What is on the underside of my blueberry leaves?
I apologize! I thought that I had responded to this two days ago, indicating that I would send another response after I got some information from an entomologist friend.
What you have appears to be bearberry whitefly. This is a link that I thought I sent to you the other day: http://ncsmallfruitsipm.blogspot.com/2010/07/whiteflies-in-blueberries-should-we-be.html
The entomologist who wrote that blog post confirmed that she thought the insects in your photos (thank you for the close-up images) were bearberry whiteflies.
Assuming that this is a home garden and not a commercial planting, she said that, in this case, she’d “be inclined to suggest a summer weight oil application repeated over a few weeks.” You might find summer oils under the name horticultural oils. Avoid dormant oils. Be sure it’s labeled for use blueberries. If this is a commercial farm, let me know, and I can send along some other recommendations.
Dr. Burrack also forwarded my e-mail to Dr. Ash Sial, who is the entomologist in GA who handles blueberries, and he responded to me, as well. Below is an excerpt of what he said:
“If the population density is high, a combination of yellow sticky traps and organic chemicals such as Natrasoap, Eco Oil, Eco-neem or other organic soaps or oils would help. Similar organic chemicals are available under different trade names. … We have seen bearberry whitefly infestations sporadically over the past 2-3 years in commercial blueberry orchards and nurseries. However, it was never found to be an economic issue to justify chemical intervention.”
Again, if you purchase any type of pesticide, be sure it’s labeled for use on blueberries.
You’re welcome to contact Dr. Sial if you’d like. His e-mail address is firstname.lastname@example.org.