As experienced growers will already know, the risks of all foliar diseases of ginseng along with Phytophthora root rot are high following the heavy rains. Ensure protection from foliar and root Phytophthora, Alternaria and Botrytis at this time.  Disease pressure will be especially high in frost damaged gardens. Other preventative measures include:

• avoid travelling through gardens with standing water
• avoid travelling through gardens when the foliage is wet
• clean and sanitize boots and machinery before entering a new garden
• scout regularly to watch for disease symptoms (consult OMAFRA Publication 848 Guide to Ginseng Production for more information on each disease) and re-apply pest control products as necessary
• increase air flow through gardens if possible to encourage drying of the leaves and soil

Don’t forget about insects and slugs. Leafrollers and cutworms have been found in ginseng gardens this week.  Leafroller damage can be mistaken for Phytophthora damage if viewed from a distance (leaves hanging straight down – see Figure 1 and 2) so it is important to look at them closely. There will also be an increased slug risk at this time as well.

Figure 1. Leafroller damage on ginseng. Note the chewed leaves and the lack of a water-soaked appearance.

Figure 2. Phytophthora leaf blight damage.