Four new species of the genus Niveomyces are described from Thailand. They were found as mycoparasites on: Ophiocordyceps infecting flies ( Diptera ) for Niveomyces albus ; ants ( Hymenoptera ) for ...N. formicidarum ; and leafhoppers ( Hemiptera ) for N. hirsutellae and N. multisynnematus . A new genus, Pseudoniveomyces with two species: Pseudoniveo. blattae (type species), parasitic on Ophiocordyceps infecting cockroaches, and Pseudoniveo. arachnovorum , found on a spider egg sac, are also described. These fungi share a common feature which is a sporothrix-like asexual morph. Based on our molecular data, Sporothrix insectorum is shown to be affiliated to the genus Niveomyces , and thus a new combination N. insectorum comb. nov. is proposed. Niveomyces coronatus , N. formicidarum and N . insectorum formed the N. coronatus species complex found on ant-pathogenic Ophiocordyceps from different continents. Pseudoniveomyces species are distinguished from Niveomyces spp. based on the presence of fusoid macroconidia in culture and a red pigment diffused in the medium, resembling to Gibellula and Hevansia . The molecular phylogenetic analyses also confirmed its generic status. The host/substrates associated with the genera within Cordycipitaceae were mapped onto the phylogeny to demonstrate that mycoparasitism also evolved independently multiple times in this family.
The whitefly, Bemisia tabaci (Gennadius), is a key pest of many economically important crops grown in the field and in greenhouses throughout the world. Because entomopathogenic fungi (EPF) are ...potential biological control agents for B. tabaci, however, minimal research has been conducted on using fungal strains to control B. tabaci. In this study, four EPF strains were isolated and identified as Lecanicillium attenuatum (Zare & Gams) JL-003, Beauveria bassiana Balsamo (Vuillemin) JL-005, Lecanicillium longisporum (Petch) JL-006, and Akanthomyces lecanii (Zimmerman) JL-007, based on rDNA-ITS sequence analysis. In comparing the virulence of the four fungi against the different life stages (i.e., eggs, 1st-, 2nd-, 3rd-, 4th-instar nymphs, and adults) of B. tabaci the mortality of B. tabaci decreased and LT50 values increased as the conidia concentration decreased in a series of conidia concentrations (1 × 105, 106, 107, and 108 conidia/mL). The fungal strains L. attenuatum JL-003 (LC50: 1.31 × 106) and B. bassiana JL-005 (LC50: 0.92 × 106) were found to be more effective than L. longisporum JL-006 (LC50: 4.97 × 107) and A. lecanii JL-007 (LC50: 6.46 × 106). Fourth-instar nymphs, eggs, and adult stages of B. tabaci were less susceptible to all fungal strains compared to 1st-, 2nd-, and 3rd-instar nymphs. The virulence of L. attenuatum, which was tested for the first time on B. tabaci, was found to be more toxic to early-stage nymphs. Our data will be useful in biological control programs that are considering using EPF against B. tabaci. Graphical Abstract
Temperature critically affects the performance of entomopathogenic fungi (EPF). Mathematical models are critical tools used in predictive microbiology but are less adopted for EPF. We selected eight ...nonlinear models to describe thermal biology; minimum (T
min
), optimal (T
opt
) and maximum (T
max
) thresholds; and maximal growth (P
max
) of EPF. Conidial germination and mycelial growth of Metarhizium anisopliae (ICIPE 7, ICIPE 20, ICIPE 62, ICIPE 69, ICIPE 78) and Beauveria bassiana (ICIPE 284) isolates incubated at 12, 16, 20, 24, 28, 32 and 36°C were measured and fitted to the models. The models were compared using the Akaike information criterion (AIC) and adjusted R
2
. The best-fitting models for germination of the isolates were the cardinal temperature model with inflection (CTMI), Ratkowsky 3 and the generalised β function, while the best-fitting models for growth were CTMI, Ratkowsky 3, Lactin 1 and generalised β function. Brière 1, Brière 2, Ratkowsky 2, and Van Der Heide least fitted most germination and growth datasets. T
min
, T
opt
, T
max
and P
max
ranged from 13.3-13.6°C, 26.3-28.1°C, 35.7-36.3°C and 95.4-100.0% for germination, and 3.7-13.7°C, 25.9-28.6°C, 35.4-37.2°C and 1.44-2.34 mm day
-1
for growth, respectively. T
opt
were below temperatures of central bee brood areas and partly mirrored temperatures of the isolates' regions of origin. The best-fitting models can be used to better match EPF with different regions' temperatures for optimal performance against target pests.
Entomopathogenic fungi are promising biocontrol agents for pest management, but they could be sensitive to application methods. Sprayers, used for both fungal and chemical products, can potentially ...harm the fungal propagules. This study investigated the impact of common hydraulic pumps (piston and diaphragm) on the viability of Beauveria bassiana Vuillemin (Ascomycota: Hyprocreales) based mycoinsecticide Botanigard® in the spray mixture. It also aimed to determine the optimal filter mesh size for the system to prevent clogging during application. The results showed significant reduction in conidial germination percentages with increasing number of passes through both types of pumps. However, in both cases the decrease was around 4% with a 90% of conidial germination which may be high enough to control the pest. The temperature of the mixture increased with the number of passes through the pumps, but it remained within the suitable range for fungal growth. When it came to filter clogging, the 32-mesh filter did not clog, the 50-mesh had a low clogging percentage, and the 80-mesh filters had higher clogging percentages (18% for suction filter and 56% for impulsion filter) after 30 passes through the system. As a conclusion, hydraulic pumps are suitable to apply B. bassiana based mycoinsecticide Botanigard®, but temperature control should be taken into account to prevent conidia damage. Using 32-mesh filters for both suction and impulsion is recommended to prevent clogging issues when applying this product.
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•Hydraulic pumps reduce Botanigard®'s viability 4% at 30 recirculation passes.•At 50 mesh and above, the filters get clogged when Botanigard® is applied.•Maintain optimal temperature for mycoinsecticide with a hydraulic sprayer is crucial.
Estimated world biopesticide sales by type in 2010 (millions of $US). CPL Business Consultants (2010). The 2010 Worldwide Biopesticides Market Summary, vol. 1. CAB International Centre, Wallingford. ...Display omitted
The development and use of entomopathogens as classical, conservation and augmentative biological control agents have included a number of successes and some setbacks in the past 15years. In this forum paper we present current information on development, use and future directions of insect-specific viruses, bacteria, fungi and nematodes as components of integrated pest management strategies for control of arthropod pests of crops, forests, urban habitats, and insects of medical and veterinary importance.
Insect pathogenic viruses are a fruitful source of microbial control agents (MCAs), particularly for the control of lepidopteran pests. Most research is focused on the baculoviruses, important pathogens of some globally important pests for which control has become difficult due to either pesticide resistance or pressure to reduce pesticide residues. Baculoviruses are accepted as safe, readily mass produced, highly pathogenic and easily formulated and applied control agents. New baculovirus products are appearing in many countries and gaining an increased market share. However, the absence of a practical in vitro mass production system, generally higher production costs, limited post application persistence, slow rate of kill and high host specificity currently contribute to restricted use in pest control. Overcoming these limitations are key research areas for which progress could open up use of insect viruses to much larger markets.
A small number of entomopathogenic bacteria have been commercially developed for control of insect pests. These include several Bacillus thuringiensis sub-species, Lysinibacillus (Bacillus) sphaericus, Paenibacillus spp. and Serratia entomophila. B. thuringiensis sub-species kurstaki is the most widely used for control of pest insects of crops and forests, and B. thuringiensis sub-species israelensis and L. sphaericus are the primary pathogens used for control of medically important pests including dipteran vectors. These pathogens combine the advantages of chemical pesticides and MCAs: they are fast acting, easy to produce at a relatively low cost, easy to formulate, have a long shelf life and allow delivery using conventional application equipment and systemics (i.e. in transgenic plants). Unlike broad spectrum chemical pesticides, B. thuringiensis toxins are selective and negative environmental impact is very limited. Of the several commercially produced MCAs, B. thuringiensis (Bt) has more than 50% of market share. Extensive research, particularly on the molecular mode of action of Bt toxins, has been conducted over the past two decades. The Bt genes used in insect-resistant transgenic crops belong to the Cry and vegetative insecticidal protein families of toxins. Bt has been highly efficacious in pest management of corn and cotton, drastically reducing the amount of broad spectrum chemical insecticides used while being safe for consumers and non-target organisms. Despite successes, the adoption of Bt crops has not been without controversy. Although there is a lack of scientific evidence regarding their detrimental effects, this controversy has created the widespread perception in some quarters that Bt crops are dangerous for the environment. In addition to discovery of more efficacious isolates and toxins, an increase in the use of Bt products and transgenes will rely on innovations in formulation, better delivery systems and ultimately, wider public acceptance of transgenic plants expressing insect-specific Bt toxins.
Fungi are ubiquitous natural entomopathogens that often cause epizootics in host insects and possess many desirable traits that favor their development as MCAs. Presently, commercialized microbial pesticides based on entomopathogenic fungi largely occupy niche markets. A variety of molecular tools and technologies have recently allowed reclassification of numerous species based on phylogeny, as well as matching anamorphs (asexual forms) and teleomorphs (sexual forms) of several entomopathogenic taxa in the Phylum Ascomycota. Although these fungi have been traditionally regarded exclusively as pathogens of arthropods, recent studies have demonstrated that they occupy a great diversity of ecological niches. Entomopathogenic fungi are now known to be plant endophytes, plant disease antagonists, rhizosphere colonizers, and plant growth promoters. These newly understood attributes provide possibilities to use fungi in multiple roles. In addition to arthropod pest control, some fungal species could simultaneously suppress plant pathogens and plant parasitic nematodes as well as promote plant growth. A greater understanding of fungal ecology is needed to define their roles in nature and evaluate their limitations in biological control. More efficient mass production, formulation and delivery systems must be devised to supply an ever increasing market. More testing under field conditions is required to identify effects of biotic and abiotic factors on efficacy and persistence. Lastly, greater attention must be paid to their use within integrated pest management programs; in particular, strategies that incorporate fungi in combination with arthropod predators and parasitoids need to be defined to ensure compatibility and maximize efficacy.
Entomopathogenic nematodes (EPNs) in the genera Steinernema and Heterorhabditis are potent MCAs. Substantial progress in research and application of EPNs has been made in the past decade. The number of target pests shown to be susceptible to EPNs has continued to increase. Advancements in this regard primarily have been made in soil habitats where EPNs are shielded from environmental extremes, but progress has also been made in use of nematodes in above-ground habitats owing to the development of improved protective formulations. Progress has also resulted from advancements in nematode production technology using both in vivo and in vitro systems; novel application methods such as distribution of infected host cadavers; and nematode strain improvement via enhancement and stabilization of beneficial traits. Innovative research has also yielded insights into the fundamentals of EPN biology including major advances in genomics, nematode-bacterial symbiont interactions, ecological relationships, and foraging behavior. Additional research is needed to leverage these basic findings toward direct improvements in microbial control.
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