A NEW phenomenon in the flood-affected parts of Sindh merits the authorities’ attention. On April 8, this newspaper published a photograph taken in a still-inundated part of Khairpur Nathan Shah, depicting trees cocooned in what appears to be a dense, cloud-like film resembling a spider web. Their appearance led local people to conjecture that spiders, displaced by floodwater, had taken refuge in the trees. No effort has been made to call in experts and determine what organism is responsible. This exercise must be undertaken, however, for the infestation may involve a hardy parasite. A senior botanist has pointed out that this phenomenon is more likely to be the work of spider mites, which are entirely different from spiders. Spider mites damage and kill plant cells; the web is there to protect their colonies against predators, not to capture insects. A single mature female spider mite can spawn a million-strong colony in less than a month. Their rapid reproductive cycle allows the species to adapt and become resistant to pesticides. Consequently, an infestation can lead to the large-scale death of trees.

Worryingly, most of the trees thus affected in Sindh are of the Acacia Nilotica species, referred to as the golden tree of Sindh due to its environmental suitability. High-density plantations of the species, which is considered a very productive forest system, have been cultivated along the plains of the River Indus. It bodes ill for the environmental health of the area if they are in danger. While spider mites are not unknown in Pakistan, it is possible that the effect of the floods was to concentrate and restrict their colonies to certain areas where Acacia Nilotica trees became easy prey. The Sindh Forest Department must ensure that steps are taken to counteract any danger.