BIOLOGY AND CONTROL OF PARASITIC WEEDS

BIOLOGY AND CONTROL OF PARASITIC WEEDS: 

BIOLOGY AND CONTROL OF PARASITIC WEEDS Mr SUBBAREDDY B. 2011-11-172

INTRODUCTION :: 

INTRODUCTION : Parasitic weeds are the plants which attack other plants by making connections and deriving part or all of their food from the host They attach themselves either to the roots or the shoots of the host plants and survive on food material available in them. The parasitic weeds are host specific ;they cannot survive in the absence of their host plants

Classification : 

Classification Parasitic weeds Stem parasitic weed Root parasitic weeds Complete Partial Complete Partial Cuscuta Loranthus Orobanche Striga

OROBANCHE SPP (Broom rape): 

OROBANCHE SPP (Broom rape) Biology and habitat : Orobanche is originated in the near east and it is an annual parasitic herb propagating by seed . The host roots exudates and induce germination of broomrape seeds within the soil and the adult plant produces vast quantities of minute seeds (0.25 mm long ). A haustorium is formed which penetrates to a vascular tissue and establishes connections with the host xylem and no chlorophyll is formed and the parasite is totally dependent on the host for its nutrition and there is interference with the hosts ability to take up water.

LOSSES: : 

LOSSES : Damage is Severe under drought condition. A single emerged parasite per V . faba plant will reduce yield by 50 percent. In India losses due to it in tobacco crop alone are estimated at 30-35 percent. Each broom rape plant may produce over a half a million seeds in a short period of about eight weeks. And disseminate by several agents and remain dormant in soil for 2-12 years. It infects the fibrous roots of tobacco, 45 days after transplanting.

Major species of broom rape : 

Major species of broom rape Species Host crops O.cernua Tobacco, sugarcane O.ramosa & O.aegyptiaca Tomato O.crenata Broad bean and brassica crops

Methods of control: : 

Methods of control: 1. Preventive methods Remove the adult plants from the field before flowering and seed production occur. The problem can be avoided by planting non susceptible crops. 2.Cultural methods Crop rotation Trap crops. suppression of Orobanche by high fertilization i.e. nitrogen. If rates of fertilizer is exceptionally high , there is suppression of O.ramosa in tomato.

PowerPoint Presentation: 

Physical methods : Hand pulling has been recommended for controlling O.cernua in tobacco in India , control being more or less complete after 3 years( Krishnamurthy and Rao 1976). In some crops pulling may be seriously disturb the crop root system as noted for egg plant . ( Misra et al.,1982). Experiments comparing zero tillage and normal cultivation suggest that reduced cultivation increases the attack by O . crenua on V.faba ( Nassib et al.,1985; Kukula and Masri , 1984). Solarisation

PowerPoint Presentation: 

Chemical Methods: Allyl alcohol sprayed at 0.1 con. is a well established alternative to hand pulling In recent years for preventing the development and emergence of parasite have been obtained with Glyphosate (0.2 kg/ha) O. crenata on V. faba ( Kaasian , 1977). Glyphosate a Dose of 60 g/ha was well tolerated but root out 120 g/ha, hence need for repetition of lower doses in preference to the application of a single larger dose (Mesa- Gercia et. al ., 1984). Partial control through herbicides such as Trifloralin and Diphenamide . Partial control of O.crenata in V.faba following treatment of the seed with a mixture of fluazifop -butyl in oil (haustorium,1984) and control of Orobanche species in tobacco with pre-emergence application of fluazifop -butyl(1kg/ha).

PowerPoint Presentation: 

Biological methods: The agronupoid fly Phytomyza orobanchiae Kalt has been successfully exploited for control of Orobanche spp in the formerly USSR and Eastern Europe. Reports of Fusarium spp being used to control O.aegyptica by inoculation of the planting holes of the host crops ,tobacco and melon ( Kassasian ; 1971).

PowerPoint Presentation: 

Resistant varieties:- Varietal resistance of sunflower to O.cernua was recognized over 50 years ago and resistance varieties have been the main defence against their parasite in the formerly USSR . Resistance of vetch ( V.sativa L) to O.crenata has been successfully identified in Spain (Martin et al ;1982).

Striga SPP (WITCH WEED) : 

Striga SPP (WITCH WEED) Biology and habitat: It is much more tropical in their distribution. Smallness of their seeds make them obligate parasite only able to develop fully after attachment to a suitable host root . The seeds then germinate , attached to tree roots of host plant and develop as total parasite below Ground but when light is available ,chlorophyll is formed and plants can photosynthesize and no longer parasitic. The efficiency of photosynthesis is only about 20 percent of that of a normal plant. (Shah et al .,1984).

Conti..: 

Conti.. There are 23 species of Striga on record of which only 3 are considered notorious. They are S.asiatica,S.hermonthica , and S.densiflora , attacking sorghum and bajra and all are found in Africa . S.asiatica is common in Asia only. In Maharastra,Karnataka and Gujarath , Sorghum is severly attacked by the striga resulting in a heavy reduction in yield. Heavy losses also occur in Tamil Nadu, A.P and certain parts of M.P.

Host plants:: 

Host plants : Species Host plants S.hermonthica Sorghum S.gesneroides Cowpea and Tobacco Others Ragi,Maize,Sugarcane,Rice,Tobacco,Ground nut and Sweet potato

  Methods of control:- : 

Methods of control:- Preventive methods :- The spread of Striga is not readily prevented because the seeds are minute (0.25 mm long) and can readily adhere to crop seed and blown or carried by water over long distances. Precaution should be taken to obtain crop seed only from uninfected areas, avoiding growing susceptible crops and growing of any broad-leaved crop will be suitable on land affected by the cereal. Cultural Methods:- Crop rotation Use of high nitrogen fertilizers is beneficial in at least delaying Striga emergence and in obtaining stronger crop growth(Behawi,1981). Using of resistant varieties, dense planting.

PowerPoint Presentation: 

2,4-D,paraquat are used routinely in maize in USA ( Eplee,1984),while bromoxyl and amytrene are less damaging to legume crops ( Orborn , 1972). In USA oxyfluorfen has been used to give more reliable prevention of Striga emergence (Eplee,1984) and the use of volatile fumigants and methyl bromide is used for localised control in USA. Highly effective chemical method in USA is the use of ethylene gas to stimulate Suicidal germination. (1-2 kg/ ha injected at 15-30 cm depth in lines 1m apart can give 80-90 percent germination of seed in the soil) (Eplee,1984). A synthetic Strigal analogues ( GR7,GR 24,etc.) have shown high activity on S.hermonthica and S.asiatica in-vitro but less successful than ethylene on field. Chemical methods :-

PowerPoint Presentation: 

Resistant varieties:- S.asiatica there are promising new lines SAR1 and SAR 2(Rao,1984). While for S.hermonthica , Framida (SRN 4841) has well proved in several areas (Ramiah,1984). In cowpea two lines ( Suvita 2 and 58-57) highly resistant to S.gesneroides , have been identified by the IITA.

LORANTHUS OR DENDROPHTHOE SPP: 

LORANTHUS OR DENDROPHTHOE SPP Biology and habitat:- Loranthus is a stem parasite of certain tropical and sub- tropical trees and bushes like the teak,rose-wood,sandlewood,mango,citrus and tea. In India about 60 species of loranthus are on record of which L.longiflorus var. Falcatus is the most damaging . Loranthus seeds are spread by birds to fresh tree branches.

Methods of control:- : 

Methods of control:- Pruning is used to remove the parasite but complete removal means removing the host branch on which it is growing . If only the parasite is cut ,there is likely to be regrowth from the haustorial base. In India control of Loranthus Ettings on teak has been successfully controlled using metrubuzin (at 1%) . The other control measure is to bore two rows of holes down the infected trees, reaching the sap wood and in each hole a mixture of 8 g coppersulphate and 1 gr 2,4-D powder is pushed in and the treatment is supposed to free the trees from loranthus for a period of about 4 years.

Conti..: 

Conti.. Ethephon (20ml/L) is used for control of loranthus in host trees in Kerala. If regrowth of parasite is seen on host plant padding with 2,4-D is effective and for minor infection salt padding is recommended. ( KAU,Kerala )

Cuscuta (Dodder): 

Cuscuta (Dodder) Biology & Habitat: The seeds of cuscuta germinate spontaneously with out involvement of any host plant and once attached to its host ,the cuscuta seedlings grows very rapidly. If no host is contracted the seedling will lose capacity to parasitize. A single dodder seedling can grow 2 km or more in length.

Cont..: 

Cont.. There are at least 170 species of cuscuta in the world. The main agriculturally important species are Cuscuta compestris , C.reflexa , C.hyalina , C.monogyna , C.chinensis , C.planiflora , C. pproximate,C.pedicillata,C.palaestina , C.epithymum,C.epillinum etc . Dodder dissiminates by seeds as well as through movement of its fragments with wind and animals.

Host plants:- : 

Host plants:- The age of the host may sometimes be critical and older plants like tomato may become resistant( sitkin,1976). Nagar and Sanwal (1984) reported that the resistance of potato to C.reflexa is apparently due to greater concentrations of calcium in this species. Weeds are often as much attacked as crops and convolvulus arvensis.L . is one of the most favoured host. Among crops most frequently parasitized crop is alfa-alfa . C.compestris has recently been reported as a problem on lentil in Syria( Bellar and kebabeh,1985). citrus also susceptible to several species and there are reports in Pakistan and Saudi Arabia.

Methods of control:- : 

Methods of control:- Preventive methods:- The use of clean seed in vital in areas where cuscuta does not occur and desirable even where it does to prevent further spread. Seed of alfa – alfa can be cleaned by specialized machinery using either velvet rollers or a combination of iron fillings and magnets the rougher seeds of the parasite. Seed cleaners of dodder mills having rollers covered with cloth is used to clean the seeds of forage crops. use non-contaminated implements in the fresh fields to avoid such use.

PowerPoint Presentation: 

Cultural methods :- Crop rotation . Kasasian (1977)reported reduction of the problem of C.compestris on alfa alfa in Saudi Arabia following the more efficient control of convolvulus arvensis on which the parasite was thriving around field edges . Cuscuta weeds like to develop normally and a dense , well grown crop of alfa alfa can provide useful control in the later stages (Dawson;1984). The early harvesting of fodder crop of alfa alfa and berseem for silage making could help in preventing the maturity of seed and thus reducing the weed population ( Bhan and Sahai,1991).

PowerPoint Presentation: 

Physical methods:- Hand pulling . Tillage (e.g. Spike harrowing) is recommended at early stages in alfalfa to prevent the initial establishment of cuscuta seedlings. Large flame throwers are used in the united states . Chemical methods:- Diniseb –acetate and diesel oil used ( kureman and tastan ,1980). For prevention of cuscuta certain residual herbicides have been used such as chlorpropham,propyzamide and chlorthal dimethyl in chickpea(Graph.et al., 1982; Bueret and Neury,1979). Propyzamide in niger seed ( Guizotia abyssinica ) Mishra et al.,1982) in onions ( Foschi and Ruppaarine,1977) and in the range of legume crops( Rao and Gupta, 1981).

PowerPoint Presentation: 

Sulfallate and pebulate in tomatoes (Hutchinson,1977). In sugarbeet , propyzamide (at1.5-2 kg/ha)applied at the 4-6 leaf stage has been successful in former USSR ( svetievski et al.,1975) and in Italy ( Foschi and Rapparine,1977). Where establishment of cuscuta occurs in alfalfa,an alternative to the drastic spot-burning or spraying is now available in the use of low doses of glyphosate , pioneered in USA by Dawson and saghi (1983), and confirmed in France ( Hacquet et al.,1983).

REFERENCES:- : 

REFERENCES:- Bewawi,F.F and Farah,A.F.1981.Effects of nitrophoska and atrazine on rotation between Soghum bicolour and Stiga hermonthica . Experimental Agriculture 17 : 425-30. Bellar , M. and Kebabeh , S.1983. A list of diseases, injuries and parasitic weeds of lentils in Syria. lens 10:30-1. Bhan , V.M. and Bhawan sahai 1991.Dodder ( Cuscuta spp ),a parasitic weed . Pesticide information XVII (2) :1-2. Dawson, J.H.1984c.Effect of carbaryl and PCMC on Dodder ( Cuscuta spp.) Control with chlorpropham . Weed science 32 : 290-2. Eplee , R.E.1984.Chemical control of Striga (In), Striga Biology and control, pp.113-23. ISCU Press. Foschi,S . and Rapparine,G.1977.The control of Cuscuta compestris Yunck and Cuscuta europaea L . Proceedings of EWRS symposium on Different methods of weed control nd their Integration , Uppsala,Sweden,pp 129-37.

PowerPoint Presentation: 

Graph, S., Herzlinger , , G., Kleifeld , Y., Bargutti , A. and Retig , B. B1982. Control of dodder in chickpea. Phytoparasitica 10:267. Hacquet , J., Dumont. R., Fer , A.,Cadot , B. and Rousselot , J. 1983. Account of trails in 1982 and 1983 for dodder control in lucern . Compete Rendu de la 12 . conference de columa , Paris. 167-78. Haustorium 1984. A new technique for Orobanche control Haustorium 13:3. Hutchinson, J. M. 1977. Control of dodder in tomatoes . Proceedings of 29 th annual California weed conference, 48-50. Kasasian , L. 1977. The control of Grass and Broad leaf Weeds and of cuscuta in young and established hasawi alfalfa, 9 pp. Publication joint agricultural research and development project, university college of north Wales and ministry of agriculture and water, Saudi Arabia. No. 106.

PowerPoint Presentation: 

Kukula,S.T and Masri,H . 1984. Integratedcultural practices and chemical control of Orobanche crenata in Fababean . Proceedings of Third International Symposium on parasitic weeds , Aleppo,Syria,pp 256-61. Kurcman,M . And Tastan , B.1980. Plant Protection Research Annual Report. Say 15,136 pp. Martin,L.M ., Morena,M.T . and Gil,J.1982.Three newcultivers of common vetch ( Vicia sativa L) Anales del institute nacional de Investigaciones Agrarias Agricola 21,33-9. Mesa- Garcia,J . and Garcia-Torres,L.1984.A competition index for Orobanche crenata forsk effects on broadbean ( vicia faba L.) Weed Research 24 :379-82. Misra,A.,Tosh,G.C ., Mohanty,D.C . and Patro,G.K . 1982.Herbicidal and selective effects of Tronamide for control of Dodder in Niger. Proceedings Eighth Asian-Pacific Weed science society conference , pp255-7.

PowerPoint Presentation: 

Misra,A ., Tosh,B.N.1982.preliminary studies on broomrape( Orobanche spp.)-A parasitc weed on brinjal . Abstract of papers, Annual Conference of Indian Society of Weed Science,pp 45. Nagar,R.and Sanwal , G.G.1984.Biochemical aspects of parasitism in Cuscuta reflexa ; inhibitor of cell wall degrading enzymes of Cuscuta by non-susceptible plants. Proceedings of Third International Symposium on parasitic weeds, Allelo,Syria , pp 175-83. Nassib,A.M ., Hussain , A.H.A. and EI Rayes , F.M.1985. Effect of variety, chemical control, sowing date and tillage on Orobanche spp infestation and faba bean yield . Fabis Newsletter 10:11-15.

PowerPoint Presentation: 

Ogborn,J.1972. The control of Striga hermonthica in peasant Farming. Proceedings of 11 th British Weed Control Conference , Brighton,UK , pp 1068-77. Rao , V.S. 1983. Principles of Weed Science , New Delhi. Rao,K.N . and Gupta, K.M.1981.Chemical control of cuscuta in pulses and other crops . Proceedings of the Eighth Asian-Pacific Weed Science Society Conference , pp.215-7. Shah,N ., Tuohy,J.,King,G . And Steward,G.R.1984.A biochemical characterization of Striga hermonthica . Proceedings of Third International Symposium on Parasitic Weeds ,Aleppo,Syria , pp. 74-80. Sitkin,R.S.1976.’Parasitie-host interactions of field dodder ( Cuscuta campestris )’. M.Sc.Thesis,Cornell University, USA,64 pp.

PowerPoint Presentation: 

THANK YOU