.1 n.qhi. h .k . . A. Kumar and fijJLu Ahmad. Indian Grassland and Fodder Research Institute, Jhansi-284003, India.DISEASES OF LEOCAENA IN INDIASubabool (Leucaena 3encocephala (Lam.) de Wit.) is a disease resistant fodder tree. A few fungal diseases viz., necrotic lesions on twigs, caused by Botryodiplcdia thepbrpmae. (Srivastava, 1955) , ClMusparium subtil* inf-ecting and Bisby, 1931); leaf spots caused by Cerosppra leucaena (Shukla and Sarmah, 1985); pink disease, caused by CQEtlClum salmanicaiux (Bakshi, 1976) and other wood rotting fungi, such as Gansaexma i nr-i rinm (A.K. Raina, 1983) have so far been recorded from various parts of India.Important diseases and other fungi associated with the leucaena in India are described here.1. Gnmmosis; The disease is characterized by gum exudation fromthe main trunk and branches. It adversely affects furtherdevelopment of the infected tree. The disease is distributed the states of Uttar Pradesh, Jammu and Kashmir, Maharashtra, Gujarat, Rajasthan and Karnataka. The disease is reported to becaused by Fusarium semitectum (Singh et al., • H™®ver, ^fungus isolated from gummosis-affected parts of trees growing at igfri was identified as Fusarium acuminatum Ell. & Ev.In 1982, 52 lines of leucaena germplasm were screened in the field against natural incidence of gummosis, using the 0 to 4 scale reported earlier (Patil et al., 1982). Only 23 of the 52 lines exhibited disease symptoms (Table 1). Disease severity varied from the highest (11.40%) in Peru types to the lowest (0.28%) in Salvador types. In Hawaiian types 6.35% severity w observed.Table 1. Intensity of gummosis on different types

of Leucaena leucocephala.

EntryNumbe r

oflines

Mean disease incidence

Mean infection index CODEX*

-%- -%-

PeruSalvadorHawaiian

22228

33.07.43.7

11.400.286.35

4.800.043.50

* Co-efficient CODEX = .01

of disease index, calculated as: .(Percent disease indicence x percent infection index)

The etiology of gummosis is debatable, and a number of views have been developed (Hegde, 1984; Anderson, 1984; and Singh et al.,1983). Detailed investigations are needed to prove pathogenicity of the fusarium. It is still not certain whether Fusarium spmitectum (Singh et al., 1983) or acuminatum is causing the disease in India and Ceylon. Involvement of three species of

is well known to cause citrus gummosis, and

p. drechsleri has been observed as a canker on leucaena associated with limited gum exudation (Van Den Beldt and Hodges,1980) .Further, there are reports that ciit or wounded living trees ooze out cell sap containing salts and carbohydrates. This slime-flux serves as an excellent nutrient medium for microbes (Tewari and Singh, 1975). Gummosis in subabool can also be a form of such a slime-flux infection.2. Seed!ina disease; Self-sown seedlings of subabool have been affected by seedling rot during rainy seasons. Water-soaked lesions on cotyledons advance towards other parts and often cause mortality. The causal fungus has been identified as ColletPtrigh. capsici (Syd.) Butl., and has also been identified from leaves of L . 1anceolata (IMI300252).3. Fan-leaf di sease; In 1980 a new disease was observed on a couple of leucaena trees. The disease was characterized by reduced tree height, shortening of internodes, and chlorotic leaves. Branch bases of affected trees formed galls that were devoid of any insects. In certain leaves the main veins of leaflets gathered together towards the mid-rib forming a partly closed fan (Figure 1). In absence of any fungal or bacterial association with the disease it is suspected to be viral in nature.Figure 1. Leaflets of leucaena forming a partly closed fan.

4. Nine additional organisms were observed on Lj. and II*. 1 anceolata at IGFRI, as noted below:__________ (IMI300251) on leaves of lanceolata:Ascochyta sp. (IMI300251 b) on leaves of L*_ lancaplata; Aspergillus f1avus (IMI282805) on pods of l£ll£PC£phala; Cladosporium sp. (IMI300235 b) on leaves of leucpcephala; Curvularia sp. (IMI300252) on leaves of Lj_ leucpcephala; Flavodon flavus on the bark of Lj_ leucpcephala;Fusarium pallidoroseum (IMI300228) on leaves of L . T.eptosphaerulina sp. (IMI300228 c) on leaves of

roseum on bark of leucocephala (IMI300239)

These fungi have not been recorded previously on Leucaena spp. in India, and FI avodon flavus (order Polyporales of basidimycetes) is a new fungus for India (Bilgrami et al., 1979).

Authors are grateful to the Director, IGFRI, Jhansi and Head, Plant Improvement Division, for their encouragement and providing necessary facilities. Leucaena germplasm provided by Dr. V. K. Gupta is thankfully acknowledged. Thanks are also due to the Director of C.M.I., and Royal Botanical Gardens, Kew, Surrey, England for identifying different fungi.

References:Anderson, D.M.W. 1984. Gum exudation by

NFTRR 2:24.Bakshi, B.K. 1976. Forest Pathology: Principles and Practice inForestry. Controller of Publications, Delhi, India, pp. 400.

Bilgrami, K.S., Jamaluddin and M.A. Rizvi. 1979. Fungi of India, Part I & II. Today & Tomorrow Printers and Publishers, N. Delhi, India.

Butler, E.J. and G.R. Bisby. 1931. The fungi of India. Imp.Coun. Agric. Res., India Sci. Monogr. 1, pp. 237, India.

Hegde, N.G. 1984. Gummosis of Leucaena leucocephala. LRR 5:31-J b • iPatil, B.D., V.K. Gupta, A. Kummar and H.K. Joshi. 1982. Reaction of parents and hybrids of Leucaena leucocephala against gummosis disease. LRR 3:33-35.

Raina, A.K. 1983. Performance of Leucaena leucocephala in the Indian Arid Zone. LRR4:35.

Singh, S., S.N. Khan and B.M. Misra. 1983. Gummosis, brown spot and seedling mortality in Su-babul: Disease incidence and pathology of the host. Indian Forester 109:185-192.

Shukla, A.N. and P.C. Sarmah. 1985. A new species of CerCQSPPJ^. on Leucaena leucocephala. Curr. Sci. 54:439.

Srivastava, S.N.S. 1955. Leucaena spp. hitherto undescribed hosts of Botryodiplodia theobromae Pat. Sci. & Cult. 20:93-95.

Tewari, V.P. and R.S. Singh. 1975. Fungi from slime-flux of trees. Indian Phytopath. 28:12-16.

Van Den Beldt, R.J. and C.S. Hodges. 1980. Phytoph.thPEa infection in Hawaii Leucaena variety trial. Leucaena Newsletter 1:56.