Current Science

A. Ratankumar Singh ¹, S. B. Singh ², S. K. Dutta ³, T. Boopathi ¹, Lungmuana ⁴, S. Saha ⁴, M. Thoithoi Devi ⁴, N. Hemanta Singh ¹

Affiliations
1 Division of Crop Protection, ICAR-Research Complex for NEH Region, Mizoram Centre, Kolasib 796 081, IN
2 Division of Social Science, ICAR-Research Complex for NEH Region, Mizoram Centre, Kolasib 796 081, IN
3 Division of Horticulture, ICAR-Research Complex for NEH Region, Mizoram Centre, Kolasib 796 081, IN
4 Division of Natural Resource Management, ICAR-Research Complex for NEH Region, Mizoram Centre, Kolasib 796 081, IN

Abstract

Mizoram is a mountainous (Lushai hill range) state with closely spaced intermountain valleys, demographically dominated by indigenous tribes (Mizo) constituting 94.4% of the total population. These tribal populations ensure the conservation of plant genetic resources for the future, for the food and nutritional security of an increasing population. Since 1976, in the northeastern hill region intensive collections of maize landraces were made by ICAR-NBPGR, New Delhi and diversity of landraces maize from this region comprised 36% of the total collection from whole India, which was the highest number of accession among other regions.

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A. Ratankumar Singh ¹, S. K. Dutta ¹, S. B. Singh ¹, T. Boopathi ¹, S. Lungmuana ¹, S. Saha ¹, Vishambhar Dayal ¹, Romila Akoijam ², S. K. Sharma ², N. Hemanta Singh ²

Affiliations
1 ICAR Research Complex for NEH Region, Mizoram Centre, Kolasib 796 081, IN
2 ICAR Research Complex for NEH Region, Manipur Centre, Lamphelphat 795 004, IN

Abstract

Tree bean, Parkia timoriana is one of the most important perennial tree legume vegetable crops in north eastern region (NER) of India. Recently, sudden death or decline is emerging as a major constraint in the production of tree bean. The prevalence, intensity and etiology of this disease have not been extensively studied. The present work was aimed at studying the symptomology, severity and etiology of sudden death or decline of tree bean in the north eastern region of India. Typical symptoms of tree bean decline were initiated with wilting of half portion of the tree, excessive shedding of leaves, gradual drying up leading to death, and secondary infestation by insects on dead trees. The highest disease severity of 68.5% was observed in warmer regions like Kolasib, Mizoram. During survey, small bark borer was recorded in all districts and levels of infestation rate (holes/ft2 of log) reached maximum up to 25.49 in Hnanthial of Lunglei district. Young trees in the range 1–10 years with 57.32% (917 trees) of total trees (1600) infected were most susceptible to the disease compared to 12.58% (201 trees) infection in old trees in the range 21–30 years. The frequently associated pathogen with sudden death or decline of tree bean was identified as Botrydiplodia theobromae at the Indian Type Culture Collection, ICAR-IARI, New Delhi. It was the most aggressive species and proven to be pathogenic to tree bean following artificial inoculation.

Keywords

Botrydiplodia theobromae, North Eastern India, Parkia timoriana, Sudden Death or Decline Disease, Tree Bean.

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