ALECTRA VOGELII PDF

Prevention and control Cultural Control Two options, catch and trap-cropping, are available for reducing the size of the A. Catch-crops are susceptible species which are ploughed in or harvested after parasite attachment but before emergence and seed production. A catch-crop of a cultivar of cowpea suitable for use as fodder has been recommended in South Africa Hattingh, This would be cut and the roots destroyed by ploughing when about two months old and when A. In a season of good rainfall, a quick-maturing crop of sunflower could then be grown with cowpea planted again in the following season. Trap-crops produce the Alectra germination stimulant in their root exudates but are not susceptible to attack by the parasite seedlings.

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It will only grow in association with a host and is of no ornamental value. The leaves of A. However, in Cameroon and West Africa, leaves of the two species are similar. Both species are known from the same areas of Cameroon and Malawi and in Malawi both have been observed growing in the same row of groundnuts. The host range is almost entirely on weeds or natural vegetation, especially the Compositae Parker, Furthermore, A. This species is occasionally found growing on tobacco and sunflower in southern Africa.

It grows up to 1 m tall. Prevention and Control Top of page Due to the variable regulations around de registration of pesticides, your national list of registered pesticides or relevant authority should be consulted to determine which products are legally allowed for use in your country when considering chemical control.

Cultural Control Two options, catch and trap-cropping, are available for reducing the size of the A. Catch-crops are susceptible species which are ploughed in or harvested after parasite attachment but before emergence and seed production. A catch-crop of a cultivar of cowpea suitable for use as fodder has been recommended in South Africa Hattingh, This would be cut and the roots destroyed by ploughing when about two months old and when A. In a season of good rainfall, a quick-maturing crop of sunflower could then be grown with cowpea planted again in the following season.

Trap-crops produce the Alectra germination stimulant in their root exudates but are not susceptible to attack by the parasite seedlings. In Botswana, grain or fodder cultivars of pearl millet and bambara, which is not attacked by the local biotype of the parasite, are potent stimulators of A. These can be used in a rotation to cause suicidal germination of the parasite and hence reduce the number of seed in the soil Parker and Riches, Improved cowpea cultivars which combine resistance to A.

These are not, however, resistant to biotypes of A. The Botswana landrace accession B has been shown to be resistant to samples of the parasite from Botswana, Malawi and Kenya, so could be used as a parent for breeding improved cultivars for East and southern Africa Riches et al.

Fite reports on resistant landraces from Botswana, and finds that cultivars with thicker stems are negatively correlated with Alectra infection. Omoigui et al. Potentially useful levels of resistance have also been demonstrated in germplasm of bambara Riches et al. Karanja et al. Kwaga et al. However, Beck found that hand pulling did not directly improve the yield of an infested bambara crop and this is likely to be the same for other susceptible species, as the majority of damage occurs before the parasite emerges above ground.

Prompt ploughing of crop residues after harvest will prevent continued seed production as host plants continue to grow on residual moisture. Biological Control No research has been reported on the development of biological control agents for A. Chemical Control A. Little attention has therefore been given to the development of chemical control. The potential for controlling the weed by treating cowpea seed with the herbicide imazaquin before planting has been demonstrated but this practice has not been commercialized Berner et al.

Magani and Lagoke report that farmers can reduce cowpea infection by A. IPM Programmes Integrated control should be built around the use of resistant crop cultivars if possible, or choice of the least susceptible cultivar that is currently available. Timely destruction of legume crop residues is important to prevent parasite seed production after harvest and trap-crops should be included in the rotation to reduce the soil seed bank.

Hand-pulling should be carried out on lightly infested areas, particularly in fields which have not previously had a history of infestation. References Top of page Anota T, Le Striga au Zaire.

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