J. Phytol. Res.9 (l): 4148,1996 WEEDS OF DELHI II. CBRTAIN MEMBERS OF GRAMINEAE

RAJM GUPTA and K.G.MUKERJI Applied Mycology LaborUmy, Department of Botany, Uniyersity of Delhi, Delhi-110 007, India.

The efficacy of pathogens for the biological control of grasses are reviewed in light of the biology of the host . Manygrasses werecollectedi.e.Araclne, Botiochola, Chloris, Cynodon, Digitaria Dactyloleclinunt, Eragrostis, Leptochola, Oplismenus, Phalais and and several pathogens were recorded on these grasses namely Puccinia, [Jstilago, Phyllochora, Abemaria; Curvularia, Drechslera, Hehninthosporiur4 Piicutaria and Sorosporium etc. Some of them can be used as biocontrol agents for these u'eeds.

Keywords: Grasses, Pathogens, Weeds. Introduction Material and Methods Weeds associated with field crops pose a Attempts were made to collect all the serious threat as it is very difficult to control graminaceous weeds growing in different parts their spread by ordinary methods. Noxious of Delbi during different seasons. Thetime o{ weeds have been defined as which arc their appearance, reproduction and capable of disrupting ordinary farming dissemination were regulady observed operations and resisting measures for control through out the year (Table 1. Fig.l A-I). or eradication. Many weeds reproduce and ldentification of these weeds weremade using spread vegetatively as well as by seeds. standard monographsl'3. The pathogens Digitaria sanguinalis, Botriochola sp, occurring on these weeds were identified4. Brachiaria sp. and Oplismenus sp. are herbs and capable of vegetative reproduction. Results and Discussion genera from different Besides producing enormous quantity of seeds Eleven were collected they also have under ground parts such as localities of Delhi Arachune, Botriochola, rhizomes, stolons, root stocks, bulbs and tubers Brachiaria, Chloris, Cynodon, Digitaria, which nrake them beyond the reach of routine Dactylolectinium, Eragro stis, Leptochola, (Fig.l). control measures. Depending on the degree Oplismenus, Phalaris and Setaria genera of competition weeds reduce the crop yield These can be separated from each leaf morphology, by 10 to 857o. WeeCs serve as alternate hosts other on the basis of their for several pathogens. flowering and seed formation. Some of the Tbe present paper describes some of genera persist through out the year, while the commonly occurring graminaceous weeds others appear only for a short duration. perennial grass of Delhi. The purpose of this survey is to note Cynodon dactylon is a with and collect the facultative parasites present long runners which strike roots at the nodes ground on these weeds, which can be further used for and have extensive under rhizomes. the control of weeds. Biological control of The leaves of Cynodon vary greatly in length pests with their natural enemies can reduce from 3 to 20 cm. Its infloresence consists of 4 our dependence upon toxic synthetic to 5 slenderpurpulishspikes upto 10cm long. chemicals. Success or failure of biological Itpropagates vegetatively more than by seeds. pathogens conEol depends on interactions between target several are known to occur on (Table (host), control agents (natural enemies) Cynodon sp. 2) i.e. C.dactylon al'vJ and the envkorrment. C.plectostachyum, Puccinia cynodontis, 43 & Mukerji 44 Gupta single spike. lJstilago cynodontis and Phyllochora clustures arranged in a Ce,rcospora oplismeni, Puccinia oplismeni, cynadontif '6 were recorded from Delhi during oplismeni ue of March and April. Alternaria Tiltetia vrtruta, U stilagircidea the months zs-:t. vitis, Cercospora cynodontis, Curvularia reported on this Plant lunata, Drechslera cYnodontis, Setaria is a annual, with erect stem, pointed, ligules S epto ria leaves flat; lanceolate, long H e lmintlw sp o r ium mbro spor um and with a frurge of hairs. Spikelets numerous cynodontis are reported from other parts of glabrous usually, flowers cylindric, tapering Indiaat3. unequal from two to tbur About 20 sPecies of Digitaria are panicles. Bristles as long as the spikelets, pale brown or reported from India. D. adscerulens is an dmes with purpule. Setaria tomcntosa is a annual gra.ss with smooth and stout culm, tinged tufted annual. Setaria glauca is a usually decumbent at the base. It exhibits loosely grass upto 150cm high. Culms perennial growth. It flowers between July mfed annual branched erect or ascending' and September. Several pathogens are simple or graminicola occurrs very reported on this plant, namely Clavicep.s Sclerospora P frequently on this Plant32' digitariae , Plry sode rma digrtariae , iricularia grasses persist through out grisea, Puccinia digitariae and Ustilago Most of the ta'20. year vegetatively. On thebasis of their longifiora the not be identified. They can be PasPalum coniugatum is a creePing leaves they can only on the basis of their tlowers, stoloniferous perennial grass' The culms are recognized of them flower in the montlr of July and 20 to 40 cm long, erect with smooth nodes' Most seed dispersal talies place in the montt The spikes are two, rarely three at lhe apex of their Some grasses have a ear just culm, widely spreading, sraightor some what of September. wheat plants as in Phalaris while in arched. The spikeletsare flattened, pale green' like they have a stiff and pnckly hairs e'g. The margins are fringed with bug white silky others hairs. Puccinia paspali and Sorosporium Setaria glauca . spikelets are paspali are found in Delhi2r'22. Drechslera Eragrostis' ciliaris minute or rarely 1/2 inch. Culms sp., Ephelis oryzac and Uredo paspali ae awnless, glabrous. Leaves very reported from other parts of India23'5' geniculately ascending short, cylindric Phalaris minor is one of the most narrow. Panicles compact, presence of long cilia trouble some weed. Morphologicallly, it is spike like, hairy due to divided from base. similar to wheat plant. It flowers after October on Palea, branches Helminthosporium till December but seeds persist till March' Drechslera ravenelii, butleri, Tilletia Drechslera (Nenae is reported on this plant bhawanii, Sclerospora reported on tliis glass20'3)'lr'34. from Delhi26'2?. tr an sv ale ns is are grass OPlismenus is annual herb, hairy, Chtoris dolichostachya a perennial I m taII stemp leafy, slender, weak and ascending with erecl. or proc€unbentstems upso linear, infloresence of often rooting at the lower points. Leaves are after branched, leaves flat, lanceolate, tapering to a fine point. generally 5 digitate, spreading spikes forming present an this Spikelets are narrowly ovoid, nearly sessile, a terminal whorl. Pathogens jointed at the base, solitary in pain or small grass are Entyloma chloridis, Puccinia J. Phytol. Res. 9 (l): 43-48, 1996 45

Tgble 1. Oecunence of weeds during the different months of year (Gramineae)

Weeds Dee, Jan. Feb. Mar. Apr. May June July Aug. Sep. Oct. Nov.

Arachdne +V +V +F +S +S +S,D Botriochola pertuta +V +V +V +F +S +S,D Chbris dolichostaclrya +V +V +V +F +S +S.D

Cynodan dacrylon +V +V +V +F +F +S Digitariaddescendens +V +V +V +V +V +V +V +V +F +S +S +V

D acglole ct in i um oe gypt i wr, - +V +V +V +F +F,S +S Eragrostis ciliaris +V +V +V +F +S +D,S

I*ptochola panicea +V +V +V +F' +S +S,D Oplismenus composltus +V +V +V +V +F +F Phalaris minor +F +F r.F +S +V +V +V +F +F +F +F Setaria tloucdta +V +V +V +F +S +S S.lomentosa +V +V +V +F +S +F

V-Vegetative; F-Flowering;S-Seed formation;D-Dispersal

Table 2: Occurence of various pathogens on these weeds. Weeds Pathogens

Paspalum conjugatum - Puccinia paspali, Sorosporium paspali, Drechslera, Uredo paspali

Chlo r i s do lic ho stac hy a - Entyloma chbridis, P uc cinia c hlo ridi s, Sphac e lothe ca c hlori.C i s, Ustilago valentula. Cynodon dactylon - Puccinia cynodantis, Ustilago cynodontis, Alternaria, Cercospora, Curvularia, Drechslera, Hemlinthosporium, Septoria cynodontis Digitaria adscendens - Claviceps digitariae, Physoderma, Piricularia grisea, Puccinia

di g itar iae, U stila g o I o ng ifalli a Eragrostis ciliaris - Drechsleraravenelii, Helminthosporiumbhawanii,Sclerospora butleri - Cercospora oplismeni, Puccinia oplismtni, Tilletia vittae, U stila ginoidae oplisme ni Phalaris minor - Drechslera avenae Setaria glnuca - Sclerosporagraminicola Gupta & N4ukerji

Fig. 1. Shorving external appearance oi A. Araclue ra('entosa. B. Dac^'lolectirtium. ae;yptitutn C.. Ilettnrthio cottpve-t.\{t. D. Ertgrostis ciliaris, E. l,er'ittthi"la panicea, F Oplismetus ctnnpasitns' J. Phytol. Res. 9 (1): 4348,1996 47

Fig. 1. G. Cynodon dactylon, H. Setaia glauca, L Elusine indica. 48 GuPta & Mukerji 16' Pavgi M S and Singh I 1971, MycopatL et chloridis,sphacelothecachloridis,Ustitago Mycol. Appl.4j 711 valentulais'37. t7. Roy A K 1965, Indian Phytopathology lE 327 above that It is quite evident from the 18. Thirumalachar M J and Mundkur B B 1951 CMI several pathogens are present on Yarious Mycol.4A I M J, Narasimhan MJ and grasses. Some of these cannotbe cultured but 19. Thirumalachar Gopalkrishnan KS 1947, Bot. Gaz.108 371 Deuteromycetes can be cultured and can be 20. Thirumalachar M J, Pavgi M S and Payak M M further used as mycoherbicide. 196O, Mycologia 52 415 21. Mundlau B B and Thirumalachar M J 1952, Ustilaginales of India Common wealth References Mycological Institute, Kew, Survey, England. 1. Malreshwari J K 1965, Illustrations oJ Flora of 22. Sydow H, Sydow P and Bulter 9l l9l2Ann. Delhi Mycol. 10743 2. Collet H l9'tl, Flora Simlez'rrs 1-650 21. Misra R P and Pall B S 1975, Curr. Sci,. 44 869 3. RaoVSlgS3,PrhciplesofweedscienceOiqd 24. Pandotra V R 1966, Proc. Indim Acad Sci. and IBH PublishingCo. 64(B) 68 4. Mukerji K G and Bhasin J 1986 Plot diseases 25. RamacharP and Cummins GB 1965,Mycapath. of India Tata McGraw - Hill - Publishing et Mycol. Appl. 251 Company Limited, New Delhi, pp'1-'{68 26. Bulter E J 1905, Pflanzenl

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