Viburnum Leaf Beetle (VLB), Cornell University

Viburnum Leaf Beetle
Leaf feeding samples

The pictures of leaves below will help you estimate leaf-feeding damage.

Viburnum leaf
beetle home

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Logo images by Kent Loeffler, Paul Weston & Craig Cramer

Estimating leaf feeding damage can be a challenge. But don't decide not to do the leaf feeding observations just because you fear you won't be able to estimate the damage accurately. Just do the best that you can and try to be consistent. Slight errors are not a big problem.

The seemingly unusual scale below is designed to make it easier for you to make consistent estimates. Most people can readily distinguish between very slight damage and 10 percent damage; 10 percent and a quarter; half, or slightly more or slightly less than half; etc.

Percent damage estimates:

0 percent eaten - Leaf appears undamaged or very slightly damaged.
10 percent eaten - Slight damage, but not approaching a quarter of the leaf area.
25 percent eaten - About a quarter of the leaf is eaten.
40 percent eaten - Slightly less than half eaten.
50 percent eaten - About half eaten.
60 percent eaten - Slightly more than half eaten.
75 percent eaten - About three quarters of the leaf is eaten.
90 percent eaten - Nearly all of the leaf is eaten.
100 percent eaten - Leaf is largely gone, except for maybe a few major veins.

We measured the actual leaf feeding damage on the sketched below (actual damage percentages). Then we rounded them off to the nearest estimated damage percentages from the list above.


0 percent actual damage 0 percent estimated damage	3 percent actual damage 0 percent estimated damage

7 percent actual damage 10 percent estimated damage	9 percent actual damage 10 percent estimated damage

12 percent actual damage 10 percent estimated damage	22 percent actual damage 25 percent estimated damage

40 percent actual damage 40 percent estimated damage	48 percent actual damage 50 percent estimated damage

59 percent actual damage 60 percent estimated damage	68 percent actual damage 75 percent estimated damage

74 percent actual damage 75 percent estimated damage	93 percent actual damage 90 percent estimated damage

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Project coordinator: Lori Brewer, ljb7@cornell.edu
Website design: Craig Cramer cdc25@cornell.edu

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