Abstracts on Sustainable Agriculture (GTZ, 1992, 423 p.): Abstracts on plant protection: 8. Activity of four plant leaf extracts against three fungal pathogens of rice.

Abstracts on Sustainable Agriculture (GTZ, 1992, 423 p.)

Abstracts on plant protection

		Acknowledgements
		1. Designing integrated pest management for sustainable and productive futures.
		2. Biotechnology's bitter harvest: herbicide-tolerant crops and the threat to sustainable agriculture.
		3. Chemistry, agriculture and the environment.
		4. Mise au point de techniques appropriées de lir qui seront utilisés par les petits agriculteurs traditionnels d'Afrique tropicale.(developing appropriate ipm technology for the traditional small-scale farmer in tropical Africa).
		5. Biological control in developing countries: towards its wider application in sustainable pest management.
		6. Transforming plants as a means of crop protection against insects.
		7. Utilization of va-mycorrhiza as a factor in integrated plant protection.
		8. Activity of four plant leaf extracts against three fungal pathogens of rice.
		9. A useful approach to the biocontrol of cassava pathogens.
		10. Evaluation of the biological activity of flax as a trap crop against orobanche parasitism of vicia faba.
		11. Insect pest management.
		12. Economic contributions of pest management to agricultural development.
		13. The effects of intercropping and mixed varieties of predators and parasitoids of cassava whiteflies (hemiptera: aleyrodidae) in Colombia.
		14. Prospects for traditional and cultural practices in integrated pest management of some root crop diseases in rivers state, Nigeria.
		15. Studies on cowpea farming practices in nigeria, with emphasis on insect pest control.
		16. Effect of various fertilizers and rates on insect pest/pearl millet relationship in Senegal.
		17. Insect pests of intercrops and their potential to infest oil palm in an oil-palm-based agroforestry system in India.
		18. Using weather data to forecast insect pest outbreaks.
		19. Insect pest management and socio-economic circumstances of small-scale farmers for food crop production in western Kenya: a case study.
		20. Rodent communities associated with three traditional agroecosystems in the San Luis potosi plateau, Mexico.
		21. Grain storage losses in Zimbabwe.
		22. Controlling weeds without chemicals.
		23. Weed management in agroecosystems: ecological approaches.
		24. Manual on the prevention of post-harvest grain losses.
		25. Evaluation of efficient weed management systems in pigeonpea (cajanus cajan l.)
		26. Weed management in a low-input cropping system in the Peruvian Amazon region.
		27. Poblaciones, biomasa y banco de semillas de arvenses en cultivos de maiz zea mays l. Y frijol phaseolus vulgaris l. Efecto de m+todos de control y rotaciones. (Weed population, biomass, and seed bank in maize and bean crops. Effects of control methods and crop rotations).
		28. Effects of groundnut, cowpea and melon on weed control and yields of intercropped cassava and maize.
		29. Intercropping and weeding: effects on some natural enemies of African bollworm, heliothis armigera (hbn.) (lep., Noctuidae), in bean fields.

8. Activity of four plant leaf extracts against three fungal pathogens of rice.

Trop. Agric. (Trinidad), 68, 4, 1991, pp. 373-375

With a view to countering obvious pollution problems in the environment and avoiding the toxic effects of synthetic chemicals on non-target organisms, investigations on exploiting pesticides of plant origin are becoming increasingly important in the field of plant pathology.

Fresh leaves of P. betle, O. sanctum, N. arbor-tristis and C. limon were collected, washed thoroughly in tap water and sterile distilled water, oven dried at 45 _ 2 C and ground to obtain 1 kg dry powder from each.

Each powder was extracted with 95% ethanol and concentrated through a rotary vacuum pump flash-evaporator to a syrupy form weighing 130 g from each powder.

The plants were selected for the present study to screen against the major fungal pathogens of rice in vitro and in vivo.

The leaf extracts were effective in reducing the radial in vitro growth was found to be the best, followed of the pathogens and in checking the spread of blast, brown spot and sheath blight diseases of rice in vivo.

Though the leaf extracts from the other two plant species tested (N. arbor-tristis and C. limon) reduced the radial growth of the pathogens in vitro at a higher concentration, they failed to check their spread effectively in the glasshouse. P. betle and O. sanctum could be used as source of a pesticide of plant origin to combat the above three pathogens of rice in the field.

This is the first record for the control of three rice diseases in vivo using P. betle or O. sanctum leaf extracts.

Much of the plant kingdom still remains unexplored for possible exploitation against major fungal pathogens.

1202 92 - 10/129

Plant protection

Study, cassava, pathogens, biocontrol, CIAT

LOZANO, J.C.