How to prevent and control pests and diseases on yew? A detailed guide to prevention and control methods

Greenhouse cutting seedlings of Southern Chinese yew (Taxus wallichiana var. mairei) have a total of 7 pests and diseases throughout the entire growing period, namely damping-off, stem rot, southern blight, Phytophthora root rot, spider mites, aphids, and scale insects. Among these, stem rot, southern blight, and aphids cause the most severe damage.

Prevention and control of stem rot in cutting seedlings

Two months after cuttings are taken, stem rot occurs at the base of the seedling stem, initially affecting individual plants and then spreading to affect entire clusters. It mainly occurs during the high-temperature seasons of summer and autumn. The occurrence and spread of the disease mainly depend on the temperature in July and August. If the disease occurs earlier, the seedlings have weak heat resistance, so the disease will be more severe. Therefore, between summer and autumn, lower the temperature of the surface layer of the seedbed soil to prevent scorching the base of the seedling stems, so as to avoid wounds that allow pathogens to invade; increase fertilizer application to promote the growth of cutting seedlings and enhance disease resistance.

Prevention and control of southern blight in cutting seedlings

This disease generally begins to occur in early June. When the temperature rises to around 30°C in July and August, it enters the initial peak period of the disease; when the temperature reaches as high as 35°C, it is the peak period of the disease; by the end of September, the disease basically stops. When it causes damage, it produces white mycelium accompanied by small brown spots. Control measures: strengthen management, build raised beds, and clear ditches for drainage; loosen the soil and weed in a timely manner; increase application of nitrogen fertilizer and organic fertilizer to promote robust seedling growth and enhance disease resistance; after cutting seedlings are affected, promptly remove diseased plants, fallen leaves, and infected substrate. Using quintozene and Bingwuzong mixed with yellow heart soil and sprinkling it on the seedbed can effectively control southern blight in cutting seedlings, with a control effect of over 95%%.

Aphid control

Aphids are one of the main pests of greenhouse cutting seedlings of Southern Chinese yew. Since the temperature inside the greenhouse is maintained above 18°C year-round, aphids do not have an overwintering problem in winter. In summer, if the outside temperature is not particularly high (≯38°C) and the cutting seedlings in the greenhouse have a certain leaf area, aphids can still continue to reproduce and cause damage. Therefore, the characteristic of aphid occurrence in the greenhouse is that they reproduce parthenogenetically, occur and reproduce year-round in the greenhouse, and have overlapping generations. Using aphid-whitefly horse emulsion sprinkled on the seedbed can effectively control aphids on cutting seedlings, with a control effect of over 95%%.

Integrated prevention and control technology

Greenhouse disinfection. Before cuttings are taken, disinfecting the greenhouse is very effective.

Disinfection methods:

(1) Greenhouse frame disinfection: use trisodium phosphate, sulfur, formalin, and other insecticidal and fungicidal disinfectants to spray or fumigate the steel reinforcement supports, walkways, and surrounding plastic film inside the greenhouse;

(2) Soil and substrate disinfection: use formalin, methyl bromide, and natural high temperatures in summer to disinfect soil and substrate;

(3) Drip irrigation system disinfection: use nitric acid and formalin solution to rinse and soak the drip emitters, drip tubes, sand filters, and stock solution tanks for disinfection;

(4) Reservoir disinfection: remove debris and sludge from the bottom of the reservoir, rinse the reservoir with clean water, and then use formalin or other disinfectants to disinfect the reservoir.

Ecological control

By regulating the temperature and humidity inside the greenhouse, keep the greenhouse air temperature at 15°C~18°C at night and around 25°C during the day, with a day-night temperature difference not exceeding 10°C. In this way, the relative humidity in the greenhouse can be controlled below 90%%, and no water film will form on the leaf surface of Southern Chinese yew cutting seedlings, so pathogens cannot invade leaf tissues and cause disease. Using heating technology is one of the effective measures for controlling temperature and humidity in the greenhouse.

Cultivation management

Prune and remove old leaves at the appropriate time to prevent excessive density of branches and leaves from creating a microclimate favorable for disease spread and occurrence; promptly remove diseased and pest-damaged branches and leaves, keep the greenhouse clean, and reduce as much as possible the sources of pathogens and pests that cause pests and diseases; strictly formulate and implement production operating procedures to prevent operators, visitors, and production tools from becoming transmitters of pests and diseases.

Biological control

This is the technology of applying microbial preparations and predatory or parasitic beneficial insects (i.e., natural enemies) to control pests and diseases in Southern Chinese yew cutting seedlings: apply biological insecticides such as insecticidal antibiotics to control pests such as aphids and spider mites; use natural enemies such as Aphidoletes aphidimyza, Aphidius gifuensis, and Phytoseiulus persimilis to control pests on Southern Chinese yew cutting seedlings.

Chemical control

On the basis of the above four control technologies, if stem rot, southern blight, and aphids still occur and cause damage, chemical pesticides or biological pesticides can be selected for 1~2 treatments.

Prevention and control of pests and diseases in yew

    The occurrence and damage characteristics of pests and diseases in greenhouse Southern Chinese yew are also significantly different from those of open-field Southern Chinese yew seedlings. Therefore, controlling pests and diseases in greenhouse Southern Chinese yew requires the application of new control strategies and control technologies. In order to effectively prevent and control yew pests and diseases, experts from relevant departments in our city, in areas such as Sanming urban district and Mingxi County, starting in 1975, beginning with yew cutting propagation, monitored, investigated, studied, and practiced the main pest and disease species and characteristics throughout the entire growth period, adopted integrated technologies such as ecological control, physical control, cultivation control, disinfection, and chemical control, and established an integrated prevention and control technology system for pests and diseases in greenhouse Southern Chinese yew cutting seedlings, which has now achieved obvious control results.

Species of pest and disease occurrence

Greenhouse cutting seedlings of Southern Chinese yew (Taxus wallichiana var. mairei) have a total of 7 pests and diseases throughout the entire growing period, namely damping-off, stem rot, southern blight, Phytophthora root rot, spider mites, aphids, and scale insects. Among these, stem rot, southern blight, and aphids cause the most severe damage.

Prevention and control of stem rot in cutting seedlings. Two months after cuttings are taken, stem rot occurs at the base of the seedling stem, initially affecting individual plants and then spreading to affect entire clusters. It mainly occurs during the high-temperature seasons of summer and autumn. The occurrence and spread of the disease mainly depend on the temperature in July and August. If the disease occurs earlier, the seedlings have weak heat resistance, so the disease will be more severe. Therefore, between summer and autumn, lower the temperature of the surface layer of the seedbed soil to prevent scorching the base of the seedling stems, so as to avoid wounds that allow pathogens to invade; increase fertilizer application to promote the growth of cutting seedlings and enhance disease resistance. Using quintozene + dexon powder mixed with water at a concentration of 0.5%% for irrigation achieves a control effect of 89%%, and carbendazim + thiophanate-methyl wettable powder mixed with water at a concentration of 0.4%% for irrigation achieves a control effect of 83%%.

Prevention and control of southern blight in cutting seedlings. This disease generally begins to occur in early June. When the temperature rises to around 30°C in July and August, it enters the initial peak period of the disease; when the temperature reaches as high as 35°C, it is the peak period of the disease; by the end of September, the disease basically stops. Control measures: strengthen management, build raised beds, and clear ditches for drainage; loosen the soil and weed in a timely manner; increase application of nitrogen fertilizer and organic fertilizer to promote robust seedling growth and enhance disease resistance; after cutting seedlings are affected, promptly remove diseased plants, fallen leaves, and infected substrate. Using quintozene mixed with yellow heart soil and sprinkling it on the seedbed can effectively control southern blight in cutting seedlings, with a control effect of over 95%%.

Aphid control. Aphids are one of the main pests of greenhouse cutting seedlings of Southern Chinese yew. Since the temperature inside the greenhouse is maintained above 18°C year-round, aphids do not have an overwintering problem in winter. In summer, if the outside temperature is not particularly high (≯38°C) and the cutting seedlings in the greenhouse have a certain leaf area, aphids can still continue to reproduce and cause damage. Therefore, the characteristic of aphid occurrence in the greenhouse is that they reproduce parthenogenetically, occur and reproduce year-round in the greenhouse, and have overlapping generations. Using 10%% imidacloprid emulsion sprinkled on the seedbed can effectively control aphids on cutting seedlings, with a control effect of over 95%%.

Integrated prevention and control technology

Greenhouse disinfection. Before cuttings are taken, disinfecting the greenhouse is very effective. Disinfection methods: (1) Greenhouse frame disinfection: use trisodium phosphate, sulfur, formalin, and other insecticidal and fungicidal disinfectants to spray or fumigate the steel reinforcement supports, walkways, and surrounding plastic film inside the greenhouse; (2) Soil and substrate disinfection: use formalin, methyl bromide, and natural high temperatures in summer to disinfect soil and substrate; (3) Drip irrigation system disinfection: use nitric acid and formalin solution to rinse and soak the drip emitters, drip tubes, sand filters, and stock solution tanks for disinfection; (4) Reservoir disinfection: remove debris and sludge from the bottom of the reservoir, rinse the reservoir with clean water, and then use formalin or other disinfectants to disinfect the reservoir.

Ecological control. By regulating the temperature and humidity inside the greenhouse, keep the greenhouse air temperature at 15°C~18°C at night and around 25°C during the day, with a day-night temperature difference not exceeding 10°C. In this way, the relative humidity in the greenhouse can be controlled below 90%%, and no water film will form on the leaf surface of Southern Chinese yew cutting seedlings, so pathogens cannot invade leaf tissues and cause disease. Using heating technology is one of the effective measures for controlling temperature and humidity in the greenhouse.

Cultivation management. Prune and remove old leaves at the appropriate time to prevent excessive density of branches and leaves from creating a microclimate favorable for disease spread and occurrence; promptly remove diseased and pest-damaged branches and leaves, keep the greenhouse clean, and reduce as much as possible the sources of pathogens and pests that cause pests and diseases; strictly formulate and implement production operating procedures to prevent operators, visitors, and production tools from becoming transmitters of pests and diseases.

Biological control. This is the technology of applying microbial preparations and predatory or parasitic beneficial insects (i.e., natural enemies) to control pests and diseases in Southern Chinese yew cutting seedlings: apply biological insecticides such as insecticidal antibiotics to control pests such as aphids and spider mites; use natural enemies such as Aphidoletes aphidimyza, Aphidius gifuensis, and Phytoseiulus persimilis to control pests on Southern Chinese yew cutting seedlings.

Chemical control. On the basis of the above four control technologies, if stem rot, southern blight, and aphids still occur and cause damage, chemical pesticides or biological pesticides can be selected for 1~2 treatments.

Prevention and control of pests and diseases in Southern Chinese yew

        Southern Chinese yew, also known as beautiful yew, is a rare tree species that combines high-grade timber, ornamental landscaping, and medicinal plants. It contains a natural chemical substance, namely taxol. At present, taxol is in very short supply on the market. Raw material prices are: crude taxol product with a content of 30%% is about 2
0 million yuan/kg, and high-purity taxol with a content of over 99.5%% is about 2 million yuan/kg. 
        Since the 1980s, yew resources have been devastated by predatory exploitation and are in an endangered state. In 1992, the State Forestry Administration listed it as a first-class precious protected tree species. Our city's Jiangle, Ninghua, Daitian, and other counties have naturally growing yew.
       Due to different environmental conditions, the occurrence and damage characteristics of pests and diseases in greenhouse Southern Chinese yew are also significantly different from those of open-field Southern Chinese yew seedlings. Therefore, controlling pests and diseases in greenhouse Southern Chinese yew requires the application of new control strategies and control technologies. In order to effectively prevent and control yew pests and diseases, experts from relevant departments in our city, in areas such as Sanming urban district and Mingxi County, starting in 1975, beginning with yew cutting propagation, monitored, investigated, studied, and practiced the main pest and disease species and characteristics throughout the entire growth period, adopted integrated technologies such as ecological control, physical control, cultivation control, disinfection, and chemical control, and established an integrated prevention and control technology system for pests and diseases in greenhouse Southern Chinese yew cutting seedlings, which has now achieved obvious control results. Species of pest and disease occurrence
        Greenhouse cutting seedlings of Southern Chinese yew (Taxus wallichiana var. mairei) have a total of 7 pests and diseases throughout the entire growing period, namely damping-off, stem rot, southern blight, Phytophthora root rot, spider mites, aphids, and scale insects. Among these, stem rot, southern blight, and aphids cause the most severe damage.
       Prevention and control of stem rot in cutting seedlings. Two months after cuttings are taken, stem rot occurs at the base of the seedling stem, initially affecting individual plants and then spreading to affect entire clusters. It mainly occurs during the high-temperature seasons of summer and autumn. The occurrence and spread of the disease mainly depend on the temperature in July and August. If the disease occurs earlier, the seedlings have weak heat resistance, so the disease will be more severe. Therefore, between summer and autumn, lower the temperature of the surface layer of the seedbed soil to prevent scorching the base of the seedling stems, so as to avoid wounds that allow pathogens to invade; increase fertilizer application to promote the growth of cutting seedlings and enhance disease resistance. Using quintozene + dexon powder mixed with water at a concentration of 0.5%% for irrigation achieves a control effect of 89%%, and carbendazim + thiophanate-methyl wettable powder mixed with water at a concentration of 0.4%% for irrigation achieves a control effect of 83%%.
       Prevention and control of southern blight in cutting seedlings. This disease generally begins to occur in early June. When the temperature rises to around 30°C in July and August, it enters the initial peak period of the disease; when the temperature reaches as high as 35°C, it is the peak period of the disease; by the end of September, the disease basically stops. Control measures: strengthen management, build raised beds, and clear ditches for drainage; loosen the soil and weed in a timely manner; increase application of nitrogen fertilizer and organic fertilizer to promote robust seedling growth and enhance disease resistance; after cutting seedlings are affected, promptly remove diseased plants, fallen leaves, and infected substrate. Using quintozene mixed with yellow heart soil and sprinkling it on the seedbed can effectively control southern blight in cutting seedlings, with a control effect of over 95%%.
       Aphid control. Aphids are one of the main pests of greenhouse cutting seedlings of Southern Chinese yew. Since the temperature inside the greenhouse is maintained above 18°C year-round, aphids do not have an overwintering problem in winter. In summer, if the outside temperature is not particularly high (≯38°C) and the cutting seedlings in the greenhouse have a certain leaf area, aphids can still continue to reproduce and cause damage. Therefore, the characteristic of aphid occurrence in the greenhouse is that they reproduce parthenogenetically, occur and reproduce year-round in the greenhouse, and have overlapping generations. Using 10%% imidacloprid emulsion sprinkled on the seedbed can effectively control aphids on cutting seedlings, with a control effect of over 95%%. Integrated prevention and control technology
        Greenhouse disinfection. Before cuttings are taken, disinfecting the greenhouse is very effective. Disinfection methods: (1) Greenhouse frame disinfection: use trisodium phosphate, sulfur, formalin, and other insecticidal and fungicidal disinfectants to spray or fumigate the steel reinforcement supports, walkways, and surrounding plastic film inside the greenhouse; (2) Soil and substrate disinfection: use formalin, methyl bromide, and natural high temperatures in summer to disinfect soil and substrate; (3) Drip irrigation system disinfection: use nitric acid and formalin solution to rinse and soak the drip emitters, drip tubes, sand filters, and stock solution tanks for disinfection; (4) Reservoir disinfection: remove debris and sludge from the bottom of the reservoir, rinse the reservoir with clean water, and then use formalin or other disinfectants to disinfect the reservoir.
         Ecological control. By regulating the temperature and humidity inside the greenhouse, keep the greenhouse air temperature at 15°C~18°C at night and around 25°C during the day, with a day-night temperature difference not exceeding 10°C. In this way, the relative humidity in the greenhouse can be controlled below 90%%, and no water film will form on the leaf surface of Southern Chinese yew cutting seedlings, so pathogens cannot invade leaf tissues and cause disease. Using heating technology is one of the effective measures for controlling temperature and humidity in the greenhouse.
       Cultivation management. Prune and remove old leaves at the appropriate time to prevent excessive density of branches and leaves from creating a microclimate favorable for disease spread and occurrence; promptly remove diseased and pest-damaged branches and leaves, keep the greenhouse clean, and reduce as much as possible the sources of pathogens and pests that cause pests and diseases; strictly formulate and implement production operating procedures to prevent operators, visitors, and production tools from becoming transmitters of pests and diseases.
       Biological control. This is the technology of applying microbial preparations and predatory or parasitic beneficial insects (i.e., natural enemies) to control pests and diseases in Southern Chinese yew cutting seedlings: apply biological insecticides such as insecticidal antibiotics to control pests such as aphids and spider mites; use natural enemies such as Aphidoletes aphidimyza, Aphidius gifuensis, and Phytoseiulus persimilis to control pests on Southern Chinese yew cutting seedlings.
       Chemical control. On the basis of the above four control technologies, if stem rot, southern blight, and aphids still occur and cause damage, chemical pesticides or biological pesticides can be selected for 1~2 treatments.