Potato aphids are active in some fields in Southern Aroostook.  The incidence of potato aphids increased markedly on all our tower traps collected Monday of this week.

Seed growers should remember that potato plants are susceptible to PVY infection as long as there is green plant material visible.



Colonizing Aphid Recommended Economic Thresholds

  • Seed: 10% of plants with aphids, or 1 winged Green peach aphid
  • Processing/Tablestock: 50% of plants with aphids, or 1 winged Green peach aphid

Colorado Potato Beetle

Colorado potato beetles are active in all areas. Adult beetles and larvae are being found throughout our scouting range.

CPB Recommended Economic Thresholds

  • 25 Adults per 50 plants
  • 75 Large Larvae per 50 plants
  • 200 Small Larvae per 50 plants

European Corn Borer

It appears that peak moth flight may have come and gone with only a minimal activity being detected this year. There may be pockets of elevated activity within the growing area. The May snow may have disrupted the over wintering.

ECB Recommended Economic Thresholds

  • 60 moths in a 7-day period in a heliothis-style trap
  • 120 moths in a 7-day period in a black light-style trap
  • 1 egg mass per 15 plants surveyed

Flea Beetle

Some potato flea beetle activity is being reported in Central Maine and Aroostook County. All growers will want to be monitoring flea beetles. An average of 15 “shot” holes per terminal leaflet is the recommended economic threshold level for potato flea beetle damage.

Flea Beetle Recommended Economic Thresholds

  • Average 15 “shot” holes per terminal leaflet

Potato Leafhopper

Potato leafhoppers are in the production area. Significant numbers have not currently been detected. This insect is capable of causing major yield impacts especially during this dry season. An edge effect or pocket effect might first be detected within a field. This is a situation that needs to be watched closely especially during the bulking period.

Potato Leafhopper Recommended Economic Thresholds

  • 10 nymphs per 100 leaves surveyed


Tarnished Plant Bug

Tarnished plant bugs are being reported throughout our scouting range. Tarnished plant bugs have a piercing sucking mouthpart. When they feed, they inject a toxin into the potato plant. This feeding damage can cause a bronzing appearance to the leaves. Ontario has established 15 adults per 50 plants surveyed as an economic threshold.