Project Number: 2092-22000-022-016-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Apr 1, 2019
End Date: Jul 30, 2021
A primary objective of our project is to use molecular gut content analysis to directly pinpoint what plants (e.g. matrimony vine) potato psyllids are dispersing from as they enter Washington potato fields in early summer. A second goal is to determine if early-season monitoring of potato psyllid in matrimony vine or other perennial host species identified in this project as sources of psyllids can be used to predict psyllid pressure expected in potato in late summer.
Psyllid interception traps will be deployed during the spring interval when psyllids first begin to appear in potato in Washington State (early June to July, depending upon location). We will use 3D-printed yellow that are designed to capture psyllids directly into a preservative, which prevents the plant DNA signal from degrading before the trapped psyllids are assayed molecularly. The traps will be monitored every 2 to 3 days for 3 to 4 weeks. Captured psyllids will be removed from trap-collection vials, placed in a fresh solution of 70% ethanol. DNA will be extracted from psyllids using a commercial kit. Each sample will first be tested for the presence of the zebra chip pathogen using routine diagnostic PCR. PCR using universal primers for the chloroplast gene, trnL, and the ribosomal gene, ITS, will then be used to amplify regions of plant DNA from the guts of psyllids. Barcoded sequences unique to each sample will be attached to PCR primers so that sequences can be paired with samples after sequencing. PCR products from each sample will be pooled into a single sample to be processed and direct-sequenced using a PacBio platform. Plant sequences will be trimmed and organized into samples based upon the sequences of the barcoded primers. The BLAST search function of the NCBI website will be used to identify plant sequences based on similarity to archived sequences. Multiple stands of matrimony vine in the Columbia Basin of Washington will be sampled using standard beat sheet methods in mid-May and in early-June to estimate densities of psyllids on this host preceding arrival of the psyllid in potato fields. Spring counts in matrimony vine will be compared to summer counts in potato fields.