Something is wrong with your plant. What’s the cause? You can begin to determine the cause of the problem by taking on the role of Sherlock Holmes – be a keen observer and ask many questions. Diagnosing plant problems is often a difficult task. There can be many different causes for a given symptom, not all of them related to insects or diseases. The health of a plant may be affected by soil nutrition and texture, weather conditions, quantity of light, other environmental and cultural conditions, and animals, including humans. Complicating this scenario is the fact that any two of the above factors can interact to give rise to a problem. For example, a prolonged period of drought may weaken plants so that they are more susceptible to pests; this is typically observed with boxwoods.

Three pests, the boxwood leafminer, mite and psyllid commonly attack American and English boxwood in Virginia and cause spotting, yellowing, and puckering of leaves.

Creating and maintaining community and school gardens has been identified as an effective strategy to increase healthy food awareness and consumption. Unfortunately, fresh fruits and vegetables have been linked to more than 450 outbreaks of foodborne illness in the U.S. since 1990. In commercial food production, employing a set of risk-reduction steps — known as good agricultural practices (GAPs) — has been pointed to by the U.S. Food and Drug Administration as the best prevention against foodborne, illness-causing pathogens.

Since 2015, Extension specialists from Virginia Tech (VT) have visited and collected plant and soil samples from several large areas of dying great rhododendron (Rhododendron maximum) in Virginia’s mountainous regions. In 2016 VT specialists met with Virginia Department of Forestry, US Forest Service personnel, and other experts to revisit some of these sites. No consistent cause of this mortality has yet been identified. It is possible that a variety of factors are stressing the rhododendrons in these areas to a point where opportunistic pathogens or insects can successfully attack and kill them. The following information summarizes our observations and diagnostic results from four separate great rhododendron mortality sites in Virginia. This information is not equivalent to a research study, which would also include samples taken from healthy great rhododendron for comparison; however, we are confident that we have ruled out two diseases that are frequently mentioned both online and anecdotally as a cause of this mortality, specifically Phytophthora root rot and Botryosphaeria dieback.