August 6, 2016

1 - Plant feeding bugs may feed on various parts of plants, including flower buds, and prevent flowers from opening.

Yard and Garden August 6, 2016

Q.
For the last two years the buds have gradually turned brown then black and ultimately never blooming. I cannot find any information on the internet regarding any disease the tree gets. I have many types of plants on my property, roses, vitex, crepe myrtle, etc. none of which have any problems. A neighbor had s similar tree from a different nursery and was about the same age. They also had the same problem, but have taken the tree down. Are you able to determine what the problem is or should I have it removed?

- Anna R.

Roswell

A.

My guess as to the culprit based on the photos was wrong. Fortunately, I also advised Anna to send samples to the Plant Diagnostic Laboratory in Las Cruces through her local NMSU Extension Agent. Dr. Carol Sutherland, NMSU Extension Entomologist, received the samples and provided the following information:

I think our culprit here is a bug---like a stink bug or a coreid bug (not a squash bug, but a member of that family). Each of the flower buds---nicely dried---have uniform-sized puncture marks in them, anywhere from one hole to four holes. When I chipped off the bud scales, the flower petals were inside---dried and wrinkled---but present. Our bug would have piercing-sucking mouthparts---like a doctor's hypodermic needle. They can suck fluids out of succulent plant tissues; then, when that gives out, they inject their saliva which starts digesting more carbs externally. Then they suck up those fluids.

I have identified Agonoscelis on common garden herbs in several places; green stink bugs like Chlorochroa would not be visible due to camouflage---green against green. Brochymena are abundant and overwinter on a variety of trees and shrubs statewide. Mozena nymphs are green and well camouflaged, too. They have been numerous on mesquite, another plant that puts out buds and then 'bean pods', although the families for mesquite and desert willow are different. Leptoglossus might be a stretch for this early in the year; same holds for the similar appearing Narnia which favors cactus buds, flowers and fruit. Those are all potential candidates. I think the punctures are too large for 'false chinch bugs'. Life is tough in a drought, and a desert-adapted plant that puts on a load of buds is so tempting for little critters in need.

The earlier photos [Dr. Sutherland received additional photos] indicated more buds were appearing on the ends of branches while the older buds were obviously already damaged. Any blooms now?

If bugs are responsible for the damage, an easy way to confirm that and also catch specimens to identify the problem for sure - get a light-colored dish pan (white is good). Hold the pan under a branch with lots of buds and blooms on it---then shake the branch over the pan. See what falls in and catch it. A resealable bag will hold the catch. If you do not want to chase bugs around and pick them up one by one, swirl the pan around several times and dump everything into the baggie. Next put them into the freezer overnight, followed by preservation (for shipping) in a vial with an alcohol swab in it.

Once Dr. Sutherland has confirmed the identification, she will recommend treatment, if any is warranted. However, based on what she has determined to this point, there is no reason to remove the tree. Many gardeners will also experience problems such as this and can receive proper identification and treatment recommendations through their local NMSU County Cooperative Extension Service office.

Marisa Y. Thompson, PhD, is the Extension Horticulture Specialist, in the Department of Extension Plant Sciences at the New Mexico State University Los Lunas Agricultural Science Center, email: desertblooms@nmsu.edu, office: 505-865-7340, ext. 113.

Links:

For more gardening information, visit the NMSU Extension Horticulture page at Desert Blooms.

Send gardening questions to Southwest Yard and Garden - Attn: Dr. Marisa Thompson at desertblooms@nmsu.edu, or at the Desert Blooms Facebook page.

Please copy your County Extension Agent and indicate your county of residence when you submit your question!