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Interactions between the entomopathogenic fungus, Beauveria bassiana SG8702, and imidacloprid on Nilaparvata lugens (Homoptera: Delphacidae) were studied in laboratory bioassays by spraying suspensions of unformulated conidia (assay 1) and aqueous dilutions of emulsifiable conidia formulation alone (assay 2) or together with imidacloprid at the sub-lethal rates of 0.5, 1.0 and 2.0 µg ml-1 (assays 3-5). Each assay consisted of five conidia concentrations plus an appropriate control and three replicates, each including 30-40 third-instar nymphs, so as to generate time-concentration-mortality data for modeling analysis. A mineral oil-based emulsion used to formulate B bassiana slightly enhanced fungal activity but had no significant impact on the background mortality of N lugens. On the basis of LC50 estimates and associated variances on days 4-12 after spraying, synergistic interactions of both agents or formulations were determined by estimating relative potencies of assay 2 over assay 1 (1.2-9.0), assay 3 over assay 2 (1.3-1.7), assay 4 over assay 2 (7.5-9.6), assay 5 over assay 2 (22.7-101), assay 4 over assay 3 (3.8-5.8), assay 5 over assay 3 (16.1-61.0), and assay 5 over assay 4 (3.0-10.5). The time-concentration-mortality modeling method was not only mathematically but also biologically robust to evaluate the interactions of B bassiana and imidacloprid on N lugens. Compared with their counterparts, enhanced fungal formulations displayed consistently earlier or greater activities against the pest species based on LC50 and LT50 estimates determined from their time-concentration-mortality relationships. The results highlight a potential for pest control by combined formulation or application of B bassiana and imidacloprid. [ABSTRACT FROM AUTHOR]

Abstract: A survey of entomopathogenic nematodes was conducted in the north Pacific (Guanacaste Conservation Area) and southeast Caribbean (Gandoca-Manzanillo Natural Refuge) regions of Costa Rica. Out of a total of 41 soil samples, 5 were positive for entomopathogenic nematodes (20.5%), with 3 (12.3%) containing Steinernema and 2 (8.2%) Heterorhabditis isolates. Morphological and molecular studies were undertaken to characterize these isolates. The Heterorhabditis isolates were identified as Heterorhabditis indica and the three Steinernema isolates were identified as two new undescribed species. H. indica was recovered from a coastal dry forest. Steinernema n. sp. 1 was isolated from a rainforest valley, between volcanoes. Steinernema sp. n. 2 was isolated from sand dunes in the Caribbean Coast (Punta Uva) near the rainforest strip along the coast. Although limited to two geographic regions, this study suggests entomopathogenic nematodes may be diverse and perhaps widely distributed in Costa Rica. A more intensive survey, covering all geographic regions is currently undergoing. [Copyright &y& Elsevier]

Abstract: 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. [Copyright &y& Elsevier]

The entomopathogenic fungus Pandora neoaphidis is an important natural enemy of aphids. ISSR, ERIC (Enterobacterial Repetitive Intergenic Consensus) and RAPD PCR-based DNA fingerprint analyses were undertaken to study intra-specific variation amongst 30 isolates of P. neoaphidis worldwide, together with six closely related species of Entomophthorales. All methods yielded scorable binary characters, and distance matrices were constructed from both individual and combined data sets. Neighbour-joining was used to construct consensus phylogenetic trees which showed that although P. neoaphidis isolates were highly polymorphic they separated into a monophyletic group compared with the other Entomophthorales tested. Three distinct subclades were found, with UK isolates occupying two of these. No specific correlation with aphid host species was established for any of the isolates apart from those in one cluster which contained isolates obtained from nettle aphid, Microlophium carnosum. ERIC, ISSR and RAPD analysis allowed the rapid genetic characterisation and differentiation of isolates with the generation of potential isolate- and cluster specific- diagnostic DNA markers. [ABSTRACT FROM AUTHOR]

In laboratory and field cage experiments, the horizontal transmission of the entomopathogenic fungus Beauveria bassiana (Boverol®) between adults of the spruce bark beetle Ips typographus was examined. In a laboratory experiment, conidia transfer between treated and untreated beetles at different ratios resulted in 96% mortality (MST 4.3 days) at a ratio of 1:1 and 90% mortality (MST 4.5 days) at a ratio of 1:2. At ratios of 1:5, 1:10 and 1:20, the mortalities at 7 days were 83, 77 and 75%, respectively. In a second laboratory experiment, the efficacy of B. bassiana was investigated after transmission from contaminated to healthy beetles over a period of 5 days. Two weeks later, the mortality of treated and untreated beetles was 99% (control mortality was 44%), while the rate of mycosis was 79% in the treatment compared to 10% in the control beetles. A single contact between one treated male (2.0×10 5 conidia/beetle) and an untreated female was found to be sufficient to transmit a lethal dose of B. bassiana of about 1.2×10 4 conidia. Two experiments in field cages in a spruce stand demonstrated horizontal transmission of B. bassiana (Boverol®) between beetles. In the first experiment the transmission was investigated following the introduction of B. bassiana -inoculated beetles into a population of untreated beetles. Significant reductions were observed in the length of maternal galleries, and the number of larvae and pupae. In the second field cage experiment, natural populations of beetles were lured into a flight cage using a pheromone trap, and treated with B. bassiana or left untreated on alternate days. In this experiment, significant reductions were observed in the number of bore holes and the length of maternal galleries, while no larvae, pupae or juveniles were found under the bark of spruce trunks in the Boverol® transmission treatment. It is concluded that B. bassiana has potential for control of I. typographus , and further field experiments are warranted to investigate its efficacy under more practical conditions. [ABSTRACT FROM AUTHOR]

Nine populations of entomopathogenic nematodes belonging to seven species of Steinernema and Heterorhabditis genera were tested against horn fly (Haematobia irritans L.). The study was carried out under laboratory conditions in three experiments: fly larvae in Petri dish, pupae in soil and pupae in manure. Eight nematode populations showed infectivity against larvae or adult fl y in the Petri dish test but only S. carpocapsae showed infectivity in the soil and in the manure tests. Soil pastures sampled from Tamaulipas did not show presence of any natural entomopathogenic nematode population. [ABSTRACT FROM AUTHOR]

Larvae of Helicoverpa armigera (Hübner), a polyphagous lepidopteran crop pest, adapt to the presence of protease inhibitors in their diet by differential regulation of multiple genes encoding digestive proteases. The time-course of their response to dietary soybean Kunitz trypsin inhibitor (SKTI) involves several stages; an initial up-regulation of all protease genes assayed (up to 12 h after exposure to inhibitor) is succeeded by a longer-term down-regulation of expression of specific genes that encode proteases most sensitive to the inhibitor, whereas genes encoding putative inhibitor-insensitive proteases continue to be up-regulated (after 24 h of exposure). Consequently, insect protease activity changes from being sensitive to the inhibitor, to being largely insensitive. The insect response is comparable in its timescale with that of the synthesis of protease inhibitors in the plant wounding response. SKTl causes similar effects on protease gene expression and gut protease activity when fed in diets containing casein or hydrolysed casein as sources of amino acid, suggesting that the insect response is not mediated through inhibition of digestive proteolysis. Soybean Bowman–Birk inhibitor, which has a broader range of inhibitory activity against gut proteases in H. armigera, but is a less effective inhibitor on an I50 basis, proves to be a more effective antimetabolite than SKTI, but does not induce inhibitor-insensitive protease activity because it causes a general up-regulation of protease-encoding genes. A possible mechanism to account for these different responses is discussed. [ABSTRACT FROM AUTHOR]

Genomic islands are regions of the bacterial genome responsible for unique aspects of bacterial behaviour, such as host symbiosis and pathogenicity. Where such regions are involved in pathogenesis, they are termed pathogenicity islands (PAIs). Photorhabdus luminescens is an insect pathogen that spends part of its life in symbiosis with a nematode and part of its life as an insect pathogen. Here, several novel PAIs from P. luminescens ssp. akhurstii strain W14 are described that encode factors involved apparently in both nematode symbiosis and insect pathogenicity. The structures of these islands are compared with those found in mammalian pathogens, and the potential cross-talk between virulence factors used against invertebrates and those used against vertebrates is discussed. [ABSTRACT FROM AUTHOR]

In laboratory bioassays, the efficacy of the entomopathogenic fungus Beauveria bassiana against the spruce bark beetle, Ips typographus, was tested under various conditions. Four of the tested isolates and the commercial product Boverol® caused 99–100% mortality when tested at a concentration of 1.0 × 107 conidia/ml at 25°C. Using B. bassiana isolate 138 at a concentration of 1.0 × 106, the median survival time (MST) was 6.1 d and significantly longer compared with the MST of 4.2 and 4.0 d at 1.0 × 107 and 1.0 × 108 conidia/ml, respectively. In the next experiment, the beetles were maintained on spruce bark, filter paper or artificial diet during the bioassay with Boverol®, and significant differences in the MST of 3.6, 2.5 and 5.3 d, respectively, were noticed. The experiment with Boverol® at different temperatures showed that the beetles lived significantly longer at 15°C (MST 8.7 d) than at 20, 25, 30 and 35°C. At 25°C, the beetles died most rapidly (MST 3.5 d). At different relative humidities (RH) of 40, 70 and 100%, nearly all beetles were dead after treatment with a suspension of Boverol® at 1.0 × 107 conidia/ml. At 40% RH, 49% of the untreated beetles died after 7 d. The best effects were achieved with the following bioassay: beetles were fed for three days on artificial diet, then dipped into a solution of 1.0 × 107 conidia/ml and transferred on a piece of spruce bark in Petri dishes at 25°C and 70% RH. [ABSTRACT FROM AUTHOR]

The entomopathogenic fungus Entomophaga maimaiga has been reported infecting gypsy moth, Lymantria dispar, larvae in the United States since 1989. Laboratory bioassays demonstrated that larvae of numerous species of native tussock moths (Lymantriidae) are susceptible to E. maimaiga. From 1997 to 2001, larvae of gypsy moth and native lymantriids were collected in long-term plots in national forests in Virginia and West Virginia to evaluate infection levels. Throughout this time, gypsy moth populations were low although increasing the last 2 years, whereas native lymantriids remained uncommon throughout. Among gypsy moth larvae, infection by E. maimaiga first occurred during 2000 and increased in both areas during 2001 as gypsy moth populations increased. Seven species of native lymantriids were collected but only three were infected: Dasychira obliquata, Dasychira vagans, and Orgyia leucostigma. Infection of these native lymantriid species did not occur in 1997–1999 and was always <50% per species during 2000 and 2001. Ecological studies were conducted to evaluate when and where native lymantriids could be exposed to E. maimaiga inoculum. Field bioassays demonstrated that E. maimaiga resting spores were active in soil at bases of trees beginning in April, especially when soil was moist, but few gypsy moth larvae were infected by airborne conidia from resting spores early in the season. In 2000 and 2001, cadavers that produced conidia were collected throughout the season and conidia were the predominant spore form produced for at least the first month of the field season. Resting spore densities in soil were high during 1997 but titers declined through the study, with the exception of an increase following E. maimaiga infections in increasing gypsy moth populations in West Virginia during 2000. [Copyright &y& Elsevier]

We measured the effect of entomopathogenic nematodes on root-knot nematodes (Meloidogyne spp.) infecting tomato and peanut. In growth chamber experiments, peanut seedlings were inoculated with 300 Meloidogyne hapla eggs and 25 infective juveniles (IJs)/cm2 of Steinernema feltiae, Steinernema riobrave, or Heterorhabditis bacteriophora. With the exception of seedling roots treated with H. bacteriophora, M. hapla inside roots and egg recovery from seedlings treated with entomopathogenic nematodes were significantly less than those in the controls. Peanut plants in the greenhouse were infested with 5000 M. hapla eggs and treated 2 weeks before, 1 week before, at the same time, 1 week after, or 2 weeks after with 25 or 125 IJs/cm2 of S. feltiae, S. riobrave, or H. bacteriophora. Pre- and post-infestation applications of S. feltiae suppressed M. hapla penetration but not egg production. Only pre-infestation applications of S. riobrave suppressed M. hapla. Only the high application rate of H. bacteriophora applied at the time of M. hapla infestation was suppressive. Tomato plants in the greenhouse were infested with 5000 Meloidogyne incognita eggs and treated with 25 or 125 IJs/cm2 of Steinernema glaseri or Heterorhabditis megidis applied at the same times as the tomato treatments. The low rate of S. glaseri suppressed M. incognita penetration into tomato roots and the high rate of S. glaseri reduced egg production. [Copyright &y& Elsevier]

Other than Bacillus thuringiensis Berliner, few bacteria are lethal to the Colorado potato beetle (Leptinotarsa decemlineata [Say]), a major pest of potatoes and eggplant. Expanded use of biologicals for the control of Colorado potato beetle will improve resistance management, reduce pesticide use, and produce novel compounds for potential use in transgenic plants. Using freeze-dried, rehydrated artificial diet in pellet form to screen bacteria lethal to other insects, we determined that strains of Photorhabdus luminescens killed Colorado potato beetle larvae. The LC50 for second instar larvae of strain HM5-1 was 6.4 ± 1.87 x 107 cells per diet pellet. In an attempt to find additional naturally occurring P. luminescens strains toxic to Colorado potato beetle larvae, we recovered, from soil, bacteria that produced a purple pigment. This bacterial strain, identified as Chromobacterium sp. by 16S ribosomal DNA sequencing, was also toxic to Colorado potato beetle larvae within 3 d. The LC50 for second instar larvae for these bacteria was 2.0 ± 0.79 x l08 cells per diet pellet, while the LC50 was approximately 1 log lower for third instar larvae. P. luminescens appeared to kill by means of a protein toxin that may be similar to the described lepidopteran protein toxins. Based on the heat and acid stability, the toxin or toxins that Chromobacterium sp. produces, while not fully characterized, do not appear to be typical proteins. In both bacteria, the toxins are made after exponential growth ceases. [ABSTRACT FROM AUTHOR]

Using nitrate non-utilizing (nit) mutants, we determined vegetative compatibility groups (VCG) among strains of Beauveria bassiana representing strains indigenous to North America, isolated from diverse insect hosts, and strains that have been mass released for insect control. Genetic similarity among these strains was analyzed using random amplified polymorphic DNA (RAPD) markers. Our data revealed 23 VCGs among the 34 strains tested, with most of these groups comprised of only a single strain. We also observed a VCG comprised of eight genetically similar strains isolated from Colorado potato beetles (CPB). Co-inoculation studies of CPB larvae with complementary nit mutants from the same or from different VCGs revealed heterokaryosis in four out of five same-VCG pairs, with only 5–17% of the sporulating cadavers generating few parasexual recombinants. In contrast, none of the infected beetles treated with non-compatible pairs generated recombinants. The large number of VCGs observed and the low frequency of in vivo recombination limited to vegetatively compatible strains indicate that this self/non-self recognition system may be an effective barrier preventing genetic exchange between dissimilar strains in the field. [Copyright &y& Elsevier]

Background: The entomopathogenic fungus Metarhizium anisopliae is being considered as a biocontrol agent for adult African malaria vectors. In the laboratory, work was carried out to assess whether horizontal transmission of the pathogen can take place during copulation, as this would enhance the impact of the fungus on target populations when compared with insecticides. Methods: Virgin female Anopheles gambiae sensu stricto were exposed to conidia whilst resting on fungus-impregnated paper. These females were then placed together for one hour with uncontaminated males in proportions of either 1:1 or 1:10 shortly before the onset of mating activity. Results: Males that had acquired fungal infection after mating indicate that passive transfer of the pathogen from infected females does occur, with mean male infection rates between 10.7 ± 3.2% and 33.3 ± 3.8%. The infections caused by horizontal transmission did not result in overall differences in survival between males from test and control groups, but in one of the three experiments the infected males had significantly shorter life spans than uninfected males (P < 0.05). Conclusion: This study shows that autodissemination of fungal inoculum between An. gambiae s.s. mosquitoes during mating activity is possible under laboratory conditions. Field studies are required next, to assess the extent to which this phenomenon may augment the primary contamination pathway (i.e. direct contact with fungus-impregnated targets) of vector populations in the field. [ABSTRACT FROM AUTHOR]

Beauveria bassiana and Paecilomyces fumosoroseus are generalist entomopathogenic fungi that infect the silverleaf whitefly (Bemisia argentifolii). We found second and third instar whiteflies to be the most susceptible larval stage to both fungi. Conidia of B. bassiana germinated most readily on the cuticle of second instars (54% germinated) and P. fumosoroseus germination was highest on third instar cuticle (45%). Fourth instars (the ultimate instar) had low susceptibility to these pathogens, and spore germination on the cuticle of fourth instars was very low for B. bassiana (7%) and intermediate for P. fumosoroseus (33%). Cuticular lipids were found to have toxic or inhibitory effects on conidia of B. bassiana and P. fumosoroseus when the spores were germinated on nutrient agar in the presence of the lipids. In the absence of added nutrients, P. fumosoroseus conidial germination increased in the presence of the lipids. To test if the inhibitory effects of the lipids were due solely to hydrophobicity (preventing water from coming into contact with the conidia) we tested the effects of synthetic long-chain wax esters. The synthetic wax esters inhibited germination of P. fumosoroseus to a degree that was similar to the effect of the cuticular lipid extracts, but the synthetic lipids did not have a significant effect on B. bassiana. Thus, the thick coating of long-chain wax esters produced by whitefly nymphs affect spore germination of fungal pathogens, but whether they play a significant role in defense against disease is not clear. [Copyright &y& Elsevier]

The effects of abiotic and biotic soil factors on occurrence of the entomopathogenic fungus Beauveria brongniartii after application at different times of the year were examined in Switzerland. Applications made from May to August generally resulted in an increase of 1–5 × 103 CFU g−1 dry soil compared to untreated control plots. Conversely, soils treated in October and November yielded no increase. Soil temperatures between 20 and 25 °C, and high clay content of the soil had a positive effect on the occurrence and density of B. brongniartii whereas increased catalase activity and temperatures above 27 °C had a negative influence. Laboratory experiments revealed that a higher number of CFUs developed after one month of incubation at 22 °C than at 12 °C. Differences were not detected after three months of incubation, indicating that growth rate was simply slower at sub-optimal temperatures. The increase was different in three native soils, but was not correlated with different clay contents of the soil. In sterilized soil, though, the differences were not detected, suggesting that biotic factors have a greater influence rather than soil texture. [Copyright &y& Elsevier]

In 1996, two searchable databases covering insect pathogens were posted on the World Wide Web: the Ecological Database of the World’s Insect Pathogens (EDWIP) and the Viral Diseases of Insects in the Literature database (VIDIL). In this paper, we describe the format and contents of EDWIP and VIDIL on the World Wide Web. EDWIP contains over 9400 pathogen–host association records, 677 negative test result or “no association” records, 4454 host species, 2285 pathogen species records, and 2057 bibliographical references. Species of Coleoptera and Lepidoptera are the best represented groups in EDWIP. Lepidopteran species account for the most associations of any host order in EDWIP, over 2500, or 27%. Of the pathogen groups, Protozoa (including microsporidia) accounted for nearly 66% of the pathogen species records and over 40% of the association records in EDWIP. Fungi account for only 18% of the pathogen species, but nearly 33% of the association records. Habitats dominated by human activities (e.g., crop, stored product, and human dwelling) account for most of the host habitats recorded in EDWIP. The United States and Japan are the most common locations and the Nearctic and Palearctic are the most common biogeographic regions reported in EDWIP. There are 4801 annotated bibliographic records in VIDIL. [Copyright &y& Elsevier]

Conidiobolus coronatus (Zygomycota) is a facultative saprobe that is a pathogen of many insect species. Almost 2000 expressed sequence tag (EST) cDNA clones were sequenced to analyse gene expression during growth on insect cuticle. Sixty percent of the ESTs that could be clustered into functional groups (E ≤ 10[sup -5]) had their best BLAST hits among fungal sequences. These included chitinases and multiple subtilisins, trypsin, metalloprotease and aspartyl protease activities with the potential to degrade host tissues and disable anti-microbial peptides. Otherwise, compared to the ascomycete entomopathogen Metarhizium anisopliae, Con. coronatus produced many fewer types of hydrolases (e.g. no phospholipases), antimicrobial agents, toxic secondary metabolites and no ESTs with putative roles in the generation of antibiotics. Instead, Con. coronatus produced a much higher proportion of ESTs encoding ribosomal proteins and enzymes of intermediate metabolism that facilitate its rapid growth. These results are consistent with Con. coronatus having adapted a modification of the saprophytic ruderal-selected strategy, using rapid growth to overwhelm the host and exploit the cadaver before competitors overrun it. This strategy does not preclude specialization to pathogenicity, as Con. coronatus produces the greatest complexity of proteases on insect cuticle, indicating an ability to respond to conditions in the cuticle. [ABSTRACT FROM AUTHOR]

Extracts from entomopathogenic fungi of the genus Hypocrella (7 species) and its anamorph Aschersonia (11 species) were screened for cytotoxicity to Sf9 and C6/36 insect cells and L929, BHK(21)C13 and HepG2 mammalian cells. Cytotoxic extracts to insect cells (ID50's10 μg ml-1) but not to mammalian cells (ID50's10 μg ml-1) conformed to the criteria of the project and were considered ‘lead’ extracts for further investigation. ‘Leads’ were found in two of the Hypocrella species: H. discoidea, and H. tamurai and in three of the Aschersonia species: A. samoensis, A. badia, and A. tamurai. Bioassay-guided fractionation of the cell extract of the fungus A. samoensis BCC 1393 led to the identification of two known anthraquinone dimers, (+)rugulosin (1) and skyrin (2) which showed selective toxicity towards insect cells. (+)Rugulosin (1) and skyrin (2) exhibited strong cytotoxic activity against the insect cell line Sf9 with respective ID50 values of 1.2 and 9.6 μg ml-1, but showed weak activity toward mammalian cells. This first report of (+)rugulosin (1) and skyrin (2) in A. samoensis is confirmed and demonstrated in another four strains of A. samoensis isolated in Thailand. The preferential cytotoxicity against Sf9 insect cells gives evidence that these insect-pathogenic fungi of the Hypocrella/Aschersonia group might be useful as an agent for pest control. [ABSTRACT FROM AUTHOR]

The nematode Heterorhabditis bacteriophora is the vector for transmitting the entomopathogenic bacterium Photorhabdus luminescens between insect larvae. The dauer juvenile (DJ) stage nematode selectively retains P. luminescens in its intestine until it releases the bacteria into the hemocoel of an insect host. We report the results of studying the transmission of the bacteria by its nematode vector. Cells of P. luminescens labeled with green fluorescent protein preferentially colonized a region of the DJ intestine immediately behind the basal bulb, extending for various distances toward the anus. Incubation of DJ nematodes in vitro in insect hemolymph induced regurgitation of the bacteria. Following a 30-min lag, the bacteria migrated in a gradual and staggered movement toward and ultimately exited the mouth. This regurgitation reaction was induced by a low-molecular-weight, heat- and protease-stable, anionic component present in arthropod hemolymph and in supernatants from insect cell cultures. Nematodes anesthetized with levamisole or treated with the antihelmenthic agent ivermectin did not release their bacteria into hemolymph. The ability to visualize P. luminescens in the DJ nematode intestine provides the first clues to the mechanism of release of the bacteria during infection of insect larvae. This and the partial characterization of a component of hemolymph triggering release of the bacteria render this fascinating example of both a mutualistic symbiosis and disease transmission amenable to future genetic and molecular study. [ABSTRACT FROM AUTHOR]

Mutualistic associations between different organisms are theoretically expected when the interests of independently reproducing units are aligned to form a single reproductive unit. This alignment does not come about easily, because models show that hosts and symbionts can be in conflict over the transmission of symbionts. Selection will favour hosts that are able to limit genetic variation of symbionts, for example by enforcing uniparental vertical transmission, while symbionts will be selected to disperse independently of the host. A crucial factor determining the evolution and elaboration of symbiotic relationships is therefore who controls the transmission of symbionts. In the fungus-growing termites (Macrotermintinae) horizontal transmission seems to be the rule as the termites normally acquire their cultivated fungus (Termitomyces) from the environment. In spite of this general pattern, uniparental, vertical transmission has evolved in two unrelated Macrotermitinae genera, where only one sex of the two primary reproductives carries asexual spores from the fungal comb of its parent colony to inoculate the new fungus comb. Remarkably, symbiont transmission is exclusively paternal in Macrotermes bellicosus, whereas symbionts are maternally inherited in all Microtermes species studied so far. Thus, in Macrotermitinae horizontal transmission is the ancestral state with two independent origins to uniparental, vertical transmission. This is in contrast to fungus-growing ants where uniparental, vertical transmission is the rule. Causes and consequences of this difference are further discussed. Despite this fundamental difference both groups evolved a similar symbiosis that is probably the key for their ecological success: the fungus-growing ants in the neotropics and the fungus-growing termites in the paleotropics. [ABSTRACT FROM AUTHOR]

Describes the results of a study of the susceptibility of different species and stages of ticks to entomopathogenic fungi. Susceptibility of Boophilus annulatus, Hyalomma excavatum and Rhipicephalus sanguineus ticks to different entomopathogenic fungi under laboratory conditions; Comparative results of bioassays using five different fungal species, which showed that some strains of Metarhizium anisopliae are highly pathogenic against various tick stages tested; Affect of fungi on tick eggs; Susceptibility of all tested tick stages including those feeding on a host to these fungi, except for adult H. excavatum ticks, which were relatively resistant.

Presents a study which examined the role of high nickel (Ni) concentration in protecting insects against pathogen attacks using tests on Melanotrichus boydi. Materials and methods used in the study; Contrast of the survival of Melanotrichus boydi against the survival of low-Ni mirid Lygus hesperus when treated with biocontrol agents; Effects of biocontrol agents on nymphs and adults of each species.

Fungal pathogens frequently form appressoria, specialized hyphal swellings on the surfaces of hosts. Production of appressoria by two entomophthoralean species that infect lepidopteran larvae, Entomophaga maimaiga Humber, Shimazu & Soper and Furia gastropachae (Raciborski) Filotas, Hajek & Humber, was investigated in vitro 6–8 h after conidial discharge. Entomophaga maimaiga appressoria were elongate, irregularly swollen structures located adjacent to the conidium or at the ends of short germ tubes. The highest percentages of appressoria were formed on hard surfaces such as polystyrene (21.5 ± 4.6%) and mylar (22.2 ± 4.3%). Nutrients or chemical stimuli were not required for appressorial formation but could stimulate growth as germ tubes. The contribution of surface hydrophobicity to appressorium formation was questionable; while appressoria were formed on hydrophobic surfaces, they were also formed to a lesser extent on glass, which is hydrophilic. When conidia of F. gastropachae were exposed to similar substrates and conditions, appressoria were never made, supporting the hypothesis that stimuli for appressorium formation can be species specific.Key words: appressorium, entomopathogenic fungi, infection process, Entomophthorales.Les champignons pathogènes forment fréquemment des appressoriums, gonflements spécialisés des hyphes sur la surface des hôtes. Les auteurs ont examiné in vitro, 6–8 h après la décharge conidienne, la production d'appressoriums chez deux espèces d'entomophthorales qui infectent les larves de lépidoptères, soient les Entomophaga maimaiga Humber, Shimazu & Soper et Furia gastropachae (Raciborski) Filotas, Hajek & Humber. Les appressoriums de l'E. maimaiga sont des structures allongées, irrégulièrement gonflées et adjacentes à la conidie ou aux extrémités de courts tubes germinatifs. Les pourcentages les plus élevés d'appressorium se forment sur des surfaces dures telles que le polystyrène (21,5 ± 4,6%) et le mylar (22,2 ± 4,3%). Les nutriments ou les stimulus chimiques ne sont pas nécessaires pour le formation des appressoriums, mais peuvent stimuler la croissance des tubes germinatifs. La contribution de l'hydrophobicité de la surface à la formation des appressoriums est incertaine; alors que des appressoriums se forment sur des surfaces hydrophobes, ils peuvent également se former sur du verre, lequel est hydrophile. Lorsqu'on expose les conidies du F. gastropachae à des substrats et des conditions similaires, les appressoriums ne se forment jamais, ce qui supporte l'hypothèse que les stimulus pour la formation des appressoriums peuvent être spécifiques à l'espèce.Mots clés : appressorium, champignons entomopathogènes, processus d'infection, Entomophthorales.[Traduit par la Rédaction] [ABSTRACT FROM AUTHOR]

We analyzed sequences of the divergent domain at the 5' end of the large subunit rRNA gene from the mitosporic entomopathogenic fungi Paecilomyces sp., Paecilomyces fumosoroseus, Paecilomyces farinosus, Paecilomyces lilacinus, Verticillium lecanii, Verticillium psalliotae, Beauveria bassiana, Aschersonia sp., Aschersonia placenta, ascomycetous Cordyceps sp., and Cordyceps militaris. Phylogenetic analysis showed P. fumosorseus as the best characterized out of the analyzed species with the B. bassiana clade as its sister group. Two of the P. farinosus isolates were invariably placed within the Verticillium cluster, which also contained C. militaris. The only analyzed P. lilacinus isolate appeared on the root of the hyphomycetous fungi and was characterized as the most distinct from all the hyphomycetous fungi tested. Polyphyly of the genus Paecilomyces was well supported by the Kishino-Hasegawa test. In all trees based on the small subunit rRNA gene sequences obtained from the GenBank(tm), V. lecanii, V. psalliotae, P. fumosoroseus, P. tenuipes and B. bassiana form, together with that of C. militaris, the best supported cluster in the tree. The rest of Cordyceps spp. constitute a distinct clade. Phylogenetic relationships derived from both tested DNA regions show polyphyly of the genus Paecilomyces and close relationships among entomopathogenic species of the genera Verticillium, Paecilomyces, and Beauveria.Key words: Paecilomyces, Verticillium, Beauveria, Aschersonia, entomopathogenic fungi, molecular phylogeny, ribosomal RNA genes.Nous avons déterminé les séquences du domaine divergent de l'extrémité 5' de la grosse sous-unité du gène de l'ARNr chez des champignons entomopathogènes à reproduction asexuée tels le Paecilomyces sp., le Paecilomyces fumosoroseus, le Paecilomyces farinosus, le Paecilomyces lilacinus, le Verticillium lecanii, le Verticillium psalliotae, le Beauvaria bassiana, l'Aschersonia sp., l'Aschersonia placenta, les ascomycètes Cordyceps sp. et le Cordyceps militaris. Les analyses phylogénétiques ont confirmé que le P. fumosoroseus était le mieux caractérisé parmi les espèces étudiées avec le clade B. bassiana considéré comme son groupe-sœur. Deux des isolats du P. farinosus ont été invariablement placés dans le groupe Verticillium qui comprenait aussi le C. militaris. Le seul isolat de P. lilacinus analysé est apparu sur les racines de champignons hyphomycètes et il s'est révélé comme le moins apparenté et le plus distinct de tous les hyphomycètes étudiés. La polyphylie du genre Paecilomyces concordait très bien avec le test de Kishino-Hasegawa. Dans chacun des arbres phylogénétiques basés sur la petite unité du gène de l'ARNr, le V. lecanii, le V. psalliotae, le P. fumosoroseus, le P. tenuipes et le B. bassiana, don't les séquences ont été obtenues de GenBank [sup TM] , formaient, avec le C. militaris, le groupe le plus étoffé de l'arbre phylogénétique. Les autres Cordyceps spp. constituaient un clade différent. Les parentés phylogénétiques observées dans les deux régions d'ADN vérifiées ont confirmé une polyphylie du genre Paecilomyces, ainsi qu'une très forte parenté avec les espèces entomopathogènes des genres Verticillium, Paecilomyces et Beauvaria.Mots clés : Paecilomyces, Verticillium, Beauvaria, Aschersonia, champignons entomopathogènes, phylogénie moléculaire, gènes codant l'ARN ribosomique.[Traduit par la Rédaction] [ABSTRACT FROM AUTHOR]

Examines the conditions underlying the contributions of government laboratories in Canada in the field of economic entomology, the science of insect control in agriculture and forestry. Development of insect pathology; Research specialties that contributed to the application of microbial insecticides; Limitations to chemical control.

Imidacloprid and the entomopathogenic fungus Beauveria bassiana (Balsamo) Vuillemin are both used to control the whitefly Bemisia argentifolii Bellows & Perring. We tested whether the two control strategies acted additively, synergistically, or antagonistically when combined for whitefly control. We found antagonism in that B. bassiana inhibited the effectiveness of imidacloprid. When B. bassiana was combined with imidacloprid, insect response was either less than or similar to (depending on B. bassiana rates) that when imidacloprid was used alone. Adding imidacloprid to B. bassiana treatments always increased mortality, but the increase was less than additive. Beauveria bassiana spore germination and colony formation were not inhibited by imidacloprid in vitro, and B. bassiana did not adsorb or degrade imidacloprid in a tank mix. We hypothesize that B. bassiana caused a behavioral response that reduced insect feeding and uptake of imidacloprid. [ABSTRACT FROM PUBLISHER]

Laboratory studies investigated the interaction between the fungal entomopathogen Beauveria bassiana (Balsamo) Vuillemin and sublethal doses of the insecticides imidacloprid and cyromazine when applied to larvae of the Colorado potato beetle, Leptinotarsa decemlineata (Say). When second instars were fed potato leaf discs treated with sublethal doses of imidacloprid and a range of doses of B. bassiana, a synergistic action was demonstrated. Similar results were observed when larvae were sprayed directly with B. bassiana conidia and immediately fed leaf discs treated with imidacloprid. No synergistic interaction was detected when larvae were fed leaf discs treated with sublethal doses of imidacloprid 24 h after application of B. bassiana conidia to larvae. However, a synergistic interaction was detected when larvae were fed leaf discs treated with imidacloprid and sprayed with B. bassiana conidia 24 h later. Although sublethal doses of both imidacloprid and the triazine insect growth regulator (IGR) cyromazine prolonged the duration of the second instar, only imidacloprid interacted with B. bassiana to produce a synergistic response in larval mortality. In leaf consumption studies, the highest dose of B. bassiana tested promoted feeding in inoculated second instars. Feeding was inhibited when larvae were fed foliage treated with sublethal doses of imidacloprid and significantly reduced when fed foliage treated with a sublethal dose of cyromazine. Starvation of larvae for 24 h immediately after B. bassiana treatment produced a similar result to the combined treatment of B. bassiana and imidacloprid and increased the level of mycosis when compared with B. bassiana controls. Imidacloprid treatment affected neither the rate of germination of B. bassiana conidia on the insect cuticle nor the rate at which conidia were removed from the integument after application. The statistical analysis used to detect synergism and the possible role of starvation-induced stress factors underlying the observed synergistic interactions are discussed. [ABSTRACT FROM PUBLISHER]

Bacteria that are vertically transmitted through female hosts and kill male hosts that inherit them were first recorded in insects during the 1950s. Recent studies have shown these "male-killers" to be diverse and have led to a reappraisal of the biology of many groups of bacteria. Rickettsia, for instance, have been regarded as human pathogens transmitted by arthropods. The finding of a male-killing Rickettsia obligately associated with an insect suggests that the genus' members may be primarily associated with arthropods and are only sometimes pathogens of vertebrates. We examined both how killing of male hosts affects the dynamics of inherited bacteria and how male-killing bacteria affect their host populations. Finally, we assessed the potential use of these microorganisms in the control of insect populations. [ABSTRACT FROM AUTHOR]

In order to screen for natural dissemination of fire blight under field conditions, insects were caught in an experimental orchard and assayed on semi-selective agar plates and by BIO-polymerase chain reaction for their contamination with Erwinia amylovora, the causative agent of the bacterial disease. The pathogen was detected on 15 out of 348 insects collected (4.3%). The insects contaminated with E. amylovora have different living habits and belong to four different orders (Homoptera, Coleoptera, Hymenoptera and Diptera) and at least eight insect families (Aphididae, Psyllidae, Coccinellidae, Curculionidae, Ichneumonidae, Formicidae, Apidae, and Muscidae) and to other Brachycera. After contact of insects with E. amylovora, the pathogen could survive at least 5 days in/on the green lacewing (Chrysoperla carnea) and 12 days on aphids (Aphis pomi). [ABSTRACT FROM AUTHOR]

Summary 1 Factors influencing horizontal transmission of the entomopathogen Beauveria bassiana in the Colorado potato beetle (CPB) were examined through a series of laboratory studies. 2 Cadaver density, cadaver life stage, ambient temperature and conidial density were the factors manipulated. 3 Mortality and sporulation of burrowing CPB prepupae both increased significantly with increased sporulating second-instar cadaver density on the soil surface. 4 Mortality rates were significantly higher when prepupae were released into laboratory arenas containing third-instar cadavers compared to second-instar cadavers. 5 Mortality and sporulation decreased significantly as temperature increased from 15 °C to 30 °C, however, no temperature-dependent behavioural response by prepupae could be identified as a potential cause. 6 An 86.1% decrease in conidial density per cadaver had no significant effect on mortality or sporulation of prepupae, indicating that this level of environmental degradation of cadavers may not significantly reduce the probability of horizontal transmission. [ABSTRACT FROM AUTHOR]

Summary 1 We modelled horizontal transmission of Beauveria bassiana in Colorado potato beetle (CPB) between larval cadavers and soil inhabiting prepupae. 2 The rate of disease transmission, based on the probability of a prepupa contacting sporulating cadavers on the soil surface, is a non-linear function of cadaver density and also dependent upon temperature. 3 The spatial pattern of cadavers is needed to estimate prepupal contacts with cadavers. Observational field studies determined Johnson distributions to model the spatial pattern of cadavers and prepupae in the field. The model also implicitly incorporates within-field larval spatial pattern into estimates of field-level horizontal transmission. 4 Potential for horizontal transmission is higher in simulations using weather data from the warmer year of 1995, than in simulations of the cooler growing season of 1993. 5 Simulations of CPB populations under northern Maine climatic conditions recorded in 1993 and 1995 suggest that horizontal transmission can range from 3 to 24% depending upon the timing of primary infection of larvae in the field. 6 Two simulated sequential applications of B. bassiana targeted at peak first instars resulted in maximum horizontal infection in both years. 7 Sensitivity analysis suggests that horizontal transmission is most sensitive to changes in the proportion of cadavers that sporulate and least sensitive to changes in the time between larval death and the onset of cadaver sporulation. 8 Field validation of the model indicates good prediction of one measure of horizontal infection, the proportion of prepupae which eventually sporulated after being released in controlled field experiments. [ABSTRACT FROM AUTHOR]

[Display omitted] • Islands often harbour unique and fragile ecosystems. • Pathogen spread poses a risk to pollinators, plant-pollinator networks and ecosystems. • The most significant threat is from the combination of invasive insects and their pathogens. Island ecosystems, which often contain undescribed insects and small populations of single island endemics, are at risk from diverse threats. The spread of pathogens is a major factor affecting not just pollinator species themselves, but also posing significant knock-on effects to often fragile island ecosystems through disruption of pollination networks. Insects are vulnerable to diverse pathogens and these can be introduced to islands in a number of ways, e.g. via the introduction of infected managed pollinator hosts (e.g. honey bees and their viruses, in particular Deformed wing virus), long-range migrants (e.g. monarch butterflies and their protozoan parasite, Ophryocystit elektroscirrha) and invasive species (e.g. social wasps are common invaders and are frequently infected with multi-host viruses such as Kashmir bee virus and Moku virus). Furthermore, these introductions can negatively affect island ecosystems through outcompeting native taxa for resources. As such, the greatest threat to island pollinator communities is not one particular pathogen, but the combination of pathogens and introduced and invasive insects that will likely carry them. [ABSTRACT FROM AUTHOR]

• eDNA activates signaling defenses but not direct defense responses in Arabidopsis thaliana. • DNA activation of signaling defense responses decreases according to the phylogenetic distance. • Self-DNA induces broad-range resistance against pathogens and pest insects with different feeding styles. Like in mammals, the plant immune system has evolved to perceive damage. Damaged-associated molecular patterns (DAMPs) are endogenous signals generated in wounded or infected tissue after pathogen or insect attack. Although extracellular DNA (eDNA) is a DAMP signal that induces immune responses, plant responses after eDNA perception remain largely unknown. Here, we report that signaling defenses but not direct defense responses are induced after eDNA applications enhancing broad-range plant protection. A screening of defense signaling and hormone biosynthesis marker genes revealed that OXI1 , CML37 and MPK3 are relevant eDNA-Induced Resistance markers (eDNA-IR). Additionally, we observed that eDNA from several Arabidopsis ecotypes and other phylogenetically distant plants such as citrus, bean and, more surprisingly, a monocotyledonous plant such as maize upregulates eDNA-IR marker genes. Using 3,3′-Diaminobenzidine (DAB) and aniline blue staining methods, we observed that H 2 O 2 but not callose was strongly accumulated following self-eDNA treatments. Finally, eDNA resulted in effective induced resistance in Arabidopsis against the pathogens Hyaloperonospora arabidopsidis , Pseudomonas syringae , and Botrytis cinerea and against aphid infestation, reducing the number of nymphs and moving forms. Hence, the unspecificity of DNA origin and the wide range of insects to which eDNA can protect opens many questions about the mechanisms behind eDNA-IR. [ABSTRACT FROM AUTHOR]

Tolypocladium, a diverse genus of fungicolous fungi belonging to Ophiocordycipitaceae, includes saprotrophic soil inhabitants, plant endophytes and pathogens of insects, nematodes, rotifers, and parasites of truffle-like fungi. Here, we review the research progress achieved for Tolypocladium regarding its taxonomy, species diversity, geographic distribution, host affiliations and ecological diversity. Furthermore, an undescribed taxon from China was established using morphology and multi-gene phylogeny. Tolypocladium inusitaticapitatum is introduced as a new species parasitizing ectomycorrhizal Elaphomyces species. It is diagnosed by its irregularly enlarged fertile heads and lemon, yellow-to-dark-brown, smooth and nearly cylindrical stipe. Phylogenetic analyses based on SSU, LSU, ITS, TEF1-α and RPB2 sequence data showed T. inusitaticapitatum to be an independent lineage separated from T. flavonigrum in the clade comprising T. capitatum, T. fractum and T. longisegmentatum. A key for identifying the sexual Tolypocladium species is also provided. [ABSTRACT FROM AUTHOR]

[Display omitted] • Both pathogen virulence and host immunity are intrinsically linked with how they respond to stress. • Insects and their pathogens are ideal for mechanistic studies that explore links between climate change and disease. • Climate change is altering the abundances and multitrophic interactions of both insects and pathogens. • To survive, insects and their pathogens can either move to track changing climate or stay put and adapt. The complex nature of climate change-mediated multitrophic interaction is an underexplored area, but has the potential to dramatically shift transmission and distribution of many insects and their pathogens, placing some populations closer to the brink of extinction. However, for individual insect-pathogen interactions climate change will have complicated hard-to-anticipate impacts. Thus, both pathogen virulence and insect host immunity are intrinsically linked with generalized stress responses, and in both pathogen and host have extensive trade-offs with nutrition (e.g., host plant quality), growth and reproduction. Potentially alleviating or exasperating these impacts, some pathogens and hosts respond genetically and rapidly to environmental shifts. This review identifies many areas for future research including a particular need to identify how altered global warming interacts with other environmental changes and stressors, and how consistent these impacts are across pathogens and hosts. With that achieved we would be closer to producing an overarching framework to integrate knowledge on all environmental interplay and infectious disease events. [ABSTRACT FROM AUTHOR]

Two entomopathogenic nematodes, Steinernema colombiense sp. nov. (strain SNIO198) (Rhabditida: Steinernematidae) and Heterorhabditis bacteriophora Poinar (strain Fresno HNI0100) (Rhabditida: Heterorhabditidae), were isolated from the Colombian Andes and cultured in the laboratory. In semi-field tests against the ground pearl Eurhizococcus colombianus Jakubski (Hemiptera: Margarodidae) on blackberry, neither species was pathogenic to crawlers and only S. colombiense was moderately infective against adults at 105 IJ/ml. Higher activity for both nematodes was observed against immature spittlebugs Aeneolamia sp . (Hemiptera: Cercopidae) infesting kikuyu grass, with H. bacteriophora and S. colombiense killing 100% and 75% of insects, respectively, in our tests. Our results demonstrate the potential use of native strains of entomopathogenic nematodes as biological control agents in Colombia. [ABSTRACT FROM AUTHOR]

Plant immunity is modulated by several abiotic factors, and microbiome has emerged as a major biotic driver of plant resistance. Recently, a few studies showed that plants also modify resistance to pests and pathogens in their neighborhood. Several types of neighborhood could be identified depending on the biological processes at play: intraspecific and interspecific competition, kin and stranger recognition, plant-soil feedbacks, and danger signaling. This review highlights that molecules exchanged aboveground and belowground between plants can modulate plant immunity, either constitutively or after damage or attack. An intriguing relationship between allelopathy and immunity has been evidenced and should merit further investigation. Interestingly, most reported cases of modulation of immunity by the neighbors are positive, opening new perspectives for the understanding of natural plant communities as well as for the design of more diverse cultivated systems. • Plants share signals and cues that affect their immune system. • This modulation of immunity affects their resistance to insects and pathogens. • Recent discoveries support the idea that immunity is also generated through allelopathic response to strangers. • The modulation of immunity by plant–plant interactions may have strong ecological consequences. [ABSTRACT FROM AUTHOR]

An explosion of data has provided detailed information about organisms at the molecular level. For some traits, this information can accurately predict phenotype. However, knowledge of the underlying molecular networks often cannot be used to accurately predict higher order phenomena, such as the response to multiple stressors. This failure raises the question of whether methodological reductionism is sufficient to uncover predictable connections between molecules and phenotype. This question is explored in this paper by examining whether our understanding of the molecular responses to food limitation and pathogens in insects can be used to predict their combined effects. The molecular pathways underlying the response to starvation and pathogen attack in insects demonstrates the complexity of real-world physiological networks. Although known intracellular signaling pathways suggest that food restriction should enhance immune function, a reduction in food availability leads to an increase in some immune components, a decrease in others, and a complex effect on disease resistance in insects such as the caterpillar Manduca sexta. However, our inability to predict the effects of food restriction on disease resistance is likely due to our incomplete knowledge of the intra- and extracellular signaling pathways mediating the response to single or multiple stressors. Moving from molecules to organisms will require novel quantitative, integrative and experimental approaches (e.g. single cell RNAseq). Physiological networks are non-linear, dynamic, highly interconnected and replete with alternative pathways. However, that does not make them impossible to predict, given the appropriate experimental and analytical tools. Such tools are still under development. Therefore, given that molecular data sets are incomplete and analytical tools are still under development, it is premature to conclude that methodological reductionism cannot be used to predict phenotype. • Physiological networks are complex. • Their non-linear, redundant architecture may prevent a reductionist approach. • However, new techniques may allow predictions from molecules to phenotype. • Premature to decide that we have reached the limits of methodological reductionism. [ABSTRACT FROM AUTHOR]

In natural environments, plants develop adaptive mechanisms at the cellular and molecular levels to cope with many external factors, e.g., insects and soil pathogens. We studied physiological stress induced by different levels of foliage removal (defoliation 30% and 60%) and by infection of root rot pathogen Phytophthora plurivora on the common Polish tree species, Betula pendula, grown in an open greenhouse. This study showed that P. plurivora damaged the root system which negatively impacted all morphological parameters. However the loss of 30% of the leaves had a positive effect on defense responses. Chlorophyll-a fluorescence parameters indicated a decrease in photosynthetic efficiency in defoliated plants, but plants inoculated with the pathogen had a higher performance index showing increased vigor of the infected plant than birches. The study demonstrated the intense immunity response of birch to P. plurivora through the expression of Hsp90 and Hsp83 genes. The trees weakened by P. plurivora became more susceptible to infection by Erysiphe ornata var. ornata. [ABSTRACT FROM AUTHOR]

Presents information on a study of the ability of insect pathogens to cause long-term stable limit cycles in their hosts. Effect of the addition of host density dependence on the likelihood of limit cycle population dynamics; Risk of pathogen infection; Impact of adding density dependence to the seasonal model.

A search for patterns in the success and failure of microbial insecticides in vegetable crops was conducted through review of four case studies: the use of Bacillus thuringiensis ( B.t.) var. tenebrionis for control of the Colorado potato beetle, the use of B.t. var. kurstaki for control of the diamondback moth, the use of various B.t.s for control of lepidopterous pests in tomatoes and celery, and the use of a granulosis virus for control of potato tuber moth. With success defined in terms of achievement of technical goals (efficacy), commercial goals (end-user and insecticide manufacturer satisfaction) and social, or public goals (environmental and health safety), only certain of the case studies could be judged a success. These successes shared a variety of features including: (1) use of the microbial insecticide as a component, rather than as the sole agent, in an integrated crop management program; (2) unavailability of conventional insecticides, due to insecticide resistance, lack of registered products or mandatory IPM programs, provided incentive for the use of microbial insecticides; (3) modification of the expectation that microbial insecticides will perform within the chemical paradigm – fast, lethal and on contact; (4) exploitation of all possible benefits of the microbial insecticide, including safety to natural enemies, as well as efficacy against the target insect, and (5) support from large private and public institutions in the form of research, grower education, scouting programs, subsidized production, and economic and legal incentives to the use of microbial insecticides. [ABSTRACT FROM AUTHOR]

Discusses the use of insect pathogens as a biological insect control agent. Need for alternatives to synthetic chemical insecticides; Insect control strategies; Use of insect pathogens; Types of pathogens.

New data gathered during 1980-1988 are presented on entomogenous fungi of the order Entomophthorales, their host-pathogen combinations and seasonal occurrence in Israel. Eight species new to Israel have been recorded during this period: Entomophthora israelensis Ben-Ze'ev and Zelig is new to science, while another, listed as E. aff. israelensis, still lacks a formal description. New for Israel are a number of entomophthoralean species attacking aquatic insects in aquatic habitats: Erynia curvispora Nowakowski, E. conica (Nowakowski) Remaudiére and Hennebert and E. ovispora Nowakowski. Other species new for Israel are: Entomophthora erupta (Dustan) Hall, Erynia lanceolata (Keller) Humber and Ben-Ze'ev and Neozygites (aff.) lageniformis (Thaxter) Remaudiére and Keller. Some host-pathogen combinations found during this period are unrecorded elsewhere, e.g. Entomophthora erupta on Creontiades pallidus, and quite a number of 'formae' belonging to the Entomophthora muscae complex. Erynia radicans (Brefeld) Humber, Ben-Ze'ev and Kenneth on whiteflies is apparently a rare combination, having been recorded only twice in Israel and once in Tchad. [ABSTRACT FROM AUTHOR]

Neem products are safe to spiders, adults of numerous beneficial insect species and eggs of many predators such as coccinellids. Nymphal/larval instars are more or less susceptible, especially under laboratory conditions. No or only slight side-effects are, as a rule, observed under semi-field or field conditions. Due to their relative selectivity ('stage selectivity') neem products can be recommended for many programmes of Integrated Pest Management as it is unlikely that they will cause severe disturbances in ecosystems. In a few exceptional cases caution is recommended but it should be borne in mind that many more so-called indifferent as well as beneficial insects and spiders are killed by synthetic pesticides as compared with neem products. Or in other words, the use of neem-based pesticides can be a substantial contribution towards preservation of biodiversity in ecosystems in spite of the fact that they are not completely safe to all stages of beneficial nematodes, mites, and insects. [ABSTRACT FROM AUTHOR]

The pages: CP-51 and CP-54 of Bacillus cereus, together with P-4 and P-14 of B. sphaericus were tested against B. thuringiensis and B. sphaericus strains. P-4 and P-14 were more different in their host range than the other two phages. Results of the bioassay against Culex pipiens larvae presented the inhibition in the larvicidal effects of phage-infected bacteria. Such inhibitory action varied according to the phage and the entomopathogenic bacterial strains. Zusammenfassung Wirkungen verschiedener Phagen von Bacillus spp. auf die larvizide Potenz von B. thuringiensis und B. sphaericus Es wurden die Phagen CP-51 und CP-54 von Bacillus cereus zusammen mit P-4 und P-14 von B. sphaericus gegen Stämme von B. thuringiensis und B. sphaericus getestet. P-4 und P-14 wiesen größere Unterschiede in ihrem Wirtskreis auf als die anderen zwei Phagen. Die Ergebnisse gegen Culex pipiens-Larven zeigten eine Hemmung der larviziden Wirkung von mit Phagen infizierten Bakterien. Diese Hemmungswirkung variierte je nach Phagus und Bakterien-Stamm. [ABSTRACT FROM AUTHOR]