Occurrence and Control of Calla Lily Mosaic Disease
Common calla lily diseases include: ① Soft rot. During the growing period, soft rot and detachment occur on the plant near the soil surface, and extending upward it causes the leaf edges to become soft, wet rot and withering, the flower color to turn brown, and the flower stalk to become soft, rot and drop off, while extending downward it causes the tuber to become slimy and soft-rotted and the roots to rot, and the plant may even wilt and die. Control measures: a....
[Distribution] Very common in the Shanghai area, and also occurring in Beijing, Xiamen and other places. Besides harming calla lily, it also harms plants of the Araceae family such as Chinese evergreen (Aglaonema) and taro.[Symptoms] Typical mosaic symptoms, with symptoms masked in the hot season; the whole plant is infected, the diseased plant's leaves become smaller, and yellow-green mosaic mottling of uneven intensity appears along the leaf veins on the leaves, or yellow stripe spots appear. The leaves are deformed, the corolla is small, and it may even fail to open normally. On colored varieties, mottling sometimes appears on the flowers.
[Pathogen] The pathogen causing calla lily mosaic disease is dasheen mosaic virus (DMV); thermal inactivation point 60-65°C. The virus particles are filamentous, with a length of 700-730 nanometers. Cucumber mosaic virus (CMV).
[Transmission routes] Virus-carrying rhizomes are the source of infection; generally crops and weeds and other virus-carrying plants can also transmit the virus through aphids. Cutting tools used on flower stems and rhizomes can also transmit the virus. It invades the host through minor wounds. Because calla lily is propagated by division of roots, the rhizomes of diseased plants are the most important source of primary infection.
[Disease occurrence pattern] The sap of calla lily mosaic disease can transmit the virus, and the green peach aphid transmits it in a non-persistent manner.
[Control methods]
1. Remove diseased plants promptly when found; mildly diseased plants must not be kept as propagation mother stock. Where conditions permit, produce virus-free plantlets through heat treatment and shoot-tip virus elimination, etc.
2. Cutting tools for flowers should be frequently disinfected with alcohol, etc., to avoid sap transmission of the virus.
3. Pay attention to controlling aphids and other virus-transmitting insects. During the period when they occur and cause damage, spray with 40% omethoate 1000-1500 times dilution or 2.5% deltamethrin emulsifiable concentrate 4000-10000 times dilution for control.