Shisham Tree Decline

Decline:

Decline is a term used to describe a tree that is generally deteriorating. It may be due to the following reasons

Clogging of vascular bundles Asphyxiation Roots bark shredding Roots injury

Shisham Tree:

Botanical name of Shisham tree is Dalbergia sisoo. Shisham is a very important tree. It has a long historical background in South Asia. Shisham tree has abundant growth at altitude of 1500 m and in the areas of annual rain fall of 750-4500 mm. It also shows abundant growth on well drained sandy loam soil. Its wood is very hard and best suitable for the furniture making.

Extent of Shisham Decline:

Decline in forest trees has been reported almost in all forest growing areas. Decline is characterized by the presence of symptoms such as reduced growth, shortened internodes, root necrosis, premature fall, yellowing and loss of foliage, dieback of twigs and branches. Generally it begins from the upper crown and increased the progressive vigor and health loss of tree (Manion, 1991). Shisham decline diseases caused 5% plant mortality during 1990-1991 and 25% during 1999-2000. In 2001 surveys of 8 districts, the roadside, canal banks and farmland plantations showed 25.56 to 43.17% mortality (Gill et al., 2001a).

Diseases of Shisham:

Most of the researchers in Pakistan have identified only one disease responsible for shisham decline i.e. dieback. However, after survey of different areas of Punjab we identified two types of diseases viz. wilting and dieback responsible for recent shisham decline in the country (Bajwa et al., 2003). In wilt disease effects produced on trees were more or less of the same type as those produced by drought or frost. The disease was first observed by Bakhshi (1954) both in natural forests and plantations in UP, India. The disease is systematic in that the entire tree shows symptoms of the attack. In the early stage, an affected tree is characterized by drooping leaves and branches, due to loss of turgor. The leaflets turn yellow, dry up and eventually drop off rendering the branches bare. The entire tree becomes thin in contrast to the adjoining dense green trees. Death of the affected tree is rapid and occurs within 4–6 months after the crown shows the symptoms of wilt. However, apart from this recently we also have found a similar disease where

death of the plant is very rapid i.e. within few weeks’ plant become leafless. This rapid wilt generally attacks the shisham plants after the end of rainy season and throughout the autumn. A similar disease but with somewhat different symptoms has also been observed where suddenly a part or whole plant becomes dry but dry leaves remain attached with the plant and the whole dried portion becomes brown in color.Destructive Diseases includeThe destructive diseases of shisham decline include,

Various diseases causing colossal damage Root Diseases Phanerogamic Parasites Foliage Diseases Physiological Disorders

i. Water Loggingii. Poor Drainage

Symptomology:The characteristic symptom if Shisham decline are as followsLeaves

Yellowing discoloration in acropetal succession Thinning of leaves Drying of end of branches Stag headedness

Stem Sunken areas at collar portion Red brown discoloration from root to 3-4 ft above ground

Roots Feeder roots become black and brittle Lack of root generation leading to death of tree within a few weeks to months

Causes of Shisham Decline:Biotic FactorsMycologists have recorded some 62 pathogenic species of fungi on shisham. Most of the fungi have been studied from mycological point of view and a little has been mentioned on pathological aspects. Bajwa et al. (2003b) reported that Fusarium solani is the cause of shisham wilt. Shakir et al. (1999) also isolated F.solani from diseased roots and assumed this organism to be the cause of shisham wilt. The causal organisms of dieback are still controversial. There is probability that more than one pathogen either singly or in combination, may be responsible for shisham dieback. It is also likely that in different regions with variable edaphic and environmental conditions, different pathogens are causing this disease. However, the most probable reason could be the misunderstanding of researchers regarding the shisham decline diseases. They generally considered different declined diseases as dieback and so they isolated different pathogens from the diseased shisham trees. Afzal et al. (2006) reported that F. solani and Ganoderma lucidum are responsible for root rot in shisham causing large scale destruction. Zakaulla (2006) undertook an intensive survey of irrigated plantations and naturally growing areas of Peshawar district, CDR and roadside plantations of Attock district under “Forest Sector Research and Development Project” of PFI Peshawar. They isolated six pathogenic fungal species from affected trees namely Botryodiplodia theobromae, Ganoderma lucidum, Fusarium solani, Helminthosporium dalbergiaea, Xylaria sp. And Poria ambigua. B. theobromae was the

most common and damaging species.Rehman et al. (2006) collected diseased samples of shisham from various districts of the Punjab for isolation of disease causing pathogen of shisham. B. theobromae was found to be the most frequent followed by P. cinnamomi and F. solani, respectively. Insects do not play any role in causing the dieback (Gul, 2004). However, termites can attack shisham once a part of the tree become dead and dry (Javaid and Afzal, 2001). Idrees et al. (2006) conducted a field survey of 20 districts of the Punjab and isolated 18 different microorganisms from different infected parts of shisham. Botryodiplodia theoromae was the most frequent fungus isolated from all the plant parts. This fungus was proved as causal agent of dieback during the study in 2003-2004 and reconfirmed in 2004- 2005. In one of our earlier studies, Fusarium oxysporum was found in abundance in the roots of dying back Shisham trees samples collected from drought affected areas of Quaid-e-Azam Campus, University of the Punjab, Lahore (Bajwa et al. 2003).A biotic Factors

Many a biotic stress factors are also known to be responsible for the initiation and severity of shisham decline diseases. Bajwa et al. (2003) recorded the highest mortality percentage of 75–80% along the canal banks. It reveals that disease incidence and severity is related to high soil moisture contents. Water seepage from the canal into the nearby areas rendering the soil water logged. Some other workers have also reported that high soil moisture level increases the severity of this disease (Sharma et al., 2000; Keerio, 2001). Keerio (2006) conducted surveys of all the shisham growing districts of Sindh viz. Ghotki, Sukhur, Khairpur, Naushahro Feroze, Nawabshah, Sanghar and Hyderabad. He also reported that water logging and drought were the primary causes of drying/dying if shisham trees which created stress conditions and made the trees vulnerable to dieback disease. According to Afzal et al. (2006) global warming and erratic rain falls could be the possible reasons of recent shisham decline in the country. Rehmatullah et al. (2006), however, did not find any relationship of dieback with soil physiological properties and plant nutrient status.Control Measures:

Chemical Control

Idrees et al. (2006) conducted various studies at Chichawatni, Charaghabad, Changa Manga andAyub Agriculture Research Institute Faisalabad for chemical control of dieback. They tried various chemicals namely Topsin-M, Dithane M-45, Trimitox Forte, Scoreand Derosal against the dieback fungal pathogens. They reported that no success was achieved when disease incidence was morethan 25%. The key to control dieback is an early detection in an area and prevention. Once the symptoms of dieback are evident in a tree, it is difficult to stop or reverseThe progress of the disease (Javaid et al., 2004) Bajwa et al. (2003b) studied in vitro toxicity of three fungicides viz. Ridomil Gold, Benomyl and Aliette were tested against wilt causing pathogen F. solani by the poisoned food technique (Nene and Thapliyal, 1979). Benomyl, the most effective fungicide in vitro trial was also proved very effective in vivo experiment. The three shisham plants of 5-10 years old, which were likely to be dead by wilting during next few weeks, managed to recover themselves from disease after treatment with Benomyl. The treatment with this fungicide may prove highly beneficial to save the shisham trees from the menace of wilting. However, there is need to study the effectiveness of this fungicide against the wilt attack in older trees. A benomyl derived fungus toxicant MBC (Methyl-2-benzi midazol

carbamate) is also known to be effective against wilting. It is a stable fungicide suitable for injection into the trees (Mcwain and Gregory, 1973).

Biological ControlBajwa et al. (2004) studied the antagonistic effect of various fungal species namely Trichoderma viride, T. harzianum, T. koningii, T. areoviride, T. pseudokoningii, Aspergillus fumigatus, A. glaucus and A. oryzae against the growth of F. solani, the cause of wilt disease in shisham.

Suggestions and Recommandations:

The following preventive and control measures are suggested to contain the problem: Plantations on clayey and waterlogged soils should be avoided. New plants should be planted in suitable sites i.e. on well-drained sandy soils. The seedbed for shisham nurseries must be disinfected before sowing. The dead, wilted and dying plants should be uprooted so that the breeding place of the

Pathogens are destroyed to stop further spread of the disease. Avoid wounding the trunk and roots. Mixed cropping is recommended rather than monoculture to avoid dieback. New shisham nurseries should be raised from the seeds and cuttings of the resistant

Variety and the susceptible varieties should be gradually replaced with the Resistant ones.

Watering is beneficial during relatively dry autumns and during dry summer months. If dieback symptoms appear, and no specific cause can be determined, try fertilization

and watering. Use Benomyl to cure wilting in young Shisham plants. Add organic materials such as farmyard manure along with some antagonistic fungi to

reduce the spread of the pathogen. With proper care and management the rate of dieback and wilt diseases can be reduced

and further problems can be prevented.

References:

Afzal, M., R.M. Rafique, A.A. Chaudhry, A.R. Chaudhry and A.M. Akhtar, 2006. Shisham dieback research at PFRI. In: Proc. 3rd Nat. Sem. Shisham Dieback, May 11, 2006. Punjab Forestry Research Institute, Faisalabad, Pakistan. Pp.16-28.

Bajwa, R., A. Javaid and M.B.M. Shah, 2003a. Extent of Shisham (Dalbergia sissoo Roxb.) Decline in Sialkot, Gujranwala, Lahore and Sargodha Districts. Mycopath, 1: 1-5.

Bakhshi, B.K., 1954. Wilt of shisham (Dalbergia sissoo) due to Fusarium solani. Nature, 174, 278-291.

Bajwa, R., A. Javaid, J.H. Mirza and N. Akhtar, 2003b. Chemical control of wilt in Shisham (Dalbergia sissoo Roxb.). Mycopath, 1: 111-113.

Gul, H., 2004. Insect and shisham dieback. . In: Proc.2nd Nat. Sem. Shisham Dieback, July 29, 2004. Punjab Forestry Reseach Institute, Faisalabad, Pakistan. pp. 40-41.

Gill, M.A., I Ahmad, A Khan, M. Aslam, S. Ali, M.M. Khan, R.M. Rafique and T. Mahmood, 2001a. Phytophthora cinnamomi. A cause of shisham decline in Punjab, Pakistan. In: Proceedings of National Seminar on Shisham Dieback, October 27, 2001. Punjab Forest Research Institte Faisalabad. pp. 21.

Idrees, M., S.S.H. Zaidi, A.U.Khan, A. Mahmood and A.S. Akhtar, 2006. Studies on organisms associated with shisham dieback and their pathogenicity. In: Proc. 3rd Nat. Sem. Shisham Dieback, May 11, 2006. Punjab Forestry Reseach Institute, Faisalabad, Pakistan. pp. 29-36.

Javaid A and M. Afzal, 2001. Incidence of Termite Attack on Trees in University of Punjab, Quaid-e-Azam Campus, Lahore, Pakistan. Pakistan Journal of Zoology. 33, 80-82.

Javaid, A., R. Bajwa and T. Anjum, 2004. Identification of some more varieties of Shisham (Dalbergia sissoo Roxb.) and their response to dieback and wilt. Mycopath, 2(2):55-59.

Keerio, G.R., 2006. Report on dying and drying of shisham in Sindh. In: Proc. 3rd Nat. Sem. Shisham Dieback, May 11, 2006. Punjab Forestry Reseach Institute, Faisalabad, Pakistan. pp. 107-109.

Mcwain P and G.F.A. Gregory, 1973. Benomyl derived fungitoxicant for tree wilt disease control. USDA For. Serv. Res. Note, N.E. Forest Expt. Sta. No. 162. RPP. 53, 2: 689 Abst.

Manion, P.D. (1991). Tree disease concepts” (2nd edition). Prentice-Hall, Englewood Cliffs, U.S.A. Pp. 402.

Nene, H.L. and P.N. Thakliyar, 1979. Fungicides in plant disease control. Oxford and IBH Publishing company, New Delhi, pp.507.

Rehman, A., S.T. Sahi and M.A. Khan, 2006. Physiology and histopathology of Shisham decline causing pathogens in Punjab. In: Proc. 3rd Nat. Sem. Shisham Dieback, May 11,2006. Punjab Forestry Reseach Institute, Faisalabad, Pakistan. pp.83- 88.

Rehmatullah, F. Ahmad, T. Aziz and M.A. Maqsood, 2006. Evaluation of soi properties for their possible role in shisham dieback. In: Proc. 3rd Nat. Sem. Shisham Dieback, May 11, 2006. Punjab Forestry Reseach Institute, Faisalabad, Pakistan. pp. 52-61.

Shakir, A.S., S.M. Khan and R. Ahmad, 1999. First report on shisham decline in Pakistan. Pak. J. Phytopathol, 11: 106.

Sharma, M.K., R.M. Singaland and T.C. Pokhriyal, 2000. Dalbergia sisso in India. In: Proc. of the sub-regional seminar on dieback of sissoo (Dalbergia sissoo), Katmandu, Nepal, 25-28 April 2000. pp. 5-16.

Zakaulla, C., 2006. Pathological investigations on shisham dieback at PFI Peshawar. In: Proc.3rd Nat. Sem. Shisham Dieback, May 11, 2006. Punjab Forestry Reseach Institute, Faisalabad, Pakistan. pp. 62-65.