Entomopathogenic Fungi Research Articles

Entomopathogenic fungi based microbial insecticides and their physiological and biochemical effects on Spodoptera frugiperda (J.E. Smith).

'The fall armyworm, Spodoptera frugiperda', represents a significant threat to maize production, a major staple crop in Asian countries. In pursuit of more effective control of this insect pest, our study assessed the physiological and biochemical effects of the entomopathogenic fungus Metarhizium anisopliae against the larvae of S. frugiperda. Results revealed that, following nine days of treatment, a high concentration of conidia (1.5x107 conidia/mL-1) was toxic to all stages of larvae (second to fifth instar), resulting in 97% mortality of the second instar, 89% mortality of the third instar, 77% mortality of the fourth instar, and 72% mortality of fifth instar. All larval instars were found to have dose-dependent mortality effects. Treated S. frugiperda larvae further displayed significant physiological, morphological, and behavioral changes. Here, treated larvae displayed significantly lower levels of acetylcholinesterase, α-carboxylesterase, and β-carboxylesterase enzyme activity when compared to control groups. Treated larvae underwent an outward morphological change as the result of a decrease in the exterior cuticle of the anal papillae and a demelanization of the interior cuticle. Treated larvae also exhibited abnormal feeding behaviors as a consequence of the negative impact of conidia treatment on the neuromuscular system. Investigation into the effect of M. anisopliae on the non-target organism, the earthworm Eudrilus eugeniae, revealed that M. anisopliae conidia did not produce significant pathogenicity following three days of treatment. Furthermore, histological analysis revealed no significant effect of the entomopathogenic fungi on the gut tissue of the non-target organism. This study highlights the potential of M. anisopliae in the control of S. frugiperda.

Efficacy of entomopathogenic fungi against the fruit fly Drosophila suzukii and their side effects on predator and pollinator insects

Efficacy of entomopathogenic fungi against the fruit fly Drosophila suzukii and their side effects on predator and pollinator insects

Effect of Selected Entomopathogenic Fungal Species on Embryonic Development of Ascaris suum (Nematoda).

The aim of the study was to evaluate the potential of using five selected species of entomopathogenic fungi (Beauveria bassiana, B. brongniartii, Conidiobolus coronatus, Isaria fumosorosea, and Metarhizium robertsii) in the bioregulation of the dispersive stages of the parasitic nematode-Ascaris suum. Experimental cultures of each of the selected entomopathogenic fungi, as well as a control culture without fungi, were incubated with A. suum eggs at 26 °C for 28 days. Development of the A. suum eggs was observed using a light microscope on the 7th, 14th, 21st, and 28th days of incubation. The API-ZYM® test was used to determine, semiquantitatively, the activity of 19 hydrolytic enzymes from the entomopathogenic fungi. The cytotoxicity of the fungi was determined using tetrazole salt MTT. It was found that none of the five tested strains of entomopathogenic fungi showed an ovicidal effect, and none of them colonized the A. suum egg shells. However, ovistatic activity was observed mainly until the 14th day of incubation by I. fumosorosea, M. robertsii, and B. bassiana. In the MTT test, M. robertsii showed moderate cytotoxicity, while the other species showed low cytotoxicity. Among the strains tested, I. fumosorosea showed the highest spectrum of hydrolase production (13 out of 19 enzymes gave a positive reaction from 3 to 5; 20-40 nM or more). The absence of morphological changes in the A. suum egg shells suggests that the antagonistic effect of the studied entomopathogenic fungi may be due to their cytotoxicity, associated with the production of secondary metabolites-toxins (M. robertsii) and enzymatic activity (I. fumosorosea).

Correction to: Relevance of entomopathogenic fungi in soil–plant systems

Correction to: Relevance of entomopathogenic fungi in soil–plant systems

Susceptibility of adult Phlyctinus (Coleoptera: Curculionidae) to entomopathogens: A first look at potential differences in a newly revised species complex

AbstractPhlyctinus callosus and P. xerophilus (Coleoptera: Curculionidae) are two cryptic species of native entimine weevils, previously grouped together under the P. callosus sensu lato concept, that are pests of economic importance to the deciduous fruit and vine industry in the Western Cape province of South Africa. Laboratory bioassays were conducted using entomopathogenic fungi (EPF) isolates of Beauveria and entomopathogenic nematodes (EPNs), Heterorhabditis indica and Steinernema yirgalemense, to determine differences in susceptibility of adult P. callosus and P. xerophilus to potential biological control agents. The test arena used was 24‐well bioassay plates with an inoculation rate of 200 infective juveniles (IJs)/insect for EPNs and 5 × 105 conidia/insect for EPF. Insects were inoculated using a 12.7 mm filter paper impregnated with 50 μL of entomopathogen suspension. Infection was determined after 96 h incubation for EPNs through dissection of cadavers. Insects inoculated with EPF were incubated in the wells for 18 days and mortality recorded daily. Cadavers were surface sterilized and observed for overt mycosis. Differential susceptibility between P. callosus and P. xerophilus was observed in EPF but not in EPN bioassays. Differential susceptibility to EPF could be due to methodology. Low adult weevil pathogenicity was found for all entomopathogens, with variable results obtained from different bioassay batches.

Imperfect match between radiation exposure times required for conidial viability loss and infective capacity reduction attenuate UV-B impact on Beauveria bassiana.

UV-B radiation represents a significant challenge for the widespread use of entomopathogenic fungi in pest management. This study focused on research of the asynchronous response between virulence and conidial viability against Ceratitis capitata adults using specific statistical models. Moreover, it was also investigated whether the observed differences in susceptibility to UV-B radiation in in vitro assays among three selected isolates of Beauveria bassiana were reflected in the above-mentioned asynchrony. While the irradiation of the three isolates of B. bassiana was associated with a significant loss of conidial viability, their virulence was not significantly affected compared to nonirradiated treatments when exposed to 1200 mW m-2 for 6 h before or after the inoculation of C. capitata. In fact, the irradiation time needed to reduce the mortality to 50% compared to the controls was 34.69 h for EABb 10/225-Fil, 16.36 h for EABb 09/20-Fil, and 24.59 h for EABb 09/28-Fil. Meanwhile, the irradiation time necessary to reduce conidial viability to 50% was 9.89 h for EABb 10/225-Fil, 8.74 h for EABb 09/20-Fil, and 4.71 h for EABb 09/28-Fil. These results highlight the importance of modeling the response of entomopathogenic fungi virulence and conidial susceptibility when exposed to UV-B radiation for the selection of environmentally competent isolates, regardless of the results obtained in previous in vitro assays on conidial germination. This strategic approach is critical in overcoming the challenges posed by UV-B radiation and holds the key to realizing the full potential of entomopathogenic fungi in pest management. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

The effects of temperature on pathogenicity of entomopathogenic fungi for controlling larval populations of the European grapevine moth (Lobesia botrana) (Lepidoptera: Tortricidae)

The European grapevine moth (Lobesia botrana) is currently the most damaging pest in many viticultural regions of South and Central Europe and is highly responsible for the development of secondary infections by Botrytis cinerea to both table and wine grapes. Entomopathogenic fungi (EPF) are considered as substantial biological control agents of insect pests. However, they are able to infect their hosts only under a narrow spectrum of environmental conditions. In this study, the effects of temperature on pathogenicity of EPF for the control of L. botrana are reported. Among a collection of 33 EPF isolates, six virulent isolates were selected for the experiments. The bioassays took place at controlled conditions, under the temperature regimes of 20, 22.5, 25, 27.5, 30, and 32.5 °C. A conidial concentration of 1 × 108 conidia/ml was prepared for each isolate, and fungi were applied by spraying them on third-instar larvae (L3) of L. botrana. Both factors, fungal isolate and temperature, significantly affected mortality of L. botrana. Most fungal isolates exhibited their highest larval mortality rates seven days post-treatment at the temperatures of 25 and 27.5 °C. Some isolates caused considerably high larval mortality that exceeded 90% under specific temperature conditions. Overall, EPF showed great potential as bio-control agents for controlling larval populations of L. botrana.

The application of the entomopathogenic fungus Akanthomyces muscarius modified GFP to study endophytization

Entomopathogenic fungi (EPF) of the genus Akanthomyces (formerly Lecanicillium) are one of the most common and important fungal entomopathogens, infecting sucking insects of the order Hemiptera mainly. The fungi can also parasitize on phytopathogenic fungi (rust, powdery mildew). The entomopathogens from these genera reported as endophytes in various plants under natural conditions [1–2], contributing to an increase in plant immunity to pathogens, as well as a decrease in plant colonization by pests. Endophytic colonization of plants by the fungus Akanthomyces lecanii can suppress the growth of the peach aphid [3]. Akanthomyces muscarius strains caused the death of moth when feeding on cabbage colonized by the fungus [4]. Endophytic properties were assessed using the A. muscarius (= Lecanicillium muscarium) strain Vl 72-GFP fluorescently labeled with GFP [5]. The transformation was done by electroporation of germinated conidia of the high-virulent “wild” strain Vl 72 by the pBARGPE1 vector harboring an eGFP gene, showed an expression of fluorescent protein without affecting fungal growth and virulence. The influence of the fungus on the growth rates of beans was revealed when leaves, sterile soil and seeds were treated with a suspension of conidia of 108 spores/ml. On the 7th day, stimulation of the growth of the stems and roots of the beans was observed when the seeds were soaked in a spore suspension of the fungus. When spraying the leaves, only the stem’s elongation was observed. The studied strain colonizes beans irregularly. When treating the seeds, the fungus was isolated in greater quantities from the roots (26%), when spraying the leaves — from the stem (36%), when watering the soil — also from the stem (43%). Infection of A. muscarius plants by spilling the soil was most effective. No effect of endophytization was found on the number of aphids after 14 days of aphid plant colonization. As a result of the introduction of the spores of Vl 72-GFP strain by shedding the soil under flower crops (lantana, gerbera, acanthus) in the greenhouse of Saint Petersburg Botanical Garden, this strain was isolated from the leaves of the Acanthus mollis L. after one month, which confirms the ability of this species to endophytic colonization of plants in greenhouse conditions. Analysis of hyphae Vl 72-GFP in the plant performed on an AxioImager M1 fluorescent microscope demonstrated the same level of fluorescence as in A. muscarius hyphae growing on the media.

The complete mitogenome of the entomopathogenic fungus Metarhizium pinghaense 15R

In this study, the complete mitogenome of the entomopathogenic fungus Metarhizium pinghaense 15 R, which is highly virulent to aphids and was isolated from Korean soil, was assembled and annotated for three ATP synthase subunits (atp6, atp8, and atp9), three cytochrome oxidase subunits (cox1, cox2, and cox3), apocytochrome b (cob), seven subunits of NADH dehydrogenase (nad1, nad2, nad3, nad4, nad4L, nad5, and nad6), two ribosomal RNAs (rnl and rns), and 19 tRNA genes. Five genes were carrying a total of eight introns, and they may encode ribosomal protein S3, LAGLIDADG and GIY-YIG endonucleases. Phylogenetic analysis based on the mitochondrial nucleotide sequence confirmed that the M. pinghaense 15 R is a member of the Clavicipitaceae, and is closely related to the species M. anisopliae, M. robertsii, and M. brunneum. The mtDNA base sequence of the M. pinghaense 15 R strain reported in this study is thought to be useful for biological resource genetic data.

Altered Gene Expression of the Parasitoid Pteromalus puparum after Entomopathogenic Fungus Beauveria bassiana Infection

Both parasitoids and entomopathogenic fungi are becoming increasingly crucial for managing pest populations. Therefore, it is essential to carefully consider the potential impact of entomopathogenic fungi on parasitoids due to their widespread pathogenicity and the possible overlap between these biological control tools during field applications. However, despite their importance, little research has been conducted on the pathogenicity of entomopathogenic fungi on parasitoids. In our study, we aimed to address this knowledge gap by investigating the interaction between the well-known entomopathogenic fungus Beauveria bassiana, and the pupal endoparasitoid Pteromalus puparum. Our results demonstrated that the presence of B. bassiana significantly affected the survival rates of P. puparum under laboratory conditions. The pathogenicity of B. bassiana on P. puparum was dose- and time-dependent, as determined via through surface spraying or oral ingestion. RNA-Seq analysis revealed that the immune system plays a primary and crucial role in defending against B. bassiana. Notably, several upregulated differentially expressed genes (DEGs) involved in the Toll and IMD pathways, which are key components of the insect immune system, and antimicrobial peptides were rapidly induced during both the early and late stages of infection. In contrast, a majority of genes involved in the activation of prophenoloxidase and antioxidant mechanisms were downregulated. Additionally, we identified downregulated DEGs related to cuticle formation, olfactory mechanisms, and detoxification processes. In summary, our study provides valuable insights into the interactions between P. puparum and B. bassiana, shedding light on the changes in gene expression during fungal infection. These findings have significant implications for the development of more effective and sustainable strategies for pest management in agriculture.

Efficacy of some Entomopathogenic Fungi Against Tomato Leaf Miner Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) in Iraq

The most important tool for biological management of several insect pests is entomopathogenic fungi. The purpose of this study was to compare the effectiveness of Beauveria bassiana and Chaetomium globosum as biological agents against Tuta absoluta. According to the findings, B. bassiana and C. globosium may be able to influence T. absoluta larvae’s eggs and third instar. By extending the duration and concentration, the fungus became more active. B. bassiana has had the greatest death rates after 7 days in the eggs and the third instar of the insect by 83.86% and 68.3% at 2 ×107 conidia mL-1, respectively.. This score was significantly differs to the C. globosium reached 60.09%and 31.7% in the destruction both eggs and the 3rd larvae-instar respectively. The outcomes also confirmed that the fungal colonies of both fungi isolated from leaves after 10 days of the application. The highest colony percentage belongs to the C. globosium 32.29% with a significant difference to the B. bassiana by 23.26%. The presence of both fungal colonies had a significant effect on the eggs, larvae, and pupae period development. Consequently, the weight of the pupal was influenced compared to the control. The B. bassiana has supremacy in comparison to the C. globosium and the control treatment. A gradual decrease has been shown in the proportion of the two fungal colonies tomato leaves after 30th days. The lowest level score was 4.17% and 9.37% for both B. bassiana and C. globosium respectively.

Перспективы применения энтомопатогенных грибов для борьбы с постельными клопами

A literature review on the effectiveness of the use of entomopathogenic fungi Metarhizium anisopliae and Beauveria bassiana for the destruction of bed bugs is given. Bed bug resistance to pyrethroids does not result in cross-resistance to infection with B. bassiana spores. Insect mortality is highly dependent on the concentration of fungal conidia, which is critical to induce horizontal transfer capable of increasing insect population mortality without the need for direct contact between bed bugs and the inoculated substrate. Pyrethroid residues on treated surfaces significantly reduce the germination of B. bassiana spores. At present, resistance of insects to mycoinsecticides in the field has not been revealed, however, it has been shown that in laboratory conditions its occurrence is possible. Keywords: entomopathogenic fungi, Metarhizium, Beauveria, biopesticides, bed bug, resistance.

Status of Natural Enemies and Entomopathogens on New Invasive Pest Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) under Maize Ecosystem in Indian Subcontinent

The pests’ natural enemies were explored by collecting FAW eggs and larvae from maize fields. The survey also revealed natural parasitism by egg parasitoids viz., Telenomus sp. (Hymenoptera: Platygastridae) and Trichogramma sp. (Hymenoptera: Trichogrammatidae), gregarious larval parasitoid Glyptapanteles creatonoti (Viereck) (Hymenoptera: Braconidae) solitary larval parasitoid Campoletis chlorideae Uchida (Hymenoptera: Ichneumonidae), and a solitary indeterminate larval-pupal (Hymenoptera: Ichneumonidae: Ichneumoninae) parasitoid. Spodoptera frugiperda is the first host record for G. creatonoti across the globe. The parasitiods were raised in the laboratory for emergence, recognition and effectiveness as natural enemies. Cotesia or Apanteles spp. were concluded to occur since emerged. Besides these, other commonly found bioagents viz., Forficula sp. (Dermaptera: Forficulidae) and entomopathogenic fungus Nomuraea rileyi (Farl.) Samson was also collected in large numbers. Therefore, the occurrence of Spodoptera frugiperda natural enemies in India represents for advocacy campaign to include their use into IPM strategies that enhance and permit bio agents to boom for control of fall armyworm.

Biological Characteristics of Beauveria majiangensis Strain MJ1015 and Optimization of Solid Medium Technology for Sporulation.

The entomopathogenic fungus Beauveria majiangensis strain MJ1015, recently isolated from white grubs on a blueberry farm in Guizhou, China, could be used as a biocontrol agent. As a first step toward determining the effect of different solid culture media, temperature, and pH on colony growth rate and sporulation, we evaluated the optimum solid medium for mycelial growth and conidia production on a commercial scale. Subsequently, we also used single-factor analysis and response surface optimization to optimize the composition of the solid culture medium. On potato dextrose agar (PDA) medium, MJ1015 grew fastest and produced the highest spore yield at 29°C and pH 5. The best solid medium for the growth and sporulation of strain MJ1015 comprised 64.70 g/l of rice, 13.00 g/l of wheat, 0.30 g/l of NaNO3, 0.36 g/l of K2HPO4 · 3H2O, and 1.00 g/l of CaCO3. Rice, NaNO3, and K2HPO4 · 3H2O were the main influencing factors. The predicted value of cultured spores using the optimal medium was 4.56 x 1010 conidia/l. The validation test results showed that the average growth rate of strain MJ1015 on the optimal medium was 85% and 96% faster than that on Sabouraud dextrose agar with yeast extracts medium (SDAY) and PDA, respectively. Sporulation was 43.90 times and 9.65 times of that produced on SDAY and PDA, respectively. Our findings provide a theoretical basis for the commercial production of B. majiangensis to control white grubs.

Synergistic of Trichoderma virede and Beauveria bassiana to Biocontrol Tomata Against and Bemisia tabaci

In Iraq, Bemisia tabaci is a major Tomato pest that causes significant crop losses, which lowers farmers’ revenue. The purpose of this study was to detect entomopathogenic fungus from dead whiteflies and to assess their relative frequency and different structural characteristics. Only two fungal species, Trichodrema virede and Beauveria bassiana, with relative frequencies of 15.07 and 10.94%, respectively, were validated microscopically as recognised entomopathogenic species out of the 11 fungal species isolated from the whitefly cadavers. The 7th day following inoculation was when T. virede and B. bassiana had the largest mortality impact on B. tabaci nymphs and adults, with an average mortality of more than 60% (with a concentration of 106 conidia/ml). In comparison to nymphs, suspension T.virede and B.bassiana. were significantly twice as pathogenic.

Efficacy of Indigenous Entomopathogenic fungi Beauveria bassiana Isolate for the Control Spodoptera littoralis (Boisduval) (Lepidoptera: Noctuidae) under Laboratory Conditions

Spodoptera littoralis is a serious threat to tomato production worldwide as it can cause yield losses. The farmers used to use synthetic chemical insecticides to control this pest, which unfortunately selects resistant populations and entails public health risks. The aim of this study was to evaluate of indigenous entomopathogenic fungi Beauveria bassiana isolate against different stages of S. littolars life. Results show high significant differences between the three concentrations of suspensions and fungi exudates of B. bassiana in addition differences among time of exposure on ratio of eggs hatching of S. littoralis the high rate of affected of B. bassiana suspension registered at concentration of 1×108 and at concentration 75% of B. bassiana exudates it was reached 32.28% and 34.15% respectively. The study showed that the mortality on 1st and 6th instar larvae of S. littoralis increased as concentration of fungi exudates of B. bassiana increased, it had been 20.51%, 24.65%and 33.45% at concertation 25%, 50%and 75% on 1st instar and reached 3.33%,7.78% and 12.67% on 6th instar of S. littoralis larvae respectively. Moreover suspension fungi of B. bassiana superior at the concentration 1×10 8conidia/1ml of distilled water in the mortality of 1st and 6th instar of S. littolaris larvae with a mortality rate 35.41% and 15.37% respectively.the results showed eggs and 1st instar of of S. littolaris larvae more sensitive to suspensions and fungi exudates of B. bassiana than the 6th instar.

Efficacy of Entomopathogenic Fungi as Prevention against Early Life Stages of the Red Palm Weevil, Rhynchophorus ferrugineus (Coleoptera: Curculionidae) in Laboratory and Greenhouse Trials.

The red palm weevil (RPW) Rhynchophorus ferrugineus is a highly destructive invasive pest for palms whose management is mainly by application of synthetic pesticides. As a key pest of date palm plantations, it is necessary to integrate environmentally safe measures for its management. Entomopathogenic fungi (EPF) have been primarily studied as a preventative control measure due to the horizontal transfer of conidia within the RPW population. We previously demonstrated the horizontal transmission of fungal conidia from an egg-laying surface to the female weevil and then to the eggs and larvae. Based on that strategy, this study aimed to evaluate the virulence of commercial EPF products and laboratory EPF preparations to RPW females and their progeny, and their ability to protect palms against infestation. As such, it serves as a screening platform for field experiments. Mortality rates of females and eggs depended on the applied treatment formulation and fungal strain. Velifer®, a Beauveria bassiana product, and Metarhizium brunneum (Mb7) resulted in 60-88% female mortality. Mb7-as a conidial suspension or powder-resulted in 18-21% egg-hatching rates, approximately 3 times less than in the non-treated control. Treating palms with Mb7 suspension or dry formulation significantly inhibits infestation signs and results in protection. These results lay the foundation for investigating the protective rate of EPF products against RPW in date plantations.

Control of sweet potato whitefly (Bemisia tabaci) using entomopathogenic fungi under optimal and suboptimal relative humidity conditions.

Sweet potato whitefly (Bemisia tabaci) is one of the most destructive pests to an extensive range of crops and vegetables. Pesticide-dependent management programs have led to severe health problems, including pesticide poisoning and cancer in human beings, as well as pesticide resistance in insect pests. Entomopathogenic fungi (EPF) are considered safe and highly effective against many pests. Therefore, identifying the pathogenicity and virulence of EPFs against Bemisia tabaci is a valuable addition to the management of their infestations. In this study, we investigated the efficacy of conidia suspensions of Aschersonia aleyrodis, Isaria fumosorosea, Beauveria bassiana, and Akanthomyces muscarius (= Lecanicillium muscarium) against nymphal stages of Bemisia tabaci in cucumber seedlings under both optimal and suboptimal conditions. All of the EPFs demonstrated significant ovicidal effects, with the highest cumulative mortalities observed in Aschersonia aleyrodis (96.46%) and I. fumosorosea-treated (94.60%) seedlings against host eggs and crawlers. Similarly, in the L4-instars experiment, Aschersonia aleyrodis and I. fumosorosea were the most efficient, resulting in cumulative mortalities of 94.82% and 94.75%, respectively. However, Bemisia tabaci cumulative mortalities on seedlings treated with Akanthomyces muscarius (78.36%) and Beauveria bassiana (85.90%) were also significantly different from untreated seedlings (7.10%). Under suboptimal relative humidity (RH) conditions (≤ 45% RH), Aschersonia aleyrodis exhibited greater tolerance to harsh conditions, causing a significantly higher infection rate in L1-L2 nymphs (~92%) compared to the approximately 32% infected young nymphs observed in I. fumosorosea-treated seedlings. All the selected EPF were more effective against the young nymphal instars. Our results also highlight the efficacy of Aschersonia aleyrodis under suboptimal conditions. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Endophytic Development of the Entomopathogenic Fungus Beauveria bassiana Reduced the Development of Galls and Adult Emergence of Leptocybe invasa in Susceptible Eucalyptus

Eucalyptus cultivation in arid regions is limited by the losses caused by the galling wasp, Leptocybe invasa Fisher and La Salle, 2004 (Hymenoptera: Eulophidae); it oviposits below the epidermis of the central veins, mainly on seedlings in nurseries and/or young plants in the field, causing galls where the insects develop. Galls modify the normal circulation of sap in vascular tissues, ultimately affecting the development of infested plants and resulting in slower growth. Eucalyptus genotypes tolerant to water stress are susceptible to L. invasa, and this pest has no effective control methods. Here, we aimed to (i) determine the initial infestation dynamics of L. invasa in Eucalyptus plants inoculated with Beauveria bassiana and (ii) identify any change in the development of galls. B. bassiana-inoculated seedlings were infested with L. invasa. Susceptible plants were unaffected, and gall development was negatively affected at multiple stages. A fungal solution containing B. bassiana reduced gall development and the emergence of L. invasa adults in eucalyptus plants at considerable rates. The total number of adult emergence holes was 89.74% fewer for inoculated plants when compared to uninoculated plants. These results can help develop B. bassiana products to control L. invasa in susceptible eucalyptus plants for improved, sustainable forestry.

The Eucalyptus snout beetle in Colombia: Selection and evaluation of entomopathogenic fungi as bioinsecticides against Gonipterus platensis

The Eucalyptus snout beetles, which belong to the Gonipterus scutellatus species complex, cause heavy damage to Eucalyptus spp. worldwide. The species was reported in Antioquia, Colombia for the first time in 2016, threatening more than 115,000 ha of planted Eucalyptus spp. Elsewhere, its damage has been controlled using Anaphes spp. as classical biological control, but Anaphes spp. are not available in Colombia, where there are no documented control methods for this species to date. We identified the Gonipterus species using molecular methods and isolated entomopathogenic fungi from naturally infected beetles collected from the current distribution area in Colombia. We characterised the fungal isolates, selecting the best to develop a biological control agent. We considered insecticidal activity, UV-B radiation tolerance, yield, germination, and enzyme activity of conidia in making our selection. We confirmed the presence of G. platensis in Colombia, with adults naturally infected by Beauveria spp. and Metarhizium spp. From the isolated native fungi, M. brunneum (CA-3), M. robertsii (RI-1), B. bassiana (CA-1) and (CA-2), B. pseudobassiana (SP-1) were identified. We found remarkable differences in response to different variables between the selected isolates and SP-1 and CA-3 were the most virulent. The SP-1 isolate stood out from the rest for being the most tolerant to UV-B radiation, alkaline media, and low temperatures, germinating faster and producing elevated levels of lipases, chitinases, and proteases. The identified promising native fungus isolate, naturally occurring on field individuals, could be used to develop a biopesticide for controlling G. platensis in Eucalyptus spp. plantations in Colombia.