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D C Steinkraus - One of the best experts on this subject based on the ideXlab platform.
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Rise and Fall of Cotton Aphid (Hemiptera: Aphididae) Populations in Southeastern Cotton Production Systems
Journal of economic entomology, 2008Co-Authors: Mark R. Abney, D C Steinkraus, John R Ruberson, Gary A Herzog, T. J. Kring, Phillip M. RobertsAbstract:The impact of natural enemies on cotton aphid, Aphis gossypii Glover (Hemiptera: Aphididae), populations in cotton, Gossypium hirsutum L., production systems in the southeastern United States was evaluated over 3 yr in irrigated commercial cotton fields. Fungal epizootics caused by the entomopathogen Neozygites Fresenii (Nowakowski) Batko reduced aphid numbers to subthreshold levels in 1999, 2000, and 2001 and occurred consistently in early to mid-July in all 3 yr. Scymnus spp. were the most abundant aphidophagous predators, although other coccinellid species and generalist predators such as spiders, fire ants, heteropterans, and neuropterans also were present. Studies using arthropod exclusion cages demonstrated little impact of predators or parasitoids on aphid populations before fungal epizootics. Arthropod natural enemies were most abundant after epizootics and may have suppressed aphid populations late in the season. Seed cotton yield, and lint quality were not affected by aphicide applications in any year of the study. Implications of these findings for aphid management in the southeastern United States are discussed.
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Predation rate and development of Coccinella septempunctata L. influenced by Neozygites Fresenii-infected cotton aphid prey
Biological Control, 2008Co-Authors: David O. Simelane, D C Steinkraus, T. J. KringAbstract:Abstract Laboratory studies were conducted to determine the effect of cotton aphids [ Aphis gossypii Glover (Homoptera: Aphididae)] infected with Neozygites Fresenii (Nowakowski) Batko (Entomophthorales: Neozygitaceae), on the number of prey attacked by and development of Coccinella septempunctata L. (Coleoptera: Coccinellidae). A diet of N. Fresenii -infected aphids (in early stages of infection) did not have a significant effect on predation rate by either the fourth-stage larvae or adults of C. septempunctata . Second-, third- and fourth-stage larvae of C. septempunctata reared on fungus-infected aphids had significantly longer stadia than those reared on uninfected aphids. Mortality of C. septempunctata larvae reared on fungus-infected aphids increased between the second and the fourth instars, whereas mortality for those reared on uninfected aphids was significantly lower than those reared on infected aphids. Feeding on N. Fresenii -infected aphids resulted in significantly smaller body size of C. septempunctata adults and a corresponding reduction in the number of eggs oviposited during a 29-day period relative to those fed a diet of uninfected aphids. Although our findings suggest that a diet of N. Fresenii -infected aphids had no effect on the number of prey consumed by C. septempunctata , it had a significant effect on the development of the predator and its capacity to reproduce. These fitness costs could alter the capacity of the predator population to reduce subsequent pest populations in cotton or adjacent crops.
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Mass harvesting of the entomopathogenic fungus, Neozygites Fresenii, from natural field epizootics in the cotton aphid, Aphis gossypii.
Journal of invertebrate pathology, 2005Co-Authors: D C Steinkraus, Gabriele O. BoysAbstract:Epizootics caused by insect pathogens sometimes occur over wide areas and result in millions of infected insects. Naturally infected insects can be considered a natural resource for harvesting insect pathogens. We developed methods to mass harvest the fungal pathogen Neozygites Fresenii (Entomophthorales: Neozygitaceae) from epizootics in Aphis gossypii (Homoptera: Aphididae) in a commercial cotton field in Arkansas. A total of 30,722 aphids infected with N. Fresenii in the mature hyphal body or early conidiophore stages were harvested, dried, and frozen. Three desiccants were compared: silica gel, dry rock salt, and wet rock salt. Silica gel was the superior material because it more rapidly and thoroughly dried cotton leaves and aphids. Using this method a mean of 193.4 infected aphids could be harvested per hour from cotton leaves dried over silica gel. The quality of harvested infected aphids was high and resulted in a mean of 70.4% sporulation from infected aphids harvested from the silica gel desiccant.
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effects of long term storage at 14 c on the survival of Neozygites Fresenii entomophthorales neozygitaceae in cotton aphids homoptera aphididae
Journal of Invertebrate Pathology, 2003Co-Authors: Mette G Vingaard, Gabriele O. Boys, D C Steinkraus, Jørgen EilenbergAbstract:Abstract Neozygites Fresenii-infected Aphis gossypii cadavers, containing dormant hyphal bodies of N. Fresenii, were stored in 4 ml glass vials at −14 °C in a standard consumer-type refrigerator/freezer for 1, 21, 30, 43, 51, and 68 months to determine the effect of storage on fungal survival. When the cadavers were removed from the freezer and placed in 25±1 ° C, 100% relative humidity, and 12:12 (L:D) conditions, N. Fresenii survival, as shown by fungal sporulation from the cadavers, was high at all storage periods. The average percentage of cadavers from which the fungus sporulated were 93, 47, 100, 100, 80, and 60% from 1, 21, 30, 43, 51, and 68 months storage periods, respectively. The number of primary conidia discharged from each sporulating cadaver was estimated using a scale of 1 (low, ca. 1000 primary conidia), 2 (medium, ca. 2000 primary conidia) and 3 (high, ca. 3000 primary conidia). The median scores for the number of primary conidia produced per sporulating cadaver were 3, 2, 3, 3, 2.5, and 1 for 1, 21, 30, 43, 51, and 68 months, respectively. Therefore, except for the longest storage period, most cadavers produced medium to high numbers of primary conidia. Mean germination of primary conidia produced from N. Fresenii-infected-aphid cadavers from each time period varied significantly from 66.3 to 86.1% in the 21 and 43 months categories, respectively. Infectivity of capilliconidia, produced from frozen N. Fresenii, to live healthy cotton aphids varied significantly from 16.7 to 68.7% from cadavers stored 68 months and 1 month, respectively. Overall N. Fresenii survived well in dried frozen cotton aphid cadavers for up to 6 years with little reduction in sporulation, numbers of spores produced, germination of primary conidia, or infectivity.
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Effects of long-term storage at −14 °C on the survival of Neozygites Fresenii (Entomophthorales: Neozygitaceae) in cotton aphids (Homoptera: Aphididae)
Journal of invertebrate pathology, 2003Co-Authors: Mette G Vingaard, Gabriele O. Boys, D C Steinkraus, Jørgen EilenbergAbstract:Abstract Neozygites Fresenii-infected Aphis gossypii cadavers, containing dormant hyphal bodies of N. Fresenii, were stored in 4 ml glass vials at −14 °C in a standard consumer-type refrigerator/freezer for 1, 21, 30, 43, 51, and 68 months to determine the effect of storage on fungal survival. When the cadavers were removed from the freezer and placed in 25±1 ° C, 100% relative humidity, and 12:12 (L:D) conditions, N. Fresenii survival, as shown by fungal sporulation from the cadavers, was high at all storage periods. The average percentage of cadavers from which the fungus sporulated were 93, 47, 100, 100, 80, and 60% from 1, 21, 30, 43, 51, and 68 months storage periods, respectively. The number of primary conidia discharged from each sporulating cadaver was estimated using a scale of 1 (low, ca. 1000 primary conidia), 2 (medium, ca. 2000 primary conidia) and 3 (high, ca. 3000 primary conidia). The median scores for the number of primary conidia produced per sporulating cadaver were 3, 2, 3, 3, 2.5, and 1 for 1, 21, 30, 43, 51, and 68 months, respectively. Therefore, except for the longest storage period, most cadavers produced medium to high numbers of primary conidia. Mean germination of primary conidia produced from N. Fresenii-infected-aphid cadavers from each time period varied significantly from 66.3 to 86.1% in the 21 and 43 months categories, respectively. Infectivity of capilliconidia, produced from frozen N. Fresenii, to live healthy cotton aphids varied significantly from 16.7 to 68.7% from cadavers stored 68 months and 1 month, respectively. Overall N. Fresenii survived well in dried frozen cotton aphid cadavers for up to 6 years with little reduction in sporulation, numbers of spores produced, germination of primary conidia, or infectivity.
Jørgen Eilenberg - One of the best experts on this subject based on the ideXlab platform.
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First survey on ecological host range of aphid pathogenic fungi (Phylum Entomophthoromycota) in Tunisia
Annales de la Société entomologique de France (N.S.), 2015Co-Authors: Ibtissem Ben Fekih, Sonia Boukhris-bouhachem, Mohamed Bechir Allagui, Annette Bruun Jensen, Jørgen EilenbergAbstract:Summary. The natural occurrence of fungal pathogens of aphids and their ecological host range was investigated in Tunisia from 2009 to 2012. The survey focused on aphid infesting different crops and weeds and included 10 different aphid species. Samples were collected from eight agricultural crops sites belonging to three different bioclimatic zones. Four pathogens from the phylum Entomophthoromycota were found to occur naturally in Tunisian ecosystems: Pandora neoaphidis (Entomophthorales: Entomophthoraceae), Entomophthora planchoniana (Entomophthorales: Entomophthoraceae), Conidiobolus obscurus (Entomophthorales: Ancylistaceae) and Neozygites Fresenii (Neozygitales: Neozygitaceae). The occurrence of entomophthoralean fungi depended on the sampling area, the bioclimatic zone, and aphid species. P. neoaphidis and E. planchoniana were the predominant pathogens infecting a wide range of aphid species whereas C. obscurus and N. Fresenii were sporadically present on a limited number of aphid species. This stu...
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effects of long term storage at 14 c on the survival of Neozygites Fresenii entomophthorales neozygitaceae in cotton aphids homoptera aphididae
Journal of Invertebrate Pathology, 2003Co-Authors: Mette G Vingaard, Gabriele O. Boys, D C Steinkraus, Jørgen EilenbergAbstract:Abstract Neozygites Fresenii-infected Aphis gossypii cadavers, containing dormant hyphal bodies of N. Fresenii, were stored in 4 ml glass vials at −14 °C in a standard consumer-type refrigerator/freezer for 1, 21, 30, 43, 51, and 68 months to determine the effect of storage on fungal survival. When the cadavers were removed from the freezer and placed in 25±1 ° C, 100% relative humidity, and 12:12 (L:D) conditions, N. Fresenii survival, as shown by fungal sporulation from the cadavers, was high at all storage periods. The average percentage of cadavers from which the fungus sporulated were 93, 47, 100, 100, 80, and 60% from 1, 21, 30, 43, 51, and 68 months storage periods, respectively. The number of primary conidia discharged from each sporulating cadaver was estimated using a scale of 1 (low, ca. 1000 primary conidia), 2 (medium, ca. 2000 primary conidia) and 3 (high, ca. 3000 primary conidia). The median scores for the number of primary conidia produced per sporulating cadaver were 3, 2, 3, 3, 2.5, and 1 for 1, 21, 30, 43, 51, and 68 months, respectively. Therefore, except for the longest storage period, most cadavers produced medium to high numbers of primary conidia. Mean germination of primary conidia produced from N. Fresenii-infected-aphid cadavers from each time period varied significantly from 66.3 to 86.1% in the 21 and 43 months categories, respectively. Infectivity of capilliconidia, produced from frozen N. Fresenii, to live healthy cotton aphids varied significantly from 16.7 to 68.7% from cadavers stored 68 months and 1 month, respectively. Overall N. Fresenii survived well in dried frozen cotton aphid cadavers for up to 6 years with little reduction in sporulation, numbers of spores produced, germination of primary conidia, or infectivity.
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Effects of long-term storage at −14 °C on the survival of Neozygites Fresenii (Entomophthorales: Neozygitaceae) in cotton aphids (Homoptera: Aphididae)
Journal of invertebrate pathology, 2003Co-Authors: Mette G Vingaard, Gabriele O. Boys, D C Steinkraus, Jørgen EilenbergAbstract:Abstract Neozygites Fresenii-infected Aphis gossypii cadavers, containing dormant hyphal bodies of N. Fresenii, were stored in 4 ml glass vials at −14 °C in a standard consumer-type refrigerator/freezer for 1, 21, 30, 43, 51, and 68 months to determine the effect of storage on fungal survival. When the cadavers were removed from the freezer and placed in 25±1 ° C, 100% relative humidity, and 12:12 (L:D) conditions, N. Fresenii survival, as shown by fungal sporulation from the cadavers, was high at all storage periods. The average percentage of cadavers from which the fungus sporulated were 93, 47, 100, 100, 80, and 60% from 1, 21, 30, 43, 51, and 68 months storage periods, respectively. The number of primary conidia discharged from each sporulating cadaver was estimated using a scale of 1 (low, ca. 1000 primary conidia), 2 (medium, ca. 2000 primary conidia) and 3 (high, ca. 3000 primary conidia). The median scores for the number of primary conidia produced per sporulating cadaver were 3, 2, 3, 3, 2.5, and 1 for 1, 21, 30, 43, 51, and 68 months, respectively. Therefore, except for the longest storage period, most cadavers produced medium to high numbers of primary conidia. Mean germination of primary conidia produced from N. Fresenii-infected-aphid cadavers from each time period varied significantly from 66.3 to 86.1% in the 21 and 43 months categories, respectively. Infectivity of capilliconidia, produced from frozen N. Fresenii, to live healthy cotton aphids varied significantly from 16.7 to 68.7% from cadavers stored 68 months and 1 month, respectively. Overall N. Fresenii survived well in dried frozen cotton aphid cadavers for up to 6 years with little reduction in sporulation, numbers of spores produced, germination of primary conidia, or infectivity.
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geographical distribution and host range of entomophthorales infecting the green spruce aphid elatobium abietinum walker in iceland
Journal of Invertebrate Pathology, 2001Co-Authors: Charlotte Marie Bisgaard Nielsen, Jørgen Eilenberg, Susanne Harding, Edda Sigurdis Oddsdottir, Gudmundur HalldorssonAbstract:Entomophthora planchoniana and Neozygites Fresenii caused infection in populations of the green spruce aphid, Elatobium abietinum, in Iceland. On this aphid species En. planchoniana was exclusively found in the western part of Iceland, while N. Fresenii was exclusively found in the eastern part of Iceland. This discrete and nearly nonoverlapping geographical distribution correlates with the distribution of two different populations of El. abietinum found in Iceland. On other aphid species N. Fresenii, En. planchoniana, Pandora neoaphidis, and Conidiobolus obscurus were documented throughout the country. Transmission experiments showed that Pa. neoaphidis and En. planchoniana could infect the eastern population of El. abietinum, although they have never been found on this population in nature. This strongly indicates that there is little or no interaction among El. abietinum, other aphids, and their respective entomophthoralean fungi in the field. Furthermore, this study is the first to record epizootics caused by N. Fresenii and En. planchoniana in the subpolar region.
Gabriele O. Boys - One of the best experts on this subject based on the ideXlab platform.
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Mass harvesting of the entomopathogenic fungus, Neozygites Fresenii, from natural field epizootics in the cotton aphid, Aphis gossypii.
Journal of invertebrate pathology, 2005Co-Authors: D C Steinkraus, Gabriele O. BoysAbstract:Epizootics caused by insect pathogens sometimes occur over wide areas and result in millions of infected insects. Naturally infected insects can be considered a natural resource for harvesting insect pathogens. We developed methods to mass harvest the fungal pathogen Neozygites Fresenii (Entomophthorales: Neozygitaceae) from epizootics in Aphis gossypii (Homoptera: Aphididae) in a commercial cotton field in Arkansas. A total of 30,722 aphids infected with N. Fresenii in the mature hyphal body or early conidiophore stages were harvested, dried, and frozen. Three desiccants were compared: silica gel, dry rock salt, and wet rock salt. Silica gel was the superior material because it more rapidly and thoroughly dried cotton leaves and aphids. Using this method a mean of 193.4 infected aphids could be harvested per hour from cotton leaves dried over silica gel. The quality of harvested infected aphids was high and resulted in a mean of 70.4% sporulation from infected aphids harvested from the silica gel desiccant.
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effects of long term storage at 14 c on the survival of Neozygites Fresenii entomophthorales neozygitaceae in cotton aphids homoptera aphididae
Journal of Invertebrate Pathology, 2003Co-Authors: Mette G Vingaard, Gabriele O. Boys, D C Steinkraus, Jørgen EilenbergAbstract:Abstract Neozygites Fresenii-infected Aphis gossypii cadavers, containing dormant hyphal bodies of N. Fresenii, were stored in 4 ml glass vials at −14 °C in a standard consumer-type refrigerator/freezer for 1, 21, 30, 43, 51, and 68 months to determine the effect of storage on fungal survival. When the cadavers were removed from the freezer and placed in 25±1 ° C, 100% relative humidity, and 12:12 (L:D) conditions, N. Fresenii survival, as shown by fungal sporulation from the cadavers, was high at all storage periods. The average percentage of cadavers from which the fungus sporulated were 93, 47, 100, 100, 80, and 60% from 1, 21, 30, 43, 51, and 68 months storage periods, respectively. The number of primary conidia discharged from each sporulating cadaver was estimated using a scale of 1 (low, ca. 1000 primary conidia), 2 (medium, ca. 2000 primary conidia) and 3 (high, ca. 3000 primary conidia). The median scores for the number of primary conidia produced per sporulating cadaver were 3, 2, 3, 3, 2.5, and 1 for 1, 21, 30, 43, 51, and 68 months, respectively. Therefore, except for the longest storage period, most cadavers produced medium to high numbers of primary conidia. Mean germination of primary conidia produced from N. Fresenii-infected-aphid cadavers from each time period varied significantly from 66.3 to 86.1% in the 21 and 43 months categories, respectively. Infectivity of capilliconidia, produced from frozen N. Fresenii, to live healthy cotton aphids varied significantly from 16.7 to 68.7% from cadavers stored 68 months and 1 month, respectively. Overall N. Fresenii survived well in dried frozen cotton aphid cadavers for up to 6 years with little reduction in sporulation, numbers of spores produced, germination of primary conidia, or infectivity.
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Effects of long-term storage at −14 °C on the survival of Neozygites Fresenii (Entomophthorales: Neozygitaceae) in cotton aphids (Homoptera: Aphididae)
Journal of invertebrate pathology, 2003Co-Authors: Mette G Vingaard, Gabriele O. Boys, D C Steinkraus, Jørgen EilenbergAbstract:Abstract Neozygites Fresenii-infected Aphis gossypii cadavers, containing dormant hyphal bodies of N. Fresenii, were stored in 4 ml glass vials at −14 °C in a standard consumer-type refrigerator/freezer for 1, 21, 30, 43, 51, and 68 months to determine the effect of storage on fungal survival. When the cadavers were removed from the freezer and placed in 25±1 ° C, 100% relative humidity, and 12:12 (L:D) conditions, N. Fresenii survival, as shown by fungal sporulation from the cadavers, was high at all storage periods. The average percentage of cadavers from which the fungus sporulated were 93, 47, 100, 100, 80, and 60% from 1, 21, 30, 43, 51, and 68 months storage periods, respectively. The number of primary conidia discharged from each sporulating cadaver was estimated using a scale of 1 (low, ca. 1000 primary conidia), 2 (medium, ca. 2000 primary conidia) and 3 (high, ca. 3000 primary conidia). The median scores for the number of primary conidia produced per sporulating cadaver were 3, 2, 3, 3, 2.5, and 1 for 1, 21, 30, 43, 51, and 68 months, respectively. Therefore, except for the longest storage period, most cadavers produced medium to high numbers of primary conidia. Mean germination of primary conidia produced from N. Fresenii-infected-aphid cadavers from each time period varied significantly from 66.3 to 86.1% in the 21 and 43 months categories, respectively. Infectivity of capilliconidia, produced from frozen N. Fresenii, to live healthy cotton aphids varied significantly from 16.7 to 68.7% from cadavers stored 68 months and 1 month, respectively. Overall N. Fresenii survived well in dried frozen cotton aphid cadavers for up to 6 years with little reduction in sporulation, numbers of spores produced, germination of primary conidia, or infectivity.
Papierok B. - One of the best experts on this subject based on the ideXlab platform.
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Les ennemis naturels d'insectes du cotonnier au Tchad : premières données sur les champignons de l'ordre des Entomophthorales
1991Co-Authors: Silvie Pierre, Papierok B.Abstract:En 1986 et en 1987, des épizooties à entomophthorales (zygomicètes) ont été observées dans des populations du puceron #Aphis gossypii$ et dans des populations adultes de l'aleurode #Bemisia tabaci$ évoluant sur cotonnier dans le sud du Tchad. C'est la première fois que la présence d'entomophthorales est signalée dans ce pays. Les auteurs présentent tout d'abord le cycle biologique de ces champignons entomopathogènes et les différents éléments morphologiques qui y sont impliqués. Etant donné qu'il est indispensable de récolter et de préparer correctement les insectes tués par une entomophthorale afin de pouvoir identifier celle-ci, les techniques utilisées sont ensuite détaillées. Les symptômes de la mycose d'#Aphis gossypii$ sont alors décrits et la morphologie respective des spores de résistance, des conidies primaires et des capilloconidies de l'agent responsable, #Neozygites Fresenii$, est illustrée. L'entomophthorose des adultes de #Bemisia tabaci$ est due à une espèce inédite de zoophthora, dont la description sera présentée par ailleurs. Les auteurs précisent, cependant, les symptômes de la mycose et illustrent à l'aide d'une autre espèce la morphologie caractéristique des conidies primaires et des capilloconidies au sein du genre Zoophthora. Jusqu'aux observations effectuées au Tchad en 1986 et en 1987, aucun cas d'entomophthorose n'était connu sur #Bemisia tabaci$. (Résumé d'auteur
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Les ennemis naturels d'insectes du cotonnier au Tchad : premières données sur les champignons de l'ordre des entomophthorales
1991Co-Authors: Silvie Pierre, Papierok B.Abstract:En 1986 et en 1987, des épizooties à Entomophthorales (Zygomycètes) ont été observées dans des populations du puceron Aphis gossypii et dans des populations adultes de l'aleurode Bemisia tabaci évoluant sur cotonnier dans le sud du Tchad. C'est la première fois que la présence d'Entomophthorales est signalée dans ce pays. Les auteurs présentent tout d'abord le cycle biologique de ces champignons entomopathogènes et les différents éléments morphologiques qui y sont impliqués. Etant donné qu'il est indispensable de récolter et de préparer correctement les insectes tués par une Entomophthorale afin de pouvoir identifier celle-ci, les techniques utilisées sont ensuite détaillées. Les symptômes de la mycose d'Aphis gossypii sont alors décrits et la morphologie respective des spores de résistance, des conidies primaires et des capilloconidies de l'agent responsable, Neozygites Fresenii, est illustrée. L'entomophthorose des adultes de Bemisia tabaci est due à une espèce inédite de Zoophthora, dont la description sera présentée par ailleurs. Les auteurs précisent, cependant, les symptômes de la mycose et illustrent à l'aide d'une autre espèce la morphologie caractéristique des conidies primaires et des capilloconidies au sein du genre Zoophthora. Jusqu'aux observations effectuées au Tchad en 1986 et en 1987, aucun cas d'entomophthorose n'était connu sur Bemisia tabac
Mette G Vingaard - One of the best experts on this subject based on the ideXlab platform.
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effects of long term storage at 14 c on the survival of Neozygites Fresenii entomophthorales neozygitaceae in cotton aphids homoptera aphididae
Journal of Invertebrate Pathology, 2003Co-Authors: Mette G Vingaard, Gabriele O. Boys, D C Steinkraus, Jørgen EilenbergAbstract:Abstract Neozygites Fresenii-infected Aphis gossypii cadavers, containing dormant hyphal bodies of N. Fresenii, were stored in 4 ml glass vials at −14 °C in a standard consumer-type refrigerator/freezer for 1, 21, 30, 43, 51, and 68 months to determine the effect of storage on fungal survival. When the cadavers were removed from the freezer and placed in 25±1 ° C, 100% relative humidity, and 12:12 (L:D) conditions, N. Fresenii survival, as shown by fungal sporulation from the cadavers, was high at all storage periods. The average percentage of cadavers from which the fungus sporulated were 93, 47, 100, 100, 80, and 60% from 1, 21, 30, 43, 51, and 68 months storage periods, respectively. The number of primary conidia discharged from each sporulating cadaver was estimated using a scale of 1 (low, ca. 1000 primary conidia), 2 (medium, ca. 2000 primary conidia) and 3 (high, ca. 3000 primary conidia). The median scores for the number of primary conidia produced per sporulating cadaver were 3, 2, 3, 3, 2.5, and 1 for 1, 21, 30, 43, 51, and 68 months, respectively. Therefore, except for the longest storage period, most cadavers produced medium to high numbers of primary conidia. Mean germination of primary conidia produced from N. Fresenii-infected-aphid cadavers from each time period varied significantly from 66.3 to 86.1% in the 21 and 43 months categories, respectively. Infectivity of capilliconidia, produced from frozen N. Fresenii, to live healthy cotton aphids varied significantly from 16.7 to 68.7% from cadavers stored 68 months and 1 month, respectively. Overall N. Fresenii survived well in dried frozen cotton aphid cadavers for up to 6 years with little reduction in sporulation, numbers of spores produced, germination of primary conidia, or infectivity.
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Effects of long-term storage at −14 °C on the survival of Neozygites Fresenii (Entomophthorales: Neozygitaceae) in cotton aphids (Homoptera: Aphididae)
Journal of invertebrate pathology, 2003Co-Authors: Mette G Vingaard, Gabriele O. Boys, D C Steinkraus, Jørgen EilenbergAbstract:Abstract Neozygites Fresenii-infected Aphis gossypii cadavers, containing dormant hyphal bodies of N. Fresenii, were stored in 4 ml glass vials at −14 °C in a standard consumer-type refrigerator/freezer for 1, 21, 30, 43, 51, and 68 months to determine the effect of storage on fungal survival. When the cadavers were removed from the freezer and placed in 25±1 ° C, 100% relative humidity, and 12:12 (L:D) conditions, N. Fresenii survival, as shown by fungal sporulation from the cadavers, was high at all storage periods. The average percentage of cadavers from which the fungus sporulated were 93, 47, 100, 100, 80, and 60% from 1, 21, 30, 43, 51, and 68 months storage periods, respectively. The number of primary conidia discharged from each sporulating cadaver was estimated using a scale of 1 (low, ca. 1000 primary conidia), 2 (medium, ca. 2000 primary conidia) and 3 (high, ca. 3000 primary conidia). The median scores for the number of primary conidia produced per sporulating cadaver were 3, 2, 3, 3, 2.5, and 1 for 1, 21, 30, 43, 51, and 68 months, respectively. Therefore, except for the longest storage period, most cadavers produced medium to high numbers of primary conidia. Mean germination of primary conidia produced from N. Fresenii-infected-aphid cadavers from each time period varied significantly from 66.3 to 86.1% in the 21 and 43 months categories, respectively. Infectivity of capilliconidia, produced from frozen N. Fresenii, to live healthy cotton aphids varied significantly from 16.7 to 68.7% from cadavers stored 68 months and 1 month, respectively. Overall N. Fresenii survived well in dried frozen cotton aphid cadavers for up to 6 years with little reduction in sporulation, numbers of spores produced, germination of primary conidia, or infectivity.