Jul 1, 2026
Resources:
[00:00:08] Dan introduces the episode, recorded in advance while he's away, featuring guest Ari Abbrescia, Organic and Sustainable Agricultural Outreach Specialist with UW-Madison Extension.
[00:00:48] Ari provides an overview of the VDIFN (Vegetable Disease and Insect Forecasting Network), including its creators — Dr. Amanda Gevens, Dr. Russ Groves, and Ben Bradford — and its role in supporting integrated pest management across the upper Midwest.
[00:02:06] Dan and Ari dig into a real-world example: why VDIFN appears to show flea beetles absent in Iowa when growers in southern Minnesota are already seeing them.
[00:03:36] Explaining the difference between Fahrenheit degree days (FDD) and growing degree days (GDD), and what those values mean within the flea beetle model.
[00:04:50] Ari clarifies that the VDIFN flea beetle model tracks the first hatched generation — not overwintering adults — which explains the apparent gap between model output and field observations.
[00:07:08] Key takeaway: VDIFN measures risk for damage, not pest presence — an especially important distinction when interpreting disease models like late blight.
[00:07:28] Dan shares how he wants to use VDIFN as a scouting lead-time tool for growers, and discusses Spinosad as a management option against adult flea beetles.
[00:08:42] Ari walks through the seed corn maggot model as a strong example of how VDIFN can directly inform planting timing decisions based on Fahrenheit degree day thresholds.
[00:10:18] Discussion of the early blight model for tomato, including how to use the biofix date and P-day accumulation to time preventative fungicide applications.
[00:11:14] Ari explains what P-days (physiological days) are and how they relate to degree days and disease severity tracking.
[00:14:31] Introduction of the Crop Risk Tool — a newer, still-developing tool built by Ben Bradford that allows users to save named locations, upload CSV field lists, and view risk across multiple models for specific sites.
[00:15:59] A key advantage of the Crop Risk Tool: it includes a 14-day NOAA-based forecast, allowing growers to look ahead and plan management decisions proactively.
[00:17:37] Comparing the two tools — VDIFN excels at visualizing spatial patterns and the movement of pest risk across the landscape; the Crop Risk Tool excels at site-specific, forward-looking risk assessment.
[00:19:23] Dan and Ari share a common wish-list feature: the ability for growers to select and view only their key pests and diseases for a saved location, rather than toggling through categories. Ari adds that text alerts are also a dream feature in early development.
[00:20:10] Dan notes that squash bugs and cucumber beetles are absent from VDIFN, sparking a discussion about overwintering adult pests and the diseases they vector, including bacterial wilt and squash mosaic virus.
[00:21:05] Conversation turns to Western flower thrips and onion thrips — including uncertainty about whether VDIFN's thrips model covers one, the other, or both — and whether the distinction matters for tomato spotted wilt virus management.
Episode summary generated using claude.ai