Title: Pesticide spraying of urban trees found to disrupt natural biological management of landscapes

[Beyond Pesticides, November 16, 2022] Putting up with moderate pest levels can attract and maintain predators and parasitoids that provide important biological control services throughout the landscape, according to research recently published in Environmental Entomology.

While scale insects can be a problem in urban areas, dropping sticky ‘honeydew’ on cars and structures, they also play a critical role in maintaining native populations of pest predators. Scientists at NC State University (NCSU) set out to understand just how important these pest populations are at maintaining their own natural enemies. To do so, researchers worked through a series of three hypotheses on the connection between urban trees, scale insects, and pest predators. Focus was first placed on investigating different oak species and comparing the number of predators between trees infested and not infested with scale. Twigs from willow oaks, sawtooth oaks, and overcup oaks were collected from scale infested and scale uninfested trees on the NCSU campus over the course of spring, and counted for their scale abundance. Then, through the summer, researchers used a sampling tool that effectively shook insects out of the tree and into a funnel collection.

Unsurprisingly, scale infested oaks contain more scale insects. But these trees also host significantly higher numbers of pest predators, with greater numbers of spiders, parasitoids, ants, and lady beetles found in infested oaks.

Original source



Article: WeedsNews5578 (permalink)
Categories: :WeedsNews:biological control, :WeedsNews:councils, :WeedsNews:ecosystem services, :WeedsNews:non-chemical control, :WeedsNews:trees
Date: 18 November 2022; 12:07:53 pm Australian Eastern Daylight Time

Author Name: David Low
Author ID: adminDavid