FAO expert stresses weed menace

The back-breaking drudgery of hand weedingWeeds do not hit the headlines like droughts, insect plagues or even swine flu, but cause substantial human misery, quietly and constantly, notes one of the UN Food and Agriculture Organisation’s (FAO) most renowned weed experts. Ricardo Labrada-Romero quotes figures produced by leading environmental organisation Landcare Research (New Zealand) which indicate that uncontrolled weeds cause crop losses equivalent to 380 million tonnes of wheat every year. When FAO reckon that more than one billion people in the world are hungry, this has a huge impact. In terms of farmland needed to grow such a quantity of wheat, using a worldwide average yield of 2.8 tonnes per hectare (FAO, 2007 estimate), this equates to a staggering 135 million hectares (335 million acres), an area twice the size of France, wasted for food production.

Weeds cause most crop losses*

Equivalent Wheat Land Lost
                               (million ha)
Weeds                         135
Diseases                     121
Insects                            65
Birds, rodents, etc           3
          
*According to FAO quoting data from Landcare Research
Worse than this, three-quarters of crop losses due to weeds are in developing countries. Mr Labrada-Romero emphasises that total economic losses will be much greater because of the time spent in manual weeding in poorer countries. "With only manual labor available, African smallholders need to weed every day and that means a family physically can't handle more than 1 to 1.5 hectares," Mr Labrada-Romero explains. "But proper management would allow them to farm more land and grow more food." Modern weed management techniques involve the integrated use of herbicides, crop rotations, and using good quality crop seed not contaminated by weed seeds. The increasing problem of weed resistance

Description

The inherited ability of a plant/weed to survive a dose of a herbicide normally lethal to that species.

Authoritative On-line References and Resources

http://www.weedscience.org/in.asp The International Survey of Herbicide Resistant Weeds monitors the evolution of resistant species and assesses their impact. All confirmed instances of new cases are listed.
to over-relied upon herbicides is noted by Mr Labrada-Romero. There are now 16 common weed species around the world resistant to the most popular herbicide glyphosate. Other non-selective

Description

A chemical product used for eliminating all types of weeds (annual and perennial grasses and broadleaved weeds).

Authoritative On-line References and Resources

http://www.weeds.iastate.edu/ An invaluable source of contemporary information about herbicides and weeds from Iowa State University.
herbicides like paraquat with different modes of action should be used to ensure efficient food production in the fight against weeds and starvation.
For more information on weed resistance click here.