Isolates Of Entomopathogenic Fungi Research Articles

Seed inoculations with entomopathogenic fungi affect aphid populations coinciding with modulation of plant secondary metabolite profiles across plant families.

Entomopathogenic fungi (EPF) can display a plant-associated lifestyle as endophytes. Seed application of EPF can affect insect herbivory above ground, but the mechanisms behind this are not documented. Here we applied three EPF isolates, Beauveria bassiana, Metarhizium brunneum and M.robertsii, as seed inoculation of wheat and bean, and evaluated the effects on population growth of aphids, Rhopalosiphum padi and Aphis fabae, respectively. In wheat and bean leaves, we quantified benzoxazinoids and flavonoids, respectively, in response to EPF inoculation and aphid infestation to elucidate the role of specific plant secondary metabolites (PSMs) in plant-fungus-herbivore interactions. Inoculations of wheat and bean with M.robertsii and B.bassiana reduced aphid populations compared with control treatments, whereas M.brunneum unexpectedly increased the populations of both aphids. Concentrations of the majority of PSMs were differentially altered in EPF-treated plants infested with aphids. Changes in aphid numbers were associated with PSMs regulation rather than EPF endophytic colonisation capacity. This study links the effects of EPF seed inoculations against aphids with unique PSM accumulation patterns in planta. The understanding of PSM regulation in tri-trophic interactions is important for the future development of EPF for pest management.

ISSR markers to explore entomopathogenic fungi genetic diversity: Implications for biological control of tobacco pests

Tobacco is one of the major industrial crops cultivated worldwide. Chemical control is the main method employed to reduce damage by insect pests. The use of entomopathogenic fungi represents an alternative to replace insecticides. The search for effective strains in the field constitutes a first step when developing a formulation. The objective of this work was to study genetic differences among isolates of entomopathogenic fungi obtained from tobacco grown soils using ISSR markers. The pathogenicity of the strains towards Helicoverpa gelotopoeon and Diabrotica speciosa was also assessed in order to search for a relationship between virulence and genetic diversity. Nineteen isolates were identified according to morphological features and molecular techniques as Beauveria bassiana (11) and Purpureocillium lilacinum (8). The diversity tree generated by ISSR analysis showed a high diversity among the strains. The pathogenicity towards H. gelotopoeon and D. speciosa was assessed and the logistic models generated showed that B. bassiana isolates LPSc1215 and LPSc1364 were the most pathogenic against both insect pests tested. In the diversity tree, these strains were grouped in a same cluster with a similarity level of approximately 85%, indicating a possible relationship between virulence and the band pattern generated.

Combining insect pathogenic fungi and a pheromone trap for sustainable management of the fall armyworm, Spodoptera frugiperda (Lepidoptera: Noctuidae)

Fall armyworm, Spodoptera frugiperda (Lepidoptera: Noctuidae), is a key invasive pest of maize and other crops in Africa. Entomopathogenic fungi play an important role in regulating the immature stages of this invasive pest as opposed to synthetic pesticides that are hazardous to human, environment and biodiversity. To tackle the adult stage of the pest (the moth) and to improve on the application strategy of the fungal-based biopesticides, this study evaluated the effect of various entomopathogenic fungi isolates on S. frugiperda moths. Twenty-two isolates (16 Metarhizium anisopliae and 6 Beauveria bassiana) were screened in the laboratory to assess their pathogenicity and virulence against S. frugiperda moths. The compatibility of the most pathogenic isolates with S. frugiperda pheromone FALLTRACT lure, the horizontal transmission of the inoculum among S. frugiperda moths, and the effect on oviposition were also determined under laboratory conditions. All 22 fungal isolates screened were pathogenic to the moths, but the mortality varied significantly among the isolates (P < 0.0001) seven days post-treatment. Beauveria bassiana ICIPE 621 and M. anisopliae ICIPE 7 outperformed all the other isolates by causing 100% mortality of the moths with the lowest LT50 values of 3.6 ± 0.1 and 3.9 ± 0.0 days, respectively. Both isolates were also found compatible with FALLTRACT lure, as the lure had no effect on the conidial germination in the laboratory. Male and female moths were able to horizontally transmit conidia of both fungal isolates to untreated moths, causing high mortality of S. frugiperda in ‘donor’ and ‘recipient’ groups. In addition, the oviposition, hatchability of eggs and longevity of larvae were significantly affected on the fungal infected females. Although single moths still retained high conidial numbers 72 h post-inoculation, the number of conidia decreased with time. These results suggest that ICIPE 7 and ICIPE 621 could be used in combination with S. frugiperda pheromone in an autodissemination approach to suppress S. frugiperda population.

Entomopathogenic Fungi as Endophytes for Biological Control of Subterranean Termite Pests Attacking Cocoa Seedlings.

This study was conducted in the scope of developing a sustainable effective approach against subterranean termite pests using entomopathogenic and endophytic fungus-based biopesticides. Termites, Odontotermes spp. workers, were tested for their susceptibility to 15 entomopathogenic fungal isolates through the direct spraying of conidia suspensions at 1 × 108 conidia/mL. In general, all the isolates screened were pathogenic, with 100% mortality 4–7 days post-inoculation. However, the most virulent isolates were Metarhizium brunneum Cb15-III; the M. anisopliae isolates ICIPE 30 and ICIPE 60; Hypocrea lixii F3ST1; and the Beauveria bassiana isolates ICIPE 279, ICIPE 706 and ICIPE 662. These isolates were further tested for their endophytic colonization of cocoa seedlings using seed soaking, soil drench and foliar spray at 1 × 108 conidia/mL. The colonization of the plant tissues by the fungi was determined using a culture-based technique. Only the B. bassiana isolates ICIPE 706 and ICIPE 279, and H. lixii F3ST1 colonized the cocoa seedlings, with varied colonization rates among isolates and inoculation methods. Three naturally occurring endophytes—Trichoderma asperellum, Fusarium solani and F. redolens—were also isolated from the cocoa seedling tissues. These findings suggest that cocoa seedlings are conducive to endophytic fungal growth either occurring naturally or from artificial inoculation Our findings could possibly lead to an innovative approach to the management of herbivory and subterranean termite pests in cocoa agroforests.

Combined effect of entomopathogenic fungi and Steinernema yirgalemense against the banded fruit weevil, Phlyctinus callosus (Coleoptera: Curculionidae)

ABSTRACT Phlyctinus callosus (Schönherr) (Coleoptera: Curculionidae), or the banded fruit weevil (BFW), causes damage to the fruits, leaves and roots of deciduous fruits and grapevines in the Western Cape province. The control of the BFW can be improved by means of combining entomopathogenic fungi (EPF) and entomopathogenic nematodes (EPNs). The combination of commercial isolates of Beauveria bassiana (Bb1), B. bassiana (Bb2), Metarhizium anisopliae (Ma1) and a South African isolate M. anisopliae (MaEA2), with Steinernema yirgalemense against BFW adults and larvae were evaluated in laboratory trials. Four treatment regimens were used where BFW were exposed to the EPF and the EPN separately, and to a combination of EPF and S. yirgalemense either immediately, 1 week or 2 weeks apart. The combined application of the different EPF isolates with S. yirgalemense resulted in higher mortality of BFW in the laboratory. With the application of S. yirgalemense 7 or 14 days after application of Bb2 and Bb1, 100% mortality for both larvae and adults, was obtained. Synergy was noted with Bb1, Bb2, Ma1 and MaEA2 when each was combined with S. yirgalemense, when applied 7 or 14 days after application of the EPF. Interactions showed that the EPF and S. yirgalemense have an additive effect when applied simultaneously, and a synergistic effect was obtained when applied 7 or 14 days after the application of the different EPF. The results indicate that the combination of EPF and an EPN show potential as an economically viable control strategy.

Isolation of indigenous strains of the white halo fungus as a biological control agent against 3rd instar larvae of tobacco caterpillar, Spodoptera litura (Fabricius) (Lepidoptera: Noctuidae)

The farmer interest in biological control-based management practices using entomopathogenic fungi (EPF) for the control of many economically important insects has increased. In this process, selection of effective strains of EPF is an important criterion to control the target insect pests in efficient manner. In this context, this research work was formulated to find out environmentally effective strains of EPF in the soils of costal districts of Andhra Pradesh, India. Out of 135 soil samples collected, 9 yielded 9 strains of Lecanicillium lecanii. Among all 9 L. lecanii isolates, the least median lethal concentration (LC50) for 3rd instar larvae of the tobacco caterpillar, Spodoptera litura (Fabricius) (Lepidoptera: Noctuidae), was 1.17 × 106 spores ml−1 in L-8, followed by 1.27 × 106 spores ml−1 in L-5 in an increasing order. Likewise, the median lethal time (LT50) values of different isolates of EPF against the 3rd instar of S. litura were calculated for the uniform highest concentration of 1 × 108 spores ml−1. Among all 9 L. lecanii isolates, the lowest median lethal time (LT50) was observed as 7.70 days by L-8, followed by 7.77 days by L-5 and 8.50 days by L-7.

Temperature tolerance and humidity requirements of select entomopathogenic fungal isolates for future use in citrus IPM programmes

Several isolates of Beauveria bassiana (Balsamo-Crivelli) Vuillemin (Hypocreales: Cordycipitacae) and Metarhizium anisopliae (Metchnikoff) Sorokin (Hypocreales: Clavicipitacae) have been investigated as possible microbial control agents of key citrus pests in South Africa. Although laboratory results have been promising, field trials against foliar pests have shown limited success. These findings highlighted the need to investigate other biological attributes of these fungal isolates besides virulence in order to select candidates that may be better suited for the foliar environment. Thus, this study investigated the influence of temperature on the in vitro growth of seven indigenous local isolates and the humidity requirements necessary to promote successful infection, in comparison with two commercial isolates (B. bassiana PPRI 5339 and M. anisopliae ICIPE 69). All the fungal isolates grew across a range of temperatures (8–34 °C) and optimally between 26 and 28 °C. Similarly, fungal infection of Thaumatotibia leucotreta Meyrick (Lepidoptera: Tortricidae) fifth instars occurred across a range of humidity levels (12%, 43%, 75%, 98%) regardless of fungal concentration, although external sporulation was restricted to treatments exposed to 98% relative humidity. It was concluded that neither temperature nor humidity, when considered alone, is likely to significantly influence the efficacy of any of the isolates in the field, given that they are active within temperature and humidity ranges experienced in South African citrus orchards.

Effects of a maize root pest and fungal pathogen on entomopathogenic fungal rhizosphere colonization, endophytism and induction of plant hormones

Some entomopathogenic fungi, such as Metarhizium spp. and Beauveria spp., closely interact with plants by colonizing the rhizosphere or growing endophytically inside root tissues. These characteristics increase the potential for endophytic entomopathogenic fungi to persist in the root system when used as biological control agents. The mechanism by which endophytic entomopathogenic fungi are capable to colonize the internal plant tissues is also influenced by plants and can be regarded as an adaptive protection acquired by plants against herbivorous insects. The mutual benefits obtained by plants and fungi through this peculiar endophytic association supports the bodyguard hypothesis. The objectives of this study were to evaluate the ability of different isolates of Metarhizium spp. and a single isolate of Beauveria bassiana, coated onto seeds, to colonize the rhizosphere and root tissues of maize (Zea mays) and to assess whether the presence of an insect pest and fungal root pathogen influenced this interaction. All the entomopathogenic fungal isolates tested were able to colonize the rhizosphere to some extent, but one isolate of M. anisopliae and the one of M. robertsii performed best. Overall, the presence of Costelytra giveni (Scarabaeidae) larvae significantly decreased rhizosphere colonization by the entomopathogens, while the phytopathogenic fungus Fusarium graminearum (Nectriaceae: Hypocreales) did not. Similarly, the presence of C. giveni decreased endophytic growth in root tissues by around 75% when considering all entomopathogens together. In contrast, a 112% increase in overall root endophytic colonization occurred in the presence of F. graminearum. Salicylic acid (SA) and jasmonic acid (JA) content in maize plants changed depending on the isolate of M. anisopliae incorporated through seed coating and root herbivory by larval presence. In the absence of C. giveni, plants treated with M. anisopliae A1080 had higher SA and JA root content than control plants. Conversely, when larvae were present, maize plants treated with M. anisopliae F672 had increased levels of both phytohormones, indicating a potentially primed state. The observed decrease in root colonization by some entomopathogenic fungal isolates in the presence of larvae of C. giveni and the increase in endophytic colonization in the presence of F. graminearum are in accordance with the bodyguard hypothesis. Additionally, the changes observed in the SA and JA content in Metarhizium treated plants corresponded to plant responses related to systemic acquired resistance and to induced systemic resistance. Our results demonstrate that biotic soil factors can shape the outcome of endophytic entomopathogenic fungi-plant interaction, as well as affecting the plant physiology.

Effect of isolates of entomopathogenic fungi in the coconut eye borer

The objective of this study was to evaluate the effect of entomopathogenic fungi on adults of Rhynchophorus palmarum (Coleoptera: Curculionidae). The experimental design was completely randomized in a factorial design (5x3) + control, composed of five treatments (isolated IBCB 66, CPATC 032, CPATC 057 and T9, and the commercial product Boveril®) and three concentrations of each fungus (107, 108 and 109 conidia.mL-1). The data of confirmed mortality were submitted to analysis of variance (ANOVA) using the Proc ANOVA of SAS, and the means compared by Tukey test at 5% probability. To determine percentage survival, confirmed mortality data were subjected to Log-Rank test using the Kaplan-Meyer method. Subsequently the values of LC50 and LT50 were estimated submitting mortality confirmed the Probit analysis. For the concentration 108 conidia.mL-1, the isolates CPATC 032 and CPATC 057 caused confirmed mortality of 52 and 44% of the adults of R. palmarum, respectively. At the concentration 109 conidia.mL-1, the isolates CPATC 032 and CPATC 057 caused mortality of 64 and 52% of the insects, respectively. For the CPATC 032 isolate, in the three concentrations tested, the insects had an average survival of 11 to 12 days. The TL50 of isolate CPATC 032 at concentrations 108 and 109 conidia.mL-1 was approximately 17 days. All isolates tested and the Boveril® product are pathogenic to R. palmarum.

Control of the Banded Fruit Weevil, Phlyctinus callosus (Schönherr) (Coleoptera: Curculionidae), Using Entomopathogenic Fungi

Phlyctinus callosus (Schönherr) (Coleoptera: Curculionidae), the banded fruit weevil (BFW), is a sporadic pest, causing damage to fruits, leaves and roots of deciduous fruits and grapevines in the Western Cape Province. Using trunk barriers to prevent the flightless weevils from reaching the leaves and fruits is labour-intensive. Entomopathogenic fungi (EPF) are effective biocontrol agents for the control of soil-borne and above-ground insect pests. Different EPF isolates were screened at 1 × 106 conidia/ml for virulence against different life stages (larvae, pupae and adults) of the BFW. The results indicated that unformulated, laboratory-cultured Beauveria bassiana 1 (Broadband®) and Metarhizium anisopliae 1 (Meta 69®) resulted in significantly higher BFW larval mortality of 97 % and 93 %, respectively, than B. bassiana 2 (Eco-Bb®) with 58 % mortality. Beauveria bassiana 1 (92 %) resulted in significantly higher pupal mortality than B. bassiana 2 (68 %) and M. anisopliae 1 (66 %). Beauveria bassiana 1 caused 90 % adult BFW mortality, which differed significantly from that obtained with B. bassiana 2 (69 %) and M. anisopliae 1 (65 %). A local EPF isolate (EA2) was compared with the commercial EPF isolates, and B. bassiana 1 (92 %) again caused significantly higher mortality of BFW adults compared to B. bassiana 2 (65 %), M. anisopliae 1 (60 %) and M. anisopliae isolate EA2 (64 %). In a sand bioassay using final instar BFW larvae, B. bassiana 1 (85 %) resulted in higher mortality than both B. bassiana 2 (55 %) and M. anisopliae 1 (70 %). The results indicated that all the commercial EPF isolates were effective against the immature and adult stages of the BFW, but with clear differences between isolates. Beauveria bassiana 1 consistently caused the highest BFW mortality under laboratory conditions. Large-scale field trials with the formulated commercial products are recommended to further demonstrate the potential use of this biocontrol agent in integrated pest management programmes.

Evaluate the Effects of Entomopathogenic Fungi Isolates on Wheat Aphid, Schizaphis graminum (Rondani) (Hemiptera: Aphididae)

Four native isolates of entomopathogenic fungi (EPF) Beauveria bassiana (B1and B2), Metarhizium anisopliae (M1 and M2 ) were isolated and evaluated against wheat aphid, Schizaphis graminum (Rondani). Three concentrations of spores suspension from each of the four fungal isolates (1×106, 1×107 and 1×108conidia) were used against adult aphid (one day old). The results showed that (B1) was the most effective according to LC50. Whereas, when testing the toxicity of crude metabolites of fungal isolates in four concentrations for each isolate, it was found that the highest effective toxin was (M1) followed by (B1), (M2) and (B2). Scanning electron microscope photographs (SEM) showed the mode of action of entomopathogenic fungi and its ability to colonize and how it infects aphid.

Pathogenicity of Saudi Arabian fungal isolates against egg and larval stages of Rhynchophorus ferrugineus under laboratory conditions

The pathogenicity of various local entomopathogenic fungal isolates from the kingdom of Saudi Arabia has been tested in the laboratory against the red palm weevil, Rhynchophorus ferrugineus Olivier (Coleoptera: Curculionidae). Fungi were coded, isolated, and purified. Beauveria bassiana (Balsamo-Crivelli) Vuillemin, coded as: BbSA-1 PDA-15 and Metarhizium anisopliae (Metsch.) Sorokin, coded as: MaSA-1 PDA-15, isolates demonstrated significant potential against R. ferrugineus larvae. A 1 × 1010 conidia/mL concentration of positive fungal isolates along with natural B. bassiana was used against different stages of R. ferrugineus. Rhynchophorus ferrugineus larvae were supplied with synthetic diets that contain preservatives and non-preservatives. The fungal isolates BbSA-1 PDA-15 and MaSA-1 PDA-15 affected the egg hatchability and caused significant larval mortality of red palm weevil. It was shown that MaSA-1 PDA-15 is one of the most pathogenic fungi against R. ferrugineus larvae followed by BbSA-1 PDA-15 and Natural B. bassiana isolates. Therefore, these local fungal isolates have the potential to be used against R. ferrugineus. Further development in the research could facilitate the farmers to save their valuable palm trees from the notorious pest.

Exploration of indigenous strains of the green muscardine fungus from soils and their pathogenicity against the tobacco caterpillar, Spodoptera litura (Fabricius) (Lepidoptera: Noctuidae)

In the recent years, the keen interest has been increased towards biological control-based management practices using entomopathogenic fungi (EPF) for the control of many economically important insects. In this management practices, selection of right strains of EPF is an important criteria to control the target pests in effective manner. In this context, this research work was formulated to find out environmentally effective strains of EPF in the soils of costal districts of Andhra Pradesh. Out of 135 soil samples collected, 8 soil samples yielded 8 strains of Metarhizium anisopliae. Among all 8 M. anisopliae isolates, the least median lethal concentration (LC50) for 2nd instar of the tobacco caterpillar, Spodoptera litura (Lepidoptera: Noctuidae) was 1.24 × 105 spores ml-1 in M-7, followed by 1.72 × 105 spores ml-1 in M-5 and 1.86 × 105 spores ml-1 in M-4 in an increasing order. Likewise, the median lethal time (LT50) values of different isolates of EPF against 2nd instar of S.litura were calculated for a uniform highest dose of 1 × 108 spores ml−1. Among all 8 M. anisopliae isolates, the lowest LT50 was observed as 186.44 hours post infection (hpi) with M-5 and 189.34 hpi with M-7.

Virulence and proteolytic activity of entomopathogenic fungi against the two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae)

The virulence and proteolytic activity of some entomopathogenic fungi isolates, viz., Metarhizium anisopliae, Beauveria bassiana, Verticillium lecanii, and Trichoderma harzianum, against the two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae), were evaluated. Common maize plants (Zea mays L.) infested with females of T. urticae were treated in vivo by spraying with suspensions of 1 × 108 conidia ml−1 concentration of selected isolates. Lethal effects of fungal isolates were assessed as percentages of daily mortalities of mites, compared to the mortality in control. Virulence of the fungi isolates was estimated based on the LC50 values calculated by probit analysis for the individuals treated by 1 × 105 conidia ml−1 concentration. Proteolytic activity of isolates was assayed on casein substrate to reflect their virulence towards T. urticae. The mite mortality rates increased with increasing conidial concentrations as well as days after treatment. The mortality rate caused by M. anisopliae isolate varied from 18.75 to 85%, with LC50 value of 4.6 × 105 conidia/ml and LC90 value of 2.4 × 108 conidia/ml during 7 days, respectively. The isolate of B. bassiana caused 15 to 70% mortality, and its LC50 and LC90 values estimated 3.3 × 106 and 7.8 × 109 conidia/ml, respectively. However, V. lecanii isolate caused 11.25 to 72.50% mortality with LC50 of 5.2 × 106 conidia/ml, while T. harzianum was potentially less virulent than other isolates causing 8.75 to 63.75% mortality rate to T. urticae with LC50 of 9.4 × 106 conidia/ml. M. anisopliae showed the highest proteolytic activity at all concentrations, followed by B. bassiana in 3rd, 5th, and 7th day post treatment. These findings recommend the selection of virulent fungal isolates for use as natural and environmentally safe agents in biological control programs to combat mite pests.

Mycoinsecticide formulations of Beauveria bassiana and Metarhizium anisopliae reduce populations of lesser mealworm, Alphitobius diaperinus, in chicken-broiler houses

Granular formulations of two entomopathogenic fungal isolates of Beauveria bassiana and Metarhizium anisopliae were evaluated as mycoinsecticides for control of lesser mealworm populations in broiler houses at a farm in southeast Queensland, Australia, over five production batches. The formulations were compared to rotated treatments of the insecticides β-cyfluthrin and spinosad, and to untreated populations. Lesser mealworm populations were measured by counting insects in bedding litter samples taken from under feed pans each week of each batch. Granular formulations applied at ≈45 g/m2 (conidia per m2: 3.4 × 1010B. bassiana; 1.28 × 1010M. anisopliae) in 0.9 m-wide bands under feedlines and along walls each batch produced mean population suppressions of 72% for B. bassiana and ≈50% for M. anisopliae, compared to untreated populations. The insecticide regimen applied at label rates to the whole floor and lower walls of houses each batch produced a mean suppression of ≈48%. An application of the fungicide imazalil for Aspergillus in batch 4 appeared to inhibit the efficacy of the mycoinsecticide formulations.

Occurrence, Identification, and Virulence of Native Fungal Pathogens Isolated From Mexican Fruit Fly (Diptera: Tephritidae) Larvae From Soils of Three Cropping Systems.

The Mexican fruit fly, Anastrepha ludens Loew, is a significant pest in mango and citrus production areas of Mexico. In this study, we evaluated the effects of some geographic characteristics, rainfall period, soil micro-environmental, and soil coverage variables on the occurrence of entomopathogenic fungi (EPF) associated with A. ludens larvae in soils of mango, grapefruit and mixed crops in central Veracruz state, Mexico. EPF isolates were characterized morphologically and identified by sequence analysis of elongation factor (EF1-1018F, EF1-1620R). We recorded four species of EPF (Metarhizium robertsii J.F. Bisch, S.A. Rehner & Humber [Hypocreales: Cordycipitaceae], M. brunneum Petch [Hypocreales: Cordycipitaceae], M. pinghaense Q.T. Chen & H.L. Guo [Hypocreales: Cordycipitaceae], and Beauveria bassiana (Balsamo) Vuillemin [Hypocreales: Cordycipitaceae]), of which Metarhizium robertsii was the most abundant and the most virulent. Also, we found that rainfall period, organic matter, coverage of herbs and forbs, and calcium levels modulated EPF occurrence. We estimated lethal concentrations for A. ludens larvae of the four most promising isolates, V3-123, V3-160, V1-332, and V3-369. Our results suggest that M. robertsii obtained from agricultural soils holds potential as a biological control agent for A. ludens.

Metarhizium anisopliae and Beauveria bassiana: Pathogenicity, Horizontal Transmission, and Their Effects on Reproductive Potential of Thaumatotibia leucotreta (Lepidoptera: Tortricidae).

The polyphagous moth, Thaumatotibia leucotreta (Meyrick) is among the major constraints to the horticultural industry in East Africa. In a search of sustainable control methods, the pathogenicity of the dry conidia of 17 Metarhizium anisopliae (Metschn.) and five Beauveria bassiana (Bals.) (Vuill.) isolates were tested against T. leucotreta moths. The conidial uptake by a single moth, horizontal transmission, and effect of fungal inoculant on egg-laying and hatchability for the pest were also assessed. The findings from this study showed that tested fungi were virulent to the moths, with 12 isolates causing mortality that ranged between 58.8 and 94.2% for M. anisopliae and three isolates between 57.6 and 84.6% for B. bassiana. The entomopathogenic fungi isolates, M. anisopliae ICIPE 69 and B. bassiana ICIPE 279 were highly virulent with low lethal times to 50% mortality (LT50) of 3.81 and 5.13 d, respectively. The isolate, ICIPE 69 conidia acquisition by a single moth were approximately 4.58 × 106 and 3.51 × 106 for males and females, respectively. The lowest survival rate (3.33 %) caused by inoculum transmission was recorded in donor males compared to 16.67% in recipient males. Fecundity was reduced by 33.6 and 25.9% for donor and recipient females, respectively. The pest can acquire conidia from the treated substrate and transmission is then possible between adults. ICIPE 69 is virulent and reduces the reproduction potential of the pest after transmission. The findings are discussed in the prospects of microbial control of this pest using an autodissemination technique.

Evaluation of host–pathogen interactions for selection of entomopathogenic fungal isolates against Oligonychus afrasiaticus (McGregor)

Understanding the interaction between pathogen virulence and host responses is very important for selecting virulent isolates of entomopathogenic fungi that control an economically important pest, such as the date palm dust mite, Oligonychus afrasiaticus (McGregor). In this study, the virulence of Metarhizium anisopliae (ARSEF 8453 and ARSEF 9374), Beauveria bassiana (ARSEF 6884 and ARSEF 8037), and Isaria fumosorosea (ARSEF 9602 and ARSEF 7284) was evaluated by virulence-regulating traits and host detoxification-related enzymatic analysis. The results revealed significant differences in virulence among all tested isolates of entomopathogenic fungi. The most virulent isolate of B. bassiana ARSEF 6884 (LT50 = 6.3 days; LC50 = 2.7 × 106 conidia ml−1) observed in the current study revealed the highest activity of cuticle-degrading protease Pr1 (2.12 ± 0.10 μmol NA ml−1 min−1) compared with the least virulent isolate of I. fumosorosea ARSEF 7284 (LT50 = 13.1 days; LC50 = 7.9 × 107 conidia ml−1). Virulent isolates successfully infected the target host and revealed lower activities of antioxidant (catalase and superoxide dismutase) and detoxification (glutathione S-transferases) enzymes at late stage infection. In conclusion, isolates ARSEF 6884 and ARSEF 9374 were found to be promising for the development of an environmentally friendly management strategy to control date palm dust mites.

Fungal isolate and crop cultivar influence the beneficial effects of root inoculation with entomopathogenic fungi in strawberry.

Root inoculations of crop plants with beneficial fungi constitute a promising strategy for growth promotion and control of above-ground pests and diseases. Here, strawberry roots (cultivar 'Albion' and 'Pircinque') were inoculated with 25 different Brazilian entomopathogenic fungal isolates of three genera and the effects on Tetranychus urticae oviposition and plant growth were evaluated in greenhouse experiments. Reductions in the number of T. urticae eggs compared to control treatments were observed on both cultivars inoculated with almost all isolates. For the cultivar 'Albion', Metarhizium anisopliae (ESALQ 1604, ESALQ 1669), M. robertsii (ESALQ 1622, ESALQ 1635), Metarhizium sp. Indet. (ESALQ 1684) and Beauveria bassiana (ESALQ 3323) increased dry weight of roots and leaves, and fruit yield, while M. robertsii (ESALQ 1634), Metarhizium sp. Indet. (ESALQ 1637) and (ESALQ 1636) enhanced fruit yield and dry weight of leaves, respectively. For the cultivar 'Pircinque', M. anisopliae (ESALQ 1669) was the only isolate observed to increase dry weight of roots. The results suggest that inoculation of strawberry roots with entomopathogenic fungi may be an innovative strategy for pest management above ground. Furthermore, these inoculations may also stimulate plant growth and strawberry production, but the effects depend on fungal strains and crop cultivar. © 2019 Society of Chemical Industry.

Proteolytic Activity of The Entomopathogenic Fungi (Penicillium sp. ) of Cockroaches (Periplaneta americana)

Cockroaches (Periplaneta americana) were the insect vectors of disease that caused adverse effects on human health. Control cockroch excessive use of insecticides can lead to residus in the environment and resistance cockroach. Therefore it was necessary to use an alternatives such as such as entomopathogenic fungal as biologycal agents. The entomopathogenic fungi penetrated via the integument of an cockroach to reach the hemocoel. Proteins were the molecules responsible for integument strength in cockroach, It was synthesis the proteases to degrading proteins. The study begins with the isolation of entomopathogenic fungi using the moist chamber method with cockroach as insect bait. Fungus that grow on cockroches are cultured and purifed on Potato Dextrose Agar (PDA) medium then identified. Identification was carried out through macroscopic observations including colony color and diameter and microscopic observations including conidia, conidiophores, hyphae, vesicles, fialids, and leg cells. The result of isolation and identification obtained as Penicillium sp. Proteases enzimatic activity tested on PDA with anlene 1%. The clear zone formed is measured to show the activity of proteases produced by Penicillium sp.