Lygus nymphs: Which ones do you count?

August 6, 2015 - Issue 20

When doing lygus counts, include adults and late instar nymphs. Nymphs are young lygus, and only the larger nymphs do enough damage to be included in sweep net counts. A key feature is the black dots on the back. Count nymphs with developing windpads or dark shoulderblade. Don’t count them if they’re small and don’t have the any sign of a dark growth where wings will be developing soon.

These small nymphs don’t feed very aggressively, and they are vulnerable to heavy rains and wind that push them down in the canopy or to the ground where they drown or get eaten by other insects.

Count these lygus nymphs, which have telltale black dots, when doing sweep net counts for lygus. Source: Roy Ellis

Count these lygus nymphs, which have telltale black dots, when doing sweep net counts for lygus. Source: Roy Ellis

Don't count these tiny ones without the black dots. This photo was taken on a lined notepad to show the size. Source: Justine Cornelsen

Don’t count these tiny ones without the black dots or signs of growth where wings would be. This photo was taken on a lined notepad to show the size. Source: Justine Cornelsen

Here's a close up view of this early instar lygus. Don't count these. Credit: Dan Johnson

Here’s a close up view of this early instar lygus. Don’t count these. Source: Dan Johnson

Count this one. It is developing wingpads and has the black dots. Credit: Keith Gabert

Count this one. It is developing wingpads and has the black dots. Source: Keith Gabert

This close up of a third instar shows the wingpads developing on the back. Count these. Credit: Dan Johnson

This close up of a third instar shows the wingpads developing on the back. Count these. Source: Dan Johnson

Click here for more on lygus thresholds and when it pays to spray.


 

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