The Indian meal moth, Plodia interpunctella (Lepidoptera: Pyralidae) is one of the most important stored product pests. Fumigation plays a significant role in the management of insect pests in stored-products. However, the use of fumigants is problematic because of their effects on the environment and high costs. Entomopathogenic organisms are environmentally friendly control agents and suppress pest populations under natural conditions. In this study, distribution and occurrence of a microsporidian pathogen, Vairimorpha plodiae (Opisthokonta: Microspora) in the populations of P. interpunctella from 12 localities representing Turkey between 2019 and 2020 are presented for the first time by confirming its effectiveness on natural populations. The presence of the microsporidian pathogen was found in 11 of 12 (91.7%) populations. In total, 863 of 3,044 samples were infected by the pathogen. Infection mean was 28.4% for all populations. Our results showed that V. plodiae infection reached to a considerably high prevalence (88.77%) in P. interpunctella populations and varied from 5.1 to 88.7% between the populations. In addition, microsporidia infections have been identified throughout Turkey. We found that V. plodiae can infect all life stages of P. interpunctella. Totally, 623 (28.5%) of 2187 larvae, 14 (37.8%) of 37 pupae, 226 (27%) of 820 adults were found to be infected by the pathogen. There were considerable differences between the dead and living larvae. The microsporidian infection was found in 26 (11.6%) of 225 living larvae, whereas it was found in 595 (30.5%) of 1,952 dead larvae. These results confirm that the microsporidia pathogen has a high spreading potential in P. interpunctella populations and can be a natural biological suppression factor on pest populations.
The epidemiological and epizootic importance of ticks has been known for a few decades since of the discovery of their role as vectors of many new diseases, and the better detection of those already known. Given the durability of chemical preparations in the environment and the increasing problem of developing tick resistance, natural strategies for biological control are sought. A promising alternative to chemical pesticides is the use of entomopathogenic organisms for effective integrated pest management of low environmental impact. A number of promising microbes have been identified during the search for effective means of controlling the tick population, but the knowledge about the impact of these pathogens on the environment and other non-target organisms is still insufficient. Previous research has still not provided a definite answer about the safety of their use. It is known, however, that the chemicals which are currently used have a negative impact on the environment and/or cause resistance. No efficient biocompound has yet been devised for commercial use. Potential microorganisms for tick biocontrol (mainly bacteria and fungi) are natural tick pathogens, living in the same environment. With their adhesive properties, and their ability to digest the cuticle, they may constitute an appropriate ingredient of bioacaricides. Until now, fungal insecticides have been used only to control crop pests.
Entomopathogenic fungi have great potential as biological control agents against insect pests. So they are being developed worldwide for the control of many pests of agricultural importance. But their effect on non-target insects, such as natural enemies has been a matter of great concern. Recently we came across an entomopathogen infecting a laboratory culture of Zygogramma bicolorata, a potential biocontol agent of noxious weed, Parthenium hysterophorus. The pathogen was isolated from the grubs and beetles and identified as Beauveria bassiana. In the present paper, the entomopathogen, B. bassiana is reported and described for the first time from the laboratory culture of Z. bicolorata.
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Grzyby entomopatogeniczne mają duży potencjał jako czynniki biologicznego zwalczania szkodników owadów, co spowodowało, że zainteresowano się ich rozwojem, w celu zwalczania wielu ważnych szkodników w rolnictwie. Są one ich naturalnymi wrogami. Ostatnio wykryto entomopatogena infekującego laboratoryjną kulturę Zygogamma bicolorata, który jest potencjalnym czynnikiem biologicznego zwalczania szkodliwego chwastu Parthenium hysterophorus. Patogen ten został wyosobniony z larw chrząszczy i określony jako Beauveria bassiana. Artykuł jest pierwszym doniesieniem i pierwszym opisem Z. bicolorata z kultury laboratoryjnej.
Helicosporidia are gut parasites of invertebrates. These achlorophyllous, non-photosynthetic green algae are the first reported to infect insects. Helicosporidia are members of the green algal class Trebouxiophyceae and are further related to the photosynthetic and non-photosynthetic genera Auxenochlorella and Prototheca, respectively, the latter of which can also turn to parasitism under opportunistic conditions. Molecular analyses suggest that Helicosporidia diverged from other photosynthetic trebouxiophytes less than 200 million years ago and that its adaptation to parasitism is therefore recent. In this minireview, we summarize the current knowledge of helicosporidian genomics. Unlike many well-known parasitic lineages, the Helicosporidium sp. organelle and nuclear genomes have lost surprisingly little in terms of coding content aside from photosynthesis-related genes. While the small size of its nuclear genome compared to other sequenced trebouxiophycean representatives suggests that Helicosporidium is going through a streamlining process, this scenario cannot be ascertained at this stage. Genome expansions and contractions have occurred independently multiple times in the green algae, and the small size of the Helicosporidium genome may reflect a lack of expansion from a lean ancestor state rather than a tendency towards reduction.
From our experiments it appears that parasitic fungus, Conidiobolus coronatus, infected 12 insect species we have tested, while another 8 species did not suffer after contact with this pathogen. The culture filtrates and mycelial homogenates of C. coronatus contain toxic proteins. By means of two steps FPLC: gel filtration followed by ion-exchange chromatography, we isolated a 30 kDa toxic protein from the culture filtrate. The 30 kDa protein appeared to be very potent on Galleria mellonella larvae: LD₅₀ was less than 5 ng/larva. Rabbit polyclonal anti-30 kDa immunoglobulins specifically recognized this fungal toxin. Using antibodies we showed that 30 kDa mycotoxin is present in C. coronatus conidia, hyphae and is released by the fungus into the incubation liquid medium.
Fungal entomopathogens can naturally regulate populations of various insects. The entomopathogen Beauveria bassiana (Bals.- Criv.) Vuill. is also able to endophytically colonize different plants. Endophytic colonization by entomopathogens may provide a source of indirect interactions between fungi and insects and has been associated with the ability of the fungus to control insect pests. The tomato leaf miner, Tuta absoluta (Meyrick) is considered one of the most devastating pests of tomato (Solanum lycopersicum L.) and its difficult control is due to its miner habit, short life cycle, and high reproductive capacity. The aims of this study were: (i) to use three different techniques, i.e. leaf spraying, seed immersion and root dipping, for the endophytic inoculation of B. bassiana in tomato plants; and (ii) to assess the effect of B. bassiana on tomato leaf consumption and mortality of T. absoluta after inoculation. The percentage of colonization by B. bassiana was assessed 7, 14 and 28 days after inoculation. All inoculation techniques employed allowed the recovery of B. bassiana, although our results showed significant differences between techniques. Leaf spraying was the most effective, with the highest percentage of colonization recorded 7 days after inoculation. We also evaluated (i) the effect on the mortality of T. absoluta by direct contact with conidia of B. bassiana, and (ii) the effect on tomato leaf consumption and mortality by indirect contact through ingestion of inoculated plant tissues with B. bassiana. Mortality bioassays showed that B. bassiana infected T. absoluta, either by direct contact or indirectly, via ingestion of inoculated tomato leaves. Direct contact showed a higher percentage of mortality and a lower median survival time (MST) than indirect contact. Significant differences in the mortality percentages of T. absoluta after exposure with B. bassiana were found among the treatments and the control. Our results suggest that the endophytic inoculation of B. bassiana in tomato crops provides the basis for further investigation, which should focus on the virulence of the endophytic B. bassiana against T. absoluta.
Bollworms comprise the most harmful and economically relevant species of lepidopteran. Helicoverpa gelotopoeon (D.) (Lepidoptera: Noctuidae) is native to America and affects many crops. Tobacco is an industrial crop in which methods of pest control rely mainly on the application of insecticides. To develop new eco-friendly strategies against insect pests it is very important to overcome the side effects of insecticides. The utilization of fungal entomopathogens as endophytes is a new perspective that may accomplish good results. The present study aimed to evaluate the ability of endophytic Beauveria bassiana (Bals.-Criv.) Vuill. to affect H. gelotopoeon life parameters and feeding behavior on tobacco plants. Beauveria bassiana LPSC 1215 as an endophyte did not reduce the amount of vegetal material consumed by H. gelotopoeon larvae but affected the life cycle period of the plague, particularly the larval and adult stages. Also, egg fertility was affected since adults laid eggs that were not able to hatch. The results of this investigation provide new information on endophytic entomopathogen potential to be incorporated in Integrated Pest Management (IPM) programs.
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