Abstract in English:

ABSTRACT Acerola cultivation has been expanding in Brazilian Northeast region. However, diseases caused by Botryosphaeriaceae fungi, such as dieback, may affect acerola orchards. This study aimed to standardize sporulation and inoculation methods, to assess Lasiodiplodia sp. aggressiveness in three hosts, and resistance of acerola genotypes to dieback. Five substrates obtained from host species and five Botryosphaeriaceae isolates were used to induce sporulation, and three inoculation methods were assessed. The aggressiveness of eight Lasiodiplodia strains isolated from acerola was compared in mango, acerola, and grapevine seedlings and fruits. The resistance of 34 acerola genotypes was assessed after inoculation with an aggressive Lasiodiplodia strain. Sporulation was higher in the mango leaf and acerola branch, and the cork-borer method was the easiest and fastest one. Acerola was the most susceptible host, and there was a difference in the aggressiveness among Lasiodiplodia sp. strains. There was a difference in susceptibility to dieback among acerola genotypes. This study provides alternative methodologies for sporulation and inoculation of Botryosphaeriaceae fungi and resistant acerola genotypes to dieback for further use in breeding programs.

Abstract in English:

ABSTRACT The genus Solenopsis, commonly known as fire ants, includes 196 species. These ants are considered pests due to the damage they cause in urban areas and agricultural systems. Their painful stingers hinder manual harvesting, and they feed on crops and engage in mutualistic interactions with aphids. As a result, there is considerable interest in identifying biological control agents and developing effective laboratory methods for evaluating their virulence. Such efforts are hindered by the fact that most available methodologies were originally designed for chemical insecticides. This study aimed to evaluate six different laboratory methodologies for testing the virulence of biological agents against Solenopsis spp. The tested approaches were: spraying water into trays with approximately 35 worker ants; pipetting water into containers with 30 worker ants; spraying water into containers with 30 worker ants; using a Potter spray tower to apply water, and treat containers with 30 workers; pipetting water onto distinct developmental stages of ants in Petri dishes; and applying water to microcolonies in Petri dishes. Additionally, various concentrations of culture media were assessed to determine their suitability for bacterial assays. Among the methods tested, the last two mentioned approaches presented fewer logistical challenges and were more likely to generate reliable data for fire ant control. The 25% Luria-Bertani medium was associated with the lowest worker mortality and is recommended as a negative control in bacterial experiments.

Abstract in English:

ABSTRACT The application of herbicides, at pre-emergence of weeds and crops, is an effective and increasingly necessary strategy, due to the control difficulties, including herbicide-resistant weeds. Thus, this article aimed to evaluate the effectiveness of sulfentrazone, alone or in mixtures, applied in pre-emergence of soybean to control Sumatran fleabane (Conyza sumatrensis), sourgrass (Digitaria insularis), and Benghal dayflower (Commelina benghalensis). The number of weeds m-2, weed control, crop injury, and soybean yield were evaluated. This research showed that mixtures with sulfentrazone are especially interesting, as with diclosulam and metribuzin + imazethapyr, in the control of Sumatran fleabane, in which diuron tends to aggregate when combined. Sulfentrazone mixed with clomazone or metribuzin, plus diuron, is especially valid for Benghal dayflower. While some triple mixtures attract attention, in the control of sourgrass, the mixtures that tend to have a better control spectrum are: sulfentrazone + clomazone + diuron, and sulfentrazone + metribuzin + diuron. Therefore, the mixtures with sulfentrazone evaluated in the experimental conditions verified in this study are promising in the integrated management of weeds and do not generate losses in soybean yield.

Abstract in English:

ABSTRACT The parasitoid Telenomus remus Nixon (Hymenoptera: Scelionidae) is a natural enemy of lepidopteran pests, and several studies have been conducted to evaluate its efficiency on eggs of Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae). Functional response is an important parameter for assessing the potential of parasitoids. The objective of this work was to evaluate the harvesting behavior and the functional response of T. remus on eggs of S. frugiperda. We conducted the experiment in an acclimatized chamber at 25 ± 2°C, relative humidity 70% ± 10% and photophase of 12 hours. For harvesting behavior, we observed that a female takes 2.4 minutes, from the placement to the first cleaning, which is 44.7 seconds, to parasite one egg. The value of the quadratic coefficient was negative (P1 < 0.0005), so it can be assumed that the functional response of T. remus to eggs of S. frugiperda was type III. The results of attack rate (a’), handling time (Th ), and number of eggs parasitized at 24 hours by T. remus were, respectively, 0.00664 and 0.5649·h-1. The sex ratio of the parasitoid was influenced by host densities, with a ratio of 0.5 at 10 and 30 egg densities, but values were not differentiated from the density of 15 eggs. Our results can be helpful for developing field studies, enhancing the knowledge and possibilities for integrated pest management.

Abstract in English:

ABSTRACT Clostridium botulinum is a strictly anaerobic spore-forming bacterium found in soil and sediments, producing botulinum neurotoxins that cause botulism. Type C botulism spores are widely present in wetland sediments and can even be found in tissues of the inhabitants of these environments. The spores germinate in conditions of a lack of oxygen, high temperatures, and the presence of a decomposing organic source, in addition to the presence of a bacteriophage that carries the gene for toxin production. Botulism in waterfowl is mainly caused by C. botulinum type C, and the standard laboratory diagnosis for toxin detection is serum neutralization in mice. However, we tested the application of polymerase chain reaction for the detection and typing of C. botulinum type C with success in three samples from birds.