Giant sensitiveplant interference at different population densities in cassava established at 10,000 plants ha⁻¹ was investigated on a Ferric Luvisol in a humid tropical environment. Interference for 12 mo was compared at 0, 10,000, 20,000, 30,000, and 40,000 plants ha⁻¹ and at natural populations (averaging 630,000 plants ha⁻¹) in four randomized complete blocks. Results showed that the order of cassava growth parameter response to giant sensitiveplant interference for 12 mo was leaf number > height > stem girth > leaf size = petiole length. The natural population density of giant sensitiveplant reduced growth faster and more than populations of 10,000 to 40,000 plants ha⁻¹ in cassava. All giant sensitiveplant populations from 10,000 plants ha⁻¹ and higher reduced storage root yield in cassava 12 mo after planting. Yield reduction increased as giant sensitiveplant population increased and the highest reduction of 85% occurred in the natural population of giant sensitiveplant.

Nomenclature: Cassava, ‘TMS 30572’, Manihot esculenta Crantz; giant sensitiveplant, Mimosa invisa Mart. MIMIN.