Over ten days into the summer, the capital’s swarming whiteflies have not appeared yet, but their arrival is almost certain as their host still exists in the city.
Tehran has been grappling with the invasion of an insect known as whitefly during the warm season for several years.
The tiny but numerous insects gradually appear from late spring days and remain in the city through summer. But this year, they have had a promising delay.
An entomology professor at Shahid Beheshti University believes that the abundant springtime rainfalls as well as reduction in environmental pollution are behind the delay in their arrival.
“Whiteflies depend on certain environmental conditions such as temperature, humidity and pollutants for each stage of their growth. The reason for their absence is the unfavorable conditions for them to lay eggs or hatch,” Shahrokh Pashaei Raad explained.
The frequent rainfalls in the spring have both decreased the insects’ eggs and delayed their larvae hatching out.
“Absence of rain and early increase in temperature over the past years had accelerated their growth,” he said.
Pollution sources, such as stagnant water, rubbish, food leftovers and rotten fruit and vegetables can provide a suitable breeding ground for the growth of insects including whiteflies, according to the professor.
Timely Measures
“Tehran Municipality’s timely measures in cleaning urban spaces and removing environmental pollution are among the causes of the reduction in whiteflies’ population,” he said.
He, however, noted that as their host plant, the white mulberry tree, still stands across the city, the denizens of Tehran cannot expect a bug-free summer.
“One cannot say they are extinct and will not cause nuisance this summer,” Pashaei Raad said.
He said specialized studies are required to determine the distinct species and the favorable living conditions for the capital’s whiteflies.
“There are various species of whiteflies each living in certain districts. For instance, a different type has developed around the lake in Chitgar Park where humidity is high,” he said, adding that knowledge of the bugs and the conditions where they can grow can help successfully control their population.
The best way to combat Tehran’s whiteflies is to identify their host and their adaptation method, he said.
