Disease Management of Tropical and Subtropical Fruits, Slides of Plant pathology

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Disease

Management of

tropical and

subtropical fruit

crops

Content

1. Introduction

2. Importance of disease management

3. Common diseases in India and their management

4. References

Importance of Disease management Disease management in tropical and subtropical fruit crops is crucial for several reasons: 1. Economic Impact : Diseases can cause significant yield losses in fruit crops. Managing diseases helps protect the economic interests of farmers and agricultural industries, ensuring a stable income.

2. Food Security : Tropical and subtropical fruits are essential for food security in many regions. Disease management ensures a consistent supply of these fruits, which are often important dietary staples. 3. Biodiversity : Many tropical fruits are native to specific regions and are part of the local biodiversity. Disease management preserves these unique fruit varieties, contributing to overall biodiversity conservation efforts. 4. Export and Trade : Tropical fruits are often exported to international markets. Strict quality standards must be met to facilitate trade. Effective disease management ensures that fruits meet these standards, supporting export opportunities.

5. Sustainability : Sustainable farming practices are vital for preserving the environment. Disease management strategies that minimize the use of harmful chemicals promote sustainable agriculture in tropical and subtropical regions**.

6. Research and Innovation:** Dealing with diseases encourages research and innovation in agriculture. Scientists and farmers work together to develop new disease-resistant varieties and environmentally friendly management techniques, advancing agricultural knowledge. 7. Community Livelihood : In many tropical regions, farming is a way of life. Disease management protects the livelihoods of farming communities, ensuring their social and economic well-being.

1. Quarantine : If area is disease free, restrict the

entry of planting material from infected to healthy area.

2. Cultural : Infected leaves, stem, fruit etc should be removed and burnt. Bordeaux paste should be applied at the cut end portions of stem. 3. Hot water treatment of root stocks at 50°C for 10-15 minutes. 4. Biological : Pseudomonas fluorescens suspension can be sprayed as biological control agent. 5. Chemicals: 1% Bordeaux mixture or 0.3%Copper Oxychloride or 500 ppm Streptocycline should be sprayed on the plant. Management

● (^) Causal organism : Fusarium oxysporum f.sp. cubens ● (^) It is one of the most devastating diseases of banana in the world being reported for the first time from Australia in 1874. ● (^) The disease is soil borne & the fungus enters the roots through the fine laterals & leads to wilting of leaves and yellowing. ● (^) When plant is cut vertically numerous brown-black lines can be seen running in all directions through the corms & upward into the leaf bases & petioles. ● (^) Splitting of pseudostem base is a characteristic symptom. ● (^) The pathogen is easily spread by infected rhizomes or suckers, farm implements or vehicles and irrigation water. ● (^) The disease is favoured by soil temp of 28°C -32°C, Relative humidity-85-90% and presence of susceptible host.

2. Panama Wilt of Banana

3. Powdery Mildew (Mango, papaya, grapes etc.): ● (^) Causal organism - Oidium mangiferae (mango), Oidium tingitanium (citrus), Uncinula necator (grapevine), Oidium indicum (papaya) etc. ● It appears as white powdery spots on leaves, affecting photosynthesis and fruit development. ● Infected leaves may curl, twist, or become distorted. Young leaves and shoots are particularly vulnerable. ● (^) Severe infections can lead to stunted growth of the affected plant. ● (^) Warm and dry conditions with high humidity favor powdery mildew growth. https://images.app.goo.gl/DVXoGUp MLsKcF3jE

citrus grapes (^) mango https://www.greenlife.co.ke/powde ry-mildew-of-mango/ https://caes.ucdavis.edu/news/arti cles/2015/02/fighting-powdery-gra pe-mildew https://gardentabs.com/orang e-tree-has-white-fungus/

4. Anthracnose (Mango, Papaya, and Others) ● (^) Causal organism: Colletotrichum gloeosporioides, Colletotrichum musae ● (^) Produces leaf spots, blossom blight, wither tip, twigs blight and fruit rot. ● (^) Small blister like spots develop on the leaves and twigs. Young leaves wither and dry. Tender twigs wither and die back symptom appears. ● (^) Affected branches ultimately dry up. ● (^) Black spots appear on fruits. ● The fruit pulp becomes hard, crack and decay at ripening, infected fruits drop. https://agritech.tnau.ac.in/crop_p rotection/mango_1.html

Management ● (^) Overcrowding of orchard should be avoided. ● Pruning and burning of infected plant parts reduces the severity of the disease. ● (^) Before storage, treat with hot water, (50-55°C) for 15 minutes or dip in Thiabendazole (1000 ppm) for 5 minutes. ● (^) Sprays with Topsin-M @0.1% before flower open and again during fruit formation. About 6-8 sprays during 1 season. ● (^) Spraying the trees with Bordeaux mixture 0.6 % or Copper oxychloride 0.2% before the onset of monsoon reduces the disease incidence. ● (^) Post harvest dipping of fruits in Carbendazim 400 ppm, or Benomyl 1000 ppm, or Aureofungin Sol 100 ppm. https://agritech.tnau.ac.in/crop_protection/ crop_protdiseases_postharvest_guava_1. html

Management ● (^) Removal and destruction of affected leaves. ● (^) Keep the banana field as weed free and remove the suckers timely. ● (^) Avoid planting at close spacing. ● (^) Provide proper drainage and avoid water logging in the fields which favours infection. ● (^) Spray 3 times with Carbendazim 0.1 per cent or Propiconazole 0.1 % or Mancozeb 0.25% and teepol (sticking agent) at 10-15 days interval, as the disease starting from initial appearance of leaf specks.

6. Mango Malformation

● (^) Causal organism: Fusarium moniliforme var. subglutinans ● (^) Disease has been distinguished into 2 groups- vegetative malformation and floral malformation. ● (^) Vegetative malformation is more pronounced in young plants. ● (^) Affected mango seedlings or young plants develop excessive vegetative branches which are swollen and have very short internodes. Sometimes dwarf branches present a bunchy top appearance. ● (^) In floral malformation, axillary buds are usually swollen. These swollen buds persist and due to their crowding at nodes they sometimes form girdles ● (^) All these branches develop floral malformation. ● (^) Malformed flowers are usually bigger in size and possesses a few pollen.

Management ● (^) Diseased plants should be destroyed ● (^) Use of disease free planting material ● (^) Incidence reduced by spraying 100- ppm NAA during October. ● (^) Spraying of Benlate along with pruning of diseased parts. ● (^) This is followed by the spraying of Carbendazim (0.1%) or Captafol (0.2%). https://agritech.tnau.ac.in/crop_protect ion/mango_3.html

7. Pink disease of Jackfruit ● (^) Causal organism : Botryobasidium salmonicolor & Corticium Salmonicolor ● (^) It is widespread in tropical and subtropical areas. ● Disease appears as a pinkish powdery coating on the stem. ● (^) Pink colour represents profuse conidial production of fungus. ● (^) Young woody branches of the affected trees lose their leaves & show die back symptoms. Pink encrustation is seen on the lower shaded side. Management ● (^) The affected branches should be pruned and cut ends should be pasted with Bordeaux paste or Copper Oxychloride paste.