Inter‐ and intraspecific variation of spider mite susceptibility to fungal infections: Implications for the long‐term success of biological control

Abstract

Spider mites are severe pests of several annual and perennial crops worldwide, often causing important economic damages. As rapid evolution of pesticide resistance in this group hampers the efficiency of chemical control, alternative control strategies, such as the use of entomopathogenic fungi, are being developed. However, while several studies have focused on the evaluation of the control potential of different fungal species and/or isolates as well as their compatibility with other control methods (e.g., predators or chemical pesticides), knowledge on the extent of inter‐ and intraspecific variation in spider mite susceptibility to fungal infection is as yet incipient. Here, we measured the mortality induced by two generalist fungi, Beauveria bassiana and Metarhizium brunneum, in 12 spider mite populations belonging to different Tetranychus species: T. evansi, T. ludeni, and T. urticae (green and red form), within a full factorial experiment. We found that spider mite species differed in their susceptibility to infection by both fungal species. Moreover, we also found important intraspecific variation for this trait. These results draw caution on the development of single strains as biocontrol agents. Indeed, the high level of intraspecific variation suggests that (a) the one‐size‐fits‐all strategy may fail to control spider mite populations and (b) hosts resistance to infection may evolve at a rapid pace. Finally, we propose future directions to better understand this system and improve the long‐term success of spider mite control strategies based on entomopathogenic fungi.

Control of two-spotted spider mite, Tetranychus urticae, on strawberry by integrating with cyetpyrafen and Phytoseiulus persimilis

“…Biological control measures such as predatory mites and natural acaricides are often effective and eco-friendly (Attia et al 2013;Iskra et al 2019;Zélé et al 2020;Nieberding et al 2022;Cruz-Miralles et al 2022). Phytoseiulus persimilis Athias-Henriot is a biological agent for the control of tetranychid mite (Basha et al 2021), which was introduced into China from Chile in 1975 (Takafuji et al 1976).…”

The African citrus triozid Trioza erytreae Del Guercio (Hemiptera: Triozidae): temporal dynamics and susceptibility to entomopathogenic fungi in East Africa

“…Such variations in psyllid mortality exposed to different entomopathogenic fungal isolates or strains have also been reported in D. citri (Gandarilla-Pacheco et al 2013). This difference in susceptibility of T. erytreae to fungal infections has been associated with inter-and intraspecific variations in virulence among fungal species and isolates (Zélé et al 2020).…”

A Review of Crop Protection Methods against the Twospotted Spider Mite—Tetranychus urticae Koch (Acari: Tetranychidae)—With Special Reference to Alternative Methods

“…Satisfactory efficiency has been achieved for Beauveria bassiana (Bals.-Criv. ), [160], Metarhizium brunneum Petch [161] and Metarhizium anisopliae (Metchnikoff) strain 442.99, Hirsutella spp., strain 457.99 and Verticillium lecanii (Zimm.) strain 450.99.…”