24 May 2011, Rome - FAO is stepping in to assist farmers in Iraq and Syria battle with silverleaf nightshade (Solanum elaeagnifolium), an invasive alien weed that sucks nutrients from the soil and starves crops of valuable water and whose berries can poison livestock if ingested.
A relative of the tomato originally hailing from tropical America, silverleaf nightshade has very deep roots and is also covered in spines, making it difficult to pull out of the ground.
The weed probably arrived in the Near-East as a result of globalization of trade, its seeds hidden in containers or in bags of agricultural commodities. It is spreading in the region on trucks and animals, or in crop seeds that have not been checked for quality assurance.
Cotton, wheat, olives threatened
More than 60 percent of the cultivated land in Syria, growing mainly cotton and wheat, has now been infested with the weed. Olive groves are also being affected and there is a big potential risk that silverleaf nightshade will soon spread to more lands.
In northwest Iraq a similar mass infestation has been reported and the weed has also been spotted in various sites in Lebanon and Jordan, where it will spread if nothing is done.
“This particular type of weed competes aggressively with crops for nutrients whilst its deep root system dries down soil moisture,” said Gualbert Gbèhounou, FAO Weed Officer.
Biodiversity is also reduced by the dominance of silverleaf nightshade, a particular concern in invaded areas. In its native tropical America habitats, silverleaf nightshade has many natural enemies which are not present in invaded areas, where it freely thrives.
Alfalfa as an option for control
On the request of the governments concerned, FAO is implementing a project to assist farmers manage and prevent further spread of silverleaf nightshade in all four countries.
“We want to introduce an integrated weed management approach, which means we will not focus on herbicides, although we might use them if we have to, but instead we would rather test sustainable alternative management possibilities,” said Gbèhounou.
The UN agency is recommendating that farmers rotate regular crops with the fodder crop alfalfa, which covers the ground and competes with silverleaf nightshade. This prevents the weed from producing new seeds and also reduces amount of weed seed in the soil.
FAO is also seeking to encourage countries to review their regulatory environments and collaborate to reinforce control of silverleaf nightshade at the national and regional levels.