What are the common diseases of lotus? A full analysis of solutions

1. Rot disease

The most common disease of lotus is rot disease, because it is soaked in water for a long time, it is very easy for problems to appear. So be careful not to let the leaves soak in water. When the soil is poor, the incidence of rot disease will be very high. At this time, an appropriate amount of fertilizer should be applied, and then some carbendazim can be sprayed for control.

2. Brown spot disease

During the rainy season, brown spots may appear on lotus leaves. At this time, the diseased leaves must be immediately cleaned up to avoid infecting other leaves. If the disease is severe, mancozeb or zineb solution can be sprayed.

The above is an introduction to the planting methods of potted lotus and the pests, diseases and solutions. I hope the above content can help you better grow potted lotus. To learn more, please follow Four Seasons Plants Network!

Common pests and diseases of lotus and their control methods

        The lotus stands gracefully. Its flowers are large and brightly colored, with a delicate fragrance. The lotus emerges from mud without
being stained, and its resolute character is even more widely praised. However, during its growth period, lotus is prone to damage from many
pests and diseases, affecting its ornamental value. The common pests and diseases are:
        1. Brown spot disease
        After onset, round lesions appear on the leaves, with a pale brown center and dark brown surroundings, often with concentric rings, and dark green mold-like growth on them. This disease is caused by fungal infection. It mostly occurs from July to September. Under warm, humid conditions and with many years of continuous planting, the disease occurs more severely; poor cultivation management and weak plant growth also lead to more severe onset.
       Control methods: 1) Thoroughly remove diseased leaves in winter; 2) In affected areas, mix a small amount of lime into the pot (tank) soil or pond soil before planting for soil disinfection; 3) Strengthen cultivation management, do not apply too much nitrogen fertilizer, and pay attention to ventilation and light; 4) Starting near the onset period, spray 65% zineb 600x solution once every 7 to 10 days, continuously 3 to 4 times, to prevent the occurrence and spread of the disease; 5) In the early stage of onset, spray 50% carbendazim or 70% thiophanate 800x solution.
       2. Black spot disease
        After infection by the pathogen, nearly round or irregular lesions appear on the leaves, 6 mm to 15 mm in diameter, brown, with concentric rings, and black mold-like growth. In severe cases, the lesions often merge and the leaves wither and die. This disease is more serious than brown spot disease in Northeast China, North China and other places. Apart from the pathogen and symptoms
being different from brown spot disease, its occurrence pattern, onset time and control methods are all basically the same as
brown spot disease.
        3. Rot disease
        This disease is a fungal disease. It begins from the lotus rhizome nodes, and the diseased part appears purplish-brown. The leaves then turn yellow, curl and die, and finally the stolons and rhizome nodes rot one after another.
        Control methods: 1) Properly mix a small amount of lime into the pond soil or pot soil, and at the same time soak the seed
rhizomes in lime milk for 10 minutes for disinfection; 2) In the early stage of onset, spray 70% thiophanate
800x solution.
       4. Aphids
       Nymphs and adult aphids often gather in groups on new leaves, curled leaves, upright leaves and flower buds to suck sap. When the population is large, the young leaves become discolored and curled, and the flower buds become deformed or fail to open, affecting the ornamental effect. This insect has strong reproductive capacity, and can reproduce about 20 generations per year. It can cause damage from May to September, especially most severely in late summer and mid-autumn.
       Control methods: 1) Spray 60x tobacco lime water or neutral washing powder 300x-400x solution; 2) When occurring in large numbers, spray 40% dimethoate emulsifiable concentrate 1500x solution.
     5. Bagworms
        Commonly known as 'bag worms'. The main species damaging lotus are the large bagworm and the tea bagworm. The larvae feed on leaves. When they occur in large numbers, they bite the lotus leaves into a mass of holes, greatly affecting appearance and flowering. The number of generations per year varies by region. In Jiangsu, Zhejiang, Hubei and other places, one generation occurs per year, and they can cause damage from when the lotus leaves first emerge until the lotus seed pods mature.
        Control methods: 1) When occurring in small numbers, manually remove the protective cases; 2) When occurring in large numbers, during the early hatching stage or young larval stage, promptly spray 50% phoxim emulsifiable concentrate 1500x-2000x solution or derris powder 500x solution (with a small amount of neutral washing powder added).
        6. Slug moths
        Commonly known as "itchy hot peppers". Those damaging lotus include the yellow slug moth, green slug moth and brown slug moth. All damage leaves as larvae. The yellow slug moth larva is yellow-green, with a body length of 25 mm. The head is small and pale brown. On the back there is a purple-brown dumbbell-shaped large marking; the green slug moth larva is 25 mm-28 mm long, yellow-green, with 4 raised protuberances from the middle legs to the 8th abdominal segment, and yellow spine hair clusters on the protuberances. Young larvae only eat the leaf mesophyll, leaving the veins, turning the leaf
into a net-like appearance. After the larvae grow larger, they bite the leaves into notches, leaving only the petiole and main veins.
       Control methods: 1) In winter and spring, dig out cocoons in the surface soil around ponds (green slug moth, brown slug moth) and cut off overwintering cocoons on nearby tree branches (yellow slug moth); 2) When newly hatched larvae are found, promptly remove the infested leaves; 3) larvae ... emulsifiable concentrate 1500x-2000x solution or 50% fenitrothion emulsifiable concentrate 1000x solution.
        7. Tobacco cutworm
        Also known as the lotus cutworm. The larva is about 30 mm long, with a black-brown head. Body color varies, ranging from light earthy yellow to dark black-green, but all have scattered small white dots. The number of generations per year varies with temperature in different places. According to observations in various places, damage is most severe from July to October each year. Newly hatched larvae gather on leaves and gnaw the mesophyll, leaving the epidermis and veins. The damaged leaves look like window screens, appearing gray-white, and turn yellow after dying. After the larvae grow slightly larger, they bite the leaves into notches. When the population is large, they can eat the leaves until they are incomplete, and can also bite flower buds and flowers.
       Control methods: 1) Manual capture and killing, taking advantage of the habit of adults laying eggs in masses and newly hatched larvae gathering on the back of leaves, promptly remove egg masses and infested leaves and dispose of them centrally; 2) During the damage period of young larvae, spray 50% phoxim emulsifiable concentrate 1500x-2000x solution or 50% carbaryl wettable powder 500x-800x solution, with good control results.

Common pests and diseases of lotus

Lotus brown spot disease

Symptoms: This disease is also called brown streak disease. Leaf spots are round or nearly round, varying in size, pale brown, with dark brown to purplish-brown margins, some showing concentric rings, and densely covered with small black spots on the spot surface. In severe cases, the lesions are densely distributed and merge into patches, and the diseased patches dry up locally.
Pathogen: Cercospora nymplaeacea .=C.enotica ., C.nelumbonis Tharp, called lotus brown spot cercospora, belonging to the Deuteromycotina fungi. Conidiophores are scattered or in clusters of several, unbranched, pale olive-brown, size 10-50×2.5-4 micrometers; conidia are long obclavate to filiform, colorless to pale, straight or curved, with as many as more than 10 septa, thin-walled, with an obvious basal hilum, size 25-125×2-3.5 micrometers.
Transmission routes and onset conditions: The pathogen overwinters on diseased residues as mycelium and conidiomata, and conidia carry out primary infection and reinfection, spreading by airflow or wind and rain. It is prone to occur in years or seasons with high temperature and abundant rain, especially frequent storms; fields with continuous cropping or with lotus plants too dense and poor permeability have severe onset. Control methods (1) Pay attention to field sanitation, and collect diseased residues during harvest or in the growing season to bury deeply or burn. (2) Implement crop rotation in severely affected land. (3) Reasonable close planting, and manage water and fertilizer well. (4) Combine with the control of lotus rot disease to spray pesticides in time to also control this disease.

Lotus black spot disease

Symptoms: After lotus is affected, chlorotic large yellow spots appear on the leaves in the early stage, more obvious on the back of the leaves. Later the lesions gradually expand, appearing as irregular brown spots, 5-15 mm in diameter. The margins sometimes have a yellow-green halo, and the lesions have concentric rings, with black mold layer on top. In severe cases, except for the veins, the entire leaf is covered with lesions. After the lesions merge, the leaves wither and yellow, and the diseased area looks as if burned by fire.
Pathogen: The pathogen of lotus black spot disease is Alternaria nelumbii (Enlows et Rand), belonging to Hyphomycetes, Moniliales. Spores are obclavate, with 7-15 transverse septa and 0-3 longitudinal septa, dark in color.
Transmission route: The pathogen of lotus black spot disease overwinters in diseased residues. It generally begins to occur after mid-May. The disease is severe in stormy weather, and damage by aphids will aggravate the condition. It is severe when nitrogen fertilizer is applied or when the water temperature in lotus tanks is too high in summer.
Control methods
1. Horticultural control: Strengthen cultivation management, remove diseased leaves, and replace the soil with new soil every year when potted.
2. Chemical control: During the onset period, trial spray 75% chlorothalonil wettable powder 500x solution for control.

Lotus rot disease

Symptoms: The disease occurs on the whole plant, starting from the seed rhizome and extending to the underground stem, petiole, leaf blade and flower stalk, etc. The underground stem initially seems asymptomatic, but some of the vessels in its cross-section turn pale brown or brown and gradually expand. Some diseased stems do not show obvious discoloration, but the stem develops longitudinal wrinkles all over or on one side. The leaves growing from the diseased stem are pale green, and later dry up starting from the leaf margin, causing the leaves to curl and even die.
Pathogen: Fusarium bulbigenum Cook et, lotus specialized form, belonging to Deuteromycotina. Small conidia are long oval, colorless, single-celled. Large conidia are colorless, crescent-shaped, pointed at the tip, curved to one side, with obvious foot cells, producing chlamydospores.
Transmission route: It overwinters as mycelium in seed lotus rhizomes and as chlamydospores in soil. Infected seed rhizomes and diseased soil become the main primary infection sources. When infected seed rhizomes are planted, the seedlings that grow become the central diseased plants. First, lesions occur in the underground stems and root systems, then spread to petioles and leaves. The central diseased plants produce spores that invade through wounds, causing reinfection. Onset conditions: Resistance differs among varieties, and deep-rooted varieties are less affected than shallow-rooted varieties. Continuous rain, insufficient sunlight or frequent storms easily induce this disease; lotus fields with poor soil permeability, or high acidity, sewage entering the field, or water temperature above 35°C.
Control methods:
1. Replace with disease-resistant varieties according to local conditions.
2. Severely affected fields should implement 2-3 year crop rotation.
3. Carefully select disease-free seed rhizomes, and use 50% carbendazim or thiophanate-methyl wettable powder 800x solution plus 75% chlorothalonil wettable powder 800x solution, spray and seed soak, cover with plastic film and seal for 24 hours, then air dry before planting.
4. Deep plow and harrow the lotus field, and apply 100-150 kg of lime per mu.
5. Strengthen fertilizer and water management, apply sufficient decomposed organic fertilizer, and topdress timely and appropriately, combining organic fertilizer with chemical fertilizer, and nitrogen fertilizer with phosphorus and potassium fertilizer; manage the water layer according to the needs of lotus at different growth stages, keeping depth appropriate, and regulating temperature and fertilizer with water to prevent aggravating the disease due to excessively high water temperature or long-term deep irrigation.
6. Promptly pull out diseased plants, then spray 50% carbendazim wettable powder 600x solution plus 75% chlorothalonil wettable powder 600x solution; the above mixed fungicide can also be used at 500 g per mu mixed with 25-30 kg of fine soil, piled and sealed for 3-4 hours, then scattered into the shallow water layer, and after 2-3 days use the above mixed agent 600x solution or 40% poly-sulfur suspension 400x solution, or 50% procymidone wettable powder 1000x solution sprayed on the aboveground petioles.

Tobacco cutworm

Prodenia litura (Fabricius) The tobacco cutworm is also known as the lotus cutworm and tobacco cutworm, belonging to Lepidoptera, Noctuidae. The tobacco cutworm occurs throughout the country and is a voracious pest. The main damage areas are in the Yangtze River basin in Jiangxi, Hubei, Hunan, Zhejiang, Jiangsu, Anhui and the Yellow River basin in Henan, Hebei, Shandong and other provinces, with lighter damage in Northeast China. The tobacco cutworm is a polyphagous pest, and the plants known to be damaged by it reach more than 290 species in 99 families, among which more than 90 species are favored food.
Damage symptoms: Newly hatched larvae gather on the back of leaves and gnaw, leaving only the upper epidermis and veins. The damaged leaves look like window screens. After the 3rd instar they disperse to cause damage, eating the leaves into notches. When occurring in large numbers, they can eat all the leaves, and even bite young tender stems. During outbreaks, after larvae eat up one field, they can migrate in groups to adjacent fields to cause damage.
Morphological characteristics, control methods
1. Biological control can use bacterial insecticides, such as domestic B.t emulsifiable concentrate or Qingchongjun No. 6 liquid, usually using a 500-800x dilution concentration.
2. Chemical control can use phoxim 50% emulsifiable concentrate 1000x dilution, deltamethrin 2.5% emulsifiable concentrate 3000x solution, or 21% mieshabi emulsifiable concentrate 4000x solution.
3. Physiological control: diflubenzuron No. 1 or diflubenzuron No. 3 20% or 25% colloidal suspension 500-10

Lotus aphid

The lotus aphid is also called the water lily aphid. It is distributed in Guangdong, Fujian, Jiangxi, Zhejiang, Jiangsu, Hubei, Hebei and other places. This insect damages lotus, water lilies, cattails and so on.
Morphological characteristics: Wingless parthenogenetic female aphid is oval, with a plump body, brown-green or dark green, covered with a thin bloom or white powder, cornicles constricted-tube-shaped, and cauda conical with 3 pairs of long hairs. Winged parthenogenetic female aphid is long oval, reddish-brown, with a shiny thorax and back, cornicles constricted-tube-shaped, wings transparent, and other characteristics similar to the wingless type.
Life history and habits: This insect occurs about 20 generations per year. It overwinters as eggs in the bud axils of woody ornamental plants such as plum blossom, peach and red-leaf plum. In the following spring, after the nymphs hatch, they first reproduce parthenogenetically and cause damage on the primary host, with severe damage from April to May. In May, winged aphids fly to the secondary hosts such as lotus, water lily, water shield and gorgon fruit and other aquatic plants to cause damage and reproduce, making the plants grow poorly, flower buds shrink, flowering quality poor or even no flowering. In autumn, winged aphids are produced and fly to overwintering sites.
Control methods: Spray 50% menazon emulsifiable concentrate 1000x solution for control, or spray 50% temephos emulsifiable concentrate 2000x solution, which has low toxicity to fish. For the control of aphids on aquatic plants, special attention should be paid to the choice of chemicals, because many chemicals are highly toxic to fish.