Iridovirus in the root weevil Diaprepes abbreviatus

Area of Science:

• * Virology
• * Entomology
• * Pest Management

Background:

• * Diaprepes abbreviatus (L.) is a significant agricultural pest.
• * Limited knowledge exists on viral pathogens affecting D. abbreviatus.
• * Invertebrate iridescent virus 6 (IIV6) is an emerging pathogen.

Purpose of the Study:

• * To investigate the infectivity and transmission of IIV6 in D. abbreviatus.
• * To characterize the pathology and tissue tropism of IIV6 in weevils.
• * To explore the potential of IIV6 as a biocontrol agent.

Main Methods:

• * Experimental inoculation of D. abbreviatus larvae and adults with IIV6 via puncture, injection, and per os.
• * Transmission studies between infected and healthy individuals.
• * Detection of virus in egg masses.
• * Ultrastructural analysis using transmission electron microscopy.
• * Polymerase chain reaction (PCR) and sequencing for virus confirmation.

Main Results:

• * First evidence of IIV6 infection in D. abbreviatus, causing patent and covert infections.
• * Successful infection achieved through multiple routes (puncture, injection, per os).
• * Transovarial transmission demonstrated, with virus detected in egg masses.
• * Virus particles observed in cytoplasm, infecting fat bodies, muscle, and nerve tissues.
• * Patent infections led to mortality within 3–4 days.
• * Covert infections detected by PCR on day 7.

Conclusions:

• * IIV6 is a novel pathogen capable of infecting D. abbreviatus larvae and adults.
• * Multiple transmission routes, including transovarial, facilitate IIV6 spread.
• * IIV6 exhibits significant tissue tropism within weevil hosts.
• * The discovery provides a foundation for developing IIV6-based biocontrol strategies against root weevils.