Ana Paula Mamprim

Effect of plant extracts and a disinfectant on biological parameters and pathogenicity of the fungus Beauveria bassiana (Bals.) Vuill. (Ascomycota: Cordycipitaceae)

The fungus Beauveria bassiana is naturally found in poultry houses and causes high rates of mortality in Alphitobius diaperinus. Laboratory and field experiments have shown the potential of this fungus as an insect control agent. However, in poultry houses, bacteria as Salmonella, can be found and have been studied alternative control methods for this pathogen. Thus, this study aimed to evaluate the effect of plant extracts and a disinfectant on the fungus Beauveria bassiana (strain Unioeste 4). Conidial viability, colony-forming unit (CFU) counts, vegetative growth, conidia production, insecticidal activity of the fungus and compatibility were used as parameters in the evaluation of the effect of these products on the fungus. Alcoholic and aqueous extracts of jabuticaba (Myrciaria cauliflora (Mart.), guava (Psidium guajava (L.)), and jambolan (Syzygium cumini (L.), at concentrations of 10% as well as the commercial disinfectant, Peroxitane® 1512 AL, were evaluated at the recommended concentrations (RC), 1:200 (RC), 0.5 RC and 2 RC. There was a negative influence of alcoholic and aqueous extracts of jabuticaba, guava and three dilutions of Peroxitane on the viability of conidia. The CFUs and vegetative growth of the fungus were affected only by the Peroxitane (all dilutions). For conidial production, the aqueous extract of guava had a positive effect, increasing production, while the Peroxitane at the R and RC concentrations resulted in a negative influence. The mortality of A. diaperinus, caused by the fungus after exposure to these products, was 60% for the peracetic acid at 0.5 RC, and above 80% for the extracts. Thus, the results showed that all the extracts and Peroxitane at RC 0.5 are compatible with the fungus B. bassiana Unioeste 4, however only the extracts had a low impact on inoculum potential.

Produtos fitossanitários alternativos contra a calcinose em Bombyx mori L. (Lepidoptera: Bombycidae)

Arq. Inst. Biol., v.84, 1-7, e0642015, 2017 RESUMO: Este trabalho objetivou avaliar os efeitos de produtos Biogermex•, Agro-mos•, Soil-Set• e Planta Clean• no desenvolvimento da calcinose branca em Bombyx mori. Os produtos foram testados em duas etapas: efeitos sobre a biologia e produção de seda pela lagarta (1) e, em seguida, em função do seu potencial na prevenção/ no controle da calcinose branca (2). Os produtos foram pulverizados sobre as folhas de amoreira (tratamento preventivo) e sobre o tegumento das lagartas (tratamento curativo). Na primeira etapa, os produtos foram aplicados durante quatro dias consecutivos, em uma das alimentações do dia. Planta Clean• — tratamento curativo — e Soil-Set• — tratamento preventivo — causaram mortalidade em 63,3 e 30% das lagartas, respectivamente. O fungo Beauveria bassiana foi inoculado na concentração 5 × 107 conídios/mL sobre folhas e insetos. Os produtos foram aplicados três horas após o fungo, em uma aplicação, e também por quatro dias em outro grupo. Um grupo de lagartas pulverizadas apenas com fungo serviu como controle. Biogermex• — tratamento curativo aplicado uma e quatro vezes — foi o mais eficiente, reduzindo a mortalidade em 25 e 26,7% respectivamente, em relação ao grupo controle. Nenhum dos produtos avaliados atuou de forma preventiva contra muscardina branca.

Selection and characterization of Beauveria spp. isolates to control the broad mite Polyphagotarsonemus latus (Banks, 1904) (Acari: Tarsonemidae)

This study was performed under laboratory conditions to identify isolates of the fungus Beauveria spp. that can control Polyphagotarsonemus latus in the greenhouse and field. Thirty Beauveria spp. isolates were tested by spraying 1 mL conidia (1 × 108 conidia/mL) on pepper leaf discs containing 15 mites. Evaluations were performed on the 3rd and 6th day post application by counting the number of dead mites. Vegetative growth and conidial production were measured from the selected isolates, and bioassays were conducted in the greenhouse on bean seedlings in plastic pots. The isolate Unioeste 53 was selected, and a conidial suspension (1 × 108 conidia/mL) was applied with a backpack sprayer. The evaluation consisted of pre- and post-treatment counts of the number of live mites on ten leaflets in both the plots treated with the fungus and control plots, and the same procedure was followed for the field experiment. In the laboratory, the Unioeste 53 isolate resulted in total and confirmed mortality rates of 70% and 57.7%, respectively. In the greenhouse, the population decreased by 76.71% by the 16th day after application. In the field, the population decreased by 66% by the 12th day after application, demonstrating the potential of this fungus for mite management.