Southwest Plant of the Month – Cane Cholla – Opuntia imbricata

Southwest Plant of the Month – Cane Cholla – Opuntia imbricata

Southwest Plant of the Month – Cane Cholla – Opuntia imbricata

Plant Form: Shrub
Plant Size: 8’ x 5’
Plant Type: Evergreen
Water: Low
Sunlight: Full Sun
Flower Colors: Purple, red

Physical Description: Mass of leafless, succulent, intricately branched stems covered with sharp spines. Large waxy petaled, reddish-purple flowers followed by persistent yellow fruit.

Care and Maintenance:
Formidable barbed spines and irritating glochids on stems. Cochineal bugs and stem borers. Safe disposal of pruned or dead stems difficult.

Gardener’s notes: Tree-like when mature. Dried stem skeleton used for canes. West Texas/New Mexico native replaced westward by similar O. spinosor in N.M./Arizona. Other native species including red fruited Christmas Cholla, O. leptocaulis, available. All easily rooted from stem joints.

Southwest Plant of the Month material courtesy of NMSU ACES
http://desertblooms.nmsu.edu/plantadvisor

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Beneficial of the Month – Wasps ( Hymenoptera) Part I – Parasitic Wasps (Various Families)

Beneficial of the Month – Wasps ( Hymenoptera) Part I – Parasitic Wasps (Various Families)

Beneficial of the Month – Wasps ( Hymenoptera) Part I – Parasitic Wasps (Various Families)

Like tachinid flies, parasitic wasps behave as parasitoids, i.e., the adults are free-living, feeding mainly on nectar, while the egg and larva (and often the pupal stage) develop inside other insects, eventually killing them. Since parasitic wasps must overcome their hosts’ internal immune defenses, they are much more restricted in the range of insects that they can successfully attack than are predators. However, they are extremely efficient at finding their hosts, and can be very effective biological control agents. Parasitic wasps’ range in size from just a few millimeters (e.g., species that parasitize the eggs of other insects) to several centimeters in length. The females of species that attack concealed hosts (e.g., those living deep within plant tissues) often have a long ‘ovipositor’ (egg-laying tube) extending from the tip of the abdomen; although this is sometimes mistaken for a ‘stinger,’ these species are harmless to humans.

Beneficial of the Month material courtesy of NMSU ACES:
Pocket Guide to the Beneficial Insects of New Mexico

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Southwest Plant of the Month – Big Bend Silverleaf

Southwest Plant of the Month – Big Bend Silverleaf

Southwest Plant of the Month – Big Bend Silverleaf

Southwest Plant of the Month
Big Bend Silverleaf
Leucophyllum candidum

Plant Form:  Shrub
Plant Size:  4’ x 4’
Plant Type:  Evergreen
Water Usage:  Low
Sunlight:  Sun
Colors:  Blue, Purple

Physical Description:  Densely foliaged, compact, rounded shrub with soft velvety, silver-gray leaves and stems, and intense deep blue-violet flowers following heavy rains from late spring to fall. Very drought tolerant.

Care and Maintenance:  Overwatering and/or poor drainage will quickly kill this plant.

Gardener’s notes:  Naturally tidy and compact in full sun. Chihuahuan desert native with several cultivars released by Texas A&M including “Silver Cloud” and “Thunder Cloud”. Similar El Paso area native, L. minus, is seldom commercially available but a hybrid with L. frutescens, “Rain Cloud” can be found commercially.

Southwest Plant of the Month material courtesy of NMSU ACES

http://desertblooms.nmsu.edu/plantadvisor/

 

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Science Triumphs

Science Triumphs

Science Triumphs

By Dudley Vines, SCMG

A few months ago Linda Walsh, a 2018 SCMG intern, emailed me (one of her mentors) worried about some spots on her cherry tree. She said they looked like tiny red bugs, but since they didn’t move she thought maybe they were some sort of scale or mites. She sprayed the tree with a light-weight horticultural oil, but didn’t see any noticeable results.

Then, at the SCMG end of training celebration, Linda approached me and told me her continuing sad tale. In my infinite Master Gardener wisdom, I said, “You sprayed with dormant oil, right? That should have taken care of scale or mites. Gosh, that’s weird. Say, did you try these brownies? They’re great.” And I headed back to the dessert table.

But later I started feeling guilty because I hadn’t paid enough attention to her problem. She was obviously concerned, because she had contacted me twice about it. And I sort of blew her off. So I emailed her the next day, saying that I had been thinking about the red spot problem and looking through some reference books.

I summed up the problem this way: (a) There were a lot of red spots on Linda’s cherry tree, (b) the spots were only on the leaf stems, and (c) she had sprayed with horticultural oil without any effect. Then I suggested that we approach the issue like Master Gardeners ought to – scientifically. I suggested that we meet at the Casita and show a sample to the extension horticulture agent, Lynda Garvin. At the same time, we could examine the red spots under one of the micro-scopes in the Casita. Then, if Lynda didn’t know what it was, she would be able to send a photo from the scope to NMSU scientists (like Dr. Carol Sutherland, the bug expert).

Mysterious red dots on a cherry tree. Because they didn’t move, the gardener thought they might be scale insects. Photo: D. Vines

It just so happened that Linda was scheduled for her first hotline duty the following Tues-day, with veteran MG Sangeeta Kala McCandless, another of her mentors. So I brought Sangeeta into the loop. Sangeeta said she had just been using the microscope with another intern while they were on hotline duty. She said she would work with Linda on diagnosing the cause of the red spots.

On Tuesday, Linda took a few samples of leaves with red spots when she went to meet Sangeeta at the Casita for hotline.

Sangeeta, being the crack diagnostician and ace microscope operator she is, helped Linda solve her problem in no time at all. “Aha!” she cried, looking at the screen. “It’s intuitively obvious to the most casual ob-server that these red dots are neither scale nor mites, nor any type of insect at all. These are simply ordinary extrafloral nectarines.”

At least, that’s how she wishes it had happened. Actually, Linda researched what they saw on the microscope and figured it out. So, the problem was resolved exactly the way it should have been – Master Gardeners used their many re-sources to research a problem and inform the worried gardener as to what action to take. Which, in this case, was none. And, in this case, the worried gardener was an SCMG intern.

When I got Sangeeta’s email identifying the red dots, I figured she was trying to spoof me, so I googled “extrafloral nectaries” and found the following:

Cherries have a sweet way to call for bodyguards: they secrete nectar in red floral glands at the base of each leaf – also called extrafloral nectaries. These are irresistible to black garden ants (Lasius niger) and they secrete nectar in small quantities so they encourage ants to scout around the tree to find the next leaf. Should they encounter a caterpillar trying to get to the leave, or an insect land on it, the ants act aggressively like they would do to defend aphids or scale insects, and keep the insects at bay.

http://abugblog.blogspot.com/2010/05/ants-helping-plants-extrafloral.html

I went outside and checked my own cherry trees, and sure enough, there were the dots. At least on my sweet cherry tree. The pie cherry tree doesn’t seem to have them.

So Linda, Sangeeta, and I all learned something new. And now we’ve shared that information with you. Which is another thing Master Gardeners do.

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Beneficial of the Month – Assassin Bug

Beneficial of the Month – Assassin Bug

Beneficial of the Month – Assassin Bug

This month we start a new feature called “Beneficial of the Month” , featuring insects that can help keep damaging pest insects under control. Sadly, these insects are often misidentified and mistaken for pests.

The following is taken from an article by Matt Simon, wired.com, 6.20.14
There are some 7,000 species of assassin bugs the world over, and each is equipped with nasty, highly hardened mouth parts called a rostrum. With this the assassin bug stabs through the exoskeleton of its prey—ants and termites and bees and such. An outer sheath peels back once inside to expose the maxillae (mouthparts used for chewing) and mandibles, according to biologist Christiane Weirauch of the University of California, Riverside.

They then inject a toxin that paralyzes the victim in a fraction of a second and begins liquefying its innards, as a spider would do to its prey. “Essentially they make the hole,” Weirauch said, “they hook the mandibles in, they inject the stuff, then once the victim stops twitching they can insert the maxillae even a little bit farther and then start slurping up the contents.”

Caution: According to Galveston County Master Gardeners, although most assassin bugs are slow-moving and non-aggressive, they will use their rostrum in self-defense if handled carelessly. Such bites may be rather painful to humans be-cause the bugs inject the same salivary secretion used to dis-solve the tissues of their prey.

This results in the death of a small area of cells at the site of the bite. The symptoms are an intense burning sensation, of-ten followed by a small, itchy lump that may persist for several days. However, no true toxin is involved so it is rare for the reaction to last long or to extend beyond the site of the bite. Some bites occur when the bugs are purposely handled out of curiosity, but most hap-pen through accidental contact while gardening or working in the open. The sharp pain associated with assassin bug bites is usually enhanced by the surprise accompanying the experience.

A reference for New Mexico beneficial insects – Guide to the Beneficial Insects of New Mexico

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