Researcher(s)
- Jessica Weyl, Plant Science, University of Delaware
Faculty Mentor(s)
- Jill Pollok, University of Delaware Cooperative Extension Plant Diagnostician, University of Delaware
Abstract
The University of Delaware Plant Diagnostic Clinic processes nearly 300 plant samples a month throughout the summer. As the only diagnostic center in the state, we receive samples from all 3 Delaware counties in addition to others sent in from Maryland, Pennsylvania, and other surrounding states. While a vast majority of issues that we come across are common, we also encounter a handful of new disease and insect issues per year. This July, for example, we received a sample with the first case of the invasive Box Tree Moth to be reported in Delaware. The triage and diagnosis process is a multi-step undertaking that can take anywhere from a few hours to a month or more. A typical sample requires research, microscopy, specialist consultation, and isolation of cultures on agar media.
Starting in late June, the Plant Diagnostic Clinic began to receive samples of Loblolly pines (Pinus taeda) from the Delaware Forest Service (DFS). These trees have experienced a rather alarming decline in just the past few months. Concerned that this could be a widespread disease issue, DFS sent in branch and needle samples from trees across southern Delaware. These trees exhibited a plethora of symptoms that could be caused by a wide variety of issues.
Following a month-long diagnostic process, we found many secondary pathogens, but they were inconsistent across the board. Results from soil tests found that three separate stands of Loblollies all had pHs under 4.5 – overly acidic, even for this highly tolerant pine. We have determined that the cause of this epidemic decline is most likely due to a combination of environmental stress factors, though the process of confirmation is still ongoing.