Focus on... Weeds (part 1)

Weeds contribute to substantial crop losses in any farming system. But they are a particular challenge to smallholder farmers in the tropics and sub-tropics where resources are limited, species are especially difficult to control, and there is often little understanding of crop/weed interactions. Weed control is often the most demanding pre-harvest operation and accounts for as much as 60 per cent of the labour used in maize production in sub-Saharan Africa. This Focus On...Weeds will be divided between this and the next issue of New Agriculturist. This edition we focus on specific weeds including Imperata, Striga and Lantana.

Waging war on weeds in Vanuatu

Wild guava in Vanuatu's grassland can take over fields if left unchecked. But it does more than ruin the pasture - cattle can disappear in it too. Herbicide is expensive, so farmers have had to look for other, more affordable options...

Running wild

Wild rice is like a wolf in sheep's clothing in rice crops. And its similarities with domestic rice make it particularly difficult to control. The key is a long term integrated approach...

Spearheading Imperata control

Imperata cylindrica used to be controlled by long fallow periods, but increasing land pressure means that is no longer possible so farmers need to look at alternative control methods to avoid their land becoming infested. Chemical control is an option, but is it a practical alternative for smallholder farmers?

Awash with weeds

Farming on Zimbabwe's environmentally-sensitive vleis (wetlands) may be a contentious issue, but with their moist soils, the attractions of cultivating these areas are clear. However the potential of the soils is rarely reached as rice and maize intercrops are plagued by perennial weeds...

Strategies to stop Striga

Combating the parasitic weed Striga requires a comprehensive strategy combining resistant varieties with efforts to improve soil fertility. And genetic modification could provide an answer too...

Lantana camara action

Lantana camara was introduced to Africa as an ornamental, flowering shrub, but with its aggressive growth and ability to take over other species, its affect on the Victoria Falls rainforest in Zimbabwe is far from pretty...