How to prevent and treat leaf spot disease and anthracnose in areca palms?
Areca palm (Dypsis lutescens) is a common green ornamental plant in homes and office areas. Summarizing the experience of flower enthusiasts, it is found that areca palms often suffer from leaf spot disease and anthracnose during cultivation. Here is a brief introduction to the symptoms and control methods of these two diseases.
Areca palm anthracnose:
1. Symptoms: After areca palm anthracnose occurs, the disease mostly starts from the leaf margins and leaf tips. The lesions are circular, semicircular or irregular in shape, yellow-brown to dark brown in color, with the diseased area slightly raised and a yellow halo at the edges. In the later stage, small black dots are produced on the lesions.
2. Occurrence pattern: The pathogen overwinters in diseased leaf debris on the ground or in diseased leaves on the plant. When conditions are suitable the following year, it forms conidia, which spread through wind and rain, causing infection and damage. This disease can occur from March to October. Plants lacking fertilizer and water, with weak growth, or with root damage during planting are all prone to infection. High temperature and high humidity favor the expansion and spread of the disease.
3. Control methods:
(1) From the early stage of onset, spray 50% thiophanate-methyl wettable powder at 800 times dilution plus 75% chlorothalonil wettable powder at 800 times dilution.
(2) Remove diseased leaves and burn them in a centralized manner or bury them in soil to eliminate the overwintering source of inoculum.
(3) In plastic sheds or greenhouses, 45% chlorothalonil smoke agent or 8% ketanling dust agent can be tried.
(4) Strengthen water and fertilizer management to enhance the disease resistance of the plant.
Areca palm leaf spot disease:
1. Symptoms: In the early stage of leaf disease, yellow-brown small spots appear, gradually expanding into streak spots, which can merge into irregular necrotic patches. Leaf tips and leaf margins are most susceptible. In severe cases, more than half of most leaves dry up and curl, as if burned by fire; the center of the lesions is dark or gray-white, surrounded by dark lines at the edges, and in the later stage, scattered elliptical small black dots appear on the diseased area.
Control methods for areca palm leaf spot disease and anthracnose
Areca palm (Dypsis lutescens) is a common green ornamental plant in homes and office areas. Summarizing the experience of flower enthusiasts, it is found that areca palms often suffer from leaf spot disease and anthracnose during cultivation. Here is a brief introduction to the symptoms and control methods of these two diseases.Areca palm anthracnose:
1. Symptoms: After areca palm anthracnose occurs, the disease mostly starts from the leaf margins and leaf tips. The lesions are circular, semicircular or irregular in shape, yellow-brown to dark brown in color, with the diseased area slightly raised and a yellow halo at the edges. In the later stage, small black dots are produced on the lesions.
2. Occurrence pattern: The pathogen overwinters in diseased leaf debris on the ground or in diseased leaves on the plant. When conditions are suitable the following year, it forms conidia, which spread through wind and rain, causing infection and damage. This disease can occur from March to October. Plants lacking fertilizer and water, with weak growth, or with root damage during planting are all prone to infection. High temperature and high humidity favor the expansion and spread of the disease.
3. Control methods:
(1) From the early stage of onset, spray 50% thiophanate-methyl wettable powder at 800 times dilution plus 75% chlorothalonil wettable powder at 800 times dilution.
(2) Remove diseased leaves and burn them in a centralized manner or bury them in soil to eliminate the overwintering source of inoculum.
(3) In plastic sheds or greenhouses, 45% chlorothalonil smoke agent or 8% ketanling dust agent can be tried.
(4) Strengthen water and fertilizer management to enhance the disease resistance of the plant.
Areca palm leaf spot disease:
1. Symptoms: In the early stage of leaf disease, yellow-brown small spots appear, gradually expanding into streak spots, which can merge into irregular necrotic patches. Leaf tips and leaf margins are most susceptible. In severe cases, more than half of most leaves dry up and curl, as if burned by fire; the center of the lesions is dark or gray-white, surrounded by dark lines at the edges, and in the later stage, scattered elliptical small black dots appear on the diseased area.
2. Occurrence pattern: The disease generally occurs from May to November. High temperature and abundant rain favor the expansion and spread of the disease.
3. Control methods:
(1) Strengthen nursery management: During the seedling raising period, appropriate shading is needed to avoid direct sun exposure.
(2) Rational fertilization: Do not apply excessive nitrogen fertilizer; it is advisable to increase potassium fertilizer.
(3) Timely chemical control: In the early stage of onset, spray 50% captan wettable powder at 300-500 times dilution, or use 70% mancozeb wettable powder at 400-650 times dilution, once a week for several consecutive times, which can effectively control this disease.
Symptoms and control methods of areca palm leaf spot disease
Symptoms and control methods of areca palm leaf spot disease
Anthracnose
Pathogen: Colletotrichum sp.
Symptoms: This disease occurs from time to time on areca palms, affecting the ornamental effect.
In the early stage of onset, chlorotic small spots appear on the leaves, which expand into nearly circular spots, light brown, 5-12mm in diameter; in the later stage, the central tissue is gray-white, and the lesion margin is reddish-brown, about 1mm wide. There are yellow small granular dots outside the spots.
Gray leaf spot
Pathogen: Pestalotiopsis palmarum (Cooke) Steyaert
Symptoms: This disease mainly damages mature leaves, causing leaf blight, affecting commercial sale and ornamental value.
In the early stage of onset, brown small spots appear on leaf margins and leaf surfaces, which mostly expand into semi-elliptical or irregular spots, dark brown, varying in size, with a yellow halo outside the spots. In the later stage, the lesions merge into large patches, causing 1/4 to 1/2 or more of the leaf to wither and yellow. When humidity is high, scattered small black granular dots appear on them.
Leaf blight
Pathogen: Caused by Phyllosticta caryotae Shen
Symptoms: This disease forms large lesions on the leaves, affecting ornamental value.
In the early stage of onset, streak-like white small spots appear on leaf margins or leaf surfaces, which expand into long strip-shaped irregular lesions, dead white in color, with brown lesion margins. Lesion expansion is limited by leaf veins.
Control methods:
1) Disease prevention through cultivation techniques: Promptly cut off and deeply bury diseased leaves when found; pay attention to water control in all seasons: when the temperature is below 10 degrees C, water once every 10-15 days; when below 20 degrees C, water once every 4-5 days; in summer, water according to weather conditions and spray water to cool down; do not apply excessive nitrogen fertilizer, and the ratio of nitrogen, phosphorus and potassium should be roughly 1:1:1.
2) Chemical protection:
Protective agents: dithianon, propineb, mancozeb
Therapeutic agents: propiconazole, difenoconazole, prochloraz, myclobutanil, etc.