During the deep winter season, the seedlings of wolfberry vegetables are in a critical nursery phase. Proper management during this period is essential to prevent the occurrence and spread of diseases. If not managed well, seedlings may suffer from various illnesses, leading to stunted growth or even total loss of the crop. This can significantly impact vegetable production and result in substantial economic losses. Therefore, effective disease prevention and control at the seedling stage are crucial for ensuring a successful and high-yield harvest. The following sections describe common diseases such as damping-off, blight, and anthracnose, along with their symptoms and control measures.
First, let's look at the symptoms of these diseases:
1. Damping-off: This disease can occur before or after the seedlings emerge. When it affects seeds before germination, it causes the radicles and cotyledons to rot, preventing proper emergence. After the seedlings have emerged, a water-soaked lesion appears at the base of the stem, which turns yellow-brown, shrinks, and eventually causes the seedling to fall over.
2. Blight: This disease typically occurs in the middle to late stages of seedling growth. Initially, dark brown oval spots appear on the stem base. During the early stages, the seedlings may wilt during the day but recover at night. As the disease progresses, the lesion girdles the stem, causing it to sink and shrink, ultimately leading to the death of the entire plant.
3. Anthracnose: This disease often starts with semi-circular brown lesions on the edges of the cotyledons. The affected tissue dies and ruptures. In severe cases, the lesions expand and cause leaf drop. The base of the stem near the ground develops red longitudinal cracks that later turn into brown, wrinkled, and slightly sunken lesions. During rainy periods, the roots may become black and rot, leading to plant death.
Next, here are some effective control methods:
1. Seedbed Selection: Avoid using soil from old seedbeds that may harbor pathogens. Instead, choose new seedbeds or loamy soil that has not been used for growing vegetables. This helps reduce the risk of disease. The selected area should be well-drained, with loose, fertile soil that allows good air circulation and water infiltration.
2. Soil Disinfection: To disinfect the seedbed soil, mix 10 grams of 50% carbendazim wettable powder per square meter with fine soil. Spread one-third of the mixture evenly on the bed before sowing, and cover the remaining with soil after planting. This method ensures that both the top and bottom layers of the seedbed are treated, achieving over 90% sterilization effectiveness.
3. Seedbed Management: Construct a high-quality seedbed that provides adequate warmth while protecting against cold winds. During rainy weather, ensure proper drainage by digging trenches to prevent waterlogging. Even on sunny days, maintain good ventilation to reduce humidity and prevent disease development.
4. Chemical Control: If signs of disease are detected, remove the affected plants immediately. Apply 75% chlorothalonil wettable powder diluted 800 times to the seedbed, repeating every 7–10 days for 2–3 applications. Alternatively, spreading wood ash on the seedbed can help reduce moisture, increase heat absorption, and improve soil potassium levels, promoting stronger and healthier seedlings with better resistance to diseases.
Lactobacillus johnsonii, a gram-positive bacterium, belongs to phylum Firmicutes, class Bacilli, order Lactobacillales, family Lactobacillaceae, and genus Lactobacillus, which is facultatively anaerobic and sometimes microaerophilic, exhibiting poor growth under aerobic conditions but better growth at reduced oxygen pressure. L. johnsonii was first isolated from human blood, with other primary sources including humans, mice, and pigs (Pridmore et al., 2004; Vazquez-Munoz et al., 2023; Zhang et al., 2019). The health-associated benefits of L. johnsonii are known for its antibacterial properties, inhibiting pathogenic bacteria such as Helicobacter pylori and Staphylococcus aureus (Aiba et al., 2019; Rosignoli et al., 2018). It is also viewed as a substitute for antibiotics in poultry feed due to its ability to suppress Clostridium perfringens (Gervasi et al., 2014). Multiple strains of L. johnsonii contain bile salt hydrolase (BSH) (Boucard et al., 2022), which has been reported to have anti-Giardia lamblia activity and reduce cholesterol (Allain et al., 2018; Zhu et al., 2022). Additionally, L. johnsonii FI9785 can produce extracellular polysaccharides (EPS), which enhances its colonization ability (Mayer et al., 2020). In clinical research, L. johnsonii can serve as an adjuvant to help alleviate type 1 diabetes and allergic rhinitis (Lue et al., 2012; Wang et al., 2022). L. johnsonii exhibits significant antimicrobial potential and has been proven to be effective in livestock farming as a substitute for antibiotics.
Probiotics, Johnsonii, extracellular polysaccharides
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