Tropicultura (Jan 2004)

Effects of Crop Sanitation and Ridomil MZ Applications on Late Blight Severity and Tomato Yields in Cameroon

  • Younyi, PC.,
  • Fontem, DA.,
  • Suh, MN.

Journal volume & issue
Vol. 22, no. 3
pp. 122 – 126


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Tomato (Lycopersicon esculentum) production in Cameroon is usually handicapped by late blight caused by Phytophthora infestans. A field trial was conducted during 1997 in Dschang, Cameroon, to assess the effect of Ridomil MZ (8% metalaxyl + 64% mancozeb) sprays, and sanitation (a weekly picking of diseased leaves) on late blight development and yield of five tomato varieties. Plots received Ridomil MZ (2.5 kg/ha) and sanitation singly or combined. Control plots were neither sprayed nor cleaned from diseased leaves. All treatments were applied ten times in a weekly schedule. Late blight intensity was assessed every 7 days and marketable fruit yields were obtained at maturity. Differences in late blight intensity between sanitation and control plots were not significant (P= 0,05). Fungicide treatments were more effective than sanitation in reducing late blight severity. Percent fruit infection was 100% in control or sanitation plots of ARP I366-1, ARP D1, ARP D2, Roma, and no marketable fruits were harvested on these treatments. Late blight was less severe on Mecline compared to the other varieties. Consequently, Mecline out-yielded Roma, ARP I366-1, ARP D1 and ARP D2 varieties. Results suggest that the fungicide-alternative method of late blight control, using sanitation is not as effective in tomato late blight management as appropriate fungicide sprays.