Algal Leaf Spot

Disease

Algal Leaf Spot

Cephaleuros virescens

additional

In a Nutshell

    Furry, green to orange spots on leavesCracks in the barks of young stemsDefoliationDistortion of fruitIncreased infection on low hanging branches

Hosts: %1$s

· Mango

Symptoms

The parasitic alga C. virescens predominantly affects leaves of mango and other hosts, but may also target branches and stems. Infected leaves shows round, slightly raised, green to orange spots of 2-4mm diameter. They are characterized by furry growth (spores of the algae) and indistinct margins. They can merge into patchy areas. In young stems, which are more susceptible to the pathogen, C. virescens may cause cracks in the bark, leading to dieback. On many trees, the leaves of low hanging branches show the worst symptoms. Algal leaf spot occurs commonly in areas of high temperatures and rainfall, and in plants with impaired growth.

Trigger

Algal leaf spot most commonly appears in locations with high temperatures and rainfall, and where the host plants are not growing well. Poor nutrition, poor soil drainage and too much or too little shade create conditions that favor the disease. The spores need water to germinate. They spread to other trees via splashing rain or wind. C. virescens take up its hosts' water and mineral salts, characterizing it as a ' water parasite'. The algal growth covers the leaves until they shed. Young superficial colonies may be washed off by frequent rains. Only those spores entering the leaves through wounds produce lesions. There is no evidence for penetrations of uninjured cuticles.

Biological Control

When the disease is mild, remove and destroy leaves with spots as well as diseased branches. Additionally, rake up and destroy affected leaves on the ground. When algal leaf spot is severe, spray a Bordeaux mixture or other copper-based products. Sprays should be applied every 2 weeks from the beginning of summer to the end of autumn.

Chemical Control

Always consider an integrated approach with preventive measures together with biological treatments if available. Use fungicidal sprays containing copper if chemical control is necessary.

Preventive Measures

    Improve growing conditions to minimize plant stressAvoid waterlogged soils through improved drainageIrrigate early in the day to ensure rapid drying of the foliageAvoid overhead irrigation whenever possibleAdd mineral fertilizer when growth is poorApply sprays containing potassium phosphateAlterate the shade of the crop, especially if dieback is occurringEnsure that plant density allows air circulation for rapid drying of leaves and fruitsEnsure good ventilation by orientating the rows appropriatelyRemove weeds from around the trees to reduce competition for nutrients and humidityAvoid lesions caused by mechanic tools




Features

Regional Weather

Get detailed forecast and actual weather data.

Plantix offers detailed weather information on the following issues:

Precipitation

Humidity

Air Pressure

Temperature

Wind speed

Plantix Community

Get in touch with experts around the world.

Post your questions

You can post your questions and pictures and get feedback from other farmers or gardeners. Plantix' experts will answer your questions related to plant diseases and pests.

MyCommunity

Exchange with Plantix users around you, in your language and related to the crops you grow.

Global Community

Connect to farmers, gardeners, experts and interested people around the world that discuss plant diseases, remedies and best practice for sustainable farming.

AI-Driven Disease Detection

Instant diagnostics and solutions based on your picture

Image Recognition

Plantix analyzes your picture within a few seconds and gives you instant feedback on your plant problem.

Customized Management Options

On top of the detection result, Plantix offers you a detailed description of possible solutions - both biological and conventional.

Preventive measures

Plantix offers information on preventive measures to protect your crop from the next attack.