Common Diseases and Pests Control Methods for White玉兰
Summary: Small experiences with white magnolia in the Flower Clinic, common diseases and pests control methods for white magnolia, keep reading!
Common diseases of white magnolia include yellowing disease, (T-J) disease, and root rot; pests include scale insects, red spiders, aphids, and tussock moths.
(T-J) disease
Mainly occurs on leaves, initially showing chlorosis with small yellow spots, which gradually expand into round or oval shapes. Several lesions may merge into irregular spots, with a light brown center and dark brown edges. Lesions on the leaf margin are semicircular, causing the leaf to twist. Severe disease can lead to leaf withering, blackening, and falling off. This disease is a fungal disease, with the pathogen overwintering in the host's diseased tissue. Overwatering and high humidity in potted plants can easily cause the disease. It usually starts in early June, with July to August being the peak period. Control methods include: improving watering methods, allowing water to flow from the edge of the pot, not too much; pruning and removing diseased leaves and shoots, clearing fallen leaves for destruction to reduce the disease source; every ten to fifteen days during the spring rain and plum rain seasons, spray an equal amount of 100 to 200 times Bordeaux mixture, 65% zineb 500 to 800 times liquid, or 70% thiophanate-methyl 1000 times liquid, for three to four consecutive times to suppress disease occurrence.
Root rot disease
A fungal disease. Excessive watering or waterlogging in white magnolia can easily cause blackening and rotting of the roots, resulting in poor growth, yellowing and falling off of leaves, or even death of the entire plant. Control methods: making efforts to improve soil drainage conditions is an important measure for disease prevention. Watering should be done when dry and wet, watering thoroughly, and paying attention to loosening the soil; during consecutive rainy days, prevent rain soaking and promptly pour out the accumulated water in the pot; place more broken tiles at the bottom of the pot for drainage. When placed outdoors, it is best to use bricks to prop up the pot to aid drainage; if the plant is infected during the growing period, it can be treated with 65% zineb 250 times liquid, 50% zineb ammonium 250 times liquid, or 50% carbendazim 500 times liquid for root soil irrigation.
Yellowing disease
Also known as chlorosis, a physiological disease. If the potting soil is alkaline and water with high salt and alkali content is used for irrigation, the leaves of white magnolia, which prefers slightly acidic soil, will gradually turn from green to yellowish-white, and severe cases can cause local leaf necrosis and brown spots. After the onset, immediately spray 0.5% ferrous sulfate solution on the leaf surface, once a week, for three to four consecutive times, and apply alum fertilizer water.
Pests and diseases
The main pests and diseases of white magnolia include yellowing disease, (T-J) disease, and red spiders, scale insects, etc. If the soil is alkaline or the irrigation water is alkaline, it can easily cause yellowing of the leaves and root rot. You can spray 0.2% ferrous sulfate solution on the leaf surface every 5-7 days. You can also frequently apply 0.5% ferrous sulfate solution for control.
White magnolia's (T-J) disease initially causes chlorosis with small yellow spots, which gradually expand into circles. Severe cases can lead to leaf withering, blackening, and falling off. Overwatering, high humidity, and poor ventilation can easily cause this disease. You can use 50% wettable powder carbendazim 500 times liquid, or 50% wettable powder thiophanate-methyl 500 times liquid, sprayed every 5-10 days for control.
Red spiders and scale insects can cause yellowing of white magnolia leaves and absorb sap, leading to plant withering. Their secretions can cause sooty mold. Scale insects can be removed with a bamboo slice when discovered. Red spiders can be controlled with 1000 times 20% trichlorfon zinc sulfate, or 50% trithion 1000 times liquid spray.
Signs of red spider damage: carefully observing the branches, you will find cobwebs, and on each leaf, you will find red spiders, which are very small, about one-fifth to one-fourth of a millimeter (what I encountered at home, but I don't know how big they can grow), crawling on the leaf edge or surface.
The above () introduces detailed explanations of common diseases and pests control methods for white magnolia, for reference and suggestion only!