Faria et al, 2010). Faria et al (2010) assumed that only vigorous conidia of Beauveria and Metarhizium which germinated quickly within 24 h incubation should be considered suitable for insect control.…”

Section: Discussionmentioning

confidence: 99%

“…Faster conidial germination indicates non-stressed conidia which play an important role for the success of biological control of insects and should be the major concern in quality control protocols for conidia-based mycoinsecticides (Faria et al, 2010). Faria et al (2010) assumed that only vigorous conidia of Beauveria and Metarhizium which germinated quickly within 24 h incubation should be considered suitable for insect control. On the other hand, conidia germinating after 24 h should be considered debilitated spores (low vigor), as they may cause low insect mortalities and thus should not be used for insect control.…”

Section: Discussionmentioning

confidence: 99%

Compatibility of conventional agrochemicals used in rice crops with the entomopathogenic fungus Metarhizium anisopliae

Silva

Quintela

Mascarin

et al. 2013

Sci. agric. (Piracicaba, Braz.)

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The toxicological impact of chemical pesticides on fungal entomopathogens and their use in tank-mixing can be directly measured through in vitro compatibility tests. This study reports the in vitro toxicity of eight insecticides, four fungicides and five herbicides in the conidial germination, vegetative growth and conidiation of Metarhizium anisopliae (strain CG 168). A conidial suspension containing the pesticide at recommended field dosage was subjected to constant agitation in a rotary shaker for 3h to simulate a tank mixing. Then, aliquots of each suspension were used to determine conidial germination, vegetative growth and conidiation on potato dextrose agar (PDA). The fungicides difenoconazole (69 mL ha -1 ), propiconazole (75 mL ha -1 ), trifloxystrobin (313 g ha -1 ) and azoxystrobin (56 mL ha -1 ) were the most harmful products to all biological stages of M. anisopliae and they should not be applied together with this fungus in tank mixing. The insecticides exhibited the least degree of toxicity to this fungal pathogen, whereas the herbicides had the greatest impact on mycelial growth. The agrochemicals compatible with M. anisopliae were the insecticides methyl parathion (240 mL ha -1 ), thiamethoxam (31 g ha -1 ), and lambda-cyhalothrin (6.3 mL ha -1 ) and the herbicides glyphosate (1560 mL ha -1 ), bentazon (720 mL ha -1 ), and imazapic+ imazapyr (84 g ha -1 ). The compatible pesticides could be simultaneously used with this bio-control agent for integrated pest management in rice production systems.

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Debilitation in conidia of the entomopathogenic fungi Beauveria bassiana and Metarhizium anisopliae and implication with respect to viability determinations and mycopesticide quality assessments

Cited by 43 publications

References 56 publications

Delayed efficacy of Beauveria bassiana foliar spray applications against Colorado potato beetle: Impacts of number and timing of applications on larval and next-generation adult populations

Delayed efficacy of Beauveria bassiana foliar spray applications against Colorado potato beetle: Impacts of number and timing of applications on larval and next-generation adult populations

Production and quality of conidia by Metarhizium anisopliae var. lepidiotum: critical oxygen level and period of mycelium competence

Compatibility of conventional agrochemicals used in rice crops with the entomopathogenic fungus Metarhizium anisopliae

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