People, Environment

Tehran Measures to Control Whiteflies Inadequate

Whiteflies besiege Tehran every summer with the rise in temperature.Whiteflies besiege Tehran every summer with the rise in temperature.

Tehran Municipality's measures in the past few years to control the population of whiteflies besieging the Iranian capital have failed to put an end to their onslaught, said the head of the provincial office of the Department of Environment.

Speaking to ISNA, Mohammad Hossein Bazgir said despite TM's preemptive actions to slash their numbers in the past few years, "we've started to see whiteflies around Tehran with the rise in temperature".

Whiteflies have been a nuisance for Tehranis every summer in the last three years. The silver leaf whitefly is one of several whitefly species infamous for their devastating impact on farmlands and plants but they are harmless to humans.

Also called the "sweet potato" fly, these sap feeders reduce the overall vigor of plants with their feeding. As infestations become severe, they cause plants to yellow and lose their leaves prematurely.

Whiteflies also produce large amounts of sticky, sugary honeydew, which in turn is colonized by black sooty mold, reducing the attractiveness and marketability of whitefly-infested crops. Bazgir said multiple factors contribute to the Tehran's plight.

"In the absence of natural predators, the whiteflies spread freely across the city, which grows hot in the summer and is home to plants favored by the pests," he said.

These flies transmit over a hundred plant viruses, but based on studies by Tehran University of Medical Sciences and the Ministry of Health headquarters, the genus found in Tehran—called Aleuroclava, is a newly discovered type that fortunately does not carry plant viruses.

While the precise source of the pest problem is still unknown, some have attributed the rise in their numbers to global warming, while others have suggested that the bugs may have piggybacked to Tehran on imported plants or fruit.

To control their population without endangering public health, TM began employing a method known as integrated pest management about two years ago.

The University of California, a leader in IPM, defines the method as an eco-friendly strategy that focuses on long-term prevention of pests or their damage through a combination of techniques such as biological control, habitat manipulation and modification of cultural practices.

"Washing out the host plants and modifying trimming and pruning methods have been undertaken by Tehran Municipality, but clearly these are not enough," he said.

Bazgir believes that the best solution is to grow and release the pests' biological predators that are collectively known as parasitoid wasps.

Isa Farhadi, the governor of Tehran County, said last year a comprehensive plan that might give Tehran its best chance at effectively combating the whitefly swarm will be finalized before the summer of 2017, but no updates on the plan have been announced yet.


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