Location: Systematic Entomology Laboratory
Project Number: 8042-22000-313-026-I
Project Type: Interagency Reimbursable Agreement
Start Date: Aug 1, 2026
End Date: Jul 31, 2027
Objective:
To enhance and strengthen pest identification of eriophyid mite species associated with important specialty crops in the Rosaceae (Rubus and Rosa species), Grossulariaceae (Ribes species), and Ericaceae (Vaccinium species), and their potential vectoring ability for known or novel viruses affecting those crops. Morphological characterization by light and scanning electron microscopy of the eriophyid mites will be combined with rapid molecular differentiation of similar mite species, and disambiguation of possible synonymy and cryptic species. Images of host plant abnormalities associated with both mite infestations and virus-like symptoms will also be captured for use as diagnostic aids. The use of scanning electron microscopy technology for image generation and sharing removes the subjective bias obvious from comparing the classical drawings of mite morphological characteristic by multiple authors using different types of light microscopy and different mounting techniques. High quality images of the mites will be made available for use as identification aids, with associated molecular assays for confirmatory testing. Mite-associated viruses detected in the crops will also be molecularly characterized, and specific molecular methods developed for rapid identification, to allow producers to screen potential propagation stocks to eliminate infected plants. Mite:virus:host interactions causing host adaptation favoring both mite replication and survival, and enhancing virus transmission will be identified, and potentially inform enhanced control measures.
Approach:
Plant materials of specialty crops in the families Rosaceae (species of Rubus and Rosa), Grossulariaceae (species of Ribes), and Ericaceae (species of Vaccinium) with associated eriophyid mites and virus-like symptoms will be solicited from acarologists, diagnosticians, and virologists in states including Arizona, Arkansas, California, Florida, Michigan, Missouri, Oregon , Pennsylvania, and Washington. Photographic images will be taken of the affected plant materials. RNA extractions will be prepared from plants with mite infestations, especially those with virus-like symptoms, and subjected to genus-level generic primers for different virus types (including emaraviruses, poaceviruses, rymoviruses, tritimoviruses, allexiviruses, and trichoviruses) known or suspected of infecting the particular crop species. RNA extracts from selected samples will also be submitted for high-throughput sequencing for viral discovery and potential genome assembly. Light and scanning electron microscope (SEM) imaging of eriophyid mites will be captured both in situ on host plant tissue, and mounted on adhesive carbon tabs for detailed high magnification images of morphological features. High resolution SEM images of mites in situ on host tissues will provide information on host interactions, such as increased trichome density. High resolution images for morphological characterization will include dorsal, ventral, and lateral views, with close-ups of features such as empodia and prodorsal shield patterns; the images obtained will be compared to published descriptions of mites known to affect the crop species from which the mites were obtained, and to morphologically similar mites affecting other crops. Detailed descriptions of any mites apparently new to science will be prepared and published. Mite DNA will be prepared and sequences obtained from key genes utilized for genus and species differentiation (including COI, 28S rRNA, and16S rRNA markers), and obtained sequences compared against the NCBI database, and especially sequences previously reported for eriophyids of the same genus and species. A combined database of symptom images, high resolution SEM images, and DNA marker sequences for each of the mites identified, as well as primer information and viral sequences for any viruses associated with mite-affected plants, will be assembled and made available for use for field identification by diagnosticians, quarantine officials, and other interested researchers, and for future comparative taxonomic studies.