pelargonii can survive in the soil for at least a year in plant tissue, but cannot survive in the absence of host debris (1). It is possible that Xanthomonas campestris pv. The bacteria can be spread on knives, in propagation medium, and by water splashing from infected leaves to uninfected plants, thus overhead irrigation should be avoided (2). After moving new stock, cuttings may rot at the base and eventually completely die (1). Latent infections are also especially important when propagating plant material through cuttings. ![]() However, they can still carry the bacterium and transfer it to daughter plants produced from cuttings without showing any outward symptoms typical of infection. Mature and woodier plants seem less susceptible to this disease. In cooler temperatures, symptoms may be masked and will not develop until warmer temperatures are achieved (3). At temperatures below 10 ☌ or above 32° C, disease development is suppressed (1). Disease development is favored around 27° C. Symptom development can occur seven days or more after infection. Plants infected as cuttings will rot at the base of the cutting and fail to produce roots (1). Once systemic vascular wilt is evident, the bacterium can cause a root rot as it travels down the plant to the roots. If a stem is cut from the plant that is infected, bacteria may ooze from the vascular system (2). Leaves will first droop, become chlorotic, and then die and fall off. This can kill individual leaves and in severe cases it may kill the entire plant. The bacterium usually travels from the leaf spots to the vascular system and causes a systemic wilt (1). Wedge-shaped areas of chlorosis and necrosis may develop with the point starting at the leaf spot and extend to the leaf margins. Eventually, these spots will turn tan to brown and will be sunken with well-defined margins. Initial symptoms include small water soaked spots that can be seen from the underside of the leaf and become visible from the upper surface of the leaf after a few days. Symptoms can vary depending on the growing conditions and individual cultivar and species affected. ![]() ![]() This bacterium is the causal agent of bacterial blight on plants in the genera Pelargonium and Geranium (1). pelargonii is a gram negative, rod-shaped, obligately aerobic, bacterium that produces yellow colored colonies when isolated on nutrient agar.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |