Web-spinning cherry sawfly

Systematic position: Neurotoma nemoralis, commonly known as the web-spinning cherry sawfly, belongs to the order Hymenoptera and the family Pamphiliidae. This insect is a significant defoliator in stone fruit orchards, characterized by the creation of elaborate silk-web nests on the foliage of host trees.

Host plants: This pest primarily affects stone fruit trees, including cherries, sweet cherries, plums, peaches, and apricots. While it has a preference for specific species, the infestation level can vary depending on local ecological conditions and the proximity of suitable host trees.

Biology and life cycle: Adult sawflies emerge in the spring, typically during the flowering period of their host trees. Females lay eggs on the undersides of leaves. Upon hatching, the larvae immediately construct silk nests, within which they live in colonies, feeding on the foliage. After maturation, the larvae descend to the soil, creating subterranean chambers to overwinter as pupae.

Nature of damage and pest significance: The damage is primarily caused by the larvae, which consume leaf tissue while protected by their silk webs. Heavy infestations can lead to severe defoliation, leaving only the veins behind. This loss of foliage reduces the tree's photosynthetic capacity, weakens its overall vigor, and may lead to poor fruit quality and reduced yield.

Control measures: Effective management strategies include:

• Manual removal and destruction of silk nests in small orchards.
• Application of contact or systemic insecticides during the peak larval hatching period.
• Deep cultivation of the soil around the base of trees in autumn to disrupt overwintering sites.
• Monitoring adult flight periods using yellow sticky traps to time treatments accurately.