A Detailed Guide to New Lily Cultivation Techniques and Disease Prevention and Control Methods

Cultivation Techniques

(1) Land Selection and Preparation

Lilies should not be grown in continuous cropping and are afraid of waterlogging, so fertile, deep sandy loam should be selected. In old production areas, a 3~4 year crop rotation should be practiced. The land should be deep plowed to 30 cm, and the base fertilizer should be well rotted: apply 2500-3000 kg of barnyard manure per mu, 100-150 kg of composted cake fertilizer, and 20~30 kg of superphosphate, then plow and harrow them into the soil, level it, and make beds with a width (including ditches) of 2 m.

(2) Raising Seed Bulbs

Lily seeds are used only for breeding; in production, bulbs are always used for planting. Seed bulbs are raised from bulbils, bulblets, scales, and so on.

1. Raising seed bulbs from bulbils: harvest the bulbils in summer when they are mature, and sow them in a seedbed in September~October of the same year. The seedbed soil should be loose and fertile. First open shallow planting furrows in the seedbed with a furrow spacing of 12~15 cm, sow one bulbil every 4~6 cm in the furrows, then rake level and cover with grass. When seedlings emerge the following year, remove the mulch at once and apply topdressing several times. After the leaves wither in autumn, dig up the bulbs. After a full year of cultivation, the bulbils have grown into small bulbs 1~2 cm in diameter. Immediately set up another seedbed and plant them with a row spacing of 33 cm and a plant spacing of 10~14 cm, covering with 6 cm of soil. After seedlings emerge in the third year, strengthen management such as fertilizer and water application, weeding, and earthing up. When they are dug up in autumn, select the larger ones as seed bulbs, and the smaller ones can be cultivated for another year.

2. Raising seed bulbs from bulblets: for varieties that produce bulblets, when digging up the large bulbs, collect the bulblets from the soil and grade them by size. Bulblets with a diameter of 5 cm and a weight of more than 20 g can be used directly as seed bulbs; those smaller than the standard should be cultivated according to the method for raising seed bulbs from bulbils.

3. Raising seed bulbs from scales: in autumn, harvest fully mature large bulbs, and choose those with a regular shape, plumpness, and no disease as mother bulbs, then use a sharp knife to cut the scales off from the base. Then select large scales and insert them immediately into a seedbed covered with sandy loam, with the base facing downward and a spacing of 3 cm between scales. After all are inserted, cover with fine sand 4~5 cm thick. Water appropriately when dry, but overly wet bed sand will cause the scales to rot. Keep the seedbed at about 2O°C. In the south, small bulb bodies the size of rice grains can form in winter of the same year, and 1~2 basal leaves can emerge in spring of the following year. After the leaves wither in autumn, dig them out; by this time the small bulbs are already the size of a fingertip. Then change to another seedbed and plant them at a spacing of 7~10 cm. After that, they can be managed according to the method for raising seed bulbs from bulbils, and after 1~2 years of cultivation they become seed bulbs.

(3) Planting

Before planting, seed bulbs should be selected, usually requiring the seed bulb weight to reach 30~50 g. In the Yangtze River basin, plant from late August to late September; in the provinces south of the Yangtze River, where winter is not severe, autumn planting is preferable. Although no seedlings emerge that year, roots develop in the soil, and in the following spring the seedlings emerge early and the plants grow quickly. Planting density depends on the variety: for Yixing lily, the row spacing is 20 cm and the plant spacing is 20 cm; for Longya lily, the row spacing is 40 cm and the plant spacing is 20 cm. Open planting furrows according to the row spacing to a depth of 10~15 cm, loosen the subsoil at the bottom of the furrows with a hoe, then plant the seed bulbs according to the plant spacing, fill fine soil around the seed bulbs, and then cover with soil to a thickness 3 times the height of the seed bulbs.

(4) Field Management

1. Intertillage and earthing up: after lilies are planted in autumn, they do not sprout until the following spring, so vegetables and other crops can be intercropped. After the intercropped crops are harvested or before the lilies emerge, carry out one intertillage to loosen the soil. In the middle growth stage, carry out intertillage and weeding another 1~2 times and earth up the soil to prevent the bulbs from being exposed and the scales from turning green.

2. Topdressing and straw mulching: in spring, after the lilies sprout and emerge from the soil and when the seedlings are 13~16 cm tall, apply fertilizer once each time, using 2500~3000 kg of human manure water or 15~20 kg of urea and the like each time. When applying urea, do not let it touch the bulbs, so it should be applied in furrows. The last topdressing must be carried out 40~50 days before harvest. During the lily growth period, excessive soil dryness and excessively high soil temperature are most taboo, so in summer topdressing can be combined with irrigation, or straw can be spread on the beds, which can both prevent water evaporation and prevent the soil temperature from rising. A small amount of sweet potato and other crops can also be appropriately intercropped in the lily field, so that the sweet potato vines and leaves cover the soil surface; the effect of lowering soil temperature is also good.

3. Removing excess shoots, pinching the top, and removing buds: in spring after sprouting and emergence, keep one strong seedling and pinch off the rest to avoid splitting of the bulbs. In summer when flower buds begin to swell, remove the flower buds promptly. For varieties with bulbils, if the bulbils are not to be kept for propagation, they should also be removed early. In May, to prevent flowering and excessive growth of stems and leaves, the stem tip can be pinched off.

(5) Harvest

Lilies should be harvested when the aboveground part has already withered. In the south, this is about mid-August. Harvesting at this time not only gives a high yield but also stores well. Harvesting should be done on sunny days; when the soil is too wet, digging should not be done, otherwise rotting easily occurs. When the bulbs are dug out, cut off the aboveground part and fibrous roots, and immediately move them indoors to avoid drying and discoloration of the scales caused by sunlight. The yield per mu is 1000 kg.

Disease Prevention and Control

1. Lily leaf blight is the most widespread and most damaging disease among lily diseases. Circular or elliptical spots of varying sizes appear on the leaves, with spot colors ranging from yellow to light brown, and in some varieties the spots have purplish red edges. In warm, humid environments, gray mold layers appear on the spots. After the spots dry, they become transparent, and the centers often rupture. When there are spots on the stems, the affected areas easily rot and break; spots on flowers are brown, and when moist they rot and have mold layers.

This disease is a fungal disease. The pathogen mycelium or sclerotia overwinter on diseased plant residues, and the following year produce conidia that infect and cause damage. Control methods: remove diseased plant residues from the field. Spray 500-fold 75% chlorothalonil solution or 500-fold 50% carbendazim solution once every 2 weeks, for 3~4 consecutive sprays.

2. Lily phytophthora blight mostly occurs on tender leaves and can also infect stems and flowers. Oily small spots first appear on the leaves and gradually expand into grayish green areas; when moist, the diseased parts have cottony mycelium and white powdery spores. In severe cases, the leaves and flowers become soft and rot, and the stems become flaccid and droop. Brown oily small spots appear on the bulbs and rot after expanding, and the rotted parts have white mold layers.

This disease is a fungal disease. The pathogen overwinters in the soil as oospores. When there is a lot of rainfall and drainage is poor, the disease is severe.

Control methods: avoid continuous cropping, and pull out diseased plants