With all of the pelting that we ’ve experienced this year , many fungous leafage spot diseases are active . hydrangea are peculiarly susceptible to several unlike leaf spot diseases that favor moist weather . Some of the most common diseases the great unwashed ask about are known as Corynespora folio billet and Cercospora leaf spot on bigleaf hydrangea .
Many of the foliage disease that are apparent in the spill are really the termination of infections that pass in the spring . As the time of year advance , these foliage fleck start out to enlarge and become more noticeable . Late summer rainfall or overhead irrigation can perpetuate these diseases and lead to defoliation or the decline of infected plants . foliage that remain pixilated for protracted full point are more potential to develop fleck .
folio spot symptoms commonly set out out on honest-to-god leaf near the bottom of the plant and move upwardly by and by in the time of year . Corynespora and Cercospora are wanton to recognize due to the dramatic purple lesion that form on the control surface of the foliage . As these smirch enlarge , they may become irregular in shape and modernise a grayish center surrounded by imperial margin . finally , the entire leaf may become a yellowish color . The fungus produces many spore in the center of each spot , which are easily spread by wind , splashing water , rainfall or irrigation .
Fungal leaf spots are generally not a major trouble for hydrangeas beyond their aesthetic appearance . Although the disease seldom kills the plant , serious outbreaks over the course of multiple years can slim industrial plant vigour . Years that lead off off with a very blotto leaping will often see more leaf spot diseases on hydrangea . By the time most people notice the disease in recent summer or fall , it ’s too previous to spray a antimycotic for the time of year . Those farewell will remain spot until they pass off in the wintertime , whether or not you spray .
Some years will be worse than others depending on the weather . Avoid vex leave wet when watering plants or use drip irrigation as an alternative . Water plants early in the morn to allow the folio to dry more quick as the Sunday rises . Infected leaves may be removed at any time during the time of year to slow down down the spreading of the disease . Also , removing and disposing the leaf that settle on the ground or that stay on the bush in the wintertime can help reduce carryover of the disease from one year to the next .
For young plants , it may be deserving the extra effort to spray as many newfangled leaves as potential in the spring as a protective metre . Older plant more often than not best support the disease . Fungicides containing chlorothalonil , mancozeb or thiophanate - methyl are most effective when put on prior to the first sign of leaf spots and to protect newly develop leave . Reapplying every 10 to 14 twenty-four hour period may be necessary to foreclose these diseases . Be sure to follow the label for practical software rates and safety precaution .
Some bigleaf hydrangea cultivars are more resistant to flick smirch diseases . Unfortunately , many of the popular varieties , specially when stressed with too much sunlight , are more susceptible to leaf diseases . A study at Tennessee State University get hold the following bigleaf hydrangea cultivars to be resistant to leaf spot diseases in both sunny and shaded environments : ' Ami Pasquier ' , ' Ayesha ' , ' Blue Bird ' , ' constantly Pink ' , ' Fuji Waterfall ( Fujinotaki ) ' , ' Miyama - yae - Murasaki ' , ' Seafoam ' , ' Taube ' , ' Tricolor ' and ' Veitchii ' . For more information , see UGA Extension Circular 973 , “ Growing Bigleaf Hydrangea . ”Paul Pugliese is the agriculture & lifelike resources agent for the University of Georgia Extension office in Bartow County .
Source : newswire.caes.uga.edu
