The present study assessed the pathogenic effect of isolates E9, IBCB425 and IBCB159 of the Metarhizium anisopliae fungus, JAB06, JAB07 and AM09 of Beauveria bassiana, IBCB133 and CB75 of Isaria fumosorosea (=Paecilomyces fumosoroseus) and CG189 and CG195 of Isaria farinosa (=Paecilomyces farinosus) against eggs and larvae of the horn fly Haematobia irritans. Eggs were inoculated with suspensions containing 10(6), 10(7) and 10(8)conidiaml(-1) of the fungal isolates and observed after 48h to determine viability. In the larvae study, eggs were allowed to hatch into fresh bovine feces that had been treated with 10(8), 10(7) or 10(6)conidiamgfeces(-1). In both studies, 5 days after initial procedures, all formed pupae were transferred to an incubator at 27+/-0.5 degrees C until the emergence of the adult flies was complete. The M. anisopliae isolates did not cause the death of H. irritans eggs, but they did promote the death of larvae that hatched from treated eggs, and therefore increased the total mortality. Isolate E9 promoted 100% mortality of treated larvae at a concentration of 10(8)conidiaml(-1). For the B. bassiana isolates, no activity was observed against insect eggs or larvae. Both I. fumosorosea isolates promoted significant mortality (p<0.05) of eggs at every concentration of conidia. Isolate CG195 of I. farinosa increased the mortality of larvae and pupae that hatched from treated eggs and promoted significant total mortality (p<0.05) of the insect at every concentration of conidia.
RESUMOLecanicillium lecanii é um fungo promissor no controle biológico de pragas e para sua utilização em campo é necessária a produção de conídios em grande quantidade. Este trabalho objetivou selecionar meios de cultura líquidos feitos com resíduos ou subprodutos agroindustriais e meios sólidos pela mistura de grãos e derivados, visando à produção dos isolados JAB 02 e JAB 45 do fungo. Como substratos líquidos utilizaram-se, em diferentes concentrações, água do cozimento do arroz e da prensa da mandioca, soro de queijo, milhocina ® , melaço, vinhaça e leite de levedura da indústria da cana, avaliando-se a esporulação e biomassa. Como substratos sólidos, combinaram-se, em diferentes proporções, trigo grosso, farelos de trigo e de soja com quirela de milho, lentilha e sorgo para JAB 02, e com painço, trigo em grão e lentilha para JAB 45, avaliando-se a produção e viabilidade de conídios. O meio contendo 4% de milhocina ® favoreceu a produção de ambos os isolados. Para JAB 02, proporcionaram melhores resultados os meios com 85% de água da prensa da mandioca, 5,5% de melaço e 100% de soro de queijo, além de misturas entre trigo grosso e farelo de trigo com lentilha (70:30%) e trigo grosso e farelo de trigo com sorgo (85:15%). Os meios com 100% da água da prensa da mandioca e 85% de soro de queijo, e as misturas entre farelo de trigo e painço (85:15%), trigo grosso e lentilha (55:45%) e farelo de trigo com trigo em grão e com lentilha (70:30%) favoreceram a produção de JAB 45.Palavras-chave: controle biológico, produção massal, substratos líquidos, substratos sólidos.
The objective of this research was to evaluate combinations of liquid media obtained from agro-industrial residues and by-products, with solid media prepared with mixtures of grains and their derivatives, aiming to increase the production of JAB 02 and JAB 45 isolates of Lecanicillium lecanii. Sporulation, conidial viability and process yield were evaluated as well as the production costs using the JAB 45 isolate as a model system were analyzed. The production of JAB 02 was not increased using the biphasic culture. For JAB 45, some combinations provided an increase in yield, especially cheese whey with wheat bran and wheat grain, with lower production costs. Viability was not influenced by the production method, and the combinations showed no differences in the process yield. The biphasic method is suitable for the production of L. lecanii, and proves to be an appropriate technology to use in mass production by biofactories.
The horn fly Haematobia irritans is one of the most important ectoparasites associated with grazing bovines. This study investigated the pathogenic activity of Metarhizium anisopliae (E9, IBCB425 and IBCB159), Beauveria bassiana (JAB06, JAB07 and AM09), Isaria fumosorosea (=Paecilomyces fumosoroseus) (IBCB133 and CB75) and Isaria farinosa (=Paecilomyces farinosus) (CG189 and CG195) fungi isolates on pupae and adult H. irritans. Groups of 20 pupae and 30 adult flies were respectively bathed and sprayed with fungal isolate suspensions containing 10(6), 10(7) and 10(8) conidia ml(-1) in bioassays conducted in laboratories. In both assays the adult flies were fed bovine blood for 15 days, and death rates were assessed daily. The E9 and IBCB425 M. anisopliae isolates caused pupae death at concentrations of 10(7) and 10(8) conidia ml(-1), and the JAB07 and AM09 B. bassiana isolates caused higher pupae mortality at a concentration of 10(8) conidia ml(-1). I. farinosa isolates were the most effective considering pupae mortality, with the CG195 inducing more deaths (56.6%) in the 10(8) conidia ml(-1) concentration suspension. Adult flies were more susceptible to the fungi's pathogenic action, since the E9 isolate of M. anisopliae and all of the B. bassiana induced death in 100% of the flies at the 10(8) conidia ml(-1) concentration suspension. The I. fumosorosea and I. farinosa isolates, on the other hand, were less effective in controlling adult flies. In both stages, but mostly the adult phase, pathogenicity was great at higher conidial concentrations.
Making bioproducts available to the market requires finding appropriate processes for mass production and formulation of biological agents. This study aimed at evaluating the Bipolaris euphorbiae production in a solid medium (fermentation in solid substrate) and in a biphasic system (growth in a liquid medium followed by growth in a solid medium), as well as determining the processes for collecting and drying conidia, under laboratory conditions. The influence of the incubation period and inoculum quantity were also investigated. The conidia were dried by using an oven (30ºC, 35ºC, 40ºC, 45ºC, 50ºC, 55ºC and 60ºC), and laminar flow, continuous air flow and aseptic chamber at room temperature. Dry conidia were obtained by sieving and grinding in a ball mill, hammer mill or grain grinder. The conidia viability and sporulation efficiency were evaluated in the solid medium and in the biphasic system. For growth period, the best sporulation on solid medium was obtained after 10 days of incubation, reaching 8.3 x 10(7) conidia g-1 of substrate. The biphasic system did not increase the B. euphorbiae sporulation (4.5 x 10(7) conidia g-1 of substrate), after 14 days, and the amount of liquid inoculum used in this system was not an important factor for increasing its production. The continuous air flow and laminar flow preserved the conidial viability (94.6% and 99.1%, respectively), while promoting a great moisture loss (62.6% and 54.0%, respectively). All the grinding processes reduced the conidia germination (86.2%, 10.5% and 12%, respectively), while sieving allowed the collecting of powdered conidia with high viability (94.8%).
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