Although deficit irrigation is used to improve fruit quality in healthy grapevines, it can potentially amplify negative effects of viral disease and reduce fruit quality in Grapevine Red Blotch Virus (GRBV) infected grapevines. Therefore, a 2-year field experiment was conducted to understand the interaction between GRBV infection and water deficits on disease development and vine physiology. Well-watered (WW) vines were irrigated at 100% of estimated crop evapotranspiration (ET c), while water deficit (WD) vines received water at 66 and 50% ET c in 2017 and 2018, respectively. Healthy (GRBV-) and infected (GRBV+) vines were confirmed by PCR assays. There were no significant effects of water deficits on foliar symptom onset in either year, but more severe water deficits in 2018 resulted in a more rapid symptom progression. GRBV+ vines had a higher Y stem compared to GRBV-vines, but the effects of virus only appeared post-veraison and corresponded to decreased leaf gas exchange. In general, vine vegetative and reproductive growth were not reduced in GRBV+ vines. Yields were highest in WW/ GRBV+ vines due to larger clusters containing larger berries. Consistent treatment effects on berry primary chemistry were limited to sugars, with no interactions between factors. Water deficits were able to somewhat increase berry anthocyanin concentration in GRBV + fruit, but the effects were dependent on year. By comparison, virus status and water deficits interacted on skin tannins concentration such that they were decreased in WD/ GRBV+ vines, but increased in WD/GRBV-vines. Water deficits had no effect on seed phenolics, with only virus status having a significant diminution. Although keeping GRBV+ vines well-watered may mitigate some of the negative effects of GRBD, these results suggest that water deficits will not improve overall fruit quality in GRBV+ vines. Ultimately, the control of fruit ripening imparted by GRBV infection seems to be stronger than abiotic control imparted by water deficits.

Anthracnose fruit rot and leaf blight caused by Colletotrichum species are important diseases of pomegranate in the southeastern United States. In this study, 26 isolates from pomegranate were identified based on pathological and molecular characterization. Isolates were identified to species based on multilocus sequence analysis with the internal transcribed spacer region, glyceraldehyde-3-phosphate dehydrogenase, β-tubulin, and chitin synthase genomic genes. Pomegranate isolates grouped within the C. acutatum and C. gloeosporioides species complexes, with more than 73% belonging to the latter group. Three species were identified within the C. acutatum species complex (C. nymphaeae [n = 5], C. fioriniae [n = 1], and C. simmondsii [n = 1]), and three other species were identified within the C. gloeosporioides species complex (C. theobromicola [n = 11], C. siamense [n = 6], and C. gloeosporioides [n = 2]). Inoculations of pomegranate fruit showed that isolates from the C. acutatum species complex were more aggressive than isolates from the C. gloeosporioides species complex. Interestingly, opposite results were observed when leaves of rooted pomegranate cuttings were inoculated. In addition, Colletotrichum isolates from pomegranate, strawberry, blueberry, mango, and citrus were cross-pathogenic when inoculated to fruit. This is the first study identifying six different species of Colletotrichum causing pomegranate leaf blight and fruit anthracnose in the southeastern United States and the potential cross-pathogenic capability of pomegranate isolates to other commercially important crops.