Solving Africa’s Weed Problem: The Role of Herbicides

1. Solving Africa’s Weed Problem: The Role of Herbicides Leonard Gianessi, CropLife Foundation

2. Weedy Maize Field Weeds compete with crops for space, nutrients, sunlight and moisture reducing crop yields. Maize Yield Reduced 90%

3. Weed Free Period Required for Optimal Yields Days After Planting Cassava 84 Maize 56 Rice 42 Sorghum 35 Akobundu, 1987

4. In Malawi, one-third of the area planted to maize by smallholders is either left unweeded or weeded after the critical six weeks. Orr, Mwale & Saiti, 2002

5. In Zimbabwe, 21% of cotton farmers abandon more than 20% of their cropped area each year as a result of weed infestations. Mavudzi, et al, 2001

6. Handweeding is the Predominant Weed Control Practice in Sub-Saharan Africa • 50-70% of the labor in crop production is spent weeding. Chikoye, et al, 2007

7. Constraints on Timely Hand-Weeding • Women can be too tired or sick (malaria) • Fields can be muddy • Competing time demands: child care • Pregnancy

8. African Yields (Tons/hectare) Maize 8 1-2 Rice 4 1 Experimental Plots Average Farmer DeVries and Toenniessen, 2001 Tittonel, et al, 2007

9. In Africa, yield losses due to weeds range from 25% to total crop failure. The majority of farmers identify weeding as the major constraint in their farming systems. Vissoh, et al, 2004

10. Handweeding Permanently Deforms Women’s Spines To weed one hectare a woman walks 10 kilometers in a stooped position.

11. African Weed Control: Current Practice • 135 million hectares, 135 million women • 200 hours/hectare • 27 billion hours • 20-100% yield loss

12. Benefits of fertilizer use dependent on weed control • Certain weeds absorb nutrients faster than crops • Without weed control, increased fertilizer use leads to more weeds • Farmers reluctant to increase fertilizer use • Increased need for hand weeding • “Labor bottleneck” • Labor not available for applying fertilizers

13. Herbicide Use Markets • Highly developed (>90% acres treated) • US, Europe, Japan, Australia, Canada • Developing • China, India • Not Developing (<5% acres treated) • Sub-Saharan Africa

14. Herbicide Use Driver: Developed Countries Shortages of workers to weed fields starting around the 1950s-60s Herbicides greatly reduced the need for weeding by hand

15. California: Weeding Vegetable Crops 1940s ‒ 1960s

16. Hand Weeding

17. Japanese Rice Weeding: 1950s 500 Hand Weeding Hours/Ha : 1 Billion Hours Total

18. Japan: Weed Control in Rice • Herbicides replace the need for 1.89 million people weeding every day for 60 days in the summer all over Japan Matsunaka, 2001

19. Pesticide Use Drivers: Developing Markets Shortages of workers to hand weed fields Need to produce more food for growing population

20. Hand Weeding in China Millions of Farm Workers are Moving to Urban Areas

21. China Weed/Crop Status: 1980s 43 million hectares heavily infested 17.5 million tons of grain lost Weedy maize field in China

22. Herbicide Use: China Million Hectares

23. Rice in India Hand weeding

24. India: Crop Herbicide Market Phillips McDougal

25. The Spraying of Chemical Herbicides is an Alternative to Handweeding

26. Weeds Killed Before Planting With Herbicides -60 hours/hectare Handweeding +2 hours/hectare Herbicide Spray

27. Cotton Experiment: 4 Weeks After Herbicide Spray Herbicide Treated Untreated -254 hours/hectare Handweeding +1.5 kg/hectare of Chemical Lagoke, et al, 1992

28. Herbicide Experiment: Kenya Maize Yields +53% Bean Yields +94% Weedy Herbicide Treated

29. Maize Experiment: Kenya “Chemical weeding was one-third of the cost of two hand-weedings.” Maina, et al, 2003

30. Herbicide Use: Smallholder Farms • 1-5% use herbicides • Lack of training of farmers • Lack of training of Extension Service workers • Lack of spray services

31. “There are more weed scientists in the state of California than in all of Africa.” Akobundu

32. What is urgently needed is graduate-level education in weed science (at the masters and doctoral degree levels) for nationals in the region. There are many U.S. funded agricultural development projects in Sub-Saharan Africa with several universities as contributing institutions. Nearly all of them have training in agricultural economics, plant breeding, and agronomy, but hardly any of the projects have included training in weed science. Akobundu, 1991

33. Herbicide Use: Lack of Interest • Weeds are seen as “women’s work” • Governments don’t take seriously • International development agencies are reluctant to support pesticide strategies

34. Lack of knowledge is the most limiting factor in the adoption of herbicide technology. There is a need to train extension workers on herbicide technology, who would in turn train the farmer. If the smallholder farmers are given technical support, they would take advantage of herbicide technology and improve crop production. Makanganise, et al 1999

35. Training in Herbicide Application is Necessary • The incorrect herbicide applied at the incorrect time and/or rate • May not work to control weeds • May damage the crop • Safety and application

36. ZAMBIA Spray Service Provision Initiative SSP initiative was conceived in early 2008 by CropLife Zambia & USAID Aimed at promoting the responsible Use of Pesticides to approximately 50,000 Small Scale Farmers GROWING FOOD - CREATING RENEWABLES - SUPPLYING SUSTAINABLY

37. ZAMBIA SSP Training in the Field SSPs are selected from among the farmers Trained in all aspects of Responsible use GROWING FOOD - CREATING RENEWABLES - SUPPLYING SUSTAINABLY

38. ZAMBIA Spray Service Provision Result Sprayed for 4,800 fellow farmers Member companies reported increased sales in areas where the programme had been implemented. GROWING FOOD - CREATING RENEWABLES - SUPPLYING SUSTAINABLY

39. Adoption of herbicide technology among female farmers has also brought behavioral change as most of them have vowed never again to weed their crops using hand hoes. CARE Zambia, 2011

40. The increased use of herbicides also triggered the adoption of fertilizers, use of hybrid seeds and an increased practice of other restorative practices such as conservation farming. CARE Zambia, 2011

41. There was consensus among Spray Service Providers (SSP’s) that it took them only one hour to apply herbicides to one hectare of crop. This means that in a season, one SSP can take care of 78 hectares. Using hand hoes, 78 hectares would require 468 family members to weed for the whole month. CARE Zambia, 2011

42. Field Day – CLF/CNFA Project Over 3000 farmers visited the plots

43. Maize Plot – Herbicide Treatment Yield +26%; -150 Hours of labor/hectare; -50% Lower costs

44. Field Day Training in Herbicides at Agrodealer

45. Phil Stahlman, Kansas State University Volunteer Instructor, Malawi Weed Trials

46. Typical Agrodealer Train agrodealers to provide extension and spraying services

47. Conclusions • Herbicide use is inevitable in African crop production • Adoption is likely to come from farmer demand

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