Key Points of Integrated Pest and Disease Control Techniques for the Chinese Medicinal Herb Agarwood

Site Selection and Land Preparation for Agarwood

Aquilaria sinensis (agarwood tree) has strong adaptability and can be planted on sheltered, sunny gentle slopes or hills at an altitude of 800-1000 m, in red soil or mountain yellow soil with a pH of 4.5-6.5. The planting site should be deep-plowed, and holes dug at a spacing of 2 m × 3 m, with about 110 plants per mu. The hole specifications are 50 cm × 50 cm × 40 cm, with 20 kg of base fertilizer applied per hole, then covered with soil pending planting.

The nursery site should be chosen in a place with appropriate shade, on a gentle slope or flat land facing east with relatively high air humidity. Deep plow early, then make beds 1 m wide and 20 cm high. Nutrition bags can also be used for seedling raising, but large-sized nutrition bags must be used.

Propagation

1. Seed collection and seed treatment. Seeds must be collected from mother trees aged 10-15 years or more. Generally in June to August, when the fruit turns from green to yellow-white and the seeds are brown, pick them together with the fruiting branches. Place the collected fruiting branches in a ventilated place to dry in the shade, not in direct sunlight. After 2-3 days, the fruit shells crack open and the seeds fall out on their own. It is best to sow and raise seedlings promptly. Otherwise, they must be properly stored, generally by sand storage, mixing 1 part seeds with 3 parts wet sand, and storing in a ventilated, low-humidity place, but for no more than 7-10 days.

2. Sowing and seedling raising. Sowing is preferably done in drills or by broadcasting. On the seedbed, open shallow furrows at a row spacing of 15-20 cm and sow, or evenly scatter the seeds on the seedbed, then gently press the seeds into the soil. Sparse and shallow sowing is preferable. After sowing, cover with 1 cm of burnt soil or fine sand, just enough to hide the seeds, then cover the bed surface with grass and water to keep moist. If there is no natural shade, a shed should be built to maintain 50%-60% light transmittance. About 5 kg of seeds are sown per mu, which can cultivate 12,000-13,000 strong seedlings.

When the seedlings grow 2-3 pairs of true leaves and reach a height of 10 cm, transplant the seedlings into nutrition bags on rainy days or on sunny afternoons. The nutrition soil formula is topsoil plus a small amount of river sand, cow dung, and superphosphate.

Scientific Planting of Agarwood

The best planting time is at the Beginning of Spring (Lichun), and seedlings should be transplanted and planted when the temperature steadily rises. Since the seedlings have few lateral roots, when planting bare-root seedlings, try to retain as much native soil as possible when lifting the seedlings. Before planting, cut off the lower lateral branches and leaves of the seedlings, keeping only some upper leaves, and cut the leaves in half; trim excessively long main and lateral roots, and dip them in fresh cow dung and yellow mud slurry; for nutrition bag seedlings, tear the plastic bags. When planting, the seedling should be upright and the roots spread out, fill soil in layers, compact, tread firmly, water thoroughly to settle the roots, and finally cover with a layer of loose soil. The survival rate can reach 95%.

Field Management

Seedling stage management: Aquilaria sinensis seeds germinate quickly, and the emerged seedlings are not drought-tolerant. After transplanting, water once in the morning and once in the evening to keep the soil moist. If there is no natural shade, build a shed for shading. From May to August each year, weed once a month to prevent weeds from covering the young seedlings. Prune branches appropriately to promote main trunk growth. After the seedlings reach 15 cm in height, apply diluted manure and urine water once every 2 months, and later increase the concentration appropriately as the seedlings grow. After 1-1.5 years of seedling raising, bag seedlings reaching 50-80 cm in height or bare-root seedlings reaching over 1 m in height can be released from the nursery for planting.

Management after planting: In the early stage after planting, water promptly according to weather conditions. During the young stage, weed and loosen the soil once every 1-2 months, and cover grass around the holes. Fertilize 2-3 times a year. In the dry season, apply light human and livestock manure water or ammonium sulfate and urea diluted with water. In the rainy season, open furrows around the holes and apply organic fertilizer mixed with superphosphate. For mature trees, open furrows and increase the application of organic fertilizer and green manure. To help the main trunk grow straight and facilitate artificial inoculation for agarwood formation, the lower lateral branches, diseased and weak branches, and excessively dense branches on the stem must be pruned. Missing plants should be replanted promptly.

Routine management after maturity includes:

1. Loosening soil and weeding: After planting, Aquilaria sinensis should have its soil loosened and weeds removed twice a year, before the summer drought in May to June and in late autumn to early winter in August to September. Spread the removed weeds around the root zone, and turn them into the soil layer by layer year by year to increase organic matter.

2. Fertilization: Fertilize at least once a year. Before the spring shoots sprout in February to March, apply human and livestock manure and urine water to promote shoot growth, germination, and accelerated growth. Where conditions permit, apply decomposed organic fertilizer in September to October and turn the weeds into the soil. At this time, furrow (hole) application should be carried out. As the tree age increases, the amount of fertilizer applied should also increase accordingly.

3. Pruning: Aquilaria sinensis is a tree species that forms agarwood in the main trunk. To promote main trunk growth and facilitate agarwood formation, timely pruning must be carried out. Gradually cut off the lower branches, diseased and insect-damaged branches, and excessively dense branches.

Three-dimensional intercropping and relay intercropping: Artificially planted Aquilaria sinensis has a long growth period. During the young stage, there is large space between plants, so in the first 3 years after planting, grain and oil crops such as tubers and beans, and short-term medicinal herbs such as Lysimachia christinae and Andrographis paniculata can be intercropped. When the rows become more closed, shade-tolerant Chinese medicinal herbs such as Alpinia oxyphylla, Amomum villosum, and Alpinia officinarum can be intercropped, so as to fully utilize natural resources, regulate the growth environment of Aquilaria sinensis, and increase economic income. After intercropping, different cultivation and management techniques are adopted according to different intercrop species, so that both Aquilaria sinensis and the intercrops grow well, achieving the goals of maintaining the land through the land itself, supporting long-term crops with short-term crops, and replacing tending with intercropping, achieving multiple benefits at once.

Integrated Pest and Disease Control of Agarwood

Seedling blight: This disease occurs in seedbeds and causes seedlings to wilt and die. Old seedbeds, poor drainage, and dense planting are prone to the disease. Control methods: (1) Disinfect the seedbed before planting and maintain reasonable dense planting; (2) In the early stage of the disease, promptly remove diseased plants and use 70% Dexon 1000-1500 times dilution or 50% carbendazim 800 times dilution to drench the soil 2-3 times, with an interval of 7-10 days each time.

Anthracnose: This disease damages leaves. It initially appears as small brown spots, then expands into round, oval, to irregular spots, and some lesions show concentric rings. In severe cases, leaves fall off. It is prone to occur during rainy and humid weather with heavy dew. Control methods: In the early stage of the disease, spray 80% Anthracnose Fumei 600-700 times dilution or 75% chlorothalonil 400-600 times dilution 2-3 times, with an interval of 7-10 days each time.

Leaf roller: It damages between summer and autumn each year. The larvae spin silk to roll up leaves and bore into and feed on the leaf mesophyll, weakening photosynthesis and affecting normal growth. Control methods:

1. Manual elimination: When rolled leaves are found, cut them off promptly and bury them deeply in a centralized manner to reduce pest damage.

2. Chemical control: Before the pests roll the leaves or at the early hatching stage of eggs, use 25% chlordimeform diluted 500 times; or spray with 80% dichlorvos emulsifiable concentrate 800-1000 times dilution, once every 5-7 days, for 2-3 consecutive times. Longhorn beetle larvae bore into the stem, branches, or stem base and feed on the xylem. In severe cases, the trunk dies.

Control methods

1. Manually capture and kill egg masses and larvae;

2. When bore holes are found, inject 80% dichlorvos 800-1000 times dilution with a syringe, then seal the opening with yellow mud. Scarab beetles often damage young buds, tender shoots, and flowers during the shoot-growing and flowering periods. Control methods: manual capture and killing, or spraying 80% dichlorvos 1000 times dilution for control.