Good programme. My congratulations. Managing a cassava/tapioca/yuca farm in the Americas, I find this dialogue to be particularly interesting. Weed management does, in fact, represent the major part of the cost of production (30-55% in my own experience). Using an approach of alternating herbicide and hand weeding management at the most "opportune" moment during the nine month crop cycle (again in my experience) is key to successful (feasible) production. In contrast to the cultivation of the world's major cereals in temperate climes, the equatorial tropics have: relatively higher year round temperature, light intensity, humidity and a wide range of aggressively adapted plant weed species with rapid rates of growth. These factors, along with the fact that the major agro-chemical companies are yet to develop selective herbicides based around Euphorbiaceae (cassava family) commercially, means that cassava as a major agro-industrial crop requires some major research and development work before it can become globally competitive with corn, wheat or soya as a source of dietary starch, rather than being a culturally indigenous food staple; the niche it currently occupies. Returning to the core topic of weed management, from my own observation and experience, I believe there could be the possibility that cassava may exhibit some "positive allelopathy" (actively promote nearby plant/weed stands). In many instances after proper tillage practice, ridging and highly controlled pre-emergent application, weed loads at 8-10 weeks post germination are seemingly higher than even fields in fallow (even in the presence of drip irrigation in the dry season). I hope to set up some tangible, sound field experiments tp investigate same, but the bioassay of the interaction (if any) would be something way beyond my capacity
