Synergistic effects of the entomopathogenic fungus Isaria javanica and low doses of dinotefuran on the efficient control of the rice pest Sogatella furcifera

The rice planthopper,Sogatella furcifera,is a piercing-sucking insect pest of rice,Oryza sativa.It is responsible for significant crop yield losses,and has developed moderate to high resistance to several commonly used chemical insecticides.We investigated the effects of the insect fungal pathogen Isaria javanica,alone and in combination with the chemical insecticide dinotefuran,on S.furcifera under both laboratory and field conditions.Our results show that I.javanica displays high infection efficiency and mortality for different stages of S.furcifera,reducing adult survival,female oviposition and ovary development.Laboratory bioassays showed that the combined use of I.javanica with a low dose(4-16 mg L^(-1))of dinotefuran resulted in higher mortality in S.furcifera than the use of I.javanica or dinotefuran alone.The combined treatment also had more significant effects on several host enzymes,including superoxide dismutase,catalase,peroxidase,and prophenol oxidase activities.In field trials,I.javanica effectively suppressed populations of rice planthoppers to low levels(22-64%of the level in untreated plots).Additional field experiments showed synergistic effects,i.e.,enhanced efficiency,for the control of S.furcifera populations using the combination of a low dose of I.javanica(1×10^(4) conidia mL^(-1))and a low dose of dinotefuran(~4.8-19.2%of normal field use levels),with control effects of>90%and a population level under 50 insects per 100 hills at 3-14 days post-treatment.Our findings indicate that the entomogenous fungus I.javanica offers an attractive biological control addition as part of the integrated pest management(IPM)practices for the control of rice plant pests.

Secondary Metabolites of Entomopathogenic Fungi, Biological Alternative for the Control of Agricultural Pests and Disease: Present and Perspectives

The use of entomopathogenic fungi (EF) in recent years has been highly effective against the different orders of insects considered pests of agricultural importance and their conidia have been commonly applied, but it has been reported that these are sensitive to the environmental conditions. For this reason, biopesticides products have been formulated based on secondary metabolites, recently. These biomolecules participate as biological control agent, such as: cyclic depsipeptides, amino acids, polyketides, polyphenols and terpenoids, affecting their morphology, life cycle and insect behavior. The use of secondary metabolites of entomopathogenic fungi opens the possibility of application in a more efficient way for the control of agricultural pests in a compatible with the environment and human health;therefore, it is important to know, analyzing the type of molecules, their effects, and their different methods of application.

Advance of entomopathogenic nematodes

This paper summarized the history and present condition of studying and utilizing entomopathogenic nematodes at home and abroad, expounded its taxonomy, life cycle and the mechanism with symbiotic bacteria killing host insect. Taxonomy, mycelial form, pathogenic function and anti-bacteria function of symbiotic bacteria were introduced. Production and utilization of entomopathogenic nematodes, the characteristic genetic improvement by use of biological engineering technology, as well as the existing problem and applying foreground were also discussed.

Isolation and efficacy of entomopathogenic fungus(Metarhizium anisopliae)for the control of Aedes albopictus Skuse larvae:suspected dengue vector in Pakistan

Objective:To isolate the entomopathogenic fungus Metarhixium anisopliae(M.anisopliae) in the local environment,and evaluate its efficacy against the suspected dengue vector Aedes albopictus in Pakistan.Methods:According to the standard procedure,M.anisopliae was isolated from the dead mosquitoes which were collected from the field or dead after the collection.Bioassay was performed to determine its efficacy.Results:The results indicated that M.anisopliae had larvicidal effect with LC,value 1.09×10~5 and LC_(50) value 1.90×10^(13) while it took 45.41 h to kill 50% of tested population.Conclusions:Taking long time to kill 50%population when compare with the synthetic insecticides,is the only drawback for the use of entomopathogenic fungus but these bio-pesticides are safe for the use.

Evaluation of the virulence of entomopathogenic fungus, Isaria fumosorosea isolates against subterranean termites Coptotermes spp.(Isoptera:Rhinotermitidae)

The entomopathogenic fungus Isaria fumosorosea Wize, formerly known as Paecilomyces fumosoroseus is reported as a promising biocontrol agent for controlling subterranean termites, particularly those belonging to the family Rhinotermitidae. In Malaysia, the family Rhinotermitidae includes two species of subterranean termites with extremely high economic importance; namely Coptotermes curvignathus Holmgren, and the Asian SLubterranean Termite (Coptotermes gestroi Wasmann). To comprehend the potential control of this soil-dwelling fungus against these subterranean termites in Malaysia, an investigation was carried out by testing the pathogenecity of 11 isolates against these termite species. All isolates showed pathogenic potential against the termite (Mortality rate of C. curvignathus:84.4%; C. gestroi:67.3%). IsolatePF49 was the most effective against both species of termites and was further tested for its virulence and mycosis.The LC_(50) values of PF49 against C. curvignathus and C.gestroi were 7.55×103 and 1.09×102 conidia/ml,respectively. The average number of days required to complete the mycosis process in C. curvignathus and C.gestroi were 4.7 and 8 days, respectively. These fungi are believed useful for protecting living trees, plants, wood,wood structures, and other cellulosic materials susceptible to termite infestation and damage.

Pathogenicity of bacterium, Xenorhabdus nematophila isolated from entomopathogenic nematode (Steinernema carpocapsae) and its secretion against Galleria mellonella larvae

The entomopathogenic bacterium, Xenorhabdus nematophila was isolated from the hemolymph of Galleria mel- lonella infected with Steinernema carpocapsae. The bacterial cells and its metabolic secretions have been found lethal to the Galleria larvae. Toxic secretion in broth caused 95% mortality within 4 d of application whereas the bacterial cells caused 93% mortality after 6 d. When filter and sand substrates were compared, the later one was observed as appropriate. Similarly, bacterial cells and secretion in broth were more effective at 14% moisture and 25 °C temperature treatments. Maximum insect mortality (100%) was observed when bacterial concentration of 4×106 cells/ml was used. Similarly, maximum bacterial cells in broth (95%) were penetrated into the insect body within 2 h of their application. However, when stored bacterial toxic secretion was applied to the insects its efficacy declined. On the other hand, when the same toxic secretion was dried and then dissolved either in broth or water was proved to be effective. The present study showed that the bacterium, X. nematophila or its toxic secretion can be used as an important component of integrated pest management against Galleria.

Microbial control of diamondback moth, Plutella xylostella L. （Lepidoptera： Yponomeutidae） using bacteria （Xenorhabdus nematophila） and its metabolites from the entomopathogenic nematode Steinernema carpocapsae

Cells and cell-free solutions of the culture filtrate of the bacterial symbiont, Xenorhabdus nematophila taken from the entomopathogenic nematode Steinernema carpocapsae in aqueous broth suspensions were lethal to larvae of the diamondback moth Plutella xylostella. Their application on leaves of Chinese cabbage indicated that the cells can penetrate into the insects in the absence of the nematode vector. Cell-free solutions containing metabolites were also proved as effective as bacterial cells suspension. The application of aqueous suspensions of cells of X.nematophila or solutions containing its toxic metabolites to the leaves represents a possible new strategy for controlling insect pests on foliage.

Interactions between Entomopathogenic Fungi and Entomophagous Insects

Direct treatment of predators with entomopathogenic fungi (EPF) at different concentrations revealed that some species, like Beauveria bassiana and Metarhizium anisopliae, were found to have detrimental effects on all developmental stages of some predator species. Other species, like Numoraea rileyi and Paecilomycis fumosorosius, showed little or no effect on treated predators. Adult predators were found to avoid feeding on fungi-infected prey. EPF could be isolated from hibernating or field-collected coccinellids. Some studies indicated that combining a fungus with a predator could increase the rate of insect control in the field. As for parasitoids, this review indicates that the developmental stages of the egg parasitoids can develop successfully in host eggs treated with fungi. However, fungus-infected hosts negatively impact the development of larval parasitoids inside such hosts and this impact depends on the species and concentration of the fungus as well as the time between infection and parasitism. Some parasitoid females can discriminate between fungus-infected and uninfected hosts and do not parasitize the infected hosts. With appropriate timing, the parasitoids or predators could be combined with fungi for the biological control of insects in the field.

Diversity of Entomopathogenic Fungi in Argane Forest Soil and Their Potential to Manage Mediterranean Fruit Fly （Ceratitis capitata）

The present study forms a part of biological control against the medfly （Ceratitis capitata） and seeks to isolate and determine the diversity of the medfly-associated entomopathogenic fungi in soil samples collected from Argane （Argania spinosa） forest, in different localities of Souss-Massa region. Search and isolation of the indigenous populations of Ceratitis capitata entomopathogenic fungi was carried out by using larvae of this pest as baits. After trapping, isolation and identification of fungal isolates, a pathogenicity test was used to select fungal strains that have significant virulence potential against the Mediterranean fruit fly. The degree of virulence was estimated by the ability of the fungus to induce the disease and/or the death in the insect and also by calculating the lethal time 50 （LT50）. The obtained results were clearly demonstrated the sensitivity of medfly to tested fungal strains and particularly to strains of Fusarium sp., Aspergillus niger and Scopulariopsis sp. that have shown high mortality rates （more than 84%） and to Trichoderma harzianum, Scedosporium sp., Epicoeeum sp. and Ulocladium sp. with more than 70% mortality for the two tested concentrations. Furthermore these strains showed short LT50 （less than 83 hours）. All these results confirm the presence of entomopathogenic fungi of Ceratitis capitata in Argane soil, and prove the potential of entomopathogenic fungi for biocontrol of the Mediterranean fruit fly under laboratory conditions.

Effectiveness of entomopathogenic fungal strains against poplar/willow weevil(Cryptorhynchus lapathi L.)larvae

The poplar and willow weevil,Crypto rhynchus lapathi L.,a major universally destructive wood-boring insect has become one of the important quarantine pests that is extremely destructive to forestry development and needs to be controlled.Entomopathogenic fungi(EPF) are considered safe and friendly for humans and the environment and play important roles in controlling insect pest populations.In this study,the screening of entomopathogenic fungi for control of C.lapathi is reported through the evaluation of virulence of four fungal Beauveria bassiana(CFCC81428,CFCC83116,CFCC83486,CFCC87297)strains,one B.brongniartii(CFCC83487) strain and one Metarhizium anisopliae(CFCC88953) strain.The virulence of the different strains was appraised by correct mortality rate,cumulative mortality rate,median lethal concentration(LC_(50)) and median lethal time(LT_(50)).B.bassiana strains CFCC81428 and CFCC83116 were the most virulent among the six strains with a mortality up to 100%,and the LT_(50) were 2.7 and 3.1 days.Five conidia concentrations of three strains(CFCC81428,CFCC83116 and CFCC87298) that caused high virulence was screened for dose-relationship.Their effect on controlling C.lapathi larvae were also determined under field condition by brushing conidia suspensions on C.lapathi larvae infested in a poplar trunk.The cumulative rate in the field was lower than those obtained from the laboratory,but the order of the virulence of different strains did not change.Mortality in all three strains occurred at their highest concentration(1.0 × 10^(8) conidia mL^(-1)).Under field conditions,the CFCC81428 strain was the most effective,causing mortalities of 80.3% and 75.2%in two plots in Beipiao and Lindian counties,respectively,followed by CFCC83116(69.1%,66.6%) and CFCC87298(60.7%,59.3%).Based on our results,the B.bassiana strain CFCC81428 has the potential as a biological insecticide to control C.lapathi larvae.

Biocontrol potential of entomopathogenic nematode,Heterorhabditis indica against pink bollworm,Pectinophora gossypiella(Saunders)(Lepidoptera:Gelechiidae)

Background The emergence of pink bollworm(PBW),Pectinophora gossypiella(Saunders)(Lepidoptera:Gelechiidae),in cotton due to Bt resistance and concealed feeding habit has created a need for alternative,eco-friendly,and cost-effective control methods.This study aimed to evaluate the bio-efficacy and reproductive potential of two native strains of entomopathogenic nematodes(EPNs),Heterorhabditis indica,namely CICR-HI-CL and CICR-HI-MN,against PBW larvae and pupae under in-vitro conditions.Results The larval assay revealed that strain CICR-HI-CL exhibited higher potency than strain CICR-HI-MN against 2nd,3rd,and 4thinstar larvae,with median lethal dose(LD50)values of 5.45,4.45,and 4.60 infective juveniles(IJs)per larva,respectively.In case of pupal bioassay,both EPN strains demonstrated greater virulence when applied directly(LD50values:29.65 and 73.88 IJs per pupa for strains CICR-HI-CL and CICR-HI-MN,respectively)compared to soil application(147.84 and 272.38 IJs per pupa).Both EPN strains successfully penetrated and reproduced on 4thinstar larvae,resulting in maximum production of 19.28 and 20.85 lakh IJs per larva in the next generation when inoculated at 30 IJs per larva.Conclusion The present study has generated useful information on the virulence and reproductive potential of two strains of EPN H.indica(CICR-HI-CL and CICR-HI-MN)against PBW,a dreaded pest of cotton.Higher virulence and reproductive potential of EPN strains demonstrated their ability to multiply,sustain and perpetuate on larval and pupal stages of PBW.The knowledge generated will help formulate effective management strategies for PBW with the inclusion of EPN as a potential biological control candidate.The soil-dwelling life stages viz.,last instar hibernating larvae and pupae of PBW can be the ideal weak links to make a successful use of H.indica for sustainable management of PBW in the cotton ecosystem.However,before taking these EPN strains to field for managing PBW,detailed studies investigating their biocontrol potential against PBW under field conditions are needed.

Interactions between Entomopathogenic Nematodes and Entomophagous Insects

The objective of this review article is to clarify the different interactions between entomopathogenic nematodes, as bio-control agents, against other bio-control agents (parasitoids and predators) proposed by the researchers. Thus, it gives clear information concerning the potential of combining them as a part of Integrated Pest Management (IPM) programs against insect pests. Some laboratory studies showed that the treatment of predacious insects by entomopathogenic nematodes (EPNs) at different concentrations can infect and kill the treated larva, nymphs and adults of predators. The percentages of mortality were found to be high (up to 100%), moderate (15% - 35%) or low (3% - 7%). Other studies revealed the resistant of treated predators to nematode-infection. Some predators that were offered infected prey avoid feeding on such prey and, in contrast, the soil predators (ants and mites) consumed the offered cadavers as well as the infective juvenile of the nematodes and did not show any detrimental effects. Mostly, parasitoids cannot complete their development inside or on nematode-infected hosts if parasitism occurs before or early after infection. The parasitoid females may avoid laying eggs in the infected hosts or cannot discriminate between healthy and infected hosts. A field study demonstrated that applying EPNs combined with the predator, Labidura riparia significantly reduced the population of the target pest compared to the nematode or the predator alone. Also, two field experiments indicated that the combination of parasitoids and nematodes can be successful for insect pest management.

Test of Culture and Biomass Production of the Entomopathogenic Fungus Beauveria bassiana （Bals.-Criv.） （Vu//., 1912） on Lactoserm, Margine and Olive Pomace

Entomopathogenic microorganisms occupy an important place among the alternative methods of fighting against pests insect. The fungus Beauveria bassiana is an agent naturally present in ecosystems. It has potential to control pest populations. In the context of biological control, the present work aims to the study of linear growth of Beauveria bassiana on different natural environments from the food industry. They are the raw whey, water and pomace, and followed the development of the fungus through a trial production of biomass on deproteinized whey.

A New Neogregarine Entomopathogen from Crioceris asparagi （Linne, 1758） in Turkey

In present study, a neogregarine from Crioceris asparagi is reported for the first time in Turkey. C. asparagi （common asparagus beetle） is an important pest of Asparagus officinalis L. crops in Turkey and the world. Therefore, determining of the protist pathogens of C. asparagi is aimed. During the study, a total of 1,099 C. asparagi adults were examined thoroughly using a light microscope. Insects were collected from the provinces of Manisa, Eskisehir and Bahkesir in Turkey, with 117 of them collected from Manisa, 204 of them from Bahkesir and 778 of them from Eskisehir. A neogregarine pathogen was found in Bahkesir and Manisa. Total infection rate was 18% for Bahkesir between the years 2014-2015 and 15.3% for Manisa in 2011. Oocysts of the neogregarine pathogen were observed only in malpighian tubes of C. asparagi adults. Fresh mature oocysts of the neogregarine was measured as 9.34 ± 0.74 lam （n = 50） in length and 5.27 ± 0.36 μm （n = 50） in width. Identification of entomopathogens is prerequisite for their use in biological control.

Effect of the Entomopathogenic Fungus, Paceilomyces farinosus （Dicks ex fr.） on the Reproductive Potential of Melasoma populi L.

The effect of the Entomopathogenic fungus, Paceilomyces farinosus on reproductive potential of female survivors, egg viability and total egg production of poplar leaf beetle Melasoma populi L. was investigated in Plant Protection Department laboratories, School of Plant Production, Faculty of Agriculture and Forestry, Duhok University in Spring 2011. Prepupae, pupae and newly emerged adults were treated with spore suspension of P.farinosus （1 ~ 10s conidia/mL）. Another group of adults were reared on sprayed poplar leaves with a same concentration of conidial suspension. Eggs production and hatching percentage were monitored daily over a 7-wk period. Overall reproductive capacity was significantly lower as compared with control. The total number of eggs per surviving female was 85.50, 149.50, 123.43 and 280.24 eggs for pre-pupa, pupa, adult and leaves treated, respectively as compared with 299.75 in control after fourth week. Pre-oviposition, ovipostion, post-oviposition days and the longevity of females and males were shorter in treated individuals compared with control. The lowest percentage hatching was 75.12% in eggs deposited by adults feed on treated leaves as compared with 98.42% in control.

Different Susceptibility in the Two Sympatric Sweet Potato Weevils, Cylas formicarius and Euscepes postfasciatus, to the Entomopathogenic Fungus Metarhizium anisopliae

Laboratory and field experiments were performed to evaluate the pathogenicity of an isolate of the entomopathogenic fungus Metarhizium anisopliae to the two sympatrically occurring weevil species, Cylas formicarius and Euscepes postfasciatus. In the laboratory bioassays, suspension of conidia, ≥106 CFU/mL, caused mortalities > 80% on adults of both weevils in seven days after inoculation. It took longer time 20 days for grain formulation of the isolate adhered on rice grains of ≥5 g/m2 (107 CFU/g) to attain similar mortalities of E. postfasciatus, but no evident mortality was obtained in C. formicarius. The grain formulation was thus less effective on C. formicarius than the suspension. Field trials were carried out over two years from 2013 to 2014, in which adults of E. postfasciatus were released two times during the field experiments for enhancement of damage on plants by this weevil, whereas the other weevil species was left to naturally invade the experimental plots by flying. The results of the experiments revealed in both years that two applications of the isolate in grain formulation, equivalent to 50 kg/hectare, sprayed manually over the ground surface reduced the infestation of plants and tuber damage by weevils of both species as much as the conventional chemical insecticide applications. The occurrences of weevils at harvest were not significantly different among treatments. The potential and possible uses of the fungus are discussed for the management of these two weevil species.

Susceptibility of Economic Dipteran Fruit Flies to Entomopathogenic Nematodes

The present review article demonstrates laboratory and field evaluations of entomopathogenic nematodes(EPNs)against different developmental stages of fruit flies.The virulence of the EPNs differed clearly even on the same insect species and/or by the same nematode species.Such differences might be attributed to some reasons such as the method of treatment as well as the concentrations of the tested nematodes.Fruit flies are among the most important insect pests infesting vegetables and fruits causing considerable losses in the yields worldwide.In laboratory studies,the tested nematodes proved to be highly virulent to larvae as percentage of mortality may reach 100%.As for treated pupae,at different ages,the results are variable and controversially;some studies revealed their moderate or high susceptibility to nematode infection and others indicated low susceptibility or resistance to infection.Treated adults,or those emerged from treated larvae or pupae,are also susceptible to infection.In semi-field and field trials,EPNs proved to be successful for reducing the populations of some fruit flies with up to 85%at concentrations not less than 100 infective juveniles(IJs)/cm^2 of soil.However,the field applications of commercial EPNs have been recommended to be 2.5-5 x 10^9 IJs/ha(25-50 IJs/cm^2 of soil).

Bemisia tabaci： The current situation in the UK and the prospect of developing strategies for eradication using entomopathogens

The sweetpotato whitefly, Bemisia tabaci （Gennadius） （Hemiptera： Aleyrodidae） remains a serious threat to crops worldwide. The damaging B-biotype is of specific economic concern because it is an effective vector of over 111 viruses from several fam- ilies, particularly geminiviruses. Bemisia tabaci is regularly intercepted on plants coming into the UK where it is subjected to a policy of eradication. The UK maintains Protective Zone status against this pest. A main pathway of entry of B. tabaci into the Protected Zone involves propagating material, especially Poinsettia （Euphorbia pulcherrima）. With increased insecticide resistance continuously being recorded, B. tabaci is becoming more difficult to control/eradicate. Recent research involving both entomopathogenic nematodes and fungi is showing much potential for the development of control programs for this pest. Both the nematode Steinernemafeltiae and the fungus Lecanicillium muscarium have been shown to be most effective against second instar B. tabaci. Fine-tuning of the environmental conditions required has also increased their efficacy. The entomopathogens have also shown a high level of compatibility with chemical insecticides, all increasing their potential to be incorporated into control strategies against B. tabaci.

Further compatibility tests of the entomopathogenic fungus Lecanicillium muscarium with conventional insecticide products for control of sweetpotato whitefly, Bemisia tabaci on poinsettia plants

The effect on spore germination of the entomopathogenic fungus Lecanicillium muscarium following direct exposure for 24 h to the insecticides Majestik, Spray Oil, Agri- 50E, Savona and Oberon for the control of both egg and second instar stages of the sweetpotato whitefly, Bemisia tabaci, was determined. Exposure to both Agri-50E and Oberon was followed by acceptable spore germination. Infectivity rates ofL. muscarium on poinsettia foliage in the presence of dry residues of the insecticides were also investigated. No significant detrimental effects on the levels of control of B. tabaci were recorded compared with fungus applied to residue-free foliage. Sequential application of the chemicals Savona, Spray Oil and Majestik with the fungus all produced mortalities of second instar B. tabaci above 90%. Incorporation of these chemicals with L. muscarium into integrated control programs for B. tabaci is discussed.

The integrated use of chemical insecticides and the entomopathogenic nematode, Steinemema carpocapsae （Nematoda： Steinernematidae）, for the control of sweetpotato whitefly, Bemisia tabaci （Hemiptera： Aleyrodidae）

The integration of chemical insecticides and infective juveniles of the entomopathogenic nematode Steinernema carpocapsae （Wesier） （Nematoda： Steinernematidae）, to control second instars of the sweetpotato whitefly, Bemisia tabaci Gennadius （Hemiptera： Aleyrodidae） was investigated. Using a sand bioassay, the effects of direct exposure of S. carpocapsae for 24 h to field rate dilutions of four insecticides （spiromesifen, thiacloprid, imidacloprid and pymetrozine） on infectivity to Galleria mellonella larvae were tested. Although all chemicals tested, except spiromesifen, produced acceptable nematode infectivity rates, they were all significantly less than the water control. The effect of insecticide treatment （dry residues of spiromesifen, thiacloprid and pymetrozine and soil drench of imidacloprid） on the efficacy of the nematode against B. tabaci was also investigated. Nematodes in combination with thiacloprid and spiromesifen gave higher B. tabaci mortality （86.5% and 94.3% respectively） compared to using nematodes alone （75.2%） on tomato plants. There was no significant difference in B. tabaci mortality when using the chemicals imidacloprid, pymetrozine and spiromesifen in conjunction with nematodes compared to using the chemicals alone. However, using thiacloprid in combination with the nematodes produced significantly higher B. tabaci mortality than using the chemical alone. The integration of S. carpocapsae and these chemical agents into current integrated pest management programmes for the control of B. tabaci is discussed.