This is a quick crop update that two occasionally damaging insects are now present in ginseng fields:

Leaf Folders

Leaf folder caterpillars (larvae of zigzag herpetogramma moths) have been found this week starting to roll up leaves and hide inside. They will be rolling up additional leaves over the next week. Now is the time to control them with insecticides. If you wait until the damage is obvious, the insects will be protected inside their rolls and no longer susceptible to insecticides. Leaf folders are a localized issue so scout fields to determine if or where sprays may be warranted. They are often worst near forested areas. Look for pale green caterpillars with a yellowish/orange head inside folded or rolled up leaf tips or edges (Figure 1). Caterpillars are 6-10 mm long at this time.

Figure 1. A zigzag herpetogramma leaf folder caterpillar.

Aphids are also present now, mostly on the developing flower stems (Figure 2). Aphids can also be localized and sprays should be based on scouting. Natural enemies like ladybird beetle larvae can sometimes control small populations and prevent significant damage without the need for a spray, but regular scouting is required to determine if populations are getting out of control.

Figure 2. Aphids on a ginseng flower stem.

Visit the Ontario Crop Protection Hub for registered control options.