Currant yellow sawfly

Nematus currani, commonly referred to as the currant yellow sawfly, is an insect belonging to the family Tenthredinidae of the order Hymenoptera. This pest is a significant concern for horticulturists, as its larvae are specialized feeders on the foliage of various berry bushes, primarily within the genus Ribes.

The primary host plants for this pest include black currant, red currant, white currant, and gooseberry. The sawfly is widely distributed in regions where these crops are cultivated, and its presence can lead to severe damage if left unmanaged, especially in private gardens and small-scale farms.

The biology of the sawfly is synchronized with the growth cycle of the host plants. The insect overwinters as a prepupa in a cocoon within the soil under the host bush. As spring temperatures rise and buds begin to swell, adult sawflies emerge to mate and lay eggs on the undersides of leaves, typically in rows along the major leaf veins.

The damage is primarily caused by the larvae, which are voracious eaters. Early larval stages create small, irregular holes in the leaves, but as they grow, they consume the entire leaf lamina, often leaving only the main veins. This extensive defoliation forces the plant to divert stored energy for leaf regrowth, which significantly reduces berry yield and quality for the season.

Effective management requires an integrated approach. Cultivation techniques such as soil cultivation beneath the canopy help destroy overwintering cocoons. During the growing season, monitoring is essential for early detection. Chemical intervention with approved insecticides should be timed carefully to protect pollinators and ensure that residues do not remain on the fruit at harvest time.

• Regular inspection of leaf undersides for egg batches.
• Fall soil tilling to disrupt the life cycle of the pupae.
• Application of bio-rational insecticides when larvae are small.
• Maintaining healthy plant vigor through proper fertilization.