DOI: 10.3897/bull.insectology.158738

Authors: Wioleta Koźbiał, Elżbieta Wójcik-Gront, Mariusz Lewandowski

Abstract: The spotted wing drosophila (Drosophila suzukii) is an invasive pest causing significant damage to soft fruit crops in Europe. Native parasitoids may contribute to its biological control, yet information on their distribution and seasonal activity in Central Europe remains limited. This study aimed to investigate the species composition and seasonal dynamics of Drosophila parasitoids in agricultural and adjacent semi-natural habitats in Poland. Fieldwork was conducted during the early, middle, and late vegetation seasons in 2021–2022 using self-constructed traps baited with Drosophila melanogaster and D. hydei as hosts. Parasitoids emerging from collected traps were identified and quantified. Three hymenopteran parasitoid species were recorded: the larval parasitoid Asobara tabida and the pupal parasitoids Trichopria drosophilae and Pachycrepoideus vindemmiae. P. vindemmiae was the most abundant species, particularly in mid-season and in semi-natural areas. T. drosophilae dominated in the early season, while A. tabida was consistently less numerous. The overall parasitoid abundance was significantly higher in semi-natural habitats compared to agricultural sites. The structure of parasitoid assemblages changed with the season, with the highest species evenness in early and mid-season samples. These results highlight the influence of habitat type and seasonality on parasitoid occurrence and suggest that certain native species, especially P. vindemmiae and T. drosophilae, could contribute to the conservation biological control of D. suzukii. Promoting semi-natural refuges may enhance the presence and persistence of beneficial parasitoids in agricultural landscapes.

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DOI: 10.3897/bull.insectology.155814

Authors: Dantje Tarore, Vivi Bernadeth Montong, Jusuf Manueke, Yermia Semuel Mokosuli, Lucia Cecilia Mandey

Abstract: This study investigates the efficacy of the entomopathogenic fungus Beauveria bassiana (Bals.) Vuill. (Ascomycota: Hypocreales) in controlling Necrobia rufipes (De Geer) (Coleoptera: Cleridae), a significant pest responsible for economic losses in copra production, aiming to determine the effective concentration required to achieve substantial mortality and reduce copra damage in storage systems. Employing a completely randomized design with five treatments and three replications, the research assessed B. bassiana concentrations (10%, 15%, 20%, 25%, and 30%) on N. rufipes mortality and copra weight loss across pest population sizes ranging from 8 to 24 adults, with mortality recorded weekly over one month and weight loss measured after one month. Data analysis using analysis of variance, followed by a least significant difference test and probit analysis, revealed mortality rates from 14.67% (±2.31%) at 10% concentration to 69.33% (±3.79%) at 30%, with an LC50 of 23.611% (±1.12%), while copra weight loss increased from 1.33 g (±0.15 g) with 8 adults to 6.87 g (±0.42 g) with 21 adults, strongly correlating with pest density. These findings demonstrate that B. bassiana effectively reduces N. rufipes populations, with higher concentrations enhancing control, and the identified LC50 provides a practical application threshold, underscoring the influence of pest population size on copra weight loss and the need for timely intervention. This approach offers a sustainable, biological strategy to protect copra, potentially minimizing economic losses in tropical storage systems.

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