High efficacy of extracts of Cameroon plants against tomato late blight disease P. Goufo, C. Teugwa Mofor, D.A. Fontem and D. Ngnokam Agron. Sustain. Dev., 28 4 (2008) 567-573 Published online: 30 August 2008 DOI: 10.1051/agro:2008036