How to prevent and control stem base rot in passion fruit?

Passion fruit is a perennial evergreen vine, but after industrial cultivation, the planting cycle in most regions is only 2-3 years or even one crop per year, such as in the Guigang area of Guangxi. The chief culprit causing this is——stem base rot in passion fruit. So what should be done about stem base rot in passion fruit? How to prevent and control it?

The occurrence of stem base rot is closely related to weak plant growth vigor, poor soil conditions, and deterioration of the rhizosphere environment. After onset, the stem base becomes soft, rots, and necroses in a ring, damaging its physiological functions so that it cannot transport nutrients, which then leads to plant death.

Therefore, to solve this problem faced by passion fruit, it is necessary to supplement nutrients for the plant while sterilizing and treating the disease, revitalize the plant, enhance its disease resistance and stress resistance, repair damaged tissues, and restore conduction functions, while also combining comprehensive management, soil improvement, and other measures.

1. Why passion fruit is prone to stem base rot

1. Passion fruit is a shallow-rooted plant; its stem and vine structure is soft, its roots grow near the surface, and the stem base and roots are easily injured, which blocks nutrient uptake, causes growth vigor to weaken, and triggers pathogen infection.

2. Excessive nitrogen fertilizer: causes excessive vegetative growth, leaves the plant internally depleted of nutrients, and weakens disease resistance and stress resistance. Excessive fruiting: overdrafts the nutrients in the plant; after harvest, the nutrients remaining in the plant are insufficient, stress resistance weakens, and overwintering injures the plant, making it susceptible to infection by pathogen sources.

3. Poor soil conditions: heavy, compacted, and acidified soil first easily breeds harmful bacteria; second, it causes poor root growth in the plant, weakens nutrient absorption capacity, leads to weakened plant growth vigor, and results in poor disease resistance.

4. Continuous cropping: continuous cropping causes the stem base rot pathogens in the soil to accumulate in large amounts, increasing the incidence rate.

2. Prevention and control measures for stem base rot in passion fruit

Key points for preventing and controlling stem base rot in passion fruit: combine treatment with nutrition, use three-dimensional medication, and improve the soil.

1. Combine treatment with nutrition: prevent early, treat aggressively; nourish and revitalize. Prevent early: preventive measures should be taken as early as the budding stage. The early growth period is when crops are easily infected by pathogens, and early medication can kill pathogens in advance and reduce the incidence rate. Treat aggressively: May to July (rainy and high-temperature) is the peak period for stem base rot in passion fruit. When this peak period arrives or symptoms first appear, treat aggressively by increasing the medication concentration and shortening the interval between applications to bring the disease under control in one go. Nourish and revitalize: stem base rot in passion fruit is directly related to weak plant growth vigor. By directly supplementing nutrients to the crop, increasing its leaf chlorophyll content, enhancing photosynthesis, and strengthening enzymatic reactions, the crop can be made robust and its immunity enhanced.

2. Three-dimensional medication: after symptoms appear, only smearing or spraying the affected site does not provide enough medication uptake by the plant. It is necessary to combine spraying, root drenching, and other methods for three-dimensional medication to ensure sufficient medication uptake and adequate nutrient supplementation.

3. Improve the soil: use biological bacteria and organic fertilizer to condition the soil, regulate acid-base balance, break up compaction, relieve salinization, and improve the rhizosphere environment. An increase in beneficial bacteria suppresses the reproduction of harmful bacteria and promotes root growth. Stem base rot is a soil-borne disease, so improving the soil suppresses the occurrence of stem base rot at the root.

Specific operations:

(1) Fertilization: use more organic fertilizer and biological bacterial fertilizer to increase soil organic matter, keep the soil loose and breathable, and improve the rhizosphere environment, which helps beneficial microbial communities survive and thereby suppress harmful microbial communities.

(2) Medication: Qingkulike, Liangguoan, and Kuifuling are Chinese herbal preparations. Through root drenching, spraying, smearing, and other methods, after absorption by the plant they can participate in its nutrient cycle, kill pathogens hidden in the phloem, and the houttuynin in them can repair damaged tissues, open up the conduction function of the vascular bundles, and block the invasion pathways of pathogens. At the same time, they also contain polysaccharides, amino acids, polypeptides, and other nutrients, which can directly supplement nutrients for the crop, provide substances the plant itself needs, participate in metabolic cycles, enhance crop growth vigor, and improve its disease resistance and stress resistance.

(3) Half a month before budding: use Kuifuling + organosilicon for orchard sanitation and spray the whole orchard. For weak trees, diseased trees, trees that bore much fruit the previous year, and yellowing trees, use Qingkulike + Diliwang + Wofengsu for root drenching. First, kill overwintering pathogens; second, supplement nutrients for the crop.

(4) Young fruit stage: spray Liangguoan + Wofengsu (once every 7-10 days, continuously for 2-3 applications).

When applying the pesticide, after spraying the leaves, spray along the stem at the stem base area. This can effectively prevent the occurrence of stem base rot, and after the liquid flows into the soil and is absorbed by the roots, it can promote root growth.

(5) After harvest: spray Kuifuling + Wofengsu + Diliwang (trial use), and at the same time combine with Qingkulike + Diliwang + Wofengsu for root drenching. After harvest, many wounds are created and sap flows out at the fruit stalks. Both are nutrients, and pathogens will take the opportunity to multiply in large numbers and invade through the wounds. Medication first can kill pathogen sources; second, it can repair wounds and block pathogen invasion pathways, reducing the incidence rate; third, it provides the plant with polysaccharides, polypeptides, amino acids, and other nutrients, revitalizing the plant and enhancing stress resistance.

(6) For plants that have already developed the disease, use undiluted Kuifuling to smear the stem base area, or spray the affected area at high concentration, while combining with Qingkulike + Wofengsu + Diliwang for root drenching and Liangguoan + Wofengsu for spraying, for three-dimensional medication.