Archival copy: for current recommendations see http://edis.ifas.ufl.edu or your local extension office. Archival copy: for current recommendations see http://edis.ifas.ufl.edu or your local extension office. ENY-863 Common Weed Hosts of Insect-Transmitted Viruses of Florida Vegetable Crops1 Gaurav Goyal, Harsimran K. Gill, and Robert McSorley2 Weed growth can severely decrease the commercial, virus attacks bell pepper, tomato, spinach, cantaloupe, recreational, and aesthetic values of crops, landscapes, and cucumber, pumpkin, squash, celery, and watercress. waterways. More information on weeds can be found in References to appropriate publications are provided for Hall et al. (2009i). Other than affecting crop production easy cross-reference and more details about the virus by reducing the amount of nutrients available to the main under consideration. Common viruses with their family crop, weeds can also influence crop production by acting as and genus names are provided in Table 2. Information is reservoirs of various viruses that are transmitted by insects. also provided for each vegetable that was reported infected Several insects transmit different viruses in different crops, by the virus, and on the insect vectors that transmit the but aphids and whiteflies are among the most important virus. Some viruses, such as Tomato mosaic virus, are not virus vectors (carriers of viruses) on vegetable crops in transmitted by vectors. Others, such as Bean common Florida. The insect vectors feed on various parts of weeds mosaic virus, can be transmitted by vectors or through seed. that are infected by a virus and acquire the virus in the Detailed information about viruses and their transmission process. They then can feed on uninfected agricultural has been summarized by Adams and Antoniw (2011). crops and transmit the virus to them. Insects are often Common and scientific names of weeds that act as virus attracted to weeds and survive on them because weeds can sources are listed in Table 3. provide food for insects when preferred food is scarce, or weeds can provide shelter from adverse conditions such as Removal of weeds that act as virus sources may be helpful bad weather or pesticide applications. Several weeds have in reducing the initial infestation by a virus of the main been reported as virus hosts by Kucharek and Purcifull crop in the same field as well as other fields that are near (2001). The current publication includes additional and the weeds. Removal of volunteer plants from field borders updated material since that time and provides links to may also help in management of viral diseases (Momol and further information on specific viruses that affect vegetable Pernezny 2006). crops. Certain volunteer vegetable plants can also act as sources of viruses that endanger the main crop. While a number of weeds in and around fields of different crops can act as virus sources for the main vegetable crop, Information on weed hosts of various vegetable viruses can some of them are particularly important because of their be found in Table 1. Virus names are often based on the ability to host a number of different viruses. A few of these name of the vegetable they attack; however, certain viruses are balsam apple (Figure 1), creeping cucumber (Figure 2), affect many different vegetables, e.g., Cucumber mosaic groundcherry (Figure 3), dayflower (Figure 4), American 1. This document is ENY-863, one of a series of the Entomology and Nematology Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Original publication date April 2012. Visit the EDIS website at http://edis.ifas.ufl.edu. 2. Gaurav Goyal, postdoctoral research associate; Harsimran K. Gill, postdoctoral research associate; and Robert McSorley, professor; Department of Entomology and Nematology, Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL, 32611. The Institute of Food and Agricultural Sciences (IFAS) is an Equal Opportunity Institution authorized to provide research, educational information and other services only to individuals and institutions that function with non-discrimination with respect to race, creed, color, religion, age, disability, sex, sexual orientation, marital status, national origin, political opinions or affiliations. U.S. Department of Agriculture, Cooperative Extension Service, University of Florida, IFAS, Florida A&M University Cooperative Extension Program, and Boards of County Commissioners Cooperating. Millie Ferrer-Chancy, Interim Dean Archival copy: for current recommendations see http://edis.ifas.ufl.edu or your local extension office. Archival copy: for current recommendations see http://edis.ifas.ufl.edu or your local extension office. black nightshade (Figure 5), hairy indigo (Figure 6), and citron (Figure 7). The American black nightshade is com- mon in Florida (MacRae 2010), and it is possible that some of the references to “nightshade” in Table 1 or to “black nightshade” may actually refer to this plant. Recognition of these common virus host plants is important because they may be reservoirs for viruses, allowing them to survive during the off-season when the main vegetable crops are not grown. Figure 3. Cutleaf groundcherry (Physalis angulata), Credits: Brent Sellers (Hall et al. 2009b) Figure 1. Balsam apple (Momordica spp.), Credits: Brent Sellers (Hall et al. 2009a) Figure 4. Dayflower (Commelina spp.), Credits: Gaurav Goyal Research, Harpenden, UK. Available: (http://www.dpvweb. net). Adkins, S., and E. N. Rosskopf. 2002. Key West nightshade, a new experimental host for plant viruses. Plant Disease 86:1310-1314. Adkins, S., S. E. Webb, C. A. Baker, and C. S. Kousik. 2008. Squash vein yellowing virus detection using nested poly- merase chain reaction demonstrates that the cucurbit weed Momordica charantia is a reservoir host. Plant Disease 92:1119-1123. Figure 2. Creeping cucumber (Melothria pendula), Credits: Gaurav Goyal Adkins, S., S. E. Webb, P. D. Roberts, C. S. Kousik, P. A. Stansly, B. D. Bruton, D. Achor, R. M. Muchovej, and C. A. Baker. 2010. A review of Ipomoviruses and Watermelon decline in Florida, pp. 333-337. In P.A. Stansly and S.E. References Cited Naranjo (eds.), Bemisia: Bionomics and management of a Adams, M. J., and J.F. Antoniw. 2011. Descriptions of plant global pest. Springer Publishing, New York. viruses. Association of Applied Biologists, Rothamsted 2 Archival copy: for current recommendations see http://edis.ifas.ufl.edu or your local extension office. Archival copy: for current recommendations see http://edis.ifas.ufl.edu or your local extension office. Figure 7. Citron (Citrullus lanatus), Credits: Gaurav Goyal Bracero, V., and L. I. Rivera. 2003. DNA analysis confirms Macroptilium lathyroides as alternative hosts of bean golden yellow mosaic virus. Plant Disease 87:1022-1025. Figure 5. American black nightshade (Solanum americanum), Credits: Gaurav Goyal Brown, L. G., and G. W. Simone. 1994. Tomato yellow leaf curl geminivirus. Plant Pathology Circ. 366. Florida Dept. of Agriculture and Consumer Services. Division of Plant Industry, Gainesville, FL. Available:(http://www.freshfrom- florida com/pi/enpp/pathology/pathcirc/pp366.pdf). Dikova, B. 1946. Establishment of tobacco rattle virus (trv) in weeds and Cuscuta. Biotechnology and Biotechnology Equipment 20:42-48. Ferreira, S. A., and R. A. Boley. 1992. Cucumber mosaic virus. Crop Knowledge Master. Department of Plant Pathology, CTAHR, University of Hawaii, Manoa. Avail- able: (http://www.extento.hawaii.edu/kbase/crop/type/ cucvir.htm). Ferrell, J. A., G. E. MacDonald, and B. J. Brecke. 2009. Benghal dayflower (Commelina benghalensis L.), identifi- cation and control. Agronomy Department SS-AGR-223. Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Available: Figure 6. Hairy indigo (Indigofera hirsuta), (http://edis.ifas.ufl.edu/ag230). Credits: Robert McSorley Baker, C., S. Webb, and S. Adkins. 2008. Squash vein Fukumoto F., F. Terami, and M. Ishii. 1993. Zucchini yellow yellowing virus, causal agent of watermelon vine decline mosaic virus isolated from wax gourd (Benincasa hispida in Florida. Plant Pathology Department Circ. 407. Florida Cogn.) and balsam pear (Momordica charantia L.) (in Dept. of Agriculture and Consumer Services, Division of Japanese). Proceedings of Kanto Plant Protection Society Plant industry, Gainesville, FL. Available: (http://www. 40:101–103. freshfromflorida.com/pi/enpp/pathology/pathcirc/pp407. pdf). Gilman, E. F. 2011. Asclepias curassavica butterflyweed, milkweed, silkweed. Environmental Horticulture FPS-49. 3 Archival copy: for current recommendations see http://edis.ifas.ufl.edu or your local extension office. Archival copy: for current recommendations see http://edis.ifas.ufl.edu or your local extension office. Florida Cooperative Extension Service, Institute of Food Hall, D. W., V. V. Vandiver, and J. A. Ferrell. 2009g. Wild and Agricultural Sciences, University of Florida. Available: radish, Raphanus raphanistrum L. Excerpt from weeds in (http://edis.ifas.ufl.edu/fp049). Florida. Agronomy Department SP 37. Florida Cooperative Extension Service, Institute of Food and Agricultural Groves, R. L., J. F. Walgenbach, J. W. Mayor, and G. G. Sciences, University of Florida. Available: (http://edis.ifas. Kennedy. 2002. The role of weed hosts and Tobacco thrips, ufl.edu/fw032). Frankliniella fusca, in the epidemiology of tomato spotted