Abstract: Good weed management strategy is based on good understanding of the intricate interactions involved in weed-crop association. Based on this assertion, field experiments were conducted to study the interference effect of Tithonia diversifolia on melon. Ten treatments were investigated in a randomized complete block experiment (RCBD) with three replications. Result showed that Tithonia interference reduced melon growth significantly (p = 0.05) with increasing length of interference. Tithonia interference in melon for smore than 4 weeks after planting (WAP) was as bad as not weeding at all while interference free period of not more than 2 WAP was equally inadequate and produced plants that were as stunted as those not weeded at all. Melon seed yield was significantly better when exposed to a minimum of 4 WAP Tithonia interference free period or a maximum of 2 WAP Tithonia interference than other treatments (p = 0.05). Highest seed yield (2825 kg ha-1) was produced by melon plants exposed only 2 WAP interference. However plot with the highest yield was not statistically significant to yield from melon plot with at least 6 weeks of initial weed freeness and the control plot (240, 2646 and 2627 kg ha-1, respectively) and for weed free melon plots of 6 and 8 weeks, respectively. Onset of crop/weed interaction affected both the dry matter and plant density of Tithonia significantly (p = 0.05). These parameters decreased with increased delay in the onset of crop/weed interaction. The implication of these findings is discussed.
O.S. Olabode , S. Ogunyemi and G.O. Adesina , 2007. Effect of Mexican Sunflower (Tithonia diversifolia (Helms) A. Gray) Interference in the Performance of Melon (Citrulus lanatus Thumb. Mansfd). Agricultural Journal, 2: 23-26.