The bacterial speck and spot pathogens can be spread easily in the greenhouse when plant density is high and plants are watered overhead. Growers planting both tomatoes and peppers, however, can purchase and plant varieties of peppers that have resistance to the bacterial spot pathogen.Īvoid overhead irrigation/watering and overwatering of transplants. Varieties resistant to the bacterial spot pathogen are not currently available. Vegetable Crop Handbook for resistant varieties that may be recommended for Mississippi. Check the latest edition of the Southeastern U.S. Varieties with resistance/tolerance to the bacterial speck pathogen are available. Though it can be difficult to distinguish between bacterial speck and spot in tomatoes, the management practices for the diseases are very similar. Volunteer tomatoes and, in the case of bacterial spot, peppers can serve as sources of inoculum. The bacteria enter plants through natural openings and wounds. These pathogens may also be spread by splashing water and wind-driven rain and on tools, machinery, and workers’ hands. These bacteria may survive on the surface of transplants without causing disease. The bacterial speck and bacterial spot pathogens can be spread easily during transplant production in greenhouses when plants are densely grown and watered overhead. Disease development is favored by high precipitation, high humidity, and temperatures between 75☏ and 86☏. These pathogens can be spread by seed and can overwinter in crop residue. Xanthomonas perforans has been confirmed on tomatoes in Mississippi (Abrahamian et al., 2017). Disease development is favored by high humidity and temperatures between 64☏ and 75☏.īacterial spot is caused by several species of Xanthomonas: X. This pathogen is seedborne and can overwinter in crop residue in temperate climates. Pathogen and Disease Spreadīacterial speck is caused by the bacterium Pseudomonas syringae pv. Symptoms of bacterial spot on a pepper fruit. Photo: Gerald Holmes, Cal Poly – San Luis Obispo,. Symptoms of bacterial spot on a pepper leaf. Symptoms of bacterial spot on a tomato fruit. Symptoms of bacterial spot on a tomato leaflet. Symptoms of bacterial speck on a tomato fruit. Photo: Gerald Holmes, Cal Poly – San Luis Obispo,. Symptoms of bacterial speck on a tomato leaflet. Symptoms associated with bacterial speck and spot on leaflets may also be confused with other diseases of tomatoes, such as early blight, gray leaf spot, and target spot. Pathogen isolation and laboratory testing are often necessary to confirm a diagnosis. However, the symptoms of bacterial speck and spot are very similar and may easily be confused with one another. Fruit lesions of bacterial spot tend to be rough compared to those of bacterial speck. In both bacterial speck and spot, lesions may coalesce to kill large areas of leaf tissue or cause streaking. Bacterial spot can also occur on peppers, and symptoms on peppers are similar to those observed in tomatoes (Figures 6 and 7). Lesions on fruits begin as small, slightly raised blisters that grow and become scab-like (Figures 4 and 5). As lesions coalesce, the foliage becomes blighted and may defoliate or remain attached to the plant. In some bacterial spot infections, leaves may have a shot-hole appearance. The tissue surrounding lesions on leaflets may become chlorotic (yellow) (Figure 3). Brown, circular lesions develop on leaves, stems, and fruit spurs. Symptoms of bacterial spot also can develop on all aboveground plant parts. A dark green halo may also develop around fruit lesions (Figure 2). Small, dark lesions that are commonly flat or slightly raised develop on infected fruits as fruits enlarge, these lesions become sunken or pitted (Figure 2). Lesions on stems, petioles, peduncles, pedicels, and sepals tend to be more elongated. These lesions extend to both leaf surfaces but are more prominent on the lower leaf surface. Round, dark-brown to black lesions develop on leaves infected with the bacterial speck pathogen over time, a yellow halo may develop around leaf lesions (Figure 1). Symptoms of bacterial speck can occur on leaves, stems, petioles, peduncles, pedicels, sepals, and fruit. Bacterial speck and spot are common bacterial diseases of tomatoes in the southeastern United States.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |