Litchi: Diseases, Symptoms and their Management

April 28, 2023 no responses

Contents show

Litchi, also called lychee, is a tropical fruit tree native to China. Litchi is an important fruit tree that is susceptible to different diseases, caused by the fungus, bacteria, and viruses. Some of the important litchi diseases are mentioned in this post:

1. Leaf Blight

Causal Organism: Fungus; Alternaria alternata.

Symptoms:

A common disease in litchi nurseries produces panicle and growing fruit blight.
The symptoms begin at the tip of the leaf as light brown to dark brown necrosis that progresses to both margins of the leaf, eventually leading to full necrosis of the affected leaves that dry up.

Management:

Spray of copper oxychloride (0.1%) or mancozeb (0.15%) to prevent the disease.
If disease severity increases, spray thiophanate methyl (0.14%) or chlorothalonil (0.15%) or difenoconazole (0.025%).

2. Twig Blight

Causal Organism: Fungus; Colletotrichum gloeosporioides and Gloeosporium sp.

Symptoms:

Death of leaves on young shoots, as well as foliar blight and tip dieback that is difficult to distinguish.
This causes a huge number of twigs to die off.
The affected leaves appear to have been burnt by sun rays.
The most severe disease damage occurs in August-September and January-February.

Management:

Fungicide spray of Copper oxychloride (0.25%) or Carbendazim (0.1%) can be done if disease severity increases.

3. Panicle / Inflorescence and Fruit blight

Causal Organism: Fungus; Alternaria alternata.

Symptoms:

Leaf blight pathogen causes panicle blight and fruit blight.
Panicle and fruit blighting occur.
Necrosis causes panicles to shrivel and dry out, whereas necrosis of the pedicel causes the rind of developing fruits to completely dry up.

Management:

Increasing natural plant defence through soil application of microbes such as Trichoderma, Mycorrhiza, and others.
Difenoconazole (0.05%), thiophanate methyl (0.1%), azoxystrobin (0.023%), or carbendazim (0.1%) spray.
The first spray is applied shortly after panicle commencement, and the second spray is applied when the fruits reach the colour-break stage (20 days before harvest).

4. Anthracnose

Causal Organism: Fungus; Colletotrichum gloeosporioides.

Symptoms:

On mature fruits, brown pinhead lesions emerge, which eventually evolve into circular dark-brown to black sunken lesions.

Management:

Copper oxychloride (0.25%), carbendazim (0.1%), difenoconazole (0.05%), or azoxystrobin (0.023%) should be sprayed.
Fungicide pre-harvest spraying aids in extending post-harvest life.

5. Wilt

Causal Organism: Fungus; Fusarium solani.

Symptoms:

Litchi trees that are young, typically less than five years old, can wilt and die within a week.
At first, the leaves turn yellow and drop, then gradually wilt and dry up, causing the entire plant to die within 4-5 days.

Management:

The use of castor cake or neem cake as manures in conjunction with biocontrol agents such as Trichoderma harzianum, T. viride, Pseudomonas fluorescens, and others has been shown to be useful in disease management.
In the absence of a biocontrol agent, rhizosphere soil can be drenched with hexaconazole or carbendazim (0.1%).