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Culture and use of entomogenous fungi for the control of insects
... Jaynes and Marucci (1947) conducted successful laboratory and field tests with the fungus against larvae of the codling moth, Carpocapsa pornonella (Linn.) in New -Iersey. Populations of the Mexican bean beetle in New York were effectively controlled by the fungus, according to Dresner (1949). ...
... One attempt to obtain fungus spores by the McCoy-Carver method terminated in a serious spore-dust explosion causing injury to the operator. Dresner (1949) tried various ways to produce Beauveria bassiana spores in quantity. Unsuccessful methods included Erlenmeyer flask culture, cultivation on live vegetable matter, cultivation on whole seeds, and inoculation of large insects. ...
... An attempt was made to reculture the media as suggested by Dresner (1949). Such a procedure resulted in greatly increased contamination of the harvested spores by spores of an Aspergillus sp. which grows readily on the oat medium. ...
... Thereafter, it suppresses the host immune system by producing a toxin called beauvericin. In a recent study, strain GHA of B. bassiana was found to be more potent against a wood boring insect Xyleborus glabratus (Carrillo et al. 2015) (1986), Burges (1998), Butt and Copping (2000), Butt et al. (1999Butt et al. ( , 2001, Whright et al. (2001), Bhattacharyya et al. (2004), Copping (2004), Zimmermann (2007) and Khan et al. (2012) ...
The growing commercialization all over the world has led to a boost in the widespread use of chemical pesticides for crop protection in agricultural fields. It has not only contributed to an increase in food production, but its toxic and non-biodegradable character has also resulted in adverse effects on environment and nontarget organisms. Moreover, most of the pests have developed resistance against them. These drawbacks of conventional pesticides have led to an increase in the need for the search of some novel, non-harmful, eco-friendly pesticides. Natural pest control materials commonly known as biocontrol agents are the most promising of them. Biocontrol agents include macroorganisms as well as microorganisms. The microorganisms used are bacteria, fungi, viruses, nematodes and protozoan. The exploitation of these natural and renewable resources is essential for a successful biocontrol strategy. The present review focuses on the use of fungi as potential biocontrol agent for insect pest management. Different fungal formulations and metabolites that have been successfully implemented for pest control and some of the recent patents in this field are also discussed here.
... Ahmed (1982) has also reported this species to attack larvae of Calopepla leayena. . Dresner (1949), on the other hand, concluded that entomopathogenic fungi could provide inexpensive and long lasting control of insect pests. Since B. bassiana and A. parasiticus infect the white grubs on contact by penetrating through the integument, they have one major advantage over other pathogens as they are not restricted in the stage of development that they can attack. ...
... Apart from natural epizootics caused by Neozygites species, few studies have been conducted to evaluate other fungal acaropathogens against spider mites. Yet, more than 60 years ago conidia of the fungus Beauveria bassiana (Balsamo) Vuillemin formulated in dust form was reported to produce 71 % mortality of two spotted spider mite (Dresner 1949 ). The red palm mite, Raoiella indica Hirst (Tenuipalpidae) was reported to have been infected by a fungus, possibly Hirsutella sp., in Florida on palms (Peña et al. 2006 ). ...
An overview of infectious microorganisms associated with pest mites is presented. Many mites are major impediments to the production of food crops either in open fields or under protected environments such as greenhouses and plastic tunnels. Reliance on chemical acaricides for management of these mites is of serious concern due to the development of resistance in mite populations, environmental disturbance and effect on human health. Several pathogens play an important role in the regulation of pest mite populations through natural epizootics. The majority of these are fungi, but other pathogens include viruses, bacteria, protozoa, and nematodes. Several successful examples of pathogens that have been produced in vitro for the control of pest mites are presented. Interaction of the pathogens with beneficial arthropods such as predatory mites is also important for implementing biological control. Prospects for the application of acaropathogens in the management of mites in various agricultural systems are discussed.
... Apart from natural epizootics caused by Neozygites species, few studies have been conducted to evaluate other fungal acaropathogens against spider mites. Yet, more than 60 years ago conidia of the fungus Beauveria bassiana (Balsamo) Vuillemin formulated in dust form was reported to produce 71 % mortality of two spotted spider mite (Dresner 1949 ). The red palm mite, Raoiella indica Hirst (Tenuipalpidae) was reported to have been infected by a fungus, possibly Hirsutella sp., in Florida on palms (Peña et al. 2006 ). ...
The Mesostigmata is a large mite order corresponding to about 20 % of all known mite species. These are found in different habitats, but are most abundant and diverse in the soil. Several mesostigmatid groups have been little studied, especially for not being abundant or for being difficult to handle, especially those living in the soil. Knowledge about the diversity of soil mites is still very small in most of the world. Considering just the number of described mesostigmatid species (let aside the number of undescribed species), the number of biological and ecological studies is very limited. Available studies most often are restricted to the evaluation of the ability of particular species to feed on pre-determined food sources. A few have received some attention, among which two superfamilies of the infraorder Gamasina, Rhodacaroidea (in the hyporder Dermanyssiae) and Parasitoidea (in the hyporder Parasitiae). This chapter comprises the biological and ecological information regarding the Mesostigmata.
... Earlier investigations indicated that some major pests could be controlled by using of formulated conidia of entomopathogenic fungi based on WP formulation successfully. For example, WP formulation of conidia against Leptinotarsa decemlineata (Feng et al. 1994), Tetranychus urticae (Dresner et al. 1949), Alphitobius diaperinus (Steinkraus et al. 1991 ). The entomopathogenic fungus, Beauveria bassiana (Balsamo) Vuillemin (Ascomycota: Hypocreales) is able to infect over 700 species of arthropods, especially insects (Tanada and Kaya 1993 ). ...
The wettable powder was prepared on the basis of aerial conidia of two isolates of the entomopathognic fungus, Beauveria bassiana. Viability and pathogenicity of conidia products were evaluated against the second-instar larva of Thrips tabaci in four cases; Conidial-product Maintained in Refrigerator (CMR), Conidial-product Maintained in Laboratory (CML), New Formulated Conidia (NFC) and New Conidia without formulation (NC). Analysis of corrected seven-day total mortality data revealed that there were sig-nificant differences among these product-cases in their pathogenicity to thrips larvae. Recorded mortality rates for CMR, CML, NFC and NC showed that the pathogenicity of CML was lower compared to three other cases for both isolates. In the next step, inorganic salts (MgCl 2 , NH 4 PO 4 , KH 2 PO 4 , MgSO 4 and NaCl) were added at a rate of 0.1 M into the both CMR and CML products. Bioassay re-sults indicated that caused total mortality of thrips larvae increased with adding of salts. Our results showed that applied carriers and salts have positively effected preserving of conidia viability and pathogenicity to the second-instar larva of the onion thrips.
... Occasional failures of fungi or nematodes are usually explained by the use of species or strains that are not adapted to the host or to local conditions (Jackson 1995;Shapiro-Ilan et al. 2002), by soil aridity and soil texture (Ellsbury et al. 1996;Kessler et al. 2003;Koppenhöfer and Fuzy 2006) or by the lack of alternative hosts (Brust 1991;Susurluk 2005). Moreover, fungi and nematodes often require high soil moisture (Milner and Lutton 1986;Helyer et al. 1992;Fargues and Luz 1998;Butt 2002;Jaronski 2008) and are sensitive to UV radiation (Ferron 1978;Burges 1981;Butt 2002). Occasional failures of soil insecticides, if not caused by resistances, are usually explained by the adsorption of insecticides to organic soil particles (Felsot and Lew 1989), chemical volatilisation and degradation at high soil temperatures (Getzin and Shanks 1970), surface runoff or leaching during heavy rainfalls (Gorder et al. 1982) or biodegradation (Felsot et al. 1982;Harris et al. 1988;Felsot and Lew 1989). ...
All three larval instars of Diabrotica virgifera virgifera LeConte (western corn rootworm, Coleoptera: Chrysomelidae) feed on the roots of maize, Zea mays (L.). We assessed the efficacies of the following four agents in controlling these larvae: (1) the entomopathogenic fungus
Metarhizium anisopliae (Metsch.) Sorokin (Hypocreales: Clavicipitaceae), (2) the nematode Heterorhabditis bacteriophora Poinar (Nematoda: Rhabditida), (3) a tefluthrin-based soil insecticide and (4) clothianidin-coated seeds. The agents were
applied in field plot experiments in southern Hungary in 2006 and 2007. Efficacy was assessed by comparing the number of emerging
D. v. virgifera adults and corresponding root damage among treatments and untreated controls. All agents significantly reduced D. v. virgifera numbers and root damage, but the relative success of each treatment was variable. On average across fields and years, the
nematode and the two insecticides reduced D. v. virgifera by 65±34% SD, while the fungus reduced D. v. virgifera by 31±7%. According to the node injury scale, the agents prevented 23–95% of potential root damage. Large-scale commercialisation
of these biological agents could offer viable and practical control options against D. v. virgifera.
... When a host is killed by an insect pathogen, it may subsequently be attacked by secondary bacterial or fungal invaders (Burnside, 1930;Boyce and Fawcett, 1947;Dresner, 1949). Tissue residues of insects killed by ascomycete Cordyceps militaris are resistant to decay, apparently because of an antibiotic substance produced by the fungus (Cunningham et al, 1951). ...
An effort was made to answer the question of whether production of antibacterial substance by Bacillus larvae, the cause of American foulbrood (AFB) disease, is the reason why bee larval cadavers (scales) contain a pure culture of that bacterium. Laboratory bioassays of antibacterial activity indicated the presence of an antibacterial agent in spent Bailey's culture medium used to grow B larvae, whereas antibiotic activity was not detected in larval scales naturally infected with B larvae. The antibacterial activity appears at the onset of B larvae sporulation in artificial medium and its potency rises during sporulation of the pathogen. The agent has a broad spectrum of antibacterial activity against Gram-positive bacilli, micrococci and Gram-negative bacteria including Pseudomonas aeruginosa. The activity of the antibacterial substance was unaffected by proteolytic enzyme digestion and by pretreatment with proteolytically active, aqueous scale filtrates. Since the antibacterial compound is not liberated during infection, the presence of pure cultures of B larvae found in bee cadavers cannot be explained simply by antibiosis. Because Apis mellifera larvae contain little or no indigenous microflora, pure cultures of B larvae in cadavers from AFB infected brood could result from little or no competition for the infecting bacillus.
... Relatively few Weld trials have been undertaken to evaluate entomopathogenic fungi against T. urticae and, even to a lesser extent, T. evansi. Dresner (1949) treated T. urticae with a dust formulation of conidia containing 0.5% spores of B. bassiana in the Weld and obtained 71% mortality. In a semi-Weld experiment using B. bassiana against T. urticae infesting chrysanthemum (Dendranthema grandiXora) (Ramat), Alves et al. (1998) obtained results that were better than the chemical pesticide us ...
The spider mites Tetranychus urticae Koch and Tetranychus evansi Baker and Pritchard are important pests of horticultural crops. They are infected by entomopathogenic fungi naturally or experimentally. Fungal pathogens known to cause high infection in spider mite populations belong to the order Entomophthorales and include Neozygites spp. Studies are being carried out to develop some of these fungi as mycoacaricides, as stand-alone control measures in an inundative strategy to replace the synthetic acaricides currently in use or as a component of integrated mite management. Although emphasis has been put on inundative releases, entomopathogenic fungi can also be used in classical, conservation and augmentative biological control. Permanent establishment of an exotic agent in a new area of introduction may be possible in the case of spider mites. Conservation biological control can be achieved by identifying strategies to promote any natural enemies already present within crop ecosystems, based on a thorough understanding of their biology, ecology and behaviour. Further research should focus on development of efficient mass production systems, formulation, and delivery systems of fungal pathogens.
... Roubaud and Toumanoff (1930) experimentally infected larvae of both Culex pipiens and Anopheles maculipennis with B. bassiana, but this result did not show high insect mortality. However, Dresner (1949) claimed that an acetone extract of the mycelium of B. bassiana would kill mosquito larvae. In the late sixties, Clark et al. (1968) conducted field and laboratory trials of B. bassiana applied as conidial dust against six mosquito species belonging to three genera Aedes, Anopheles and Culex. ...
Laboratory bioassays of two development stages, blastospores (BS) and conidiospores (CS) of Beauveria bassiana (strain GK 2016) against Aedes aegypti larvae were conducted at 27 degrees C. In Study 1, against 24 h post-hatched larvae, both BS and CS stages showed significant difference in their respective larvicidal efficacy over the control (P less than 0.0001). Larval mortality between 24 and 96 h post-exposure was significantly higher than any other time period investigated. Significantly higher larval mortality was observed with BS or CS at 10(8) ml-1 over lower concentrations (P less than 0.05). In Study 2, against different age groups, 12-24 h post-hatched larvae showed significantly higher mortality when treated with BS or CS than older age groups (P less than 0.05). A significant difference was found in the larvicidal potency of B. bassiana at different fungal stages.
... One of the earliest experiments in which a fungus was tested against a phytophagous mite was probably a field application of B. bassiana spores for the control of T. urticae by Dresner (1949). He treated two-spotted spider mites on kidney beans with a dust containing 0.5% spores of the fungus and obtained a mortality of 71%. ...
An overview is given of studies on diseases of mites. Knowledge of diseases of mites is still fragmentary but in recent years more attention has been paid to acaropathogens, often because of the economic importance of many mite species. Most research on mite pathogens concerns studies on fungal pathogens of eriophyoids and spider mites especially. These fungi often play an important role in the regulation of natural mite populations and are sometimes able to decimate populations of phytophagous mites. Studies are being conducted to develop some of these fungi as commercial acaricides. Few bacteria have been reported as pathogens of the Acari but in recent years research has been concentrated on intracellular organisms such as Wolbachia that may cause distorted sex ratios in offspring and incompatibility between populations. The role of these organisms in natural populations of spider mites is in particular discussed. The effect of Bacillus thuringiensis on mites is also treated in this review, although its mode of action in arthropods is mainly due to the presence of toxins and it is, therefore, not considered to be a pathogen in the true sense of the word. Microsporidia have been observed in several mite species especially in oribatid mites, although other groups of mites may also be affected. In recent years, Microsporidia infections in Phytoseiidae have received considerable attention, as they are often found in mass rearings of beneficial arthropods. They affect the efficacy of these predators as biological control agent of insect and mite pests. Microsporidia do not seem to have potential for biological control of mites.
Agriculture is the most important economic activity around the world with its contributions reflected by its share in the gross domestic product of countries. It ensures food security, provides raw materials for many industries and employment opportunities. Today, pest and diseases are among the main challenges plaguing the agricultural sector. More specifically, phytophagous mites are devastating many economically important crops worldwide. Tetranychus urticae Koch (Two-spotted spider mites), Raoiella indica Hirst, (red palm mites), Polyphagotarsonemus latus Banks (broad mites) and Panonychus ulmi Koch (European red mites) are widely known for their extensive damage to crops. To control these mites, farmers have incorporated the use of pesticides into their farming systems. However, chemical control comes with many problems such as insect resistance, detrimental environmental effects and various human health implications. As such biological control is an environmentally friendly alternative that uses bio-control agents such as predators, pathogens and parasitoids to control pests. In this review, it was found that predators and pathogens were the most widely used biocontrol agents, specifically, the Amblyseius spp. Berlese were most effective and widely documented. The available literature also suggests that for successful control of agricultural mites via biological control, there needs to be a clear understanding of the behaviors of these mites and the bio-control agents used.
The entomopathogenic fungus Beauveria bassiana (Bals.) Vuil. was recorded for the first time on Anacridium aegyptium L. in Crete. The insects were fed on pieces of leaf subjected to a serial dilution of spores over three to four orders of magnitute. Comparative studies on the virulence of B. bassiana (I 91612 local isolate) and Metarhizium anisopliae var. acridum (IMI 330189 standard isolate of IIBC) showed that M. anisopliae var. acridum was more virulent than B. bassiana at a conidial concentration lower or equal to 106 per ml while they were similarly virulent on first stage nymphs at 107 conidia per ml.
Mites pose a serious problem to plants worldwide, attacking crops and spreading disease. When mites damage crops of economic importance the impacts can be felt globally. Mites are among the most diverse and successful of invertebrates, with over 45,000 described species, with many more thousands to be discovered. They are responsible for a significant portion of the losses of crops for food, fibre, industry and other purposes, and require expensive and often controversial pest control measures. Understanding these mites is vital for entomologists, pest researchers, agronomists and food producers. Knowledge of mite pests helps to inform control strategies and optimize the production of economic plants and the agrarian economy. This encyclopedia provides a thorough coverage of the mites and the problems they cause to crops, yet it is easily searchable, organised by mite species and subdivided into helpful headings. It takes a worldwide view of the issue of mites injurious to economic plants, describing mites prevalent in different regions and discussing control methods appropriate in different environments. This book provides an encyclopaedic reference to the major mites, described by family in terms of their internal and external morphology, bio-ecology and family systematics. Methods of mite collection and laboratory study is described, as well as species diagnostic characteristics, worldwide distribution, host plants, identification by the type of damage they cause and control strategies, including chemical and biological intervention and integrated pest management measures. Mites of the following families are included: (Eriophyoidea, Tarsonemidae, Tuckerellidae, Tenuipalpidae, Tetranychidae, Acaridae, Penthaleidae). The Handbook of Mites of Economic Plants is an important resource for students of entomology and crop production, and as a thorough reference guide for researchers and field workers involved with mites, crop damage and food production.
In recent years, biological methods have been used widely for controlling stem-boring pests in forests. In this study, the larvae of Xylotrechus rusticus (L.) (Coleoptera: Cerambycidae) were infected with 4 strains of 2 species of Beauveria (Hypocreales: Cordycipitaceae). Larval detoxifying and protective enzyme activities were measured at different times after infection. The results showed significant differences in the pathogenicity of the 4 strains. The most virulent strain, Beauveria bassiana (Bals.-Criv) Vuill. strain BbCC01, caused 93.3% mortality, with an estimated LT50 of 4.69 d. The detoxifying and protective enzyme activities in larvae infected with strain BbCC01 changed significantly. To resist the infection, the activities of the detoxifying enzymes (carboxylesterase, glutathione S-transferase, and acetylcholinesterase) first increased and then slowly decreased. The activities of the protective enzymes (catalase, superoxide dismutase, and peroxidase) showed a similar trend. The enzyme activities peaked at 72 to 96 h post-infection. In this study, the B. bassiana strain BbCC01 proved to exhibit high virulence towards X. rusticus larvae. This research provides important information regarding the biological control of X. rusticus and elucidates the patterns of detoxifying and protective enzyme activities in the susceptible larvae.
The carmine spider mite, Tetranychus cinnabarinus (Boisduval), is one of the most economically important pests of greenhouse-grown vegetables and ornamentals in southwestern Turkey (Antalya). The pest is generally controlled by repetitive applications of chemicals, resulting in environmental pollution and resistance in pest population. In this study, field efficacy of emulsifiable concentrate (EC) formulations of two entomopathogenic fungi, Beauveria bassiana strain PPRI 5339 and Metarhizium anisopliae strain F52 was evaluated against the mite on greenhouse-grown cucumbers in two consecutive growing periods, fall-winter 2010 and spring 2011. Only one trial was conducted for both fungal products in each growing season. Application rates are expressed in quantity of product delivered in 1000 l of water/ha. The B. bassiana product (min. 4 × 109 conidia/ml) was applied at 1, 1.5, and 2 l/ha and the M. anisopliae product (5.5 × 109 conidia/ml) at 0.75, 1, and 1.25 l/ha. The results showed that mortality rates of eggs and motile stages (larva, nymph and adult) of the pest varied with increasing time, and differences of the mortalities at each sampling date were generally significant among the different conidial concentrations of both fungal products. Whereas the B. bassiana product was particularly effective against eggs, causing 81.7% and 78.1% mortalities in 2010 and 2011, respectively; the M. anisopliae product was more effective against motile stages of the pest, achieving 80.6% and 82.1% mortalities in 2010 and 2011, respectively. The results suggest that both fungal products have potential to be used to control T. cinnabarinus in greenhouses.
Phytophagous mites cause biotic stress to its host plant and adversely affect the marketable produce causing losses to growers. Cost effective and energy efficient measures are needed to provide alternative ways to limit chemical treatments which disrupts biotic balance and leads to secondary pest outbreaks, pest resistance and resurgence. Among eco-friendly measures, cultural control, use of mite and insect predators, botanicals/bio-pesticides, fungi, bacteria and virus play an important role in managing mite population in various agricultural crops. The performance of natural enemies is also influenced by host plant characteristics and environmental conditions. Natural enemies efficient on crop may not do well on other crops, e.g., Phytoseiulus persimilis does not do well on tomato because the mites become trapped on glandular hairs on the leaf petioles. Secondly, it performs better under warm, humid conditions whereas; Mesoseiulus longipes is frequently used under hot and dry conditions to control spider mites. Compatibility of Entomopathogenic fungi with other control measures and its safety towards non target organisms makes them good candidates for phytophagous mites' control.
Phytophagous mites of the genus Tetranychus are commonly found attacking ornamentals in production plants and indoor landscapings. The control of those pest organisms is normally done by means of chemical pesticides. Problems of pest resistance and side effects of those products' use have led growers to look for alternative pest control methods. Biological control has been practiced on such ornamental crops as roses, chrysanthemum and different tropical foliage crops, by using almost exclusively the predatory phytoseiid mite Phytoseiulus persimilis Athias-Henriot. This predator is sold commercially by a number of suppliers in different countries. Other species of predators as well as species of pathogens have not been sufficiently studied. More extensive use of biological control depends upon further explorations of prospective species of predators and pathogens, probably waiting to be discovered in poorly studied areas around the world.
Among the four entomophthoraceous species, Entomophthora coronata, E. apiculata, E. thaxteriana, and E. virulenta, only the first two species produced culture filtrates that were toxic when inoculated
into the hemocoels of the larvae of seven insect species. The culture filtrates, however,
produced no apparent toxicity when fed to the larvae of Galleria mellonella. The fungi produced mycotoxins in all media suitable for their growth in vitro and in vivo. The mycotoxins produced by the two fungi had similar properties and appeared to
be identical, but E. coronata produced much more toxin than E. apiculata in the same period of time. More toxin were produced by both fungi in shake than
in stationary cultures. The median effective doses (ED50) of the culture filtrates (96-hour cultures) were estimated from data.
The mycotoxin was not chemically identified, but tests indicated that it was a protein
of small molecular weight. The mycotoxin caused a characteristic blackening sign in
inoculated larva of Galleria mellonella; it also inhibited metamorphosis and affected larval feeding. These signs and symptoms
varied among the seven insect species. The mycotoxin also inhibited bacterial growth
in dead G. mellonella larva.
In Galleria mellonlela larva, the mycotoxin apparently altered the staining properties of the hemolymph
and caused the clumping and coagulation of the hemocytes. Silk gland cells also showed
pathologies, but other tissues and organs appeared to be unaffected. Blood color changes
and clumping of the hemocytes did not occur in fungus-infected larvae.
The bioefficacy of entomopathogenic fungi Beauveria bassiana (strain ITCC-4668) was evaluated against two spotted spider mite Tetranychus urticae Koch under field conditions. Highest reduction in T. urticae population was recorded in B. bassiana (0.3× 10 9 conidia ml-1) treated plots (62.36 %) followed by Ethion 50 EC (0.05%) (61.97 %), B. bassiana at 0.3× 10 8 (56.69 %) and 0.3× 10 7 (55.59%) conidia ml-1. A significant negative correlation was found between the average number of mites and chlorophyll content (r=-0.766). In uninfected leaves higher chlorophyll content was recorded (1.016 µg/ml) as compared to mite infested leaves (0.166 µg/ml). B.bassiana treatment improved the total chlorophyll content (0.346 µg/ml), chlorophyll a (0.079 µg/ml) and chlorophyll b content (0.267µg/ml).
O estudo da patogenicidade de Beauveria bassiana (Bals.) Vuill. ao ácaro Tetranychus urticae Koch foi desenvolvido a 25 ± 2°C, 70 ± 5% UR e 12 horas de fotofase, utilizando-se fêmeas recém-emergidas. Os ácaros foram mantidos durante seis dias em discos de folha de Canavalia ensiformis (L.) DC. inoculadas com B. bassiana, isolado 447, nas concentrações: 5x106, 1x107, 5x107, 1x108, 5x108 e 1x109 conídios/ml. Este isolado mostrou-se patogênico a T. urticae, apresentando aumento nos valores das mortalidades acumuladas (total, corrigida e confirmada) à medida que a suspensão de conídios se tornou mais concentrada. Nas seis concentrações testadas, os valores de mortalidade corrigida ao sexto dia, foram inferiores a 50%, sendo observada apenas na concentração de 1x109 conídios/ml, mortalidade total superior a 50%.
The composition of the medium most suitable for the submersed cultivation of the entomopathogenic fungus Beauveria bassiana has been determined by its growth and the production of blastospores. The composition of the medium is glucose, 2.5%; starch, 2.5%; corn-steep liquor, 2.0%; NaCl, 0.5%; CaCO3, 0.2%; pH 4.5. An optimum yield, as measured by the dry-matter production (68.7 mg/5 ml) and the spore concentration (6.43 × 108/ml), was obtained after 72 hours.
Laboratory studies were conducted to determine the effects of the mycoinsecticide Naturalis-L (Beauveria bassiana conidial formulation) on the twospotted spider mite Tetranychus urticae. Compatibility of B. bassiana with triflumuron (benzoylphenyl urea typically used as an insecticide, but also with acaricide effects), was also investigated in order to incorporate both in the control of this pest. For each juvenile stage, 180–22,800 viable conidia/mL on deutonymphs, 380–12,160 viable conidia/mL on protonymphs, and 712–7480 viable conidia/mL on larvae were evaluated. For the adult stage, the concentrations ranged from 213 to 54,720 viable conidia/mL. The mortality data used in the analysis were those accumulated after 5 days of treatment for deutonymphs and protonymphs, 7 days for larvae and 9 days for adults. The lethal concentration to kill 50% (LC50) for the juvenile stages was 3184 viable conidia/mL (their probit-log concentration regression lines were the same), and 1949 viable conidia/mL for adults. No significant differences in mortality were observed among egg age classes (24-, 48-, 72-, and 96-h-old eggs) at the tested concentrations (1400–22,800 viable conidia/mL). When B. bassiana was combined with 0.25g Alsystin (25% triflumuron as a wettable powder)/L, mite egg mortality decreased significantly. Triflumuron reduced mycelial growth but not conidial germination of B. bassiana. This fungus is a possible candidate to be included in integrated pest management programs with triflumuron of T. urticae. In such programs, the possible antagonist effects of triflumuron should be considered.
Laboratory assay showed Beauveria bassiana (Bals.) Vuill. to be present in approximately 15% of the combined populations of forest collected living Hylobius pales and Pachylobius picivorus.
During studies on the control of the onion maggot, Hylemya antiqua (Meig.), in late September, 1958, from one to 10 dead adults were found clinging to the tops of onion leaves in a three-acre field of green bunching onions in the Toronto area (Fig. 1). The dead flies were more abundant in the outside three rows, adjoining a non-cultivated grassy area, than throughout the rest of the field. A fungal growth was evident between the abdominal terga and sterna in many specimens. Infected live flies were somewhat pale, appeared bloated, and moved very sluggishly in comparison with non-infected adults. Dead flies were sent to Dr. G. Bucher, Entomology Laboratory, Belleville, Ontario, who identified the pathogen as Empusa muscae Cohn.
Metarhizium anisopliae conidia were formulated with three granular carriers and nine dust diluents and stored over an 8- to 12-month period at 4° or 20°C. The virulence of formulations, with the exception of two dust preparations, was reduced significantly compared to unformulated conidia against Culex pipiens pipiens larvae. The formulation components most detrimental to conidial virulence were corn cob granules, diatomaceous earth, and two Kaolinite diluents. This was exampled by a decline in virulence from ca. 100% for unformulated conidia to 36% or below for these formulations. LT50 values also increased from 2.4–2.6 days for unformulated conidia to above 6 days. In contrast, a diluent derived from dried castor oil (Thixcin R) significantly enhanced conidial virulence at several doses above that of unformulated conidia against C. pipiens larvae. Enhancement occurred whether conidia were formulated prior to storage or stored separate from the diluent and mixed prior to application. The Thixcin R formulation was more effective against Anopheles stephensi larvae, but virulence was reduced against Aedes aegypti larvae. A bentonite formulation (Bentone-38) also maintained conidial virulence effectively, but Thixcin R was a superior diluent. It was shown that conidial virulence of formulations was not correlated with differences in conidial viability. The preparations that were applied dry by a surface method were more virulent than when an aqueous suspension containing a surfactant was used. The results demonstrate the need to assess efficacy of mycoinsecticidal formulations in a virulence bioassay prior to field testing.
Metarhizium anisopliae was mass cultured on tapioca chips and rice bran, supplemented with waste fish meal extract or urea, in specially designed large aluminium vessels.
The suitability of entomopathogenic organisms as part of a suite of control measures in integrated pest management schemes in forestry is critically reviewed. The use of fungi, viruses, bacteria, protozoa and nematodes as control agents of forest insect pests is discussed with particular reference to the contrast between these organisms and chemical control methods. In general entomopathogenic organisms are environmentally more suitable than the latter and, although currently more expensive in monetary terms, are in the long run less expensive in terms of deleterious side effects such as human health hazards and destruction of non‐target organisms. The fact that many of these organisms are able to persist in the environment, despite their target organisms being at low levels, also makes them more attractive to use than conventional insecticides. The considerations that need to be given before using such organisms, and future developments, are discussed. The use of entomopathogenic fungi and baculoviruses as components of IPM systems is highly recommended and seen as a real alternative to chemical control methods in forestry.
Preliminary investigations have shown the presence of pathogenic fungi in natural populations of the cassava green spider mites. Among others, Entomopthora sp. and Hirsutella sp. were isolated from dead mites sampled from the field. Laboratory bioassays have given mite mortality of up to 60%, indicating the possibility of utilizing some of these pathogens in mite control. Tests with Beauveria bassiana, isolated from lepidopteran pests, have also shown that the mite is susceptible to this fungus.RésuméDes études préliminaires ont montré, la présence de champignons pathogènes, dans des populations naturelles d'acariens (verts) du manioc. Entre autres, Entomopthora sp. et Hirsutella sp. ont été isolés des échantillons d'acariens (verts) morts prélevés sur le terrain. Des études en laboratoire ont montré un taux de mortalité allant jusqu'à 60%; ce qui suggère la possibilité de l'utilisation de certains champignons pathogènes, dans le contrôle d'acariens. Des tests réalisés avec Beauverua bassiana isolé des Lépidoptères ravageurs ont également montré que l'acarien (vert) est sensible à ce champignon.
The muscardine-fungi are nor toxic neither pathogen for man and warmblooded animals. Reactions of sensitive persons working
with spores of this fungi are not of general but of allergic nature. Against such allergic reactions it is possible to protect
by breath protection, dress with long sleeves and gloves.
An overview is given of diseases in mites, caused by infectious microorganisms. Many pathogens play an important role in the
regulation of natural populations of mite populations and are for this reason subject of research on the feasibility to develop
such pathogens to biological control agents. Several examples are given of successful application of pathogens for the control
of mite pests, but also failures are discussed. Most studies concern fungal pathogens of tetranychids and eriophyids; some
of these fungi are possible candidates for biological control agent of species of noxious mites. An interesting group of pathogens
form the intracellular symbionts: bacteria that may cause unusual effects in their hosts, such as parthenogenesis, feminization,
male killing and incompatibilities. This group of bacteria is present in many invertebrates species and are presently widely
studied as new molecular techniques have become available that make detection of such symbionts possible. Attention is also
given to quality control of beneficial mites that are being used in integrated control programs. Beneficial mites, as e.g.
predatory mites, may also be infected by microorganisms (bacteria, viruses, microsporidia), resulting in poor performance
of the predator. Prospects for the application of pathogens in IPM systems are discussed.
An outbreak of an insect pest may be controlled in a few days by fungi of the familyEntomophthoraceae. Isolation and culture of such fungi is often difficult. A simple and successful method is herein recommended, utilizing a substrate of hen's egg yolk previously coagulated 40–50 minutes at 80°C in a hot air oven. The medium is prepared in tubes in a slanted position. The culture technique, starting with conidia is described. Coagulated yolk is also a suitable medium for successive transfer and maintenance ofEntomophthoraceae cultures. Stock cultures maintained at room temperature must be transferred once every three or four weeks.
If desirable, subcultures ofEntomophthoraceae fungi may be held in test tubes at greater intervals. For this purpose tubes are filled with whole milk 3–4 cm in depth and sterilized at 100°C three times or autoclaved at 110°C for 15 minutes. The fungi grow essentially in the top layer of milk fat. Such cultures live up to 1 1/2 months, some species survive 4 months. Milk agar, milk oatmeal agar, beef extract pepton yolk agar, and potato pieces are also suitable for cultivation. The growth on such substrates is not as good as on the coagulated yolk.
Media with 25 international units of penicillin and 50 gamma of streptomycin per ml did not influence the growth ofEmpusa aulicae
Reich. and oneEmpusa sp. isolated fromAphis fabae
scop. Isolation and cultivation of entomophagousEntomophthoraceae are considered to be as important for experiments in biological control as for studies on taxonomy and biology of distinct species.
The ability of the fungus Beauveria bassiana to kill mosquito larvae, adults, and eggs was challenged with Culex tarsalis, Culex pipiens, Anopheles albimanus, Aedes aegypti, Aedes sierrensis, and Aedes nigromaculis. B. bassiana was found most effective in killing larvae when applied as a conidial dust to the surface of the water. This was attributed to the primary sites of invasion being the perispiracular lobes of the larval siphon. During May and June of 1966, the mortality of C. pipiens larvae in outdoor test ponds ranged from 70% to 95% following an application of 3 lb. of viable conidia per acre. The Anopheles and Culex larvae tested all proved to be susceptible to the fungus while the Aedes larvae were not.In laboratory tests against the adults of C. tarsalis, C. pipiens, A. aegypti, A. sierrensis, A. nigromaculis, and A. albimanus, conidia of B. bassiana produced 100% mortality within 5 days after exposure, while less than 50% occurred in corresponding controls. Outdoor tests against the adults of A. nigromaculis in screen cages were less successful, yielding only 58% mortality. In this case, the fact that adults rested on the screen walls of their test cages, rather than in the dusted grass that had been provided, may explain the low mortality. Eggs of Culex and Aedes exposed to the conidia of B. bassiana hatched normally.
Fusarium oxysporum was isolated from diseased larvae of the mosquito Aedes detritus collected in the marshy areas of Camargue, Southern France. The larvae of A. detritus and Culex pipeins pipiens were infected experimentally by contaminating water with conidia obtained from fungal cultures as well as by diseased cadavers. More than 80% mortality was obtained in the laboratory. Injured and young larvae demonstrated increased susceptibility to fungal infection. Histological preparations showed that spores germinating in the intestinal lumen were able to cause infection and the mycelium thus produced infected all tissues. Current experiments have shown that the fungus remains active even in greater quantities of water. Thus the disease may be considered as a possible limiting factor for mosquito populations, and eventually its use in biological control of mosquitoes merits further investigation.
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