Tuesday, December 26, 2017

A New Insect That Sucks (but does little else)

About a week ago Tim Chenowith, one of our Arboretum gardeners, brought a new pest to my attention. It appeared to be some sort of sucking insect that was peppering the Senna wislezini that is part of our Southwest collection near the Rose Garden. At first I thought it was an aphid, however It did not have the two spiracles, sharp protuberances that occur on the rear of the insect, that are key identifying marks of most aphids. It was also unusual in that the ‘honeydew’ it produced was solid, and stayed on the bugs rear end until it broke off, in which case it would stick to the plant that the bug was infesting almost like sugar crystals but a little more oval in appearance. Since I hadn’t seen this pest before I did what I usually do faced with an unidentifiable pest; I sent a picture of it to Gevork Arakelian, the entomologist for Los Angeles County’s Agricultural Commissioner Weights and Measures office.
Small insect peppers this Senna with small balls of solid sugar. 
In the old days I would send the whole pest and it would be relatively involved process of sending via the county courier, the County’s own parcel post and letter delivery service. Although most times it would get to the Ag Commissioner's office intact, if I had to send the package containing the live pest on a Friday it would not get opened until Monday -sometimes resulting in an indiscernible mass of what was, just several days before, once a living pest. Now it’s pretty easy, I just position my iPhone a half an inch above the eyepiece of my microscope and take a pic. The result is then photoshopped until all the highlights, furrows, ridges, antennae and other insect parts that Gevork might need for an ID are mostly visible.

At the top is one of the insects, the thing on its rear end is a mass of solid honeydew. The white masses are surrounding the four insects in the picture are solid honeydew produced as the result of the pest excreting a sugary waste out of its rear end.  

 Gevork got back to me the the next day. He pretty much nailed it. It was a Caesalpinza psyllid, a small sucking insect that apparently causes little or no damage to its host. here is the description he sent me:

 CAESALPINZA PSYLLID, Freysuila dugesii, -(Q)-This psyllid is one of several in the genus that feed on leguminous shrubs and trees in Caesalpinia and Poinciana. The first California record comes from Palm Desert, Riverside County, where it was collected on a golf course by County Ag Biologist Richard Shaffer in January. The host was Caesalpinia cacalaco. This small shrublike plant with yellow and orange flowers is being commonly planted these days in many southern California and Arizona locations. Our specimens were confirmed by Dr. Ian Hodkinson in England. Little is known about this psyllid as it has been collected only sparingly over the years. It is most likely native to Mexico, the native home of the host. No apparent injury such as galling or malformations to the plants were noted. It is likely restricted to these hosts and whether it will cause damage to them in the future in ornamental plantings is unknown.

This also makes sense because Senna wislezini is closely related to the host, Caesalpinia cacalaco. It might infest Mexican Bird of Paradise plants (Caesalpinia pulcherrima), but if it did it would probably not damage the plants.    So thankfully this pest is probably nothing to worry about, but I'll keep an eye on it. Interestingly the coating of sticky solid honeydew balls could be a manner of camouflage for the pest, making it tough for birds to discern the sticky sugar balls from the psyllid.

Tuesday, November 28, 2017

Meyer Lemon Turns Green -Is it Infected With Yellow Dragon Disease?

I was sent this pic by a client who wondered if the green skin of this Meyer lemon meant that it had Huanglongbing disease, a malady that is threatening Southern California's citrus groves. He also added that other than the green skin, the lemon tasted the same. 

Well this citrus probably does not have Huanglongbing. The greening associated with the disease is usually very uneven. What is happening is probably a process called 're-greening' that is common in some oranges, like Valencias. After the oranges ripen their skins start turning green again. This does not change the sweetness of the orange or its taste. This 're-greening' can happen to Meyer lemons, because they are actually oranges that taste and look like lemons. Also, 're-greening' occurs more frequently during warm winters, which we are currently experiencing. 

Thursday, October 19, 2017

Harbingers of Fall

It's coming up on the season here in the L.A. area that seems to resemble Autumn. There is discernable change in some of the plants that originate in temperate areas. That change can resemble the classic fall color change with vivid hues of orange, red, and yellow -or it can be a ripening and drying out that can look similarly spectacular. Above are cardoon plants whose flower heads have dried to create star-like straw-yellow seed heads. 
Another angel on the cardoon plants with their straw colored seed heads in the Herb Garden. 

Of course this is Southern California, and although we've renamed brown 'gold' to cope with the long (up to 9 months) dry season, just add a little water and flowering trees will do their thing here. The fabulous pink flowered Floss silk trees (Ceiba speciosa) reliably bloom just around world series time. This one is located just north of the cactus and succulent garden. 

Another view of the Ceiba speciosa located north of the Cactus and Succulent garden. Notice the karst river stone with viewing hole. 

One of our most impressive specimens of Ceiba speciosa stands just east of the gateway fountain and greets Arboretum visitors as the enter. It is a variety introduced by the Arboretum in the 80's called 'September Splendor'.

This really impressive patch of Japanese anemone is hidden somewhere between the Korean steeles and Meyberg falls. 

Right now is a great time to do some hummingbird watching. There are several different species clamoring for one of their favorite nectar sources; the Mexican sage (Salvia leucantha)

Wednesday, October 11, 2017

Around the Arboretum -Early October

Mushrooms (probably Agaricus sp.) 'flushing' near the administration building. 

Mexican sage (foreground) ; Rainbow gum (tree in the background)

Can you see the Freeman's maples starting to turn color?

Madagascar Moringa tree and leafless Plumbago. 

Looking north from the road in front of the Cafe. 

Yellow Golden rain tree flowers. 

Nandina domestica (Heavenly bamboo) turning bright red and orange for the fall. 

Ceiba speciosa (Silk floss tree). 

Bauer fountain. 

Bauer fountain. 

The Canada geese are back!

Saturday, August 26, 2017

Wooly Oak Aphids

I received a call from a client who complained that their oak tree was dropping fuzzy stuff all over the area underneath its canopy. I asked them to bring it in and this is what I saw:

Leaf with cottony wax and visible aphids. 

I then put it under a magnifying scope and was able to see the culprit:

Closeup showing (l) aphid, (r) egg surrounded by waxy 'wool' produced by the aphids.

It was Wooly Oak Aphid, one of a pantheon of insect pests that attacks oaks. Like many pests on oak it is mostly not a threat, just a nuisance. Time is the usual insecticide, with infestations resolving themselves within a month or two when increasing attacks by predators and the changing physiology of the oak itself lead to its demise.

Links to more information on the Woolly Oak Aphid:

Woolly Oak Aphids - BugGuide.Net
woolly oak aphids, Stegophylla brevirostris, on black oak leaf. - YouTube
Aphids Management Guidelines--UC IPM
woolly oak aphids -Stegophylla brevirostris Quednau and Diphyllaphis microtrema Quednau
Dancing woolly aphids will probably stab you - Scientific American Blog Network

Friday, August 25, 2017

A Handful of Climate Appropriate Trees

The following trees have been picked because they are relatively climate appropriate. Keep in mind that 'climate appropriate' means more than just low water use. Many east coast and european trees require not only water but also cold winters in order to remain healthy. Also, many tropical trees are frost sensitive here and have problems with frost either killing or damaging them. To find a specimen of these trees here at the Arboretum just click on the icon for that tree in the map above. For more information on each tree just click on the link associated with its name and it will take you to the Cal Poly Selectree Database entry for that tree if it exists. 

Afrocarpus falcatus

Geijera parviflora

Melaleuca linariifolia

Lagerstroemia indica

Citrus and other Fruit Trees

Ceiba speciosa (Chorisia speciosa)

Moringa hildebrandtii

Brachychiton rupestris

Callistemon viminalis 'Red Cascade'

Eucalyptus torquata

Corymbia (Eucalyptus) citriodora

Cedrus atlantica

Draceana draco

Olea europaea ssp africanus

Sequoia sempervirens

Quercus polymorpha

Quercus  rhysophylla

Platanus mexicana

Tuesday, August 22, 2017

LAist Names Us One of the Best Places in L.A. to Watch Birds

Bluebird at the Arboretum

Popular Los Angeles blog LAist.com has named the Arboretum one of the best places to watch birds. We are also listed by the Pasadena Audubon Society as one of the best places to watch birds as well.  There have been over 250 species of birds observed here, so, yes we are.

This is great news, I'm going to tweet it. 😁

Tuesday, August 15, 2017

Glassy Winged Sharpshooter

Glassy Winged Sharpshooter

I had several of these brought into my office several days ago. They are partly responsible for the demise of Oleanders all across Southern California. Their feeding activity centers around the water conducting tissue in the plant they are attacking. The orange bulb shaped area that you see on the bottom of the leafhopper in the picture is its 'head pump', a muscular organ that helps the insect pump the watery xylem fluid (mostly water coming from the roots) from the plant and through its body. 

Glassy Winged Sharpshooter
This feeding method means that it doesn't have to compete with sap sucking insects like aphids and scale, but it does require the insect to process a lot of fluid through its digestive track because xylem fluid is lean on nutrients like sugar and dissolved nitrogen compounds. This causes if to expel water out of its anus like crazy, as can be seen in this video. These insects are partly or mostly responsible for trees that 'rain' drops of fluid down around you in the summertime. 

Should you control these pests? Generally, no. However if the squirting gets to be too much you might try a pyrethrum based organic control like Pyganic, however be very selective as far as what and where you spray because this insecticide, like many pyrethrum based products, will eliminate beneficial and predatory insects as well as the pest.

Wednesday, July 19, 2017

What Is There To Do and See at the L.A. County Arboretum & Botanic Garden When it’s really Hot?

It’s Summer here at the Arboretum. This time of year can be hot -we just had some pretty healthy 105 degree plus days. Besides slathering on sunscreen, wearing cool clothing, carrying (and drinking) plenty of water and fluids,  and wearing a hat or carrying a sun blocking umbrella, what can you do to really enjoy your day here besides the usual survival 101 skills?

Plan to visit areas that are shady and cool!  We have compiled a list of the 7 coolest places in the Arboretum so that you don’t have to wait for cooler weather to visit. So here are the 7 coolest places in the Arboretum, from furthest to closest:

1. Meyberg Falls
2. The Historic Section
3. The Bamboo Grove
4. The Tropical Rainforest
5. The Tropical Greenhouse
6. The Celebration Garden
7. The Arboretum Library

Let’s take a look.

Meyberg Falls 

Meyberg Falls

On just about any day here at the Arboretum you can find a dozen or more people hanging out here. Besides visitors, it’s popular with wedding photographers, music video producers and feature film makers. Katy Perry’s ‘Roar’ Video, Beyonce’s ‘Survivor’ video and the Rock video scene in “Wayne’s World” were just some of the many that were filmed there.
Lucky Baldwin's Queen Anne Cottage

The Historic Section

When San Francisco hotelier and millionaire Lucky Baldwin decided to invest in property here in the L.A. area, the Santa Anita ranch was one of the first purchases he made. Lucky’s ranch was surrounded by dry communities, so alcohol, gaming and horse racing were regular activities. To raise his ranch’s status above that of a mere roadhouse he featured fine varietal wines, a first class hotel, and to attract a higher class of clientele, authors, actors, opera singers and other celebrities of the day as featured guests. These celebs would stay at Lucky’s Queen Anne Cottage and give lectures, recitals and concerts to attract the staid citizens of the surrounding towns.

This historic section of the Arboretum is planted with many large trees, many over 100 years old, that provide shade -and a large lawn that is popular with weddings and other events.

Shady path through a bamboo grove here. 

The Bamboo Grove

The Arboretum has many exemplary collections, including over 60 different species of bamboo. Some of these bamboo, like Phyllostachys aurea, have formed dense and shady groves where you can duck in and avoid the sun in a cool, green forests of the grassy plants. The interiors of these groves can resemble green caverns and they are very popular with videographers, photographers and artists. A word of warning; be careful of the many small, stake-like stumps that can pose a tripping hazard.
The Tropical Rainforest

The Tropical Rainforest

Situated on the North side of Baldwin lake, the Tropical Rainforest is an area that represents the forests of the tropics and subtropics. Situated under tall Cypress trees from the American South and Mexico, this shaded paradise contains a collection of cycads, a grove of bamboo, and a disparate collection of tropical trees from around the world. There are several benches located in the forest, making it the perfect place to sit down and relax.
Inside the Tropical Greenhouse

The Tropical Greenhouse

When the weather is boiling hot the Tropical Greenhouse, located to the North of the main entrance, is not. That’s because it is usually kept to a constant temperature somewhere around 85 degrees -a relative ice box when the temperature is hovering around 105. Inside are orchids, ferns, bromeliads and even a Cocoa tree, the source of chocolate.

Small courtyard fountain in the Demonstration Garden. 
Top of the Weeping Fountain in Lew Watanabe's meditation garden vignette in the Demonstration Garden. 

The Celebration Garden

This area is a cool collection of shaded ‘vignette’ gardens that used to make up the Sunset demonstration garden, an area originally envisioned in the envisioned as being a demonstration and an inspiration to do-it-yourself landscapers. It’s last refurbishing, back in 1998, featured vignettes from cutting edge landscape architects and designers. Still visible today are a shady lawn garden, a courtyard fountain garden, a low water use deck area that uses synthetic recycled deck elements, a California native garden that uses polished granite as a faux stream, a shaded walk among California coastal redwoods and Canary Island pines, and finally a traditional Japanese meditation garden fashioned by the late Sierra Madre garden designer Lew Watanabe. Lew’s garden contains an example of his signature ‘weeping wall’ fountains, granite sculptures that are painstakingly made level so that the water pumped out the top covers the top and side of the fountain with a thin film of flowing water.

The Arboretum Horticultural Library

The Arboretum Horticultural Library

One of the finest collections of horticultural and botanical texts on the west coast, it is also a fine example of mid-century modern architecture.

A recent remodel has rendered its interior space true to its mid-century roots. Come inside and see the newly revealed vaulted ceiling, true-to-period lamps and furniture and spacious, yet less claustrophobic book shelving. Say 'Hi' to myself and librarian Susan Eubank. And, most importantly, enjoy the massively effective air conditioning.

Map to the Above Locations