LILAS DES INDES : LES VARIÉTÉS DE LARGERSTROEMIA QUI RÉSISTENT À L’OÏDIUM (Le Quotidien du jardin)

NewsJardinTV, the channel that shares your passion for plants, gardens, botany, nature, and gardening, presents this new episode of its program "The Daily Garden," produced by Nicole and Patrick Mioulane. Patrick Mioulane, editor-in-chief of NewsJardinTV, answers our subscriber Dominique, who posted the following question: "My old crape myrtle has had powdery mildew for many years, a white bloom that covers the buds. I didn't do anything for a long time, but last year I tried Bordeaux mixture, which covered the tree in a terrible blue. Then I tried milk and baking soda, all without much success. Do you have any better advice?" Lagerstroemia indica, also known as crape myrtle or summer lilac, has already been featured in several videos on NewsJardinTV:    • LILAS DES INDES LES MEILLEURES VARIÉTÉS DE...      • TOUT SAVOIR SUR LE LILAS D’ÉTÉ ET BIEN LE ...      • LILAS DES INDES (LAGERSTROEMIA) DÉCOUVERTE...   This small tree with its remarkable blooms is commonly attacked by the fungus Erysiphe australiana, whose mycelium covers the flower buds with a white powder that prevents flowering and causes stunted growth. This fungal disease is known by the generic name powdery mildew. The genus Erysiphe comprises approximately 450 species of microscopic fungi belonging to the division Ascomycetes, characterized by their spores contained in globular capsules called asci. Many ascomycetes are very useful, such as Penicillium (used in antibiotics and cheeses), morels, and truffles. Some associate with algae to form lichens. Erysiphe species are phytopathogens, all vectors of powdery mildew, notably Erysiphe necator, the dreaded powdery mildew of grapevines, and Erysiphe alphitoides and Erysiphe hypophylla, which cause powdery mildew of oak trees. Other fungi are vectors of powdery mildew: Podosphaera pannosa on roses and Prunus, Podosphaera leucotricha on apple and pear trees, Podosphaera fusca on cucurbits and beans, and Golovinomyces on cucurbits, chicory, lettuce, and potatoes. Erysiphe australiana overwinters in dormant buds as conidia, which ensure the asexual reproduction of the fungus. When they germinate in the spring, they trigger the epidemic. Warm days and cool nights, marked by long periods of dry weather during the day and humid weather at night, favor the development and spread of the disease. Powdery mildew appears on young leaves in the spring, which struggle to reach a third of their normal size and fall prematurely. The internodes are short, the flower stalks are stunted and deformed, and the buds fail to open. The young, fleshy tissues are the most susceptible. The most effective preventative measures are to plant Lagerstroemia in full sun and to choose resistant varieties. Remove any suckers growing at the base of the tree, as they are highly susceptible to powdery mildew, and the fungus spreads rapidly to the upper parts of the plant. Avoid pruning the plants too severely, as this will stimulate the growth of new shoots that are particularly prone to powdery mildew, but these new shoots are also the ones that bear the flowers! Here is our selection of crape myrtles considered resistant to powdery mildew: ‘Grand Cru’ (red flowers) The Indiya Charm’s series by Sapho: ‘Summer Ember’, ‘Summer Camaïeu’, ‘Summer Fuchsia’ and ‘Summer Violet’ The With Love series by Globe Planter: ‘Virgin’, ‘Eternal’ The Summer Charm series by Promesse de Fleurs: ‘Arapaho’ (purple-pink), ‘Tuscarora’ (bright pink), ‘Hopi’ (bright pink), ‘Miami’ (dark pink), ‘Tonto’ (light red) are available on some websites. Since treatments with chemical fungicides are prohibited by the Labbé Law of January 2019, the only direct control remains the spraying of sulfur at the time of bud break and at the beginning of inflorescence formation. Organic solutions: horsetail manure, baking soda, or milk diluted to 10% sprayed on the plants are Supposed to block the development of the fungus. Liquid black soap must be added as a wetting agent to keep the product on the foliage. Thank you for watching this daily program. We hope you enjoyed this short video interlude. The entire NewsJardinTV team wishes you pleasant moments in our company and looks forward to seeing you tomorrow at 7 p.m. for a new program: "THE GARDEN DAILY." It's on NewsJardinTV and nowhere else! The topic of the next program will be: My name is Nigèle, and I would like you and your lovely wife Nicole to introduce us to this flower. I suppose you know the saying: "Nigella cures everything except death."