Currant Borer

What it looks like

Adults are small, blue-black moths with clear wings and yellow bands, so they look like wasps. Larvae are whitish caterpillars with a brown head, about 1/2 inch long.

Damage

Larvae bore down the center of canes and hollow them out. Infested canes wilt, leaf out weakly, and break easily. Yields drop.

How nematodes help

The caterpillars live inside the canes, not in the soil, so nematodes must be sprayed onto the base of the canes and into cut ends.

In Australia, growers successfully used S. bibionis against this borer in commercial currant fields. That nematode is now counted as S. feltiae, the nematode in Scanmask. In field trials, S. feltiae also controlled 77 to 93% of related clearwing borers.

In university research, the timing that worked best was late summer to fall, after the eggs hatch and the young caterpillars bore into the canes, and early spring, before they finish feeding.

How to apply

Treat with Scanmask.

When: March to September.

Where: Spray the canes, especially near the base and any cut or pruned ends, until wet. Prune out and destroy wilted canes.

See How to apply for step-by-step directions, or use the calculator on the Scanmask Spray page to see how much you need.