Allelochemicals Biologica... - Name

ALLELOCHEMICALS : MANAGEMENT OF PLANT-PARASITIC NEMATODES 17
and environmental factors contribute to the inconsistency of nematode control observed
in research trials on crop rotation and cover crop systems, biofumigation, and
biochemical pesticides. It is likely that synthetic chemical nematicides will continue
to fill short-term nematode control needs while research continues to improve
nonchemical and biopestide-based approaches, which will eventually become the
management strategies of choice (Thomas, 1996). In this chapter we will review
examples of plants known to release allelochemicals into soil while actively growing,
when incorporated into soil as green manures or organic amendments, and the direct
application of purified allelochemicals or formulations of biopesticides for plantparasitic
nematode control.
2. ROTATION AND COVER CROPS
There are many examples of crop rotation sequences that passively suppress nematode
populations which will not be reviewed here. Examples of active nematode suppression
in crop rotation sequences are typically found with plant species that produce and
excrete allelopathic compounds. These compounds then affect plant-parasitic
nematodes in the rhizosphere either directly or indirectly by altering rhizosphere
microbial populations (Halbrendt, 1996). For the purpose of this chapter, allelopathic
Table 1. Rotation/cover crops that actively suppress
parasitic nematode populations in soil.
Common Name Scientific Name References
American joint vetch Aeschynomene sp. Rodriguez-Kabana et al., 1991a
Bahia grass Paspalum spp. Rodríguez-Kábana et al., 1994b
Castor bean Ricinus communis Rodriguez-Kabana et al., 1991b
Marigold Tagetes spp. Tyler, 1938
Steiner, 1941
Uhlenbroek and Bijloo, 1958, 1959
Good et al., 1965
Hairy indigo Indigofera hirsuta Rodriguez-Kabana et al., 1988b
Horse bean Canavalia ensiformis Rodriguez-Kabana et al., 1992b
Partridge pea Cassia fasciculata Rodriguez-Kabana et al., 1991a
Rodriguez-Kabana et al., 1995
Sesame Sesamum indicum Rodríguez-Kábana et al., 1994a
Showy clotalaria Crotalaria spectabilis Rodriguez-Kabana et al., 1992b
Sorghum-sudan grass S. bicolor X S. vulgare var. sudanense Kinloch and Dunavin, 1993
Sudan grass Sorghum vulgare var. sudanense Mojtahedi et al., 1993a
Sunn hemp Crotalaria juncea Sipes and Arakaki, 1997
Robinson et al., 1998
McSorley et al., 1999
Wang et al., 2001
Velvet bean Mucuna deeringiana Rodriguez-Kabana et al., 1992a
Weaver et al., 1993
Taylor and Rodriguez-Kabana, 1999
Vargas-Ayala and Rodriguez-Kabana, 2001
Vetch Vicia spp. Minton et al., 1966
Minton and Donnelly, 1967