Flat limb of sapota

PATHOGEN
SYMPTOMS
MANAGEMENT

1. FLAT LIMB OF SAPOTA COLLEGE OF AGRICULTURAL TECHNOLOGY (Affiliated to Tamil Nadu Agricultural University, Coimbatore-3) Kullapuram (Po), ViaVaigai Dam, Theni-625 562 STUDENT Miss. GOWSIKA M ID. No. 2015021041 COURSE TEACHER Dr. PARTHASARATHY S Asst. Professor (Plant Pathology)

2. Common name Flat limb of sapota Local name Flat leaf disease, Fasiciation disease, Flattened disease.

3. HISTORY Bose and Metha (1951) recorded fasciated twigs and mummified fruits of sapota in Uttar Pradesh and could isolate the P estalotia only. Flat limb in sapota was first reported from Maharastra and Gujarat by Singh (1972).

4. SIGNIFICANCE It can cause yield loss up to 40% by limiting the fruit bearing of infected twigs.

5. DISTRIBUTION World Mexico , America. India Maharastra , Gujarat, Tamil Nadu, Karnataka, West Bengal and Andhra Pradesh.

6. CAUSAL ORGANISM Anamorph stage (asexual stage) Botryodiplodia theobromae Telomorph (sexual stage) Botryospheria rhodina

7. SYMPTOMS Branches of affected trees become flat and twisted. Leaves become thin, small and yellow. Infested plant produces cluster of leaves and flowers on the affected twigs. Flowers remain infertile.

8. If fruits are set they are undersized , hard and fail to ripen. Foliage and fruit fall prematurely . If cold dry condition prevailed more branches developed symptoms, but hot weather delayed symptom appearance. If the summer onset flat limb branches produced round, normal looking branches .

9. Flattened twigs © www.eurekamag.com

10. PATHOGEN The fungi produces pycnidia . Young conidia are hyaline thin walled and single celled. Matured conidia are dark brown in colour and two celled. They were ovoid to elongated and round at end.

11. © www.tnauagriportal.com

12. SYSTEMATIC POSITION Kingdom - Fungi Division - Ascomycota Class - Dothideomycetes Order - Botryosphaeriales Family - Botryosphariaceae Genus - Botryodiplodia Species - B. theobromae

13. FAVOURABLE CONDITIONS High humidity Temperature of 24°C – 32°C. Frequent rains. Moist conditions favours the development of disease (October to November)

14. MODE OF INFECTION Primary spread Through ascospore from perithecia . Secondary spread Wind borne conidia

15. INTEGRATED DISEASE MANAGEMENT Collection and destruction of infested twigs. Pruning of affected branches followed by spraying of captan or thiram 0.3%. Spraying of 0.1% Mancozeb or Mancozeb and Metalaxyl 0.1% helps to effectively control the disease.

16. REFERENCES https://eurekamag.com> research https://www.yumpu.com Chaube.H.S , V.S Pundhur , ‘Crop diseases and their management’, fourth edition 2005 PHI Learning Private Limited, New Delhi. Harry Waren Anderson, ‘Diseases of fruits and vegetable crops’ J.V Publishing house, Jothpur .