Cultivation

• Fusarium Yellows of Cabbage

  2026-03-10    Views：208

  Symptoms and Control MethodsSymptomsAlso known as cabbage yellows or wilt disease.It mainly attacks cruciferous vegetables such as cabbage, Chinese kale, cauliflower, etc.Infected plants show wilting, stunting, and yellowing.On Chinese kale and heading cabbage, leaf margins turn purple and leaf bases become brown.Lower leaves drop one after another.Vascular bundles in infected leaves and stems turn black, extending from the base toward the leaf margins, which distinguishes it from black rot.PathogenFusarium oxysporum f.sp. conglutinans (Wollenw.) Snyd. et Hans.A fungus belonging to Deuteromycetes.Stroma and mycelium: initially white, gradually turning brown to pink.Macroconidia: scarce, cylindrical to fusiform, both ends pointed, basal spur present, mostly 2–3 septa,size 25–33 × 3.5–5.5 μm.Microconidia: abundant, ovoid to elliptical, unicellular,size 6–15 × 2.5–4 μm.Chlamydospores: terminal or intercalary.No sporodochia, synnemata, or sclerotia produced.Transmission and Disease ConditionsThe pathogen survives in the soil.In dry years, excessively high or prolonged soil temperature burns roots in the plow layer and slows secondary root growth, impairing water uptake and causing root suberization and disease.Outbreaks often occur in some years or under off‑season cultivation in Shaanxi, Hubei, Sichuan, etc.It has become an important disease in cruciferous crop production.Control MethodsUse resistant varietiese.g., Changchun Kuai Cai, Shenyang Kuai Cai, Jiyan No. 3, Danza No. 1 rapeseed, etc.Sow at proper timeAvoid early sowing; try to avoid high‑temperature and dry seasons.Improve field managementPractice moderate hardening‑off.Prevent soil drought at the seedling stage.Irrigate frequently to cool the soil when soil temperature is high, ensuring normal root development.Chemical controlSpray or drench with the following fungicides at about 10‑day intervals, 1–2 times:40% Carbendazim·Sulfur SC, 600–700×50% Thiophanate‑methyl·Sulfur SC, 800×50% Mixed Sulfur SC, 500×20% Sodium Dichloroisocyanurate (Cai Jun Qing) SP, 400×12.5% Enhanced Carbendazim Concentrate SL, 200–300×Apply 100 mL per plant.Plant growth regulatorsSpray leaves 2–3 times with:Yunda‑120 plant growth regulator, 3000×, orFuer 655 liquid fertilizer: 80 g/667 m² in 30 kg water.Nutrient solutionsApply Plant Power 2003 nutrient solution or Huangye Su Lü (Yellow Leaf Green‑up agent).

• Bacterial Soft Rot of Chinese Cabbage

  2026-03-10    Views：168

  Symptoms and Control MethodsSymptomsBacterial soft rot of Chinese cabbage usually occurs at the heading stage.Infection starts at the base of the petioles.Initially, infected tissues show water‑soaked, translucent lesions, which later expand into light grayish‑brown wet rot.Affected tissues become slimy, and the surface shrinks when dehydrated, often exuding off‑white bacterial ooze with a foul odor.In severe cases, the pith becomes rotten.At the early stage of infection, outer leaves wilt under strong sunlight but recover in the morning and evening.Gradually they fail to recover, and outer leaves collapse to the ground, exposing the head.In some cases, rot starts from the margins of outer leaves or the head itself.Diseased leaves become thin and papery when dry.Infected plants are easily knocked over.The disease continues to develop during storage, causing rot in storage pits.Infected seed plants will continue to develop symptoms after transplanting and may die completely.Conditions for Disease DevelopmentThe pathogen mainly overwinters on infected plants or in storage pits with seed plants, and is carried to the field in the following year.It spreads via irrigation water, rainwater, and insects.The use of manure containing undecomposed diseased residues can also spread the pathogen.The bacterium invades the host through wounds and natural openings, and multiplies in parenchyma tissues.The pathogen can infect Chinese cabbage seedlings at the root hair zone and lie latent in vascular tissues.The infection rate of seedling roots in the field can reach 95%.Disease outbreaks occur under anaerobic conditions caused by irrigation.Crops planted on raised beds are less affected than those on flat beds.Rotation with gramineous crops also reduces disease severity.Early sowing, low‑lying fields, poor drainage, heavy clay soil, and flood irrigation all increase the incidence.Control MethodsUse resistant varietiesResistant varieties include Lübao, Zhongbai No. 1, Beijing Xiaozha 50, Jindong Zhongqing No. 1, Longxiebai No. 2, Lianbai No. 1, Ji Baicai No. 4, Xinza No. 1, Lu Bai No. 7, Luguang 18, Lu Bai No. 10, Lu Bai No. 11.Localities may select suitable varieties according to local conditions.Sow at the proper timeThe occurrence of soft rot is closely related to sowing date.The optimal sowing date for controlling downy mildew and virus disease is also suitable for controlling soft rot.Treat 150 g of seeds with 100 g of Caifengning B1.Prepare land thoroughly, plant on raised beds, and improve field managementSoft rot can spread via running water through wounds.Poor land preparation and waterlogging are major causes of soft rot.Planting on raised beds can significantly reduce soft rot in non‑saline‑alkali soils.Avoid excessive hardening off in dry years.Prevent root and leaf injury during field operations.Water evenly after heading to avoid physiological wounds.Remove and discard diseased plants before irrigation.Apply lime or fungicide in the diseased holes before watering.Control insects to reduce infection courtsFrom the seedling stage, control leaf‑eating and boring pests, including cabbage caterpillar, cabbage armyworm, beet armyworm, diamondback moth, cabbage webworm, cabbage maggot, and striped flea beetle.Virus disease, downy mildew, black rot, and other diseases may also aggravate soft rot, so their control is also necessary.Chemical control in the fieldRemove diseased plants immediately when found.Sprinkle lime in the diseased holes.Spray the whole field withAgricultural streptomycin 4000× dilution, orNeomycin 4000× dilutionevery 10 days for 2–3 consecutive applications.Alternatively, apply 300 g of Caifengning B1 mixed with 250 L of water per 667 m² for root irrigation.

• Damping-off of Chinese Cabbage

  2026-03-10    Views：187

  Description and Control MethodsSymptomsAfter Chinese cabbage is infected with damping-off, water-soaked lesions appear on the stem base near the ground.The stem then shrinks, causing the seedling to collapse or wilt.Under high humidity, white cottony mold grows on the infected parts or the soil surface.Conditions for Disease DevelopmentDamping-off is caused by Pythium spp. such as Pythium aphanidermatum.The pathogen overwinters as oospores in the top 12–18 cm of soil and can survive for a long time.In spring, under favorable conditions, it germinates to form sporangia, which infect the host via zoospores or germ tubes.Hyphae living saprophytically in the soil can also produce sporangia, whose zoospores infect seedlings and cause damping-off.Secondary infection in the field mainly comes from sporangia and zoospores produced on diseased seedlings, which are splashed by irrigation or rainwater onto the stems and roots near the soil surface.The suitable soil temperature for pathogen growth is 15–16°C; growth is inhibited above 30°C.The optimal soil temperature for infection is about 10°C.Low temperatures are unfavorable for host growth but allow the pathogen to remain active.Low temperature and high humidity during the seedling stage are especially conducive to disease occurrence.Control MethodsTo cultivate strong seedlings and prevent damping-off:Cover the seeds with a layer of nutrient soil after sowing.After watering thoroughly, cover with plastic film to maintain temperature and humidity.After emergence, spray with 0.2%–0.3% potassium dihydrogen phosphate 2–3 times to enhance disease resistance.At the early stage of disease:Spray with 25% metalaxyl WP at 800× dilution.Or treat seeds with 75% chlorothalonil WP or 70% mancozeb WP.Or spray with 69% dimethomorph·mancozeb WP at 900× dilution.

• Alternaria Leaf Spot of Chinese Cabbage

  2026-03-10    Views：170

  Description and Control MethodsSymptomsAlternaria leaf spot of Chinese cabbage is a systemic fungal disease.It mainly infects the leaves, starting from the seedling stage, and is most severe during the middle and late rosette stages, affecting head formation and quality.Infection is usually most serious on the lower and middle leaves; small lesions may also appear on the top of the inner leaves in severe cases.Initially, small black spots appear on the leaves, which gradually expand into dark brown lesions with concentric rings.The centers of lesions may crack or perforate.Under high humidity, mold grows on both sides of the lesions.Affected parts or entire leaves turn yellow and scorched.Conditions for Disease DevelopmentThe occurrence of Alternaria leaf spot is related to climate, cultivar resistance, and cultivation management.High temperature and high humidity favor disease development.Epidemics easily occur at about 17 °C with continuous rain or fog.Disease severity varies among cultivars.Early-sown crops are more severely infected than late-sown ones.Over-irrigation and insufficient basal fertilization increase disease incidence.Seed treatment before sowing reduces infection in the seedling and mid‑late growth stages.Field observations show that the disease is most severe on outer leaves, less on head leaves, and mildest on inner leaves.Older lower leaves are infected earlier and more severely.Infection spreads upward from the lower leaves and inward from outer leaves.Control MethodsIntegrated control should be adopted, focusing on agricultural control, combined with resistant cultivars and timely fungicide protection.Crop rotation and field sanitationAlternaria leaf spot attacks a wide range of cruciferous vegetables.Continuous cropping of crucifers increases disease severity.Rotate with legumes, cucurbits, or solanaceous crops.Clean fields promptly after harvest to reduce inoculum.Improve field managementTimely thinning and final planting: retain vigorous seedlings.Formula fertilization:For a target yield of 10 000 kg per mu, apply 5000 kg fully decomposed farmyard manure and 50 kg phosphate fertilizer before sowing.Topdress during seedling, rosette, and heading stages with 16 kg N, 8 kg P₂O₅, and 18 kg K₂O per mu.Irrigation: light and frequent irrigation at seedling stage, proper water control at rosette stage, sufficient water and fertilizer at heading stage; avoid flooding.Sowing date: appropriate late sowing (about one week before Start of Autumn) without reducing head formation.Use resistant cultivarsIn the county, highly resistant, high‑yielding and storable cultivars includeQingza Zhongfeng, followed by Fengkang 78, Fengkang 79, Fengkang 80, etc.Seed treatmentTreat seeds with 0.3%–0.4% of 75% chlorothalonil WP or 70% mancozeb WP to kill seed‑borne pathogens.Chemical controlApply fungicides immediately when initial infected plants appear, at 7–10‑day intervals, 2–3 times total.Recommended fungicides:50% iprodione WP, 1000× dilution75% chlorothalonil WP, 600× dilution70% mancozeb WP, 600× dilution64% oxadixyl·mancozeb WP, 500× dilution