What are the control methods for lily pests and diseases?

In the middle and late growth stages, the bulb and stem roots are prone to root rot, showing bright dark-brown rot spots.

Basal rot easily occurs at the stem base of the plant, causing leaves to droop and turn yellow; leaf spot disease can also infect the leaves, causing the plant to stop growing. Bulb and scale rot disease shows brown to dark-brown spots on the underground stem, gradually expanding into the interior of the stem and causing the bulb to rot. There is also a damping-off disease, in which the young leaves of diseased plants show yellow-green or white spots, and in severe cases the leaves turn brown and curl.

Control: damping-off is a physiological disease, while other diseases are all caused by fungi. 50% carbendazim can be used at 1 kg per mu for root drenching, or mixed with a 100-fold dilution of 50% amobam. Note that diseased plants should be pulled out immediately at the early stage of disease onset and control measures taken at once.

2. Lily symptomless virus, also called lily virus or "lily curl-stripe virus"

(1) Symptoms: generally asymptomatic, or with mild mottling and crinkled stripes on the leaves. It easily forms mixed infections; when mixed-infected with CMV, necrotic spots appear, and when mixed-infected with tulip breaking virus, brown necrotic spots or stripes appear.

(2) Distribution: it occurs in both the south and north of the Yangtze River in China, and is especially severe in Xiamen.

(3) Pathogen: the virus particles are filamentous, long and slightly curved, 650 nm long and 18 nm in diameter. Transmitted by sap and by aphids. Lilium longiflorum is used as the diagnostic host. Lily bulbs sold on the market generally carry the virus.

(4) Control: select virus-free bulbs as planting material. Strengthen aphid control. Lily symptomless virus can also harm tulips, so these two ornamental flowers must not be mixed-planted, intercropped or grown in continuous cropping.

Lily seeds have an extremely short lifespan and lose their germination capacity after half a year of storage, and seedlings grown from seed require many years of cultivation before they can flower. Therefore, cutting propagation is used: the scales of old bulbs are broken off, and the base of each scale should carry a small part of the stem base plate, then buried in clean fine sand or mud, with the upper half of the scale exposed above the soil surface, and kept indoors or in a shade shed. After 3 to 4 months, 1 to 2 small bulbs can grow; break them off and plant them in a seedbed to continue growing. Pot them in spring, and after 3 years of cultivation they can flower.

After lily bulbs are dug up, low-temperature treatment and storage are necessary to achieve year-round flowering. First keep them at 15°C for 4 to 5 days, then lower the temperature to 9°C and keep for 3 weeks, then lower it to 0°C to 5°C and keep for 8 weeks, completing the low-temperature vernalization stage, after which they can enter long-term storage at -2°C. Before storage, however, they must be graded, cleaned, disinfected and packaged. After digging, separate the large and small bulbs. Small bulbs that have already sprouted or grown new roots can be planted immediately; large bulbs that have grown new roots should be stored at low temperature.