Book contents
- Frontmatter
- Contents
- List of contributors
- Acknowledgments
- 1 Biological control of weeds in the tropics and sustainability
- 2 Acacia nilotica ssp. indica (L.) Willd. ex Del. (Mimosaceae)
- 3 Australian Acacia species (Mimosaceae) in South Africa
- 4 Ageratina adenophora (Sprengel) King and Robinson (Asteraceae)
- 5 Azolla filiculoides Lamarck (Azollaceae)
- 6 Cabomba caroliniana Gray (Cabombaceae)
- 7 Invasive cactus species (Cactaceae)
- 8 Chromolaena odorata (L.) King and Robinson (Asteraceae)
- 9 Clidemia hirta (L.) D. Don (Melastomataceae)
- 10 Coccinia grandis (L.) Voigt (Cucurbitaceae)
- 11 Eichhornia crassipes (Mart.) Solms–Laub. (Pontederiaceae)
- 12 Lantana camara Linn. (Verbenaceae)
- 13 Mimosa diplotricha C. Wright ex Sauvalle (Mimosaceae)
- 14 Mimosa pigra L. (Leguminosae)
- 15 Parthenium hysterophorus L. (Asteraceae)
- 16 Passiflora mollissima (HBK) Bailey (Passifloraceae)
- 17 Pistia stratiotes L. (Araceae)
- 18 Prosopis species (Leguminosae)
- 19 Salvinia molesta D. S. Mitchell (Salviniaceae)
- 20 Solanum mauritianum Scopoli (Solanaceae)
- 21 Application of natural antagonists including arthropods to resist weedy Striga (Oranbanchaceae) in tropical agroecosystems
- 22 Biological control of weeds in India
- 23 The role of International Institute of Tropical Agriculture in biological control of weeds
- 24 The role of Secretariat of the Pacific Community in the biological control of weeds in the Pacific Islands region – past, present, and future activities
- Index
21 - Application of natural antagonists including arthropods to resist weedy Striga (Oranbanchaceae) in tropical agroecosystems
Published online by Cambridge University Press: 04 August 2010
- Frontmatter
- Contents
- List of contributors
- Acknowledgments
- 1 Biological control of weeds in the tropics and sustainability
- 2 Acacia nilotica ssp. indica (L.) Willd. ex Del. (Mimosaceae)
- 3 Australian Acacia species (Mimosaceae) in South Africa
- 4 Ageratina adenophora (Sprengel) King and Robinson (Asteraceae)
- 5 Azolla filiculoides Lamarck (Azollaceae)
- 6 Cabomba caroliniana Gray (Cabombaceae)
- 7 Invasive cactus species (Cactaceae)
- 8 Chromolaena odorata (L.) King and Robinson (Asteraceae)
- 9 Clidemia hirta (L.) D. Don (Melastomataceae)
- 10 Coccinia grandis (L.) Voigt (Cucurbitaceae)
- 11 Eichhornia crassipes (Mart.) Solms–Laub. (Pontederiaceae)
- 12 Lantana camara Linn. (Verbenaceae)
- 13 Mimosa diplotricha C. Wright ex Sauvalle (Mimosaceae)
- 14 Mimosa pigra L. (Leguminosae)
- 15 Parthenium hysterophorus L. (Asteraceae)
- 16 Passiflora mollissima (HBK) Bailey (Passifloraceae)
- 17 Pistia stratiotes L. (Araceae)
- 18 Prosopis species (Leguminosae)
- 19 Salvinia molesta D. S. Mitchell (Salviniaceae)
- 20 Solanum mauritianum Scopoli (Solanaceae)
- 21 Application of natural antagonists including arthropods to resist weedy Striga (Oranbanchaceae) in tropical agroecosystems
- 22 Biological control of weeds in India
- 23 The role of International Institute of Tropical Agriculture in biological control of weeds
- 24 The role of Secretariat of the Pacific Community in the biological control of weeds in the Pacific Islands region – past, present, and future activities
- Index
Summary
Introduction
Parasitic flowering plants are defined by the production of specialized nutrition-deriving structures, the haustoria, that form a functional link to their hosts. Species of Striga (witchweeds) are obligate hemiparasites, and connection to a host plant is fundamental for them to survive. Seeds of Striga cannot germinate until a ‘chemical’ such as strigol and sorgolactone exuded by the host root indicates the vicinity of a host. Host-recognition factors that can activate development programs in Striga spp. are termed xenognosins (Lynn et al., 1981). Atsatt (1977) proposed that parasitic plants probably use host defence chemicals as cues to stimulate the germination and growth of the haustorium, and which have originally evolved in the host to deter harmful organisms. Akiyama et al. (2005) suggest that plants release chemicals (sesquiterpene lactones) from their roots as signals fostering their symbiosis with arbuscular mycorrhizal fungi, and that these signals are used by Striga to detect host roots. Several strigolactones found in root exudates of various plant species (Yasuda et al., 2003) stimulated germination in seeds of Striga species under laboratory conditions.
Striga is an r-strategist; that is, it allocates lots of energy to produce large numbers of minute seeds to reduce the risk associated with host finding. Producing many minute seeds increases the chance that at least a few seeds will get close enough to the roots of a suitable host plant. Numbers of seeds per plant average 58000 in S. asiatica, and numbers over 200000 almost certainly occur in well-grown S. hermonthica.
- Type
- Chapter
- Information
- Biological Control of Tropical Weeds Using Arthropods , pp. 423 - 437Publisher: Cambridge University PressPrint publication year: 2009
- 1
- Cited by