Rice

• Conclusions and Recommendations of the FAO Global Workshop on Red Rice control
• Reducing herbicide use with agronomic practices in onion grown after rice
• FAO Workshop on Echinochloa Control, 27 May 2001, Institute of Plant Protection, Beijing, China

Conclusions and Recommendations of the FAO Global Workshop on Red Rice control

(Varadero, Cuba, 30 August- 3 September 1999)

1. There is an evident increase in red rice incidence in many rice producing countries, due to the increase of direct-seeded areas.
2. The Global workshop suggests using the term weedy/ red rice instead of red rice because there are several biotypes with white pigmentation which interfere with rice cropping.
3. Most of the countries attending the global workshop have data on different biotypes of weedy/red rice and their characterization. It is extremely important that all countries affected by this pest make efforts to characterize existing biotypes and their behaviour in field conditions, data that will later serve to improve measures for the control of this weed.
4. There are others countries where the magnitude of the problem posed by weedy/red rice has not been estimated and/or studied, e.g. Senegal and other countries in West Africa. However, in these countries studies have been carried out regarding the negative incidence of some endemic wild Oryza species, such as O. barthii, O. longistaminata and O. punctata.
5. There is no simple method for the control of weedy/red rice. Only through integrated control approach reduction of weedy/ red rice infestation can this be effectively achieved.
6. The main sources of weedy/red rice infestation are rice seeds contaminated with weed seeds and weedy/red rice seed bank in soil. Therefore any control measure should be aimed at reduction of infestations from these sources.
7. In some countries the presence of some weedy/red rice seeds is tolerated in rice seeds. However, experience on the control of this weed from other countries that use advanced technologies shows that not even one single weedy/red rice seed should be tolerated in rice seeds.
8. National institutions and those in charge of seed production should make every effort to produce rice seeds free of weedy/red rice seeds. It is also important to create awareness at the rice farmer level about the incidence of weedy/red rice and the importance of its control in order to improve yields and yield quality and to increase incomes.
9. The reproduction of basic and foundation seed should be carried out in areas that are totally free of weedy/red rice infestation. Certified rice seeds should be free of weedy/red rice seeds.
10. Control measures against weedy/red rice in the field are diverse and their implementation will depend on the specific site conditions. However, any control measure should be aimed at reduction of weedy/red rice seed bank in soil in the medium or long term.
11. To date the most efficient control measures have been those based on the combination of wet soil preparation to bring about the emergence of weedy/red rice seeds, followed by the application of herbicide over the weed stand and before rice seeding, e.g. glyphosate, and water management before and after seeding.
12. Under upland and irrigation conditions, it is advisable to implement, whenever possible minimum tillage or zero tillage combined with the use of non-selective herbicides. This practice is cheap and sustainable by rice farmers.
13. For better development of weedy/red rice control it is important to determine the socio-economic factors affecting the adoption of some optimal control measures.
14. Within the context of integrated management it is necessary to conduct regular studies of the behaviour of available rice cultivars in terms of their ability to compete with weedy/red rice, life-cycle and tolerance to submersion during flooding.
15. The use of post-emergence herbicides in the process of land preparation needs improvement. It is necessary to find other chemical alternatives in order to avoid repeated use of the same chemical. This also applies to post-harvest application in rice areas.
16. The socio-economic feasibility of crop rotation in areas with high infestations of weedy/red rice should be studied in order to improve the methods for controlling the weed and also preserving soil fertility.
17. It is also advisable to make a more in-depth study of the effect of water management and fertiliser application on weedy/red rice infestations in different soil conditions.
18. Generally all research on this topic should aim at sustainable reduction of weedy/red rice seed bank in soil through integrated control procedures.
19. A web page on weedy/red rice is considered a good option for good exchange of experiences on this area of pest management. The workshop suggested locating this web page at the University of Turin, Italy, under the leadership of Dr Aldo Ferrero, possibly financed by the European Union project on weedy rice. This web page could have as its main objective the publication of a database of the institutions, personnel and available results on weedy/red rice control.
20. The need to develop more activities related to farmer's education on weedy/red rice control is evident. To this end, it was suggested that technical assistance could be given by FAO to implement a regional project (e.g. in Latin America). It is obviously important that relevant authorities from the countries give priority to the solution of this problem in rice and officially request assistance from FAO.
21. Due to the magnitude of the weedy/red rice problem in several countries and its increased incidence, it was suggested that working groups on this subject be set up within the framework of existing weed societies, such as IWSS, EWRS, SWMH and others. Such working groups should stimulate research in order to find new control solutions.

Reducing herbicide use with agronomic practices in onion grown after rice

A.M. Baltazar, E.C. Martin, M.C. Casimero, F.B. Bariuan, S.R. Obien and S.K. De Datta

Summary

Studies to evaluate the effect of various agronomic practices on weed growth and on yields were conducted in Nueva Ecija during the 1996-97 and 1997-98 dry seasons in farmers' fields grown to transplanted bulb onion (Allium cepa L.) or shallot after rice (Oryza sativa L.).Treatments ranged from a single cultural practice (mulching, tillage,

Source: The Philippine Agricultural Scientist, Vol. 83, No.

1,pp34-44, Jan-Mar, 2000.