Abstract Polyethylene mulched bed widths (28, 56, 84 and 112 cm) with methyl bromide-chloropicrin gas mixture (67-33%, 280 kg/ha) soil fumigation were evaluated in 2 tests for soil pest control and production of tomato (Lycopersicon esculentum Mill.). In 2 other tests, methyl bromide-chloropicrin rates of 0, 70, 140, 210 and 280 kg/ha applied under a 112-cm wide mulched bed were evaluated. Populations of root-knot nematodes, parasitic soil fungi, and root-gall indices decreased with increases in mulched bed width. All fumigation rates resulted in decreased populations of root-knot larvae, Fusarium spp., Pythium spp., Rhizoctonia solani and root-gall indices compared with non-fumigated plots. In greenhouse tests, tomato seedlings emerged and survived best in potted soil from mulched plots with the widest bed and those treated with the highest rate of fumigant. Marketable tomato yields increased linearly with increased bed width in 1 test whereas yields were similar among treatments in the other tests.