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More Information about potato production in Cameroon

The World Potato Atlas Cameroon Chapter

1. Late blight occurrence and LB severity by major production area in the country. What crops were affected (tomato, potato, others)? Disease sources (seed, cull piles, volunteer plants, soil)

Late blight occurs in the highland areas of the west, northwest, southwest and Adamawa provinces. It is more severe in the wet season (March – October) than in the dry season (November – February), when early blight is more prevalent. Late blight is reported today as the most important disease of garden huckleberries (Solanum scabrum), potatoes and tomatoes (Fontem et al, 1999). Some varieties of the local eggplant (Solanum macrocarpon) are also susceptible (Fontem et al, 2001b). Source of infection is from leaves touching the soil, infected seeds or volunteer plants.

2. Disease impact on the industry, consumers and country

Yield losses caused by late blight foliage infection can reach 71% in potato (Fontem and Aighewi, 1993; Fontem, 1998; Fontem et al, 2001a), 100% in tomato (Fontem et al, 1996; Fontem 2003) and 45% in garden huckleberry (Fontem et al, 2003). Potato tubers in storage can be infected (Fontem, 1991).

3. Fungicide use (amounts, types, etc.)

With the increase in late blight severity, farmers may require a limited number of fungicide applications. Field trials were conducted to test the efficacy of three co-formulated Ridomil Plus* (12% metalaxyl + 60% cupric oxide), Galben Plus* (18% benalaxyl + 60% cupper metal) and Anteor Super*(9.6% cymoxanil + 40% copper metal) on late blight control. Results showed that Ridomil Plus is the most effective of the three fungicides (Nana, 2000). Maneb is the most used fungicide on tomato (Fontem et al, 1999).

4. Other LB control measures (resistant cultivars, forecast systems, none)

Genetic materials (clones and tuber families) were received from CIP, Lima. These are evaluated in different locations under conditions favorable to late blight development. The research sites used for late blight screening of potato genotypes include Babungo (1175 m), Santa (1700m), Upper Farm (2000 m), Mbiyeh (2400 m), and Nkongle (2500 m). The planting is scheduled such that the growing period of the crop coincides with the peak of the rainy season. This is to favor late blight development and selection of resistant genotypes.

Five potato clones (392280.10, 392217.26, 392242.17, 392221.39 and 380385.2) are being selected with promising yield and late blight reaction qualities. They out-yield Cipira and Tubira and will soon be released to replace both varieties. Clones 392280.10 and 392217.26 have late blight readings of 9% each at 75 days after planting, compared to 100% for Cipira and Tubira during the same period.

5. LB control effectiveness (fungicide or host resistance failures)?

In 1987, a collaborative research project was initiated between the Cameroon Institute of Agricultural Research for Development (IRAD) and the International Potato Center (CIP) to improve potato production in Cameroon.  About 100 clones were received from CIP in 1988 and evaluated in different environments for late blight resistance and other agronomic traits. In 1992, this project released three varieties namely Cipira (CIP Clone 381381.13), Tubira (381406.6) and Bamira (720055) that were adapted to local conditions, had high yields (>25 t/ha) and resisted late blight infection (Martin et al, 1994). Cipira and Tubira were eventually accepted by farmers and became important high-yielding late blight resistant varieties in Cameroon and potato seed was exported to neighboring countries. Both varieties are listed today among the most susceptible potato varieties (Fontem, 2001).

6. Pathogen population characteristics

Isolates of P. infestans were collected from tomato, potato and garden huckleberry and cross infectivity tests were carried out. The huckleberry isolates infected all three hosts in a similar way, while the potato isolates were more aggressive on potato. The tomato isolates varied in their aggressiveness, but infected the two other hosts. About 50% of all the isolates were metalaxyl resistant. (Fontem et al, 2001c)

7. Disease risks and/or major needs?

A major constraint is the cost, quality and availability of good seed.

8. Any publications on late blight in the country?

Foncho A F. 1989. Future plans and strategies for potato research in Cameroon. p. 33–41 In: Report of Workshop, Bamenda, Cameroon. 25–30 Sept. 1988.  

Fontem D A. 1991. An assessment of potato diseases in the western highlands of Cameroon. Biosciences Proceedings 2: 82–86.  

Fontem D A. 1993. Survey of tomato diseases in Cameroon. Tropicultura 11:87-90.

Fontem D A. 1998. Dynamics and Integrated Management Potato Late Blight in Cameroon. Ph.D. Thesis. University of Benin, Lome, Togo. 161 p.

Fontem D A. 2001. Influence of rate and frequency of Ridomil Plus applications on late blight severity and potato yields. African Crop Science Journal 9:235–243.

Fontem D. A. 2003. Quantitative effects of early and late blights on tomato yields in Cameroon. Tropicultura 21 (1): 36-41.

Fontem D A and B Aighewi. 1993. Effect of fungicides on late blight control and yield loss of potato in the western highlands of Cameroon. International Journal of Pest Management 39: 152–155.

Fontem D A, M Y D Gumedzoe, R Nono-Womdim and R T Opena. 1996. Impact of early and late blights on the yield of tomato in Cameroon. TVIS Newsletter 1:7–8.

Fontem, D A, M Y D Gumedzoe and R Nono-Womdim. 1999. Biological constraints in tomato production in the western highlands of Cameroon. Tropicultura 17:88–92.

Fontem D A, M Y D Gumedzoe and M O Olanya. 2001a. Quantitative effects of late blight on potato yield in Cameroon.  African Crop Science Proceedings 5: 449-453.

Fontem, D A., B F Njualem, and M Olanya. 2001b. Reaction of solanaceous and asteraceous species to Phytophthora infestans, causal agent of potato late blight. Biociences Proceedings 8: 354-362.

Fontem, D A, G R. Tsopmbeng Noumbo, M A P Owona, and M O Olanya. 2001c. Infectivity and sensitivity to metalaxyl of Phytophthora infestans isolates from huckleberry, potato and tomato. Biociences Proceedings 8:341-353.

Fontem, D A and J Sofa. 2001d. Impact of chemical fungicides and cowdung filtrates on late blight severity and tomato yields. African Crop Science Conference Proceedings 5: 473-477.

Fontem D A, Songwalang A T, Berinyuy J E and Schippers R R. 2003. Impact of late blight on huckleberry yields in Cameroon. African Crop Science Journal 11: (3) 163-170.

Martin C, P Demo, D Njualem, T Gass and C Ntonifor. 1995. Late blight resistant varieties for Cameroon. American Potato Journal 72:513–522.

Nana F, 2000. Effect of co-formulated fungicides (Anteor Super, Galben Plus and Ridomil Plus) on late blight management in seed and ware and potato fields. Mémoire d’Ingénieur Agronome. Université de Dschang. 47 p.

Russel E J. 1954. Potato blight in West Africa. Empire Journal of Experimental Agriculture 22:19–22. 

9. Is tuber blight an increasing problem?

Tuber blight is an important problem, especially during storage. Late blight tuber blight is often associated with gangrene, Fusarium dry rots, and bacterial soft rot infections (Fontem, 1991). Blight incidence may reach 21% for tubers stored for up to two months without prior sorting or chemical treatment (Fontem, 1991).

10. Other comments

We are in the process of testing plant products (crude extracts and essential oils) for fungitoxicity to the mycelial growth of P. infestans. We hope to find environmentally friendlier products that can be used for late blight management in garden huckleberries, potatoes or tomatoes. We have tried compost extracts (cowdung filtrates) but did not have any positive control of late blight in the field (Fontem and Sofa, 2001d).

Prepared by Dominic A. Fontem, University of Dschang. Email: dfontem(at)yahoo.com

Links to World Potato Atlas (WPA)

http://research.cip.cgiar.org/confluence/display/wpa/Cameroon