Use Of Entomopathogens Research Articles

RNAi-mediated silencing of NlGRP3 augments the insecticidal virulence of Metarhizium anisopliae to the brown planthopper Nilaparvata lugens

The rapid development of insecticide resistance reinforces the urgent need to develop eco-friendly strategies for controlling Nilaparvata lugens (brown planthopper, BPH), the most destructive insect pest of rice. Both entomopathogens and RNA interference (RNAi) provide attractive alternatives to chemical insecticides. In this study, we demonstrated the synergistic potential of the combination use of entomopathogen- and RNAi-mediated approaches to control BPH. The β-1, 3-glucan recognition protein (βGRP) encoding gene NlGRP3 was identified and its potential role in immune defense was characterized in BPH. The open reading frame (ORF) of NlGRP3 is 1740 bp in length, encoding a 65.8 kDa protein with conserved CBM39 and GH16 domains that typically existed in the βGRP family members. NlGRP3 was shown to be differentially expressed across developmental stages and highly transcribed in the immune responsive tissues haemolymph and fat body. Topical infection with a fungal entomopathogen Metarhizium anisopliae could significantly up-regulate its expression level. RNAi-mediated silencing of NlGRP3 resulted in significantly decreased survival rate and increased susceptibility to fungal challenge in the fifth-instar BPH nymphs. The greatly enhanced mortality of NlGRP3-silenced BPH following fungal infection might be in part directly due to the immune suppression by down-regulating expressions of antimicrobial peptide genes and the imbalance of the bacterial community harboring in BPH body. Our results highly demonstrated that suppressing the insect innate immune defense through RNAi targeting the immune-related genes could effectively strengthen the biocontrol efficacy of fungal entomopathogens, providing clues to the combination use of RNAi and entomopathogens as a promising approach for BPH control.

Biology, classification, and entomopathogen-based management and their mode of action on Tuta absoluta (Meyrick) in Asia.

Tuta absoluta, known as the South American tomato leaf miner, significantly impacts tomato plants (Solanum lycopersicum) economically on a global scale. This pest, belonging to the Gelechiidae family, is native to South America and was first identified in Peru in 1917. Since its discovery, T. absoluta has rapidly spread to Europe, Africa, and Asia, severely threatening tomato production in these regions. The widespread application of chemical pesticides against this pest has resulted in significant environmental harm, including contamination of soil and water, and has had negative effects on non-target species such as beneficial insects, birds, and aquatic life. Although substantial research has been conducted, biological control methods for T. absoluta remain insufficient, necessitating further study. This review covers the Biology, Classification, and Entomopathogen-Based Management of T. absoluta (Meyrick) in Asia. It provides essential insights into the pest's life cycle, ecological impacts, and the potential of entomopathogens as biocontrol agents. The detailed information presented aims to facilitate the development of sustainable pest control strategies, minimizing environmental impact and promoting the use of entomopathogens as viable alternatives to chemical pesticides in controlling T. absoluta insect pest.

Can we manage alien invasive insects without altering native soil faunal communities? A field trial on Popillia japonica

Biological and integrated pest control are key assets to environmentally friendly management of cropland. Use of entomopathogens against target pests is common, yet the effects of such released organisms on native, non-target invertebrates are currently poorly known. This is particularly true for relatively inconspicuous components of agroecosystems such as soil biological biota. Popillia japonica, a polyphagous alien invasive scarab beetle native to Japan, is now present in Europe where huge efforts are being conducted to control the pest and slow its spread. In particular, entomopathogenic nematodes and fungi have been used for larval control. Here we test the effects of those agents on both P. japonica larvae and non-target soil biota by comparing soil arthropod assemblages before and after treatment of field plots in an irrigated perennial meadow.Application of an indigenous strain of the nematode Heterorhabditis bacteriophora resulted in significant reduction in numbers of P. japonica larvae. In contrast, an indigenous strain of the entomopathogenic fungus Metarhizium robertsii failed to provide significant control. We found no evident effect on non-target edaphic arthropods under either treatment in comparison to untreated control plots. Some taxa, namely Collembola and Acarina, showed a disproportionate increase in treated plots, suggesting that some changes may occur in the long term, at least in particular arthropod groups. Our results suggest the selected strain of H. bacteriophora is an excellent candidate for managing P. japonica larvae with minimal adverse impact on non-target species and ecosystem functioning.

Dos inseticidas ao controle biológico de pragas na cana-de-açúcar: uma experiência de meio século na Venezuela

Biological control has been established as a unique measure for managing borers of the genus Diatraea and the candelilla Aeneolamia spp., both of which are key pests of sugarcane in Venezuela. Optimal results have been achieved with the use of parasitoids and entomopathogens. Systematic releases of the Amazonian fly Lydella minense from the mid-20th century and the establishment of the braconid wasp Cotesia flavipes from 1987 led to effective control of borers. In the case of Aeneolamia varia, a pest formerly controlled with frequent insecticide applications, an efficient solution was the introduction of the entomopathogenic fungus Metarhizium anisopliae in 1977. This measure has been established as efficient in controlling adult Aeneolamia, though nymphs were less controlled. This issue was effectively addressed in 2004 with the introduction of the entomopathogenic nematode Heterorhabditis bacteriophora, which has been widely used as a biological measure to avoid the application of insecticides. To illustrate this, we can consider the case of Azucarera Río Turbio. Despite experiencing a reduction in cultivated areas in recent harvests due to various factors, this establishment has witnessed a significant decline in Diatraea infestations over the past 58 years. Infestation rates have decreased from 15% to 3.18%, resulting in a saving of 170,552.62 metric tons valued at USD 49,196,045. The cost of implementing biological control measures amounts to USD 1,187,189, translating into a favorable benefit-cost ratio of USD 41.44. Before the adoption of biological control methods, Aeneolamia infestations were exclusively controlled using chemical insecticides applied to both the foliage for adults and the soil for nymphs. Concurrently, since then, entomopathogenic fungus M. anisopliae, produced by national companies, has been deployed across 87,000 hectares between 1986 and 1990. Moreover, since 2004, the use of entomopathogenic nematodes to control Aeneolamia nymphs has been integrated into pest management practices.

Entomopathogens in the integrated management of forest insects: from science to practice.

The most important aim of the integrated management of forest insect pests remains the prevention of insect outbreaks, which are a consequence of the interaction of many factors in forest ecosystems, including species composition, age and health of the forest, soil type, the presence of natural enemies, and climatic factors. Integrated pest management until now has been achieved using measures aimed at shaping the functioning of stands in a changing environment. The aim of this review is to summarize research on the use of entomopathogens (microorganisms and nematodes) in the management of forest insect pests and to identify the principal knowledge gaps. We briefly describe the main research directions on the use of pathogens and nematodes to control insect pests and discuss limitations affecting their implementation. Research on entomopathogens for the biocontrol of forest insects has provided a wealth of knowledge that can be used effectively to reduce insect populations. Despite this, few entomopathogens are currently used in integrated pest management in forestry. They are applied in inoculation or inundation biocontrol strategies. While the use of entomopathogens in forest pest management shows great promise, practical implementation remains a distant goal. Consequently, sustainable reduction of forest pests, mainly native species, will be largely based on conservation biological control, which aims to modify the environment to favor the activity of natural enemies that regulate pest populations. This type of biocontrol can be supported by a range of silvicultural measures to increase the resilience of stands to insect infestations. © 2023 Society of Chemical Industry.

Protein Levels in Metarhizium anisopliae (Metschn.) Sorokīn Infested Tomato Fruit Borer Helicoverpa armigera Hubner (Lepidoptera; Noctuidae)

The tomato fruit borer, Helicoverpa armigera Hubner (Lepidoptera; Noctuidae), is responsible for significant yield losses in tomatoes and employing chemical pesticides leads to unwarranted environmental issues. The use of entomopathogens in tomato Integrated Pest Management reduces the dependency on chemical insecticides. The green muscardine fungus Metarhizium anisopliae is an important entomopathogen used worldwide against many lepidopteran and coleopteran pests. The potential of M. anisopliae depends on its ability to overcome the host defence mechanisms. The immune system in the H. armigera in response to M. anisopliae infection can be revealed using protein analysis. The order of efficacy of four M. anisopliae strains against second and fourth instar H. armigera under laboratory conditions was ICAR SBI VS 8 > ICAR SBI I >ICAR SBI S69 > ICAR SBI MA4. The protein concentration increased with a decrease in M. anisopliae strain concentration in the second and fourth H. armigera larvae. The highly virulent ICAR SBI VS 8 infested H. armigera showed a decline in protein concentration up to 168 h (14.99 mg/g). The second and fourth instar H. armigera, showed similar protein concentration trends in response to M. anisopliae infestation. The virulent ICAR SBI VS 8 strain can resist the host insect's immune response and cause infection to the H. armigera.

Effects of commercial entomopathogen-based formulations on Neoseiulus sp. in pine trees

Biological control is a growing branch in Brazil, and with it comes the need to obtain efficient enemies in the control of pests. The use of entomopathogens has expanded and with it comes the need to investigate their selectivity to non-target organisms. The present work was conducted in a pinecone (Annona squamosa L.) orchard with the objective of evaluating in which locations of the plant (lower, middle or upper third) and the effects of the entomopathogens: Beauveria bassiana, Metharhizium anisoplie and Bacillus thuringiensis on the predatory mite. Sixteen weekly applications were made between March and August 2017 with a constant pressure knapsack sprayer, nozzle type JA-2 with the jet directed at the entire plant. The treatments consisted of the use of three entomopathogenic biological products: Dipel, Beuaveria bassiana JCO and Metarhizium anisopliae JCO applied alone and in combination. Eight treatments were performed, as follows: T1-Spraying with M. anisopliae + phfos (Quimifol) + adhesive spreader (Agral), T2-Spraying with B. bassiana + phfos (Quimifol) + adhesive spreader (Agral), T3-Spraying with B. thruringiensis + phfos (Quimifol) + adhesive spreader (Agral), T4-Spraying with M. anisopliae + B. basisiana + phfos (Quimifol) + adhesive spreader (Agral), T5- Spraying with M. anisopliae + B. thruringiensis + phfos (Quimifol) + adhesive spreader (Agral), T6- Spraying with B. bassiana + B. thruringiensis + phfos (Quimifol) + adhesive spreader (Agral); T7- Spraying with M. anisopliae + B. bassiana + B. thruringiensis + phfos (Quimifol) + adhesive spreader (Agral) e T8-Testify, spraying with phfos (Quimifol) + adhesive spreader (Agral). The results indicate a preference of the Neoseiulus sp. mite for the middle third of the plant canopy. The results obtained indicated that the entomopathogens influenced the population of the Neoseiulus sp. mite until the sixth week after treatment, where the combination of Metarhizium anisopliae + Beauveria bassiana + Bacillus thuringiensis was the one that most negatively affected the population of the predatory mite Neoseiulus sp.

High temperature exposure reduces the susceptibility of Helicoverpa armigera to its nucleopolyhedrovirus (HearNPV) by enhancing expression of heat shock proteins.

High temperatures will occur more frequently with global warming, with potential impacts on the efficacy of biological control agents. Heat shock proteins (HSPs) are induced by high temperature, but their possible roles in pest resistance to entomopathogens remain unexplored. We investigated the effects of high temperature (35 °C) on Helicoverpa armigera resistance to H. armigera nucleopolyhedrovirus (HearNPV) and the putative roles of HSPs in this process. Even short periods (24 h) of high temperature (35 °C) reduced mortality in HearNPV-infected H. armigera larvae. Sustained 35 °C exposure significantly shortened developmental time, and increased fresh weight and locomotor activity in infected larvae. Moreover, high temperature inhibited virus replication and thickened the epidermis of H. armigera, resulting in reduced spread of infection from cadavers. Real-time polymerase chain reaction (PCR) analysis showed that expression of 11 HSP genes was altered by the 35 °C treatment, and that mostly small heat shock protein (sHSP) genes were up-regulated, the same sHSPs were induced when larvae were infected with HearNPV. Finally, RNA interference (RNAi) suppression of these sHSPs showed that only Hsp24.91 and Hsp21.8 diminished H. armigera defensive responses to HearNPV infection. Even short periods of exposure to high temperature can significantly reduce susceptibility of H. armigera larvae to HearNPV by stimulating the production of sHSPs which enhance immune responses, with important implications for the use of entomopathogens as biological control agents under global warming scenarios. © 2022 Society of Chemical Industry.

Entomopathogenic Fungal Screening against Two Spotted Spider Mites, Tetranychus urticae Koch in Tomato and Broad Mite, Polyphagotarsonemus latus (Banks) in Chilli

Background: Entomopathogenic fungi are microorganisms that specifically infect and often kill insects and other arthropods. Most are non-pathogenic to plants and relatively non-toxic to humans and animals. Use of fungal entomopathogens can be an alternative to insecticides and could help in bio-intensive pest management. The current study aimed to study the pathogenicity of entomopathogenic fungal isolates against two Spotted Spider Mites, Tetranychus urticae Koch in tomato and broad Mite, Polyphagotarsonemus latus (Banks) in chilli. Methods: An extensive survey for the natural occurrence of entomopathogenic fungi on insects and mites was made in different agro climatic regions of Tamil Nadu during 2013 and 2014. Survey revealed the occurrence of two entomopathogenic fungi viz., Beauveria bassiana (Balsamo) Vuillemin and Metarhizium flavoviride Gams and Rozsypal var. minus. Laboratory experiment was conducted to evaluate the pathogenicity of fourteen isolates of Beauveria bassiana, Metarhizium anisopliae and Lecanicillium lecanii against Tetranychus urticae and Polyphagotarsonemus latus. Result: In opposition to T. urticae, the Beauveria bassiana isolate Bb 112 showed the highest toxicity of all the other isolates tested, with low LC50 value of 0.6 x106 spores ml-1 and LT50 of 92.60h. Against P. latus, Bb 112 had high virulence with low LC50 value of 0.3x106 spores ml-1 and LT50 value of 92.32h. Hence, there is potential for use of entomopathogenic fungi in the field conditions as an alternate control method in combating the insect pests and other arthropod pests since they are considered natural mortality agents and are environmentally safe.

The Role of Chrysoperla carnea (Steph.) (Neuroptera: Chrysopidae) as a Potential Dispersive Agent of Noctuid Baculoviruses.

Simple SummaryBaculoviruses (BV) infect several lepidopteran pests of economic importance, such as the beet armyworm Spodoptera exigua. The joint use of microbiological and macrobiological strategies may improve the efficacy of control. Laboratory bioassays were developed to evaluate the interactions between two BVs: the multiple nucleopolyhedroviruses of S. exigua (SeMNPV) and Autographa californica (AcMNPV), and the predator Chrysoperla carnea. The excretion products of the predator’s larvae (drops) and adults (meconia) were microscopically examined after the ingestion of BV-infected S. exigua larvae. For both types of excreta and BVs, viral occlusion bodies (OBs) (resistance forms) were observed. These OBs were infective to healthy S. exigua larvae when applied in water suspension and in direct deposition. The virulence of meconia was higher in suspensions (higher viral load), while larval drops were more virulent in direct application due to their liquid nature and their easiness of consumption. The fitness of C. carnea was slightly affected by the consumption of both BV-infected prey. No preference was shown between healthy and BV-infected S. exigua, and both were preferred vs. the aphid Macrosiphum euphorbiae. Our findings present C. carnea, and particularly its larvae, as a promissory candidate for BV dispersion in the field.Baculoviruses (BV) are highly effective against lepidopteran pests of economic importance such as Spodoptera exigua. The combined use of entomopathogens and macrobiological control agents requires the study of their relationships. Laboratory bioassays were developed to evaluate the interactions between the multiple nucleopolyhedroviruses of S. exigua (SeMNPV) and Autographa californica (AcMNPV), and the predator Chrysoperla carnea. The microscopic examination of predator’s excreta (larval drops and meconia) after the ingestion of BV-infected S. exigua revealed the presence of viral occlusion bodies (OBs). The reinfection of S. exigua larvae with BVs-contaminated excreta by using OBs water suspensions or by direct application both yielded high mortality values but different speed-of-kill results. Meconia killed before in suspensions due to their higher viral load and larval excretion drops did so in direct application due to their liquid nature and their easiness of consumption. The prey-mediated ingestion of SeMNPV and AcMNPV triggered slight effects in C. carnea, which were probably derived from the food nutritional quality. Chrysoperla carnea larvae did not discriminate between healthy and BV-infected S. exigua, while a preference was shown for S. exigua (healthy or infected) vs. Macrosiphum euphorbiae. Our findings present C. carnea, and particularly its larvae, as a promissory candidate for BV dispersion in the field.

Biological control of Drosophila suzukii

Abstract Drosophila suzukii (Matsumura) is native to East Asia but has widely established in the Americas and Europe, where it is a devastating pest of soft-skinned fruits. It has a wide host range and these non-crop habitats harbor the fly which then repeatedly reinvades crop fields. Biological control in non-crop habitats could be the cornerstone for sustainable management at the landscape level. Toward this goal, researchers have developed or investigated biological control tactics. We review over 100 studies, conducted in the Americas, Asia and Europe on natural enemies of D. suzukii . Two previous reviews provided an overview of potential natural enemies and detailed accounts on foreign explorations. Here, we provide an up-to-date list of known or evaluated parasitoids, predators and entomopathogens (pathogenic fungi, bacteria, nematodes, and viruses) and summarize research progress to date. We emphasize a systematic approach toward the development of biological control strategies that can stand alone or be combined with more conventional control tools. Finally, we propose a framework for the integrated use of biological control tools, from classical biological control with host-specific Asian parasitoids, to augmentative and conservation biological control with indigenous natural enemies, to the use of entomopathogens. This review provides a roadmap to foster the use of biological control tools in more sustainable D. suzukii control programs.

Habrobracon hebetor and Pteromalus cerealellae as Tools in Post-Harvest Integrated Pest Management.

Consumers are increasingly demanding pesticide-free grain/legumes and processed foods. Additionally, there are more restrictions, or complete loss, of insecticides labelled for use in managing stored grain insects in post-harvest ecosystems. Suppression of post-harvest pests using parasitic wasps is a more sustainable alternative than chemical pesticides. Habrobracon hebetor (Say) (Hymenoptera: Braconidae) and Pteromalus cerealellae Ashmead (Hymenoptera: Pteromalidae) are two important parasitoids that limit economically important pests of stored products. Host searching ability and reproductive performances of H. hebetor and P. cerealellae depend on a wide range of factors, such as host species, commodities, and environmental conditions. Further, use of entomopathogens can complement the ability of parasitoids to regulate pest populations. This review provides information on aspects of H. hebetor and P. cerealellae biology and successful regulation of post-harvest pest populations.

The role of abiotic factors in the pupation of Thaumatotibia leucotreta Meyrick (Lepidoptera: Tortricidae) in the soil

Abstract A key focus area of the South African citrus industry is the improved control of the phytosanitary citrus pest Thaumatotibia leucotreta (Lepidoptera: Tortricidae). New methods of control for this pest are continually being sought and the use of entomopathogens as biological control agents of the soil-dwelling life stages of T. leucotreta has shown great promise. Current understanding of T. leucotreta pupation biology, behaviour and survival is limited; thus, improving upon this knowledge would be useful for the biological control of this life stage. Abiotic factors, namely soil texture class, ground cover, soil compaction and soil moisture, were investigated in the laboratory, aiming to determine the effects of these on T. leucotreta pupation variables. The investigations consisted of an examination of the wandering behaviour of larvae prior to pupation site selection, the pupation behaviour after selecting a pupation site, and eclosion biology and success. These abiotic factors often had a limited influence on T. leucotreta pupation. Interesting consistencies included limited wandering behaviour, the shallowness of T. leucotreta pupation and a high eclosion success in sandy loam soils in certain cases. These factors are likely to have both positive and negative implications for entomopathogenic biological control programmes.

Synergistic and additive interactions of Serratia marcescens S-JS1 to the chemical insecticides for controlling Nilaparvata lugens (Hemiptera: Delphacidae).

The combined use of entomopathogens and chemical agents has been suggested as an alternative strategy to control pest insects. However, the effectiveness of combinations of entomopathogenic bacteria and insecticides against rice planthoppers is largely unknown. Here, we evaluated the separate and combined effects of an entomopathogenic bacterium, Serratia marcescens S-JS1, and spirotetramat or thiamethoxam insecticides against third-instar nymphs of Nilaparvata lugens Stål (Hemiptera: Delphacidae) under laboratory and greenhouse conditions. Under laboratory conditions, the combinations caused higher mortality in the third-instar nymphs of N. lugens and produced a synergistic or additive effect compared with the treatments with either bacterial suspension or insecticide alone. Application of S-JS1 (1 × 109 cfu/ml) in combination with 20 mg/liter spirotetramat resulted in 80.5% of N. lugens nymphal mortality, compared with 52.7% in spirotetramat alone treatments, and interactions resulted in a synergistic responses. Other combination treatments of S-JS1 with either insecticide concentration all exhibited additive interactions. In further greenhouse tests, S-JS1 (1 × 109 cfu/ml) + spirotetramat (20 mg/liter) and S-JS1 (1 × 109 cfu/ml) + thiamethoxam (5 mg/liter) showed additive effects against the nymphs, and were found to be most effective relative to their individual treatments on days 5 and 9. Our results indicate that S. marcescens S-JS1 combined with insecticide may provide a promising new strategy for controlling N. lugens.

Epidemiology of Entomopathogens: Basis for Rational Use of Microbial Control of Insects

Abstract. Epidemiological studies are important for successful use of entomopathogens for pest management. Although microbial control of insects is applied epidemiology, there are few epidemiological-ecological studies, which partially explains why the use of entomopathogens has ended in failure. Isolated studies using preserved strains of entomopathogens in a laboratory might contribute to lack of efficacy under field conditions. An option is regional exploration of entomopathogens as the basis for epidemiological diagnoses, because this would enable identifying the most prevalent species and isolates that presumably have greater potential for use in pest management. Field epidemiological/ecological diagnoses allow identifying factors that induce the development of epidemics, including the range of hosts, plants, and cropping systems. Understanding their prevalence, dispersal, and pathogenicity is key to successfully detect pathogens in the field. Basic epidemiological characterization includes measuring...

Evaluation of Entomopathogenic Fungi and Delivery Methods for Management of Thrips in Chillies

ABSTRACTSuccessful use of entomopathogenic fungi as microbial control agents of thrips depends on strain virulence, an appropriate delivery system, and timing of application. Use of fungal entomopathogens can be an alternative to synthetic insecticides and could play an important role in bio-intensive pest management. Entomopathogenic fungi may be able to be used for management of chilli thrips, Scirtothrips dorsalis Hood. Laboratory bioassays were performed to evaluate fungal isolates of Beauveria, Metarhizium, Lecanicillium against chilli thrips using different delivery systems. The LC50 values against S. dorsalis indicated that the Beauveria bassiana isolate, Bb 112, had the highest virulence with the lowest LC50 values of 0.6 × 106 spores·mL−1. The time mortality response of S. dorsalis to fungal pathogens indicated that isolate Bb 112 had the lowest LT50 value, 97.68 h. In pot culture on chilli (Capsicum frutescens L., cv. K2), among the entomopathogenic fungal isolates (Bb 111, Bb 112, Bb 101, B2, Bb NBAIR, Bb SBI, and Ml flavoviride var. minus), application of Bb 112 at 108 spores·mL−1 had the highest cumulative mean thrips population reduction, 59.73% and 53.88% in both pot culture experiments. The controlled droplet applicator (CDA) delivery system was effective for application of Bb 112 at 108 spores·mL−1 against S. dorsalis. Mycoinsecticides applied with the CDA sprayer can be used in management of low to moderate populations (two to three thrips per leaf) of S. dorsalis.

Lower Termite Associations with Microbes: Synergy, Protection, and Interplay.

Lower-termites are one of the best studied symbiotic systems in insects. Their ability to feed on a nitrogen-poor, wood-based diet with help from symbiotic microbes has been under investigation for almost a century. A unique microbial consortium living in the guts of lower termites is essential for wood-feeding. Host and symbiont cellulolytic enzymes synergize each other in the termite gut to increase digestive efficiency. Because of their critical role in digestion, gut microbiota are driving forces in all aspects of termite biology. Social living also comes with risks for termites. The combination of group living and a microbe-rich habitat makes termites potentially vulnerable to pathogenic infections. However, the use of entomopathogens for termite control has been largely unsuccessful. One mechanism for this failure may be symbiotic collaboration; i.e., one of the very reasons termites have thrived in the first place. Symbiont contributions are thought to neutralize fungal spores as they pass through the termite gut. Also, when the symbiont community is disrupted pathogen susceptibility increases. These recent discoveries have shed light on novel interactions for symbiotic microbes both within the termite host and with pathogenic invaders. Lower termite biology is therefore tightly linked to symbiotic associations and their resulting physiological collaborations.

Growth of Verticillium tricorpus—A Saprophytic Fungus and Potential Entomopathogen of Cocoa Pod Borer as Affected by the Medium and Light

Cocoa pod borer (CPB) has endangered Indonesian cocoa. Use of entomopathogen in biocontrol of pests is considered to be environmentally friendly approach. Verticillium tricorpus has been reported to be a potential agent for controlling CPB. The aim of this research was to study the possibility in using alternative, easy and cheap media and also the role of intensity and quality of light for mass production of V. tricorpus. The experiments were laid out in split-plot design as factorial, where every combination treatment was replicated three times. Medium, in form of semi-synthetic and natural, was treated as the main plot, while light as sub-plot. Results of this study showed that for the growth and development of fungus V. tricorpus, the use of alternative natural media in form of a mixture of cocoa pod husk and maize was the best. Use of cocoa dextrose agar (CDA) as semi-synthetic medium was more suitable for the growth and development of V. tricorpus compared to potato dextrose agar (PDA). The semi-synthetic and natural media consisted of cocoa husk and maize are suitable for cocoa production area in Indonesia, where mostly cocoa is planted in lowland area and mostly is also suitable for corn but not for potato growing. Growth of the fungus colony especially on CDA medium reached its optimum condition when using white light with the intensity of 1,000 lux. This study proved that the requirement for light quality was different between growth and development purposes. Development of V. tricorpus until the production of conidia in optimal condition was reached with the use of yellow light with the intensity of 1,000 lux.

PATOGENISITAS CENDAWAN ENTOMOPATOGEN Beauveria bassiana (DEUTEROMYCOTINA: HYPHOMYCETES) PADA BERBAGAI STADIA KEPIK HIJAU (NEZARA VIRIDULA L.)

Pathogenicity of Beauveria bassiana Bals. Vuill. (Deuteromycotina:Hyphomycetes) on various stages of eggs and nymphs of the green stink bug (Nezara viridula L.) . The green stink bug (Nezara viridula L.) is one of the important soybean pod-sucking bug besides brown stink bug (Riptortus linearis) and green stink bug (Piezodorus hybneri). Up to now, pest control mostlyrely on the chemical insecticides, The objectiveof this experiment was to study the pathogenicity of Beauveria bassianaon various stages of eggs and nymphs of the green stink bug. Experiment was conducted in the laboratory of Entomology, Indonesian Legumes and Tuber Crops Research Institute (ILETRI) Malang, from January to June 2011. The treatments consists of various eggs and nymphs stages of green stink bug. The results showed that B. bassiana was able to infect the eggs green stink bug both of the newly laid and the six days old eggs. As a results of this infection, 96% eggs did not hatched. The younger of eggs, the more susceptible to B. bassiana. The infected egg prolonged hatching periods to three days. B. bassianawas also toxic to all stages of the green stink bug, especially to the first and second instarswith mortality rate of 69-96%. The nymph of third, fourth, ad fifth instar and adult stage were more tolerant to the B. bassiana infection. This study suggest that one way to control green stink bug be the use of entomopathogen B. bassiana againts their ggs or younginstar.

Imidacloprid Inhibits Behavioral Defences of the Leaf-Cutting Ant Acromyrmex subterraneus subterraneus (Hymenoptera:Formicidae)

Leaf-cutting ants have evolved a range of defensive strategies which complicate the use of entomopathogens for their control. One of these behavioral strategies is self-grooming, which increases when ants detect the presence of fungal conidia on their integuments. We have previously shown that insecticides, when used at ultra-low concentrations, can be synergists of entomopathogenic fungi. It is possible that certain insecticides could modify ant behavior in a way that increases the chances of a fungal infection taking hold. The current study investigated the effects of the neonicotinoid insecticide Imidacloprid (IMI) and the entomopathogenic fungus Beauveria bassiana on self-grooming and locomotion behavior of Acromrymex subterraneus subterraneus workers when ants were exposed to the agents separately or together. Initially 10, 20 and 40 ng/insect IMI was topically administered to worker ants. Four hours after administration, the ants were placed into an experimental arena and self-grooming and locomotion behaviors were recorded for 10 min. Separate groups of ants were exposed to filter paper discs impregnated with conidial suspensions and 4 h later their behavior was monitored for 10 min. Subsequently, ants were treated with 10 ng/insect IMI, immediately exposed to fungal suspensions and 4 h later their behavior was monitored. The 10 ng/insect IMI treatment resulted in higher locomotor activity and lower self-grooming when compared to vehicle, 20 ng and 40 ng IMI treatments. Exposure to fungal conidia produced low locomotion and high self-grooming behaviors. The 10 ng IMI + fungal conidia treatment resulted in lower self-grooming and higher locomotion behavior. These alterations caused by a low concentration of IMI could increase ant susceptibility to infection by entomopathogenic fungi and are thus of interest for future tests in the development of integrated pest management strategies.