Pathogenicity of Fusarium oxysporum f. sp. lycopersici (Sacc.) Isolates in Causing Tomato Wilt Disease on Two Tomato (Solanum lycopersicum L) Varieties

Abstract

Pathogenicity test of Fusarium oxysporum isolates in causing tomato wilt disease (TWD) was carried out on two tomato varieties (UC 82B and Rio-grande) in a screen house located at the Teaching and Research Farm of Federal University of Agriculture, Makurdi during 2015 cropping season. The experiment was a 2 x 11 factorial laid out in Completely Randomized Design (CRD) and replicated three times. F. oxysporum isolates tested were coded as: FoAs1, FoAs2, FoAg, FoNb, FoSb, FoAm, FoAk, FoOr, FoAd and FoUAM together with an uninoculated control. All the isolates of F. oxysporum tested were pathogenic, causing wilt on the plants from 3 weeks after inoculation (WAI), with severity of wilt been significantly higher (P≤0.05) in FoUAM. Isolates of F. oxysporum showed significant difference (P≤0.05) both in incidence and severity compared with the control. Effect of F. oxysporum isolates on some agronomic characteristics such as plant height, number of fruits, fruit weight and number of branches on the two varieties of tomato at 12 weeks after sowing (WAS) was significantly different (P≤0.05) with the control experiment. Highest severity score of 5.00 was calculated in FoUAM while the least of 4.33 was in FoSb compare with uninoculated value of 2.50. It is therefore, concluded that the two tomato varieties are pathogenic to F. oxysporum isolates and illicit disease in tomato hence reduced the yield of the crop.