What are the difficulties in cultivating Schisandra chinensis? A complete analysis of practical countermeasures

Cultivating Schisandra chinensis artificially to replace wild resources has already become an inevitable trend in the development of the Schisandra chinensis industry. Many difficulties have also emerged in the production process of artificially planting Schisandra chinensis, and these difficulties have seriously hindered the path of Schisandra chinensis production toward intensive, large-scale, and industrialized development, and are also the fundamental reason for the current lack of large-scale successful experience in artificially cultivating Schisandra chinensis. Regarding the harm caused by pests and diseases, pesticide residues, and drift. The overall countermeasure is: adhere to the three principles of prevention, mitigation, and treatment. Prevention: in the process of Schisandra chinensis cultivation, consistently implement the policy of placing greater emphasis on prevention than on treatment, act early to seize the initiative. Take preventive measures before trouble arises and avoid being passive. In recent years, due to consecutive warm winters, the development of Schisandra chinensis has advanced, so all agronomic measures must also be carried out earlier. Among the 24 solar terms, after Awakening of Insects, Schisandra chinensis should be protected according to local phenological conditions. To prevent certain fungi in the atmosphere from attaching to the stems and vines of Schisandra chinensis, the specific measure is to spray Bordeaux mixture, prepared with equal amounts of quicklime and copper sulfate, one part each, and 200 parts water. After Schisandra chinensis leafs out, promptly spray broad-spectrum fungicides and foliar fertilizers, Bihu + polyoxins + fulvic acid. Mitigation: if nearby farmland is sprayed with butyl ester pesticides, we must take targeted measures and spray mitigating agents, or spray foliar fertilizers to improve immunity. At this stage, prevention should focus mainly on leaf blight. Spray pesticides against Deuteromycota fungi. Treatment: if diseases still occur when protective and mitigating measures are ineffective, apply the right remedy for the condition. Carry out timely treatment. Strictly prevent the loss of the optimal prevention and treatment timing, which causes losses. For the treatment of several common diseases, please follow the methods in the Schisandra chinensis pest and disease section below. Keep firmly in mind the lesson of the large-scale damage to Schisandra chinensis in Heilongjiang in 2007, and never allow the tragic situation to repeat itself.

I. Harm to Schisandra chinensis from herbicide soil residues and drift phytotoxicity

1. Soil residue phytotoxicity: farmland where long-residual herbicides such as triazines, sulfonylureas, and imidazolinones have been used cannot be planted with Schisandra chinensis within two years. If, because the herbicide use situation on the planting plot in the previous two years is unknown, the herbicide phytotoxicity to Schisandra chinensis is relatively severe, it cannot be remedied, because at present in agricultural production there is still no way to solve the problem of soil residues of long-residual herbicides. Sometimes the phytotoxicity symptoms are relatively mild, appearing as leaf wilting in the middle growth stage, with leaves recovering upright in the morning and evening, plants becoming rigid and not growing, similar to drought symptoms, and roots developing slowly. At this time, root irrigation with 500 times diluted Compo Basacote/Kapco solution, and foliar spraying of the full-nutrient foliar fertilizer Bihu, Yecui, or Shimalv at 300-500 times dilution, and also foliar fertilizers such as Xian U Su, Kebang, Lüshen, and Yebanwang, can simultaneously coordinate the relationship between aboveground and underground growth and promote root development, enhancing the resistance of Schisandra chinensis to adverse environmental conditions such as phytotoxicity, thereby enabling Schisandra chinensis to return to normal growth.

2. Herbicide drift phytotoxicity: herbicide drift phytotoxicity refers to herbicide phytotoxicity produced on Schisandra chinensis when herbicides used on surrounding farmland drift with the wind onto it. Herbicide drift is caused by two reasons: one is that the wind force is relatively strong during spraying, causing the herbicide to drift; the other is that the herbicide has a relatively low boiling point, and at higher temperatures it volatilizes due to ground transpiration, and the gaseous herbicide combines with water vapor in the air, drifts with the wind onto crops, or under the effect of temperature differences the gaseous herbicide re-condenses on the leaf surface of Schisandra chinensis. For example: 2,4-D butyl ester begins to volatilize and drift at 15°C above zero, and is the main herbicide variety causing drift phytotoxicity. The main manifestations of drift phytotoxicity are: in spring, newly grown functional leaves curl, and in severe cases the leaves turn black, wither, and fall off. For herbicide drift phytotoxicity occurring during the flowering period, petals wilt, accompanied by early petal shedding, decreased or lost pollen viability, difficulty in pollination, and the phenomenon of flowers without fruit. Because drift phytotoxicity causes severe damage to functional leaves in the early stage, resulting in insufficient nutrient accumulation, fruit drop begins to appear in mid-June, with reduced yield in mild cases and total loss of production and harvest in severe cases. It is recommended to use 2,4-D isooctyl ester instead of 2,4-D butyl ester, because its volatility is relatively low and it can reduce the occurrence of drift phytotoxicity. After drift phytotoxicity occurs, immediately use Compo Basacote/Kapco 500 times + Shimalv 500 times or Bihu + fulvic acid foliar spray, and the phytotoxicity symptoms will improve significantly.

II. The "alternate bearing" phenomenon of Schisandra chinensis

The so-called "alternate bearing" refers to the phenomenon in which the number of fruits produced after the fruiting stage of Schisandra chinensis alternates between different years. The occurrence of off-years seriously affects the planting benefits of Schisandra chinensis. The direct reason for the occurrence of an off-year is that in that year there are few female flowers and many male flowers. The decisive factor for the number of female and male flowers in that year lies in the flower bud differentiation period around August of the previous year (an on-year), and the factors affecting flower bud differentiation in Schisandra chinensis are multifaceted, closely related to tree nutrition, load, light, temperature, soil moisture content, endogenous hormone levels, and so on. Cultivation experience with Schisandra chinensis shows that if the fruit yield per plant is too large or management is poor, nutrient elements first satisfy the needs of the fruit, and only the surplus nutrient materials can be transported into the buds. Due to the lack of nutrient elements, female flower differentiation is blocked, and the result of flower bud differentiation is few female flowers or all male flowers. Therefore, in Schisandra chinensis cultivation, attention should be paid to regulating the load of the tree, reasonable pruning, attention to pest and disease control, and strengthening measures such as fertilization and irrigation, especially spraying full-element foliar fertilizer during the flower bud differentiation period to meet nutritional needs. For specific operations, see Chapter 6, Orchard Management of Schisandra chinensis.

III. Pests and diseases of Schisandra chinensis