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1.
James F. Kelly Darrell W. Anthony Charles R. Dillard 《Journal of invertebrate pathology》1981,37(2):117-122
The susceptibility of the mosquitoes Aedes aegypti, Aedes taeniorhynchus, Anopheles albimanus, Culex pipiens quinquefasciatus, Culex salinarius, and Culex tarsalis to infection by the microsporidian Vavraia culicis was determined. Using 18-hr exposures to 5 × 103, 1 × 104, 5 × 104, and 1 × 105 spores/ml, C. salinarius, C. tarsalis, and A. albimanus were found to be significantly more susceptible than A. aegypti. The most severe infections were observed in C. salinarius and C. tarsalis, although heavy infections of approximately 1 million spores per adult were recorded at the higher dosages in all species tested except A. aegypti. Production trials indicated that up to 5.4 × 108 spores could be routinely produced in individual corn earworms, Heliothis zea. Inactivation of the spores by sunlight was measured by observing the subsequent incidence of infection and spore production in A. albimanus. These two measurements provided an LT90 of 5.5 and 3.3 hr, respectively. 相似文献
2.
Toxicity tests of three strains of Bacillus sphaericus against late instars of 12 culicine mosquito species indicated a wide range of susceptibility. Culex pipiens and C. salinarius were highly susceptible (LC50s < 104 spores/ml) to strain 1593, and C. pipiens and C. restuans were highly susceptible to strain 2013-4. The potency of strain SSII-1 was approximately one-tenth that of strains 1593 and 2013-4 against C. pipiens. Susceptibility of Aedes species to strain 1593 was highly variable. At temperatures ≥ 20°C, A. fitchii, A. intrudens, A. stimulans, and A. vexans were moderately to highly susceptible (LC50s 6 × 103−4 × 104 spores/ml), A. triseriatus was only slightly susceptible (LC50 > 106 spores/ml), and A. aegypti was refractory. Susceptibility of Aedes mosquitoes to strain SSII-1 was less variable, with LC50s against A. aegypti, A. canadensis, A. stimulans, and A. triseriatus all being between 104 and 106 vegetative cells + spores/ml. All species of mosquitoes tested were, in general, highly susceptible to B. thuringiensis var. israelensis (LC50s 2.3 × 103−2.5 × 104 spores/ml). In B. sphaericus toxicity tests, decreased temperatures resulted in up to a 16-fold increase in LC50 and a substantial reduction in probit line slope. First-instar A. aegypti larvae were more susceptible to B. sphaericus strain SSII-1 than the three later instars, which were approximately equally susceptible; however, no significant difference was observed in the susceptibility of the four instars of A. triseriatus. 相似文献
3.
Among six strains of Bacillus thuringiensis and five other species of Bacillus, only two strains of B. thuringiensis, strains HD-1 and BA-068, were toxic to Aedes aegypti larvae within 24 hr. The LC50s were 5.6 × 104 and 2.4 × 105 spores/ml for strains HD-1 and BA-068, respectively. The toxic factor(s) was heat sensitive and γ ray resistant and preliminary evidences indicated that it was associated with the crystalline body of B. thuringiensis. 相似文献
4.
Paula A. Rojas-Pinzón Juan J. Silva-Fernández Jenny Dussán 《Applied Entomology and Zoology》2018,53(2):183-191
Aedes aegypti (L.) is the main vector of tropical diseases such as dengue, chikungunya and Zika. Due to the overuse of insecticides, Ae. aegypti resistant populations have increased. Biological control with Lysinibacillus sphaericus (Ahmed) has been used against Culex sp. and Anopheles sp. Although Ae. aegypti is refractory to the binary toxin of L. sphaericus spores, vegetative cells have been shown to be effective against Ae. aegypti larvae. In this work, the effect of L. sphaericus vegetative cells on Ae. aegypti temephos-resistant larvae was assessed under lab and simulated field conditions. L. sphaericus caused about 90% mortality of insecticide-resistant Ae. aegypti larvae under simulated field conditions. Likewise, Ae. aegypti larvae were more sensitive to mixed cultures of L. sphaericus than to individual strains; then, the most effective mixed culture exhibited an LC50 of 1.21 × 105 CFU/mL with Rockefeller larvae and 8.04 × 104 CFU/mL with field-collected larvae. Additionally, we found that mixed cultures composed of two L. sphaericus strains were more effective than a culture formed by the three strains. Our results suggest that mixed cultures comprising L. sphaericus vegetative cells could be useful for controlling temephos-resistant populations of Ae. aegypti, as evidenced by the effectiveness demonstrated under laboratory and simulated field conditions. 相似文献
5.
Wan Fatma Zuharah Md Rodzay Rohaiyu Wahizatul Afzan Azmi Hideyuki Nagao 《Journal of Asia》2021,24(2):24-29
Considering the rapid transmission of the dengue virus, substantial efforts need to be conducted to ward-off the epidemics of dengue viruses. The control effort is depending on chemical insecticides and had aroused undesirable conflicts of insecticide resistance. Here, we study the entomopathogenic fungus, Metarhizium anisopliae as a promising new biological control agent for vector control. The pathogenicity effects of Metarhizium anisopliae against field and laboratory strains of Aedes albopictus and Aedes aegypti larvae were tested using the larvicidal bioassay technique. The results demonstrate that the treatments using M. anisopliae isolate MET-GRA4 were highly effective and able to kill 100% of both Ae. albopictus and Ae. aegypti mosquito larvae at a conidia concentration of 1 × 10?/ml within 7 days of the treatment period. The fungus displayed high larvicidal activity against laboratory and field strain of Ae. aegypti larvae with LC50 values (9.6 × 103/ml, 1.3 × 103/ml) and LC95 values (1.2 × 10?/ml, 5.5 × 105/ml) respectively. For Ae. albopictus, LC50 values for laboratory and field strains were (1.7 × 104/ml, 2.7 × 104/ml) and the LC95 values were (2.1 × 10?/ml, 7.0 × 105/ml) respectively. Interestingly, the susceptibility of field strain towards M. anisopliae was higher as compared to the laboratory strain Aedes larvae. In which, the causative agents of all the dead larvae were verified by the virulence of M. anisopliae and caused morphological deformities on larval body. The findings from this study identify this isolate could be an effective potential biocontrol agent for vector mosquitoes in Malaysia. 相似文献
6.
Selection of Antonospora locustae (Protozoa: Microsporidae) with higher virulence against Locusta migratoria manilensis (Orthoptera:Acrididae) 总被引:1,自引:0,他引:1
Xianhong Zhou 《Biocontrol Science and Technology》2009,19(4):421-427
Antonospora locustae is a microsporidian parasite of grasshopper insects that is used as a biological control agent. We report on laboratory selection of isolates from different regions with increased virulence. Bioassays were conducted against third instar nymphs of Locusta migratoria manilensis. AL2008L01 was originally imported from the USA in 1986, AL2008M01 was isolated from Melanoplus differentialis in USA and AL2008F01 was isolated from infected Fruhstorferiola tonkinensi collected in Guangdong, China. The results showed that all three isolates can infect the locust and that pathogenicity increased gradually with increased dose. The LD50 values of the original isolates at the highest dose (5×106 spores/nymph) were 19, 23 and 22 days and LD50 values were 3.2×105, 3.4×106 and 0.7×106 spores/g, respectively. After selecting for three generations, the virulence of all isolates increased significantly. LT50s were reduced to 17, 20 and 21 days at the highest dose (5×106 spores/nymph) and LD50s were reduced to 1.4×105, 2.5×105 and 1.7×105 spores/g. 相似文献
7.
《Saudi Journal of Biological Sciences》2022,29(1):385-393
Culex pipiens mosquitoes considered as vectors for many arboviruses such as the West Nile virus and encephalitis virus showing a global impact on human health. The natural management of the aquatic stages of this pest is crucial for maintaining an insecticide-free and sustained environment. The present work focused on studying the biological and biochemical effects of the entomopathogenic fungi: Metarhizium anisopliae, Beauveria bassiana, and Paecilomyces lilicanus, against 3rd instar larvae of Culex pipiens laboratory colony. The results revealed that M. anisopliae showed maximum larval mortality (88%) with the lowest lethal time (LT50) (22.6 hrs) at 108 spores/ml followed by B. bassiana (73.33%) with LT50 (38.35 hrs), while P. lilicanus showed minimum percent mortality (65%) with highest LT50 (51.5 hrs). The median lethal concentration (LC50) values were found to be 1.027 × 105 spores/ml for M. anisopliae, 1.24 × 106 spores/ml for B. bassiana, while it was 8.453 × 106 spores/ml for P. lilicanus. A reduction in female fecundity, number of hatched eggs, pupation and adult emergence percentage were recorded. The biochemical analysis of the treated larvae revealed different quantitative decrease in total soluble proteins, lipids, and carbohydrate hydrolyzing enzymes compared to control. Histopathological effects of fungal infection upon insect cuticles, muscles, and midgut were investigated. Based on the obtained results, M. anisopliae proved its superior virulent effect as a bio-control agent against Cx. pipiens. 相似文献
8.
The pathogenicity of Nosema carpocapsae for codling moth was studied using dose-infectivity experiments. The IC50 (median infective concentration) was similar for the five larval instars (range 4.0 × 103 to 6.7 × 104 spores/ml). Spore loads in moths ranged from 6.0 × 106 to 7.1 × 107 spores per moth and varied with dose and with larval age at infection. The infection does not cause mortality but does reduce the fecundity and fertility of infected moths. Nosema carpocapsae is transmitted transovarially as well as horizontally. Infected eggs were not produced by healthy females mated with infected males, although such pairs generally produced fewer eggs than healthy pairs. 相似文献
9.
When larvae of the Indian meal moth, Plodia interpunctella, were fed diets containing spores of Nosema plodiae, the number that survived to the adult stage decreased and the rate of adult emergence was retarded as the concentration of spores was increased; all surviving adults were infected. Also, when larvae were reared on diets containing spores of Nosema heterosporum, the number that survived to the adult stage decreased as the concentration of spores was increased; however, no relationship was apparent between concentration of spores and the rate of adult emergence. The LC50's of N. plodiae and N. heterosporum were 8.09 × 106 and 4.52 × 103 spores/g diet, respectively, which confirmed preliminary observations regarding the relative virulence of the two species of Nosema to Indian meal moth larvae. 相似文献
10.
Fawrou Seye Thomas Bawin Slimane Boukraa Jean-Yves Zimmer Mady Ndiaye Frank Delvigne Frédéric Francis 《Applied Entomology and Zoology》2014,49(3):453-458
Aphids (Homoptera: Aphididae) are sap-sucking insect pests that feed on several plants of agronomical importance. Entomopathogenic fungi are valuable tools for potential aphid control. As part of a selection process, laboratory bioassays were carried with five different concentrations of Aspergillus clavatus (Desmazières), Aspergillus flavus (Link) and Metarhizium anisopliae ((Metschnikoff) Sorokin) spores against the pea aphid, Acyrthosiphon pisum (Harris). Aspergillus isolates induced higher mortalities than M. anisopliae, which is a well-known entomopathogen in the literature. Lethal concentrations (LC50 and LC90) were 1.23 × 103 and 1.34 × 107 spores/ml for A. flavus, 4.95 × 102 and 5.65 × 107 spores/ml for A. clavatus, and 3.67 × 103 and 9.71 × 107 spores/ml for M. anisopliae 5 days after treatment. Mycelia development and sporulation on adult cadavers were observed 48 h after incubation. The intrinsic growth rate of A. pisum decreased with increased spore concentration for all fungal strains, suggesting an increase in pathogen fitness related to a consumption of host resources. In conclusion, Aspergillus species could be useful in aphid control as pest control agents despite their saprophytic lifestyle. This is also to our knowledge the first report of A. clavatus and A. flavus strains pathogenic to aphids. 相似文献
11.
Violet Berikashvili Kakha Sokhadze Eva Kachlishvili Vladimir Elisashvili Michael L. Chikindas 《Probiotics and antimicrobial proteins》2018,10(4):755-761
This study was conducted to elucidate cultivation conditions determining Bacillus amyloliquefaciens B-1895 growth and enhanced spore formation during the solid-state fermentation (SSF) of agro-industrial lignocellulosic biomasses. Among the tested growth substrates, corncobs provided the highest yield of spores (47?×?1010 spores g?1 biomass) while the mushroom spent substrate and sunflower oil mill appeared to be poor growth substrates for spore formation. Maximum spore yield (82?×?1010 spores g?1 biomass) was achieved when 15 g corncobs were moistened with 60 ml of the optimized nutrient medium containing 10 g peptone, 2 g KH2PO4, 1 g MgSO4·7H2O, and 1 g NaCl per 1 l of distilled water. The cheese whey usage for wetting of lignocellulosic substrate instead water promoted spore formation and increased the spore number to 105?×?1010 spores g?1. Addition to the cheese whey of optimized medium components favored sporulation process. The feasibility of developed medium and strategy was shown in scaled up SSF of corncobs in polypropylene bags since yield of 10?×?1011 spores per gram of dry biomass was achieved. In the SSF of lignocellulose, B. amyloliquefaciens B-1895 secreted comparatively high cellulase and xylanase activities to ensure good growth of the bacterial culture. 相似文献
12.
《Zentralblatt für Mikrobiologie》1984,139(1):57-60
From newly emerged adult Simulium damnosum from Kaduna River, Northern Nigeria, a mosquito-virulent strain of Bacillus sphaericus was isolated. In another four cases non-virulent B. sphaericus were present. The isolate exerted a LC50 of 50 spores/ml for Culex pipiens L4-larvae and was less virulent for Anopheles stephensi (400 sp/ml) and Aedes aegypti (800 sp/ml). 相似文献
13.
Laboratory experiments with 4th-instar larvae of Aedes aegypti and Anopheles albimanus (Diptera: Culicidae) demonstrated that the entomocidal bacterium, Bacillus thuringiensis var. israelensis, can grow vegetatively, sporulate, and produce toxin in cadavers of mosquito larvae. In A. aegypti, spore counts rose from 2 × 102/cadaver 4 hr after treatment to 1.4 × 105/cadaver approximately 72 hr later, whereas in A. albimanus spore counts per cadaver increased from 2.2 × 103 between 4 and 24 hr to 3.2 × 105 at 72 hr post-treatment. Bioassays of larval cadavers indicated that toxicity associated with sporulation of B. thuringiensis var. israelensis reached a maximum level approximately 72 hr after treatment. These results demonstrate that under appropriate conditions B. thuringiensis var. israelensis can use the substrates available in larval cadavers for growth and sporulation. 相似文献
14.
Saovanee C. Dharmsthiti Somsak Pantuwatana Amaret Bhumiratana 《Journal of invertebrate pathology》1985,46(3):231-238
Two newly developed media, H4 and H7, were found to be highly suitable for culturing Bacillus thuringiensis subsp. israelensis and B. sphaericus, respectively. These media contained 0.05% K2HPO4 and 4% HDL (H4 medium) or 0.05% K2HPO4 and 7% HDL (H7 medium); HDL is the by-product from a monosodium glutamate factory. Tests to compare endospore formation and toxicity values of B. thuringiensis subsp. israelensis in H4 medium and nutrient broth supplemented with salts and glucose (NBSG) medium were carried out in a 3-liter fermentor. The viable cell count and LC50 value of B. thuringiensis subsp. israelensis in H4 medium at 48 hr were 2.5 × 108 cells/ml and 10?7.2 (dilution), respectively, while those in NBSG medium were 1.6 × 108 cells/ml and 10?6.5, respectively. In the case of B. sphaericus grown in H7 medium, the number of cells and LC50 value were found to be 1.4 × 109 cells/ml and 10?7.8, respectively. B. sphaericus grown in nutrient broth supplemented with salt and yeast extract (NBSY) were found to produce 6.4 × 108 cells/ml and an LC50 value of 10?6.8. The toxicity of B. thuringiensis subsp. israelensis was tested against Aedes aegypti larvae, while that of B. sphaericus was tested against Culex quinquefasciatus. The cost of 10 liters of medium for production of B. thuringiensis subsp. israelensis and in B. sphaericus and H4 and H7 was $0.02 and $0.03, respectively. The cost of these newly developed media was much less than that of NBSG medium ($7.05 per 10 liters) for cultivation of B. thuringiensis subsp. israelensis and NBSY medium ($11.67 per 10 liters) for cultivation of B. sphaericus. 相似文献
15.
Armin R. Gemmrich 《Phytochemistry》1975,14(2):353-357
A soluble enzyme which converts proline to glutamic acid using NAD as coenzyme was isolated from young prothallia and spores of the fern Anemia phyllitidis. The purification was about 36-fold. The pH optimum is between 10·2 and 10·7; the Km for proline is 4·6 × 10−4 M and for NAD 3·4 × 10−4 M. There are no multiple forms of this enzyme, as proved by gel electrophoresis. 相似文献
16.
María Guadalupe Maldonado-Blanco Johanna Lizzette Gallegos-Sandoval Gabriela Fernández-Peña Carlos Francisco Sandoval-Coronado Myriam Elías-Santos 《Biocontrol Science and Technology》2014,24(2):180-189
Three Metarhizium anisopliae and three Beauveria bassiana isolates were cultivated in media containing casamino acids, soybean flour or sunflower seed flour and were shaken for three days. M. anisopliae presented similar yields of around 106 submerged spores/ml without significant differences among them, whereas B. bassiana produced yields of around 108 spores/ml, of which GHA strain produced more submerged spores in the casamino acids medium. The other two strains showed no significant difference in the production of submerged spores in the three media used. Differences in mortality on Aedes aegypti larvae were observed with the submerged spores of Metarhizium depending on isolate and medium used. M. anisopliae 2157 caused significantly higher mortality (40%) when cultivated in casamino acids medium. It presented an LC50 of 8.93 × 105 submerged spores/ml water against mosquito larvae five days after application, whereas it caused 27% mortality in Ae. aegypti adults 10 days after application. In conclusion, fungal nutrition affected virulence of some isolates of M. anisopliae against Ae. aegypti larvae while such an effect was not noted for B. bassiana isolates. 相似文献
17.
A Magnoler 《Journal of invertebrate pathology》1974,23(2):190-196
The pathogenicity of an American isolate of the nucleopolyhedrosis virus of Porthetria dispar was studied. Laboratory data on third-instar larvae showed that mortality was directly related to virus concentration. The computed LD50 was 1,729 PIBs/larva or 72 PIBs/mg larval body weight. The LT50's for 2.5 × 106, 2.5 × 105, 2.5 × 104, 5 × 103, and 2.5 × 103 PIBs/larva were 8.1, 9.9, 11.3, 12.2, and 13.1 days, respectively. Approximately 37 and 60% of the total larval mortality occurred during the third- and fourth-instar, respectively. The periods to pupation and the pupal weights of survivors apparently were not affected by virus concentration. Moth emergence from surviving pupae was not reduced. 相似文献
18.
G M Rothe 《Archives of biochemistry and biophysics》1974,162(1):17-21
Two l-lactate dehydrogenase isoenzymes and one dl-lactate dehydrogenase could be separated from potato tubers by polyacrylamide-gel electrophoresis. The enzymes are specific for lactate, while β-hydroxybutyric acid, glycolic acid, and glyoxylic acid are not oxidized. Their pH optima are pH 6.9 for the oxidation and 8.0 for the reduction reaction.The Km values for l-lactate for the two isoenzymes are 2.00 × 10?2 and 1.82 × 10?2, m. In the reverse reaction the affinities for pyruvate are 3.24 × 10?4 and 3.34 × 10?4, m. Both enzymes have similar affinities for NAD and NADH (3.00 × 10?4; 4.00 × 10?4, and 8.35 × 10?4; 5.25 × 10?4, m).The dl-lactate oxidoreductase may transfer electrons either to NAD or N-methyl-phenazinemethosulfate. The Km values of this enzyme for l-lactate are 4.5 × 10?2, m and for d-lactate 3.34 × 10?2, m. Its affinity for pyruvate is 4.75 × 10?4, m. The enzyme is inhibited by excess NAD (Km = 1.54 × 10?4, M) and has an affinity toward NADH (Km = 5.00 × 10?3, M) which is about one tenth of that of the two isoenzymes of l-lactate dehydrogenase. 相似文献
19.
R.J. Milner 《Journal of invertebrate pathology》1976,28(2):185-190
Two methods of infection, i.e., feeding known numbers of spores and rearing larvae in contaminated peat, were used to bioassay the susceptibility of Rhopaea verreauxi to Bacillus popilliae var. rhopaea at 23°C. The susceptibility of the three larval instars was similar as measured by the ID50 and IC50 values. However, within an instar, newly molted larvae were less susceptible than mature larvae when infected by the contaminated peat method. It is suggested that this was due to reduced food intake. The range of ID50 values for all bioassays with R. verreauxi larvae were 1.1 × 107 to 4.0 × 107 spores per larva, and IC50 values were 3.4 × 106 to 5.0 × 107 spores per g of contaminated peat. The slope of the probit line was always low (0.6 to 1.8) except for young first-instar larvae infected by contaminated peat when the slope was 4.0. Disease per se did not affect food intake, though intake was reduced at high doses of contaminated peat. Young larvae often died without developing symptoms but, with increasing age, infected larvae were more likely to develop symptoms. Bioassays with Othnonius batesi and Rhopaea morbillosa indicated a much lower susceptibility per os than for R. verreauxi. It is concluded that the potential for using B. popilliae var. rhopaea to control R. verreauxi is high, but the bacillus is unlikely to be of value in control of O. batesi or R. morbillosa. 相似文献
20.
R. J. Milner 《BioControl》1973,18(3):305-315
The pathogenicity ofNosema whitei was studied using a dose-mortality technique; larvae ofTribolium castaneum were reared for the duration of each experiment in flour mixed with known numbers of spores. The susceptibility of each of
the first 5 larval instars was compared. The LD50 (for mortality after 20 days) increased consistently from the first instar (1.8×106 spores/g) to the fifth instar (1.0×1010 spores/g). The slopes of the probit lines increased consistently as age increased (from b=1.1 to b=3.9). Two factors which
reduce the development time ofT. castaneum, high temperature and high humidity, both reduced the pathogenicity ofN. whitei. Thus pathogenicity decreased as the temperature was increased fram 25°C (LD50=4.2×106) through 30°C (LD50=1.3×107) to 35°C (LD50=3.2×106), also pathogenicity decreased consistently as humidity was increased fram 10%, through 30, 50, 70% to 90% R.H. Adults, emerging
fromNosema free larvae, became infected only when exposed to a very high dose (2×1010 spores/g for 14 days from the day of emergence). Infected larvae were treated for 1 hr. at 45°C in an attempt to cure the
infection. The infected larvae were not cured, rather the treatment had an adverse alfect on their survival.
This work financed by a Science Research Council (U.K.) studentship is based on a thesis submitted for a degree of Ph. D. at the University of Newcastle-upon-Tyne. 相似文献
Résumé La pathogénicité deNosema whitei a été étudiée en élevant des larves deT. castaneum dans de la farine mélangée à des quantités connues de spores. La sensibilité des larves diminue uniformément en fonction de l'age; La DL50 varie de 1,8×106/g (1er stade) à 1,0×1010 spores/g (5e stade). Deux facteurs, qui accélèrent le développement deT. castaneum, des températures et des humidités élevées, réduisent tous les deux la pathogénicité deN. whitei. Les adultes ne peuvent être infectés qu'en les exposant à la dose extrêmement élevée de 2×1010 spores/g. Un traitement par la chaleur (45°C pendant une heure) n'a pas réussi à guérir les larves.
This work financed by a Science Research Council (U.K.) studentship is based on a thesis submitted for a degree of Ph. D. at the University of Newcastle-upon-Tyne. 相似文献