Field and Laboratory Investigations with Entomophthora fresenii, a Pathogen of Tetranychus Spp.1

Carner, G. R.; Canerday, Don T.

doi:10.1093/jee/61.4.956

Cited by 30 publications

(6 citation statements)

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“…Epizootics of this fungus have been observed to occur during periods of high atmospheric moisture (> 90% RH) and temperatures below 30°C (Carner and Canerday, 1968;Humber et al, 1981;Brandenburg and Kennedy, 1982;Smitley et al, 1986). These observations suggest that prevailing atmospheric conditions affect the development of the fungal pathogen.…”

Section: Introductionmentioning

confidence: 99%

“…0168-8162 © 1995 Chapman & Hall reported to attack Eutetranychus banksi (Weiser and Muma, 1966), its association with various tetranychid mites has been the subject of widespread research (Selhime and Muma, 1966;Carner and Canerday, 1968;Kenneth et al, 1972;Nemoto and Aoki, 1975;Carner, 1976;Brandenburg and Kennedy, 1982;Smitley et al, 1986;Klubertanz et al, 1991;Mietkiewski et al, 1993). Epizootics of this fungus have been observed to occur during periods of high atmospheric moisture (> 90% RH) and temperatures below 30°C (Carner and Canerday, 1968;Humber et al, 1981;Brandenburg and Kennedy, 1982;Smitley et al, 1986).…”

Section: Introductionmentioning

confidence: 99%

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Effect of temperature, humidity and photoperiod on mortality of Mononychellus tanajoa (Acari: Tetranychidae) infected by Neozygites cf. floridana (Zygomycetes: Entomophthorales)

et al. 1995

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The effect of temperature, humidity and photoperiod on the development of Neozygites cf. floridana (Weiser and Muma) in the cassava green mite, Mononychellus tanajoa (Bondar) was studied in the laboratory. Dead infected mites began to appear 2.5 days after inoculation. At 33 and 28°C peak mortalities were higher and occurred earlier (after 2.5 days), than at 23 and 18 ° C. Mean LTs0 (time for half the infected mites to die) decreased with increasing temperature as follows: 3.9, 3.0, 2.9 and 2.5 days at 18, 23, 28 and 33 ° C, respectively. When placed under conditions of high relative humidity for a period of 24 h, the percentage of dead infected mites from which the fungus sporulated was highest at 28 ° C (51.4%) and lowest at 33 ° C (6.5%). The development of the fungus inside the mite was not significantly affected by ambient humidity or photoperiod. No significant interactions between tested factors were found.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effect of temperature, humidity and photoperiod on mortality of Mononychellus tanajoa (Acari: Tetranychidae) infected by Neozygites cf. floridana (Zygomycetes: Entomophthorales)

et al. 1995

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“…Virtually no critical experimental work has been performed on the role of entomogenous fungi in the regulation of spider mite populations. Yet, fungal pathogens are commonly found infecting significant proportions of spider mite populations (Carner & Canerday, 1968;Muma, 1969;Brandenburg & Kennedy, 1982b).…”

Section: Introductionmentioning

confidence: 99%

Role of the entomogenous fungus, Neozygites floridana, in population declines of the twospotted spider mite, Tetranychus urticae, on field corn

Smitley

Kennedy

Brooks

1986

Entomologia Exp Applicata

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In field plots in which populations of predaceous species were suppressed using carbaryl, populations of the twospotted spider mite, Tetranychus urticae Koch, on field corn declined in association with aerial dispersal of the mites or with epizootics of the entomogenous fungus, Neozygites floridana Weiser & Muma. The relative importance of these two factors varied from year to year depending on environmental conditions. When moist weather conditions induced epizootics of N. floridana before corn plants became heavily infested with mites, the pathogen appeared to be the major factor causing mite population declines. When dry weather conditions allowed mite populations to expand unchecked until corn plants became entirely infested, mite aerial dispersal was the major factor associated with mite population declines. In every field in which there was an epizootic of N. floridana, routine applications of the fungicide maneb delayed epizootics and reduced or delayed the impact of the pathogen on mite populations. The total number of Neozygites-infected mites produced in maneb-treated plots throughout the test period was significantly greater than that in untreated plots when epizootics were initiated during periods of mite population growth. Fewer total infected mites were produced in maneb-treated plots compared to untreated plots when epizootics were initiated during periods of mite population decline.

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“…Field evidence shows that Neozygites sp. epizootics can indeed decimate local mite populations (Carner and Canerday, 1968;Smith and Furr, 1975), but data are lacking to assess whether these populations are virtually driven to extinction or resurge to give rise to a next cycle.…”

Section: Discussionmentioning

confidence: 99%

Modelling Fungal (Neozygites cf. Floridana) Epizootics in Local Populations of Cassava Green Mites (Mononychellus Tanajoa)

et al. 1997

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General rightsIt is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), other than for strictly personal, individual use, unless the work is under an open content license (like Creative Commons). Disclaimer/Complaints regulationsIf you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: http://uba.uva.nl/en/contact, or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible. ABSTRACTThe fungus, Neozygitis cf. floridana is parasitic on the cassava green mite, Mononychellus tanajoa (Bondar) (Acari: Tetranychidae) in South America and may be considered for classical biological control of cassava green mites in Africa, where cassava is an important subsistence crop, cassava green mites are an imported pest and specific natural enemies are lacking. Spider mites generally have a viscous structure of local populations, a trait that would normally hamper the spread of a fungus that is transmitted by the contact of susceptible hosts with the halo of capilliconidia surrounding an infectious host. However, if infected mites search and settle to produce capilliconidia on sites where they are surrounded by susceptible mites before becoming infectious, then the conditions for maximal transmission in a viscous host population are met. Because the ratio between spider mites and the leaf area they occupy is constant, parasite-induced host searching behaviour leads to a constant per capita transmission rate. Hence, the transmission rate only depends on the number of infectious hosts. These assumptions on parasite-induced host search and constant host density lead to a simple, analytically tractable model that can be used to estimate the maximal capacity of the fungus to decimate local populations of the cassava green mite. By estimating the parameters of this model (host density, per capita transmission rate and duration of infected and infectious state) it was shown that the fungal pathogen can reduce the population growth of M. tanajoa, but cannot drive local mite populations to extinction. Only when the initial ratio of infectious to susceptible mites exceeds unity or the effective growth rate of the mite population is sufficiently reduced by other factors than the fungus (e.g. lower food quality of the host plant, dislodgement and death by rain and wind and predation), will the fungal pathogen be capable of decimating the cassava green mite population. Under realistic field conditions, where all of these growth-reducing factors are likely to operate, there may well be room for effective control by the parasitic fungus. 0168-8162

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Field and Laboratory Investigations with Entomophthora fresenii, a Pathogen of Tetranychus Spp.1

Cited by 30 publications

References 0 publications

Effect of temperature, humidity and photoperiod on mortality of Mononychellus tanajoa (Acari: Tetranychidae) infected by Neozygites cf. floridana (Zygomycetes: Entomophthorales)

Effect of temperature, humidity and photoperiod on mortality of Mononychellus tanajoa (Acari: Tetranychidae) infected by Neozygites cf. floridana (Zygomycetes: Entomophthorales)

Role of the entomogenous fungus, Neozygites floridana, in population declines of the twospotted spider mite, Tetranychus urticae, on field corn

Modelling Fungal (Neozygites cf. Floridana) Epizootics in Local Populations of Cassava Green Mites (Mononychellus Tanajoa)

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