Lace Bugs

Lace bug damage is not noticed until late in the summer.

The stippling causes yellow pinpoints in the leaves. When there is extensive damage, leaves appear yellow.

Note: Evergreen shrubs with lace bug damage now will show damage until leaves drop in two years.

Lace bug damage is distinguished from mite damage by dark specks of excrement on the underside of the leaves. Similar damage is caused by greenhouse thrips, so inspection is necessary to differentiate between the two. Lace bugs have lacelike wings, and thrips are diffi cult to see.

Females lay eggs partially into the plant tissue, hidden under excrement. Wingless nymphs are seen with the adults. There are several generations in a year. Adults overwinter under bark plates, making it diffi cult to have effective control in the dormant season. As soon as temperatures are favorable, we will begin monitoring for lace bug activity.

What you can do

• Help increase plant vigor through proper irrigation and plant care. Stressed plants (e.g., from too much sun) are more likely to be damaged by lace bugs. A healthy plant will better resist insect damage.

What In Harmony can do

• Apply horticultural oil. This is a highly refined petroleum oil which is effective at reducing lace bug populations. It is safe and has limited effects on benefi cial insects.

Reference
Pests of Landscape Trees and Shrubs, an Integrated Pest Management Guide. 1994. UC Publication 3359.