Beatriz Maria Diaz

Bio: Beatriz Maria Diaz is an academic researcher from Concordia University Wisconsin. The author has contributed to research in topics: Integrated pest management. The author has an hindex of 1, co-authored 1 publications receiving 12 citations.

Cocoon Heat Tolerance of Pheretimoid Earthworms Amynthas tokioensis and Amynthas agrestis

Abstract: In the United States earthworms of two Asian species (Amynthas tokioensis and A. agrestis) are leading a northward invasion into temperate forests and horticultural landscapes. Some studies have shown temperature sensitivity in earthworms, but none has explicitly tested the range of heat tolerance for A. tokioensis and A. agrestis cocoons. This study tested the hypothesis A. tokioensis and A. agrestis cocoons would become nonviable when exposed to 55 C in a laboratory setting. Clitellate earthworms of A. tokioensis and A. agrestis were established in replicate incubation cultures to quantify cocoon production rate and to obtain cocoons of known source. Cocoons were then exposed to heat treatments (3 or 15 d at 20, 30, 40, 45, 50, 55, or 60 C) to determine viability after heat exposure. Twelve A. tokioensis and A. agrestis earthworms produced as many as 74 and 82 cocoons in 20 d, respectively (overall mean = 0.14 ± 0.10 cocoons earthworm–1 d–1). All heat treatments ≥40 C resulted in zero viability (P < 0.001), but the 30 C treatment was no different than the control at 20 C (P = 1.000). These findings were consistent regardless of species, treatment length, or period of incubation during which the cocoons were collected. The threshold of tolerance was between 27.1 C (maximum of the 30 C treatment) and 38.1 C (minimum of the 40 C treatment) for A. tokioensis and A. agrestis cocoons. These data may guide management decisions concerning the spread of A. tokioensis and A. agrestis to new locations.

Exploring the Role of Supplemental Foods for Improved Greenhouse Biological Control

Abstract: Small modifications in greenhouse agroenvironments can have a big impact on the success of biological control programs. For instance, the application of supplemental foods during and after the release of natural enemies onto crop plants, could considerably improve their long-term reproductive and population growth prospects. As such, food supplementation represents a valuable biological control supportive strategy, helping to grow natural enemy populations before pest establishment, akin to creating a standing-army to defend crops against future pest invasions. In many places of the world, food supplementation represents a relatively new but growing component or biological control research, with increasingly better resources available to guide producers, IPM practitioners, or researchers wanting to apply or optimize such strategies to their local agents and environments. In this review, we summarize the current stage of knowledge associated with various supplemental food types, which work best to support specific beneficial arthropods as well as some tools and techniques for successfully applying this biological control-enhancing strategy. We also summarize some current challenges to the use of supplemental foods and discuss what future research is needed to adapt and optimize food supplementation for a diversity of natural enemy species.

DNA barcode assessment and population structure of aphidophagous hoverfly Sphaerophoria scripta: Implications for conservation biological control.

Abstract: With the advent of integrated pest management, the conservation of indigenous populations of natural enemies of pest species has become a relevant practice, necessitating the accurate identification of beneficial species and the inspection of evolutionary mechanisms affecting the long-time persistence of their populations. The long hoverfly, Sphaerophoria scripta, represents one of the most potent aphidophagous control agents due to a worldwide distribution and a favorable constellation of biological traits. Therefore, we assessed five European S. scripta populations by combining molecular (cytochrome c oxidase subunit I- COI, internal transcribed spacer 2- ITS2, and allozyme loci) and morphological (wing size and shape) characters. COI sequences retrieved in this study were conjointly analyzed with BOLD/GenBank sequences of the other Sphaerophoria species to evaluate whether COI possessed a sufficient diagnostic value as a DNA barcode marker to consistently delimit allospecific individuals. Additionally, the aforementioned characters were used to inspect the population structure of S. scripta in Europe using methods based on individual- and population-based genetic differences, as well as geometric morphometrics of wing traits. The results indicate numerous shared COI haplotypes among different Sphaerophoria species, thus disqualifying this marker from being an adequate barcoding region in this genus. Conversely, the analyses of population structuring revealed high population connectivity across Europe, therefore indicating strong tolerance of S. scripta to environmental heterogeneity. The results imply a multilocus approach as the next step in molecular identification of different Sphaerophoria species, while confirming the status of S. scripta as a powerful biocontrol agent of economically relevant aphid pests.