Are pesky Azalea bark scales attacking your blueberry plants?
The azalea bark scale, Eriococcus azaleas, is a prominent pest of rhododendron, azalea, and huckleberry (Vaccinium spp.). It has been reported in the Eastern US, as well as Belgium and Russia. This is a pest that generally does not kill hosts, rather it causes aesthetic damage. Honeydew can be an inconvenience as well.
How Is It Spread?
- Eggs are deposited into the white waxy egg sac in late April
- Crawlers hatch out of eggs in June-July
- Crawlers prefer branch crotches and twigs where they insert their mouthparts
- Overwinters as nymph
- There is one generation per year. (Possibly two in southern states)
- Leaf yellowing is often visible after June or July
- Sooty mold growing on honeydew can be found under tree or on limbs
- Branch dieback
- White waxy threads of the females egg sac near twig crotches prior to June or July
- Small winged adults males are generally on leaves around August through September
- Crawlers are reddish, tiny, mobile, and typically found around June or July
We recommend using Organocide 3-in-1 Garden Spray to control azalea bark scale. Dilute the concentrate version at 3 fl oz per gallon of water and directly spray onto the bark to control the nymphs before they become adults.
Spray the adult scales so Organocide 3-in-1 Garden Spray will slide under their bodies and block their spiracles (breathing holes) causing them to suffocate. It also leaves a micro-film on the plant that will repel egg laying females because they know it’s harmful to their eggs. To break their life cycle, spray once a week for 4 consecutive weeks. If scales appear again in two weeks repeat spraying for another week.