Environmental Factors Affecting Conidial Sporulation and Germination of Entomophthora gammae1

Newman, G. G.; Carner, G. R.

doi:10.1093/ee/4.4.615

Cited by 23 publications

(4 citation statements)

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“…In the current study field observations also showed that rainfall was essential for sporulation to occur on infected cadavers. The importance of environmental moisture for spore formation of entomopathogenic fungi in host cadavers is well documented (see Hajek et al, 1990;MacLeod et al, 1980;Milner & Lutton, 1986;Newman & Carner, 1975;Steinkraus & Slaymaker, 1994;Wilding, 1969) although relationships between sporulation and humidity vary considerably between different species of entomopathogenic fungi. Climatic data indicates that heavily overcast conditions associ-ated with prolonged or intermittent rainfall are similarly associated with increased and more prolonged periods of high relative humidity during the night (Figure 1).…”

Section: Discussionmentioning

confidence: 99%

Seasonal patterns of persistence and infectivity of Metarhizium anisopliae var. acridum in grasshopper cadavers in the Sahel

Arthurs

Thomas

Lawton

2001

Entomologia Exp Applicata

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Field‐based experiments were conducted to evaluate the fate and infectivity of the entomopathogenic fungus Metarhizium anisopliae var. acridum (Deuteromycotina: Hyphomycetes) in grasshopper cadavers in the Sahel. Unlike uninfected cadavers, which were rapidly scavenged, those infected with the fungus persisted in the environment for a number of weeks. The environmental factor most associated with cadaver disappearance was rainfall. The high environmental humidity associated with rainfall was also required for sporulation of the fungus on host cadavers, although the likelihood of sporulation differed between microsites. Characteristics of the infection profile from infective cadavers were investigated by the sequential exposure of uninfected hosts to sporulating cadavers in field cages. This experiment revealed that cadavers remained infective for > 30 days, with the net infectivity changing through time. The most likely explanation for these changes is climatic influences on both the fungus and host. High humidity was not required for infection. A measurement of the transmission coefficient between healthy hosts and sporulating cadavers in the field was obtained at a realistic density of infectious cadavers. This revealed a figure of 0.45 m2 day−1. Overall, these experiments show that following host death, M. anisopliae var. acridum can be persistent in the environment, sporulate on host cadavers and reinfect new hosts at a realistically low field density, although at least in arid or semi‐arid areas, rainfall may be critical to the horizontal transmission of this pathogen.

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Section: Discussionmentioning

confidence: 99%

Seasonal patterns of persistence and infectivity of Metarhizium anisopliae var. acridum in grasshopper cadavers in the Sahel

Arthurs

Thomas

Lawton

2001

Entomologia Exp Applicata

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“…In the case of Entomophthora, the conidia could not survive exposure to humidities below 75% RH (189,301).…”

Section: Influence 0/ Temperature and Humiditymentioning

confidence: 99%

Biological Control of Insect Pests by Entomogenous Fungi

Ferron¹

1978

Annu. Rev. Entomol.

353

139

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+6160In spite of the recent advances in insect pathology, the study of mycoses caused by entomogenous fu ngi has held a relatively modest position. The major research effort has been directed toward the study of bacteria and viruses whose potentialities as biological control agents fo r the microbial control of insect pests of crops were considered to be greater. This attitude probably can be explained by the increase in our knowledge of general microbiology, especially medical, with more emphasis in the fi elds of bacteriology and virology than in mycology.However, fo r the past 15 years, research with the entomogenous fu ngi has bene fited from a renewed interest, which arose from a better understanding of the role of natural phenomena in the regulation of insect populations, among which epizoot ics caused by fu ngi have played a determinant part in certain cases. Furthermore, there was a need to develop new techniques of biological control for the expanding application of the concepts of integrated control.Because of this there is an increasing number of scientific publications devoted to this problem. The acquisition of new knowledge and the evolution of research programs are so rapid that it is absolutely necessary to devote an ever-increasing effort to the analysis and compilation of the data contained in the literature. Since the majority of the publications concerning mycoses in insects are not in English, they suffer from a limited distribution. Although I cannot possibly pretend to have studied all the existing world literature concerning this subject that has been pub lished during the past fe w years, nevertheless, through direct contact, on various occasions, with Czech, German, Japanese, Polish, Soviet, and other colleagues, I have come to realize the importance of their contributions and the need to be acquainted with their work despite the barriers of language. Therefore, the purpose of this paper is an objective review of both the results achieved in the study of the pathology of mycoses and the possible application of entomogenous fu ngi in biologi-409

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“…The dependence of capilliconidia of E. radicans #11-18 on temperature €or persistence is interesting, considering that temperature is less inhibitory than r.h. to various stages in the life cycle of entomophthoralean fungi under controlled and natural conditions. Sporulation, conidial germination and conidial longevity, for example, take place at a rather wide temperature range, but at a very narrow r.h. range: 3 90% (Yendol, 1968;Newman & Carner. 1975;Shimazu, 1977: Millstein, Brown & Nordin, 1982Milner, Soper & Lutton, 1982;Milner & Bourne, 1983;Sampedro, Uziel& Latge, 1984;Smitley, Brooks & Kennedy, 1086: Hajek.…”

Section: Discussionmentioning

confidence: 99%

Effect of meteorological variates on persistence of primary conidia and capilliconidia of Erynia radicans (Zygomycotin: ntomophthorales) under natural conditions

Uziel

Shtienberg

1993

Annals of Applied Biology

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Persistence of conidia of an isolate of Erynia radicans (Syn. Zoophthora radicans) was investigated in relation to the meteorological conditions which occurred during autumn-winter of 199CL91 in the coastal plain in Israel. Capilljconidia shielded from the sun, placed on the abaxial surface of leaves of Plumeria acuminata, persisted for 24 h to at least 120 h. Exposed capilliconidia, placed on the adaxial surface of the same leaves, died within 24 h. Almost all the primary conidia shielded from the sun (placed on the abaxial surface of the same leaves) died within a single day. Conidial viability was expressed in subsequent germination on an agar medium.Capilliconidial persistence was closely related to the daily air temperatures, expressed as cumulative day-degrees. Differences in relative humidity had no substantial effect on capilliconidial mortality. At daytime temperatures of s 20"C, mortality after 24 h incubation was lowest ( S 34%) and the persistence duration, longest (at least 120 h). Increases in daytime temperature up to 24°C for a few hours increased mortality (37-57% after 24 h incubation) and shortened the persistence duration (72-120 h). Exposure to 2429°C during daytime greatly increased mortality (65588% after 24 h) and further shortened the persistence duration (24-48 h). Daytime temperatures of > 29°C were lethal to all capilliconidia within 24 h. Temperature had a profound effect on capilliconidial persistence also under controlled environmental conditions. The significance of capiliiconidial persistence is discussed in relation to activity of the fungus in its natural environment.

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Environmental Factors Affecting Conidial Sporulation and Germination of Entomophthora gammae1

Cited by 23 publications

References 0 publications

Seasonal patterns of persistence and infectivity of Metarhizium anisopliae var. acridum in grasshopper cadavers in the Sahel

Seasonal patterns of persistence and infectivity of Metarhizium anisopliae var. acridum in grasshopper cadavers in the Sahel

Biological Control of Insect Pests by Entomogenous Fungi

Effect of meteorological variates on persistence of primary conidia and capilliconidia of Erynia radicans (Zygomycotin: ntomophthorales) under natural conditions

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