Cucurbit crops include beloved fruits and vegetables such as cucumber, squash, watermelon, melon and pumpkins. These crops are exposed every year to the disease cucurbit downy mildew which reduces yield and quality of the fruit (Figure 1 below).
Farmers currently manage downy mildew with weekly fungicide applications, which commonly start a few weeks after the seeds have been planted. These fungicide applications are more effective when they are applied preventatively at very early stages of the disease. My research as a PhD student and FFAR Fellow at North Carolina State University is about optimizing the use of fungicides to have the most effective disease management while reducing the number of fungicide applications. To do this, my advisor, Dr. Lina Quesada, and I need to know exactly when the pathogen is getting to the grower’s fields so growers only apply fungicides when the pathogen is present and not waste fungicide when it is not.
Currently, growers know the disease has arrived at their fields using scouting. This entails visually searching their fields for disease symptoms. But by the time the disease is visible, it is often too late for effective treatment. My research focuses on catching spores, the microscopic part of the pathogen that is airborne, and then using a laboratory test to detect the presence of the pathogen before you can see any visual symptoms in the field. Think of this as a COVID test, but instead of swabbing your nose for viral particles, we are swabbing the air for pathogen spores. By doing this, we can know exactly when the pathogen arrives at our field sites.
One of the most common spore sampling devices is a stationary impaction sampler or rotorod trap (Figure 2). These are usually placed on a pole and tend to work very well on research station plots that are small in acreage. A major challenge is how to replicate the results from a research station plot to a commercial grower field with large acreage. 
For the spore traps to work on a commercial scale, we knew that a different design was needed. In the attempt to find solutions, we decided that perhaps collaborating with another lab was a good idea. And we were right.
We met with Dr. Lirong Xiang’s lab in the department of Biological and Agricultural Engineering. We explained the problem and what was needed. Then, the magic of collaboration began. The engineering team had ideas on how to make this work in ways that we had never even considered. A few months after the initial meeting, they showed us the finished product: a vacuum spore trap that we could mount on moving vehicles (Figure 3). This design provided two major advantages: the vacuum allows for more air to be sampled in less time; and the ability to mount a spore trap on a vehicle has the potential to aid in large acreage sampling.
