COMMON NAME: Black rot of grapes SCIENTIFIC NAME of causal agent: Guignardia bidwelli (anamorph Phyllosticta ampelicida)   DISEASE DESCRIPTION: Black rot of grape is caused by the ascomycete Phyllosticta ampelicida, a fungus which is commonly referred to as Guignardia bidwelli in the scientific community [1]. In grape-growing areas which experience warm and humid conditions in the spring and early summer, this disease has the potential to significantly decrease grape yield and wine quality [1]. Typically, a rainy period followed by 2-3 days of foggy weather favors development of… Read More →

*NOTE: This plant disease is NOT KNOWN to occur in the US or in Texas.   COMMON NAME: Acacia Rust SCIENTIFIC NAME: Uromycladium tepperianum   DISEASE DESCRIPTION This disease is only found on Acacia spp. in Asia, New Zealand and Australia.  The pathogen is not found in Texas or North America, and should not be confused with the Ravenelia fungus depicted on the calendar.  There are many exotic pathogens found worldwide that threaten crops and trees if they were introduced into the U.S.  For this reason, great efforts… Read More →

  COMMON NAME: Bacterial Leaf Scorch of Blueberry SCIENTIFIC NAME: Xylella fastidiosa subsp. multiplex [1]   DISEASE DESCRIPTION Bacterial leaf scorch (BLS) of blueberry is one of the more recently described of the five different diseases of landscape and crop plants caused by the bacterium Xylella fastidiosa and covered in this series.   SYMPTOMS: Symptoms of infection are necrosis of leaves, a burnt edge of older leaves, stem yellowing, and dieback[2]. These symptoms are typical of all of the Xylella scorch infections of plants.  New shoots are very… Read More →

COMMON NAME: Fire Fungus SCIENTIFIC NAME: Anthracobia melaloma   DISEASE DESCRIPTION Although not a disease, this fungus caused a growth on trees killed in Bastrop, TX, during the devastating wildfire in 2011.  Prior to being properly identified, the fungus was considered to be a public health menace.   SYMPTOMS Initially appears in the areas most intensely impacted by recent wildfires as white/cream colored fungal growth on trees that eventually turns an orange color [1]. The fruiting bodies are orange cup or disk shaped structures (ascocarps) with small brown… Read More →

Note: One thing learned from making this assignment is to ensure that the student understands which pathogen that we are requesting them to find information.  Acacia Rust is an example where this common name is used  but may refer to disease caused by different causal agents. The student focused on a destructive pathogen of Acacia (not in the US), while I was hoping that information would be gathered on the Acacia Rust that occurs in the US. So Dr. Appel has provided the information below for the rust… Read More →