September 2018 The objectives of this proposal are 1) To determine the temperature and relative humidity optima for Guignardia citricarpa pycnidiospore infection and production on citrus twigs, leaf litter, and fruit; 2) To determine the relative potential of Guignardia citricarpa to form pycnidiospores on citrus twigs, leaf litter, and fruit; 3) To determine whether Guignardia citricarpa can survive and reproduce on citrus debris on grove equipment. Work on the field sample qPCR has continued with just the newly collected samples remaining. Sampling wrapped up in August. The data continues to be assembled and graphed but the major conclusions have not changed with the newly processed samples. DNA quantities tend to be lower than 10^2 fg in most samples but can increase to 10^3 fg. The data has not been processed on a per mg of bark tissue yet and it is expected that the fg/mg of tissue will become more consistent among samples. We now have samples from Sept 2016 to end of May 2017 and while DNA quantities of P. citricarpa are low, the fungus is always present. In the conidia suspension samples, the DNA quantities on average were higher than the amount of DNA on the twigs on the same date up. The amount of DNA tended to have peaks at three month intervals. This data is being analyzed in terms of environmental variables to see the number of spores and quantity of DNA. For the relative humidity and temperature experiment, samples are being processed from the 32C treatment and 16 and 36C treatments are underway. Some observed trends include that pycnidia form rapidly at 32C but may be sterile and the greatest number of spores occur around 24C. The data is still being prepared for analysis. An incubator has become no longer functional so this has slowed the experimental process down. Treatments 20C and 28C remain to be completed. In the work for disinfectants, data on spore survival in the presence of citrus debris and disinfectants was organized. Materials and Methods for a manuscript were written and data analysis is proceeding.