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Who's Been Mining My Citrus?

Advice for the Home Gardener from the Contra Costa Master Gardeners Help Desk

Description of the client's problem:

Typical Leafminer damage to
young citrus leaf
The client has citrus trees that are not doing well. It looked like a pest, but she couldn't detect any insects. There are deformed and curling leaves with curvy track marks, especially on the new growth.

Advice From the CCMG's Help Desk:
The pest that is causing the new leaf growth on your citrus trees to curl is most likely the Citrus Leaf Miner. The adult stage is a very small moth, which lays eggs on young citrus leaves. When the larvae emerge from the eggs a week or so later, they bore into the leaves and begin feeding, leaving minute trails observable on the surface of the leaves. As the larvae grow, the trails become more pronounced and noticeable.

Adult Citrus Leaf Miner
Phyllocnistis citrella
size: ~ 1/4"

After feeding for two to three weeks inside the leaf tissue, the larva emerges and enters a pupal stage. At this point, the leaf curls over the pupa to protect it. The pupal stage lasts from one to three weeks. Because the life cycle moves so quickly (between three and seven weeks, depending on the ambient temperatures), multiple generations of the pest can develop in warm weather.

You can see photos of the leaf miner moth and the damage it causes at this website: website also contains information about management of this pest.

Typical damage to
young citrus shoots
Except for the aesthetics of the damage, mature citrus trees (those over four years of age) can usually sustain damage from leaf miners with relatively little effect on the overall health of the tree and without loss to fruit production. Less mature trees (under 4-5 years) or trees that are heavily infected may sustain bigger setbacks, but leaf miner attack is rarely fatal.

Since the leaf miner pest typically attacks only the new leaf growth regardless of the age of the tree, there are some cultural strategies that you can use to reduce the prevalence of the new growth, such as limiting pruning to once a year (pruning encourages new growth), going easy on fertilizing, and not over-watering. Past experience with this leaf miner indicates that we might see a year or two of damaged trees as it has only just arrived in our area, but as the natural enemies develop, it should be less of a problem. Use of pesticides is not recommended at this time and in most instances would be ineffective because the miner is inside the leaf and it may kill off beneficial insects.

Hopefully this information answers your question and will help you managing this pest. Please do not hesitate to contact us again if you have questions.

Contra Costa Master Gardeners Help Desk

Note: The Contra Costa Master Gardener Help Desk is available year-round to answer your gardening questions.  Except for a few holidays, we're open every week, Monday through Thursday for walk-ins from 9:00 am to Noon at 75 Santa Barbara Road, 2d Floor, Pleasant Hill, CA  94523. We can also be reached via telephone:  (925) 646-6586, email:, or on the web at


Posted on Monday, December 22, 2014 at 12:27 AM

Daily Life For Master Gardeners



Bat Blind

By Andrea Peck


The topic of bats came to me while perusing Facebook.  I was scrolling away in that semi-conscious stupor that accompanies non-intellectual internet pursuits and there it was: a little cutie patootie. Or in actual English, a cute animal picture. This was unlike any other animal picture I've seen before. This one was a bat. Sure, it was a baby bat, but seriously when did bats get so cute? When I was a youthful teenager, all bats were menacing creatures with rabies. They even flew down low and got caught in your hair. On purpose. That's what my dad told me, anyway. The only cute bat that I know is Stellaluna, but then again, she thought she was a bird.

Well, I stand corrected. Bats have cuteness potential.

Most gardeners are aware that the horror flick version of aggressive, blood-thirsty bats is a slightly hysterical view. That doesn't change the fact that bats are simply unappealing. It's probably those crescent-shaped claws and rubbery wings – oh, and the freaky color. The skeletal physique that wraps around contortionist-style doesn't help. The picture below illustrates my point. I mean, the anatomy!


On the other side of the spectrum, bats are prized for their voracious insect appetite. They'll eat what happens to be on the menu for the night whether that be cutworm moths, chafer beetles, potato beetles, spotted cucumber beetles (yum!) or the dregs, mosquitos, midges and flies (yuck!). An average colony of insect-eating bats can eliminate 100 tons of insects in one season. Per night, the average bat consumes ¼ to ½ its body weight in insects.

Bats serve a significant ecological purpose particularly in the rainforest. Fruit eating bats disperse seeds over miles as they fly during the night hours. Nectar feeding bats pollinate fruits such as, bananas, mangoes, dates and figs. In desert areas, bats are the main pollinators of the pipe organ cactus and the agave. Insect eating bats protect plants by controlling pests that are out past their bedtime. California is home to 25 types of bats, 23 of which are insectivores. The other two survive on pollen and nectar.

Perhaps part of the dark mystique that surrounds the bat is its hours of activity. Bats are nocturnal creatures, leaving the roost when you're just heading in. Insects, their main meal source, are most active during the early evening hours. Echolocation allows them to use sound vibrations to determine distance, speed and even identification of some prey. Rainy weather stops the bat short, however. Apparently the rain interferes with their ability to echolocate.

Because of the bats ability to hunt insects, many gardeners erect a bat house and hold an open invitation to the local bat society. It is important to remember before you purchase a bat house for, say, $3.00 at a yard sale, that you know about bats – the whole picture, not just the glorified version.

First, bats don't like their houses placed on poles. That answers the question that I've had for the last few years: why have no bats moved into my bat house? I have it in the yard. It's on a pole. I painted it black like that one article 4 years ago told me to do. No takers.

Bats like to live on a structure. The pole is cold and when they have their hairless young, they get cold and you know that moms of all species do not settle when baby isn't happy. The bat home must be 12-18 feet above the ground. Not in a tree, though. Too many predators.

But, we're skirting the issue. After reading a bit about bats, I am somewhat happy that my black-bat-house-on-a-pole did not lure in Ma and Pa bat. This is why: bats do carry disease. Yes, rabies is a reality – though a slight one. But, because I have kids and they (or one of their friends) would probably climb that pole and grab those bats by their hook-wings, I am probably very lucky that we did not get any renters.

The chances are low that 1) your cute bat has rabies and 2) you will be bitten by this rabid bat, but the chance is there nonetheless. And if you are pretty relaxed like me, you'll think, oh, its nature and they have those stomach shots. We have modern medicine, right? Yes and yes, but rabies can be fatal. In fact, it is always fatal unless treated.

So that stopped me short.

Bats are wonderful and necessary animals. Currently, the number of bat colonies is in decline and if you have a large garden or own land where you can place a bat home, then your story is different. But, for me, in a small home, with a small garden, kids and pets, it is best not to encourage that close of a connection.

If you happen upon an injured bat, or one that is on the ground, let it lay there protected for a while and see if it recovers on its own. Sometimes bats will tire during migration. If it is cold, place a box or other simple structure over the bat until it is able to warm up and continue on. Never touch a bat, rabies is transmitted through a bite. Use gloves if you must handle a bat. If you have come into contact with a bat, seek medical attention. Often a bite goes unnoticed, so don't take any chances.

Now, if you are in the clear and you want to attract those night stalkers, there are a couple of other things you can do to your garden to make it more welcoming. Plant night blooming or night scented flowers. Below is a list:

Salvia Nicotiana


Evening Primrose
Nightflowering/Silene catchfly
Purple coneflower
Four o'clocks
Aromatic herbs
Butterfly Bush

Place a bird bath or source of water within a ¼ mile of the bat house. Change the water regularly. Encourage the growth of sheltered areas along fences where vines or hedges meet; these may provide additional roosting sites.

Also, keep the nightlight on – it will serve as a bat buffet. Just make sure to keep a little distance.

For more information take a peek at the UCIPM pest notes:





Posted on Sunday, December 21, 2014 at 12:23 PM

Tree Pruning


Prune With a Purpose

By Kim McCue  UCCE Master Gardeners


Several of my neighbors trim all the branches off their Mulberry and Crepe Myrtle Trees.  I think it's unsightly, but should I be doing the same?  Ann M., Paso Robles


The answer is no; emphatically, no!  Based on aesthetics alone the argument can be made against pruning trees to within an inch of their lives, but you should know such severe pruning of mature trees actually does jeopardize the trees health and creates more work in the long run.


The practice of topping trees, sometimes called “hat racking”, is usually done to reduce size by cutting all branches to a stub.  Ironically, topping actually stimulates vigorous upright growth all around each cut.  That new growth is anchored in just the top layers of parent tissue.  As a result, a single sturdy branch is replaced by multiple branches that are weakly attached to the tree.  As you can imagine, this creates a dense canopy of branches that are easily broken off making them hazardous and messy. 


Topping trees is detrimental to the trees health in many ways.  Large, open cuts are ripe for disease and pest invasion.  Drastically reducing the canopy exposes bark that was previously shaded, possibly resulting in sun scald.  The ensuing flush of dense, new growth inhibits air circulation, again making the tree more susceptible to disease.  All that tender, new growth is also preferred by many insect pests that are not able to feed on the mature, hardened wood that has been cut away. 


If handled properly and planted in a suitable site, mature trees rarely need much pruning.  If reducing size is a must, thinning cuts produce the best results by removing a branch at its origin or shortening it to a lateral growth bud.  This allows the tree to maintain its natural growth habit and does not usually encourage a flush of vigorous growth. 


Aggressively topping leaves you with an unattractive tree that now requires frequent pruning to manage the abundant growth and ensuing issues that go along with it. So be kind to your landscape trees and prune with the purpose of maintaining their natural beauty and their health.  For more information on pruning techniques please visit:

Posted on Sunday, December 21, 2014 at 12:09 PM

Bruce Hammock: Scientist Extraordinaire

Bruce Hammock, circa 1980
Bruce Hammock today
It's obvious that Bruce Hammock doesn't spend much time in a hammock.

Research lab, yes. With colleagues, postdoctoral researchers, graduate students and undergraduate students, yes.

Hammock, a distinguished professor of entomology at UC Davis who holds a joint appointment with the UC Davis Comprehensive Cancer Center, has just been selected a  fellow of the National Academy of Inventors (NAI), which honors academic invention and encourages translations of inventions to benefit society.

He is now one of five UC Davis NAI fellows, including Chancellor Linda P. B. Katehi, who was inducted in 2012; Jerry Woodall in 2013; and Kyriacos A. Athanasiou and M. Saif Islam), both elected this year with Hammock in the 170-member Class of 2014 fellows.

A member of the UC Davis faculty since 1980, Hammock has made major innovations in multiple fields. Most recently his laboratory found potent enzyme inhibitors that dramatically reduce inflammation, inflammatory pain and neuropathic pain. He is the founder and CEO of EicOsis, and through EicOsis, the compounds are in clinical trials for companion animals and the  Pre-Investigational tional New Drug Application (Pre-IND) Consultation Program  for neuropathic pain in human diabetics. Hammock is  developing both enzyme inhibitors and natural products as drugs for use in the United States and developing countries.  In agriculture, his laboratory developed the first recombinant viruses as greeninsecticides, while in environmental chemistry, they pioneered the use of immunodiagnostics for environmental analysis and biosensor development, currently applying alpaca nanobodies to sensor technology.

Hammock is a member of the U.S. National Academy of Sciences, a fellow of the Entomological Society of America, and the recipient of the Bernard B. Brodie Award in Drug Metabolism, sponsored by the America Society for Pharmacology and  Experimental Therapeutics. He directs the campuswide Superfund Research Program, National Institutes of Health Biotechnology Training Program, and the National Institute of Environmental Health Sciences (NIEHS) Combined Anayltical Laboratory.

Hammock, who received his bachelor of science degree magna cum laude from Louisiana State University in entomology and chemistry, and his doctorate from UC Berkeley in entomology and toxicology, working in xenobiotic metabolism, describes himself as a basic scientist who “sometimes fines something interesting.” He attributes his success to “having wonderful colleagues and students.”

He also describes himself as “an avid, if incompetent hiker and climber,” and occasionally teaches white-water kayaking with UC Davis Outdoor Adventures.

 By the way, he and his lab also holds an annual water balloon battle outside Briggs Hall every summer. It's usually amounts to a 10-minute battle because the Hammock lab works hard and plays hard.

NAI, founded in 2010, now has 414 fellows representing more than 150 prestigious research universities and governmental and non-profit research institutions.  

Included:  61 presidents and senior leadership of research universities and non-profit research institutes, 208 members of the other National Academies, 21 inductees of the National Inventors Hall of Fame, 16 recipients of the U.S. National Medal of Technology and Innovation, 10 recipients of the U.S. National Medal of Science, 21 Nobel Laureates, 11 Lemelson-MIT prize recipients, 107 Fellows of the American Association for the Advancement of Science, and 62 fellows of the Institute of Electrical and Electronics Engineers.

Congratulations, Professor Hammock! Getting elected “is a high honor bestowed upon academic innovators and inventors who have demonstrated a prolific spirit of innovation in creating or facilitating outstanding inventions and innovations that have made a tangible impact on quality of life, economic development, and the welfare of society,” NAI officials said.

Bruce Hammock is a new fellow of the National Academy of Inventors. (Photo by Kathy Keatley Garvey)
Bruce Hammock is a new fellow of the National Academy of Inventors. (Photo by Kathy Keatley Garvey)

Bruce Hammock is a new fellow of the National Academy of Inventors. (Photo by Kathy Keatley Garvey)

Bruce Hammock in a hammock--something you don't see often! (Photo by Cindy McReynolds)
Bruce Hammock in a hammock--something you don't see often! (Photo by Cindy McReynolds)

Bruce Hammock in a hammock--something you don't see often! (Photo by Cindy McReynolds)

Posted on Friday, December 19, 2014 at 9:35 PM

Don't Miss Bohart Museum Open House Dec. 20: Insects and Art

Greg Kareofelas: Bohart associate, naturalist, photographer. (Photo by Kathy Keatley Garvey)
When you use the words "insects," "art" and the "Bohart Museum of Entomology" in the same sentence, you immediately think of the artistic/scientific team of Fran Keller and Greg Kareofelas.

And you'll meet them and see their amazing work at the Bohart Museum of Entomology's open house from 1 to 4 p.m. Saturday, Dec. 20 in Room 1124 of the Academic Surge Building, Crocker Lane, UC Davis campus. The event, appropriately themed "Insects and Art," is free and open to the public.

Keller, who received her doctorate in entomology from UC Davis this year, and Kareofelas, a Bohart associate (volunteer) and naturalist (he specializes in butterflies and dragonflies), will staff a table at the museum. Together they've created insect posters (think dragonfiles and butterflies), insect-themed t-shirts and a children's book, "The Story of the Dogface Butterfly." The book, focusing on California's state insect, the California dogface butterfly, features text by Keller, photos by Kareofelas and Keller; and illustrations by UC Davis graduate Laine Bauer. The educational book is available in the Bohart Museum's gift shop.

Fran Keller: entomologist, artist, teacher and author (Photo by Kathy Keatley Garvey)
Keller, a graduate of Sacramento City College, earned her UC Davis doctorate in entomology,   studying with major professsor Lynn Kimsey, Bohart Museum director and UC Davis professor of entomology. Keller now teaches at Sac City. She's a talented teacher and an enthusiastic scientist who specializes in beetles, but she really likes everything science-based.

Like Keller, Kareofelas is known for his enthusiasm and fascination with insects. His volunteer association with the Bohart Museum dates back 25 years; that's how long he has donated specimens to the museum and assisted with projects.  He's collected moths and butterflies in California, Nevada and South America. He's reared numerous butterfly species, including California dogface, Gulf Fritillaries, monarchs and swallowtails. In rearing them, he's able to see and share the life cycle (egg, larva, chrysalis and adult). This skill enables him to tell what egg and what caterpillar will turn into what butterfly. That's an identification skill not many have.

Both Keller and Kareofelas enjoy photographing insects. (Check out Kareofelas' image of overwintering lady beetles (aka ladybugs).

The Bohart Museum open houses are always family-oriented. The family activity on Dec. 20 will be crafting small insect sculptures out of wire and beads, said Tabatha Yang, the Bohart's education and outreach coordinator.

This poster is the work of Fran Keller and Greg Kareofelas.
Among other art displayed at the open house will be that of:

  • Diane Ullman, professor of entomology and co-founder and co-director of the UC Davis Art/Science Fusion Program. Ullman and colleague Donna Billick, co-founder of the program, taught Entomology 001 students how to fuse art with science. Their work is displayed around campus and beyond.
  • Students from Art 11, a beginning printmaking class taught by lecturer Bryce Vinkorov of the UC Davis Department of Art and Art History. The class borrows educational drawers from the museum and then creates works of art inspired by the assortment of insects. Vinkorov says: ""My classes have used bugs from the Bohart as inspiration for their linocut prints for the past thee years. They are fascinated by the variety of color and body shapes of these bugs. The larger color prints are linocut reductions. I am very thankful that the Bohart lets this kind of cross-pollination happen."
  • Kathy Keatley Garvey, communications specialist for the UC Davis Department of Entomology and Nematology and an avid insect photographer.  One of her macro images of a flameskimmer dragonfly graces the Entomological Society of America's 2015 world insect calendar.
  • Nicole Tam, an entomology undergraduate student and artist. Her work includes insect-themed drawings and paintings.
  • The late Mary Foley Benson, a former Smithsonian Institution scientific illustrator who lived the last years of her life in Davis, and worked for faculty in the Department of Entomology (now the Department of Entomology and Nematology).
  • Tom Roach of Lincoln, photographer, and Leo Huitt of Woodland, wood sculpture. Their work is on permanent display in the Bohart.

The museum, founded by noted entomologist Richard M. Bohart (1913-2007), houses a global collection of nearly eight million specimens, and is also the home of the seventh largest insect collection in North America, and the California Insect Survey, a storehouse of the insect biodiversity.

Special attractions include a “live” petting zoo, featuring Madagascar hissing cockroaches, walking sticks and tarantulas. Visitors are invited to hold the insects and photograph them. The museum's gift shop, open year around, is stocked with  T-shirts, sweatshirts, books, jewelry, posters, insect-collecting equipment and insect-themed candy.

The museum holds open houses throughout the academic year. Its regular hours are from 9 a.m. to noon and 1 to 5 p.m. Mondays through Thursdays. The museum is closed to the public on Fridays and on major holidays. Admission is free. 

The remaining schedule of open houses:

  • Sunday, Jan. 11: “Parasitoid Palooza,” 1 to 4 p.m.
  • Sunday, Feb. 8: “Biodiversity Museum Day,” noon to 4 p.m.
  • Saturday, March 14: “Pollination Nation,” 1 to 4 p.m.
  • Saturday, April 18: UC Davis Picnic Day, 10 a.m. to 3 p.m.
  • Sunday, May 17: “Name That Bug! How About Bob?” 1 to 4 p.m.
  • Saturday, July 18: “Moth Night,” 8 to 11 p.m.

More information is available by contacting (530) 752-0493 or Tabatha Yang, education and public outreach coordinator at


Overwintering lady beetles, aka ladybugs, in Colusa County. (Photo by Greg Kareofelas)
Overwintering lady beetles, aka ladybugs, in Colusa County. (Photo by Greg Kareofelas)

Overwintering lady beetles, aka ladybugs, in Colusa County. (Photo by Greg Kareofelas)

This children's book,
This children's book, "The Story of the Dogface Butterfly," is the work of Fran Keller, Greg Kareofelas and Laine Bauer.

This children's book, "The Story of the Dogface Butterfly," is the work of Fran Keller, Greg Kareofelas and Laine Bauer.

Posted on Thursday, December 18, 2014 at 5:54 PM

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