BIG BAD GRASS by Vince Lazaneo, UCCE San Diego County Home Horticulture Advisor

Healthy Garden—Healthy Home

Retail Nursery Newsletter An Information Source for Retail Nursery Professionals

and Their Customers

Volume 4, Issue 2 August 2009

Healthy Garden—Healthy Home

Helping to improve water quality in

San Diego County through the

implementation of Integrated Pest

Management practices.

It’s The Water That Connects Us!

Pampas Grass 1

Myoporum Thrips 1

Don’t Plant a Pest 2

UC Publication Discounts 3

Free Workshops and POP Materials

4

IPM Kiosk Available 4

Inside this issue:

Most gardeners recognize Pampasgrass, Cortaderia selloana and its cousin, Jubatagrass C. jubata. Both plants form large mounds of long arching leaves with saw-tooth edges topped with showy flower stalks. These plants were intro-duced into California dec-ades ago and planted in many home gardens be-fore we realized their harmful invasive nature.

Pampasgrass and Jubatagrass are well

adapted to our local envi-ronment and wind can carry their tiny seeds up to 20 miles. The massive size of each clump crowds out native species which also reduces wild-life habitat. Large stands of pampasgrass create a serious fire and flood hazard. The plant can also harbor pests includ-ing rats and snakes.

Removing clumps of pampasgrass and jubatagrass from

(Continued on page 3)

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Pampasgrass

Update on Myoporum Thrips Research by James A. Bethke and David A. Shaw, UCCE San Diego County Farm Advisors

Myoporum is a popular landscape plant throughout most of Cali-fornia, and different spe-cies/cultivars can be found as tall trees, shrubs or ground cover. Myoporum is popular be-cause it can be used in numerous landscape ap-plications, it is relatively pest free, and it is drought tolerant, which in this day and age is a benefit to be sure.

Unfortunately, for the last few years this plant species has been attacked by a small insect called a thrips (singular and plural word form). Thrips are small slender insects that can cause a significant amount of damage to flowers and terminal plant growth.

There are more than 200 species of thrips in Cali-fornia that affect orna-mental and crop plants. For more information about pest thrips and their control, see www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7429.html. Thrips can also vector numerous plant diseases, especially plant viruses such as the tomato spotted wilt virus (www.ipm.ucdavis.edu/PMG/r783102211.html).

The thrips spe-cies found on Myoporum doesn’t have a common name yet, but many of us call it the Myoporum thrips, which makes sense since it only at-tacks plants in the genus Myoporum. For those of us that are entomologists, this insect has only re-cently been described, and its scientific name is Klambothrips myopori Mound and Morris (scientific names are fol-lowed by the authors of the article that describes them), see www.mapress.com/zootaxa/2007f/zt01495p045.pdf. For a pest note on the Myoporum thrips, see

(Continued on page 2)

Myoporum Thrips Damage

Don ’ t plant a pest! brochure available in English and Spanish

FREE through UCCE San Diego County Office.

PAGE 2 RETAIL NURSERY NEWSLETTER VOLUME 4 , ISSUE 2

Don’t Plant a Pest by Vince Lazaneo, UCCE San Diego County Home Horticulture Advisor

Our mild climate allows us to plant a wide variety of ornamen-tal plants from all around the world in our gardens. Unfortunately, some introduced ornamental plants don’t stay in our gardens. Their seed, root or stem fragments jump the fence and spread into natural areas. They grow fast and crowd out native vegetation. They can block streams, causing floods and produce so much biomass that they become a serious fire hazard in natural areas.

The good news is that most garden plants stay where they were planted and fulfill their in-tended role. By removing invasive problem plants and choosing suit-able replacements, we can help protect California’s natural land-scape and reduce the risk of fire and flood damage to our homes and properties.

Plants that are invasive in one climate and habitat type may not be invasive in another. The problem plants listed below have escaped from gardens and invaded natural areas throughout southern California. Photos of these plants and suggested alternatives can be seen at www.cal-ipc.org the Califor-nia Invasive Plant Council website: iceplant or hotentot fig (Carpobrotus edulis) , Algerian ivy (Hedera caneriensis), periwinkle (Vinca major), pampas grass (Cortaderia selloana and C. jubata), fountain grass (Pennisetum setaceum), brooms (Retama mono-sperma, Genista monspessulana, Cytisus striatus, Cytisus scoparius, and Spartium junceum), acacia (Acacia cyclops), Mexican fan palm (Washingtonia robusta), Brazilian pepper (Schinus terebinthifolius) ,

eucalyptus – blue and red gum (E. globulus and E. camaldulensis).

Myoporum Thrips cont. from page 1 www.cdfa.ca.gov/PHPPS/ppd/PDF/Klambothrips_myopori.pdf. In addi-tion to the problems that California has been experiencing with this invasive pest, Hawaii has now con-firmed that they also have the pest and are seeking help.

Myoporum throughout the state has been severely impacted by the introduction of this pest. Be-cause virtually all terminal growing tips are affected and there is no time for the plants to recover from injury, plant death is now common. The terminal growth is stunted and twisted into galls that protect the insect from pesticide contact and predators. Therefore, populations can build to high numbers, and we have observed that thrips popula-tions are continuous year round, although lesser in number during winter months. During yearlong monitoring of the terminals of un-treated plants in our studies, we found that they become so severely stunted that all the terminals turn black and die.

We have been studying the insect’s biology and seasonal oc-currence here in San Diego

County. In addition, we have con-ducted several pesticide trials to help determine the most effective active ingredients that can be used against this pest. Our early trials told us that some pesticides are not very effective against the pest, but they can cause enough mortality to the pest that they permit plant re-covery. We also determined that there is a natural predator that oc-curs within the twisted plant tissue, the minute pirate bug, Orius spp.

Our trials have indicated that Myoporum recovers nicely with treatment applications and that ac-tive ingredients in the pesticides such as imidacloprid plus bifen-thrin, and thiamethoxam work well against this pest as a foliar spray application. Other treatment appli-cations that encouraged regrowth and recovery of landscape planted Myoporum were the following, abamectin, spinosad, acetamiprid, and dinotefuran. We also deter-mined that as a foliar spray, acetamiprid, imidacloprid, and dinotefuran caused the greatest impact on the natural enemy, min-ute pirate bugs. Systemic drench

treatments may work much better while allowing the natural enemies to survive as well. We plan on test-ing some of these systemic insecti-cides on Myoporum trees soon.

Studies are underway to determine the extent of the suscep-tibility of various forms of Myoporum to the Myoporum thrips. Cultivars of Myoporum parvifolium appear to be resistant to the thrips and may be a good replacement for M. ‘Pacificum’. While the tree froms of M. laetum, including the cultivar ‘Carsonii’, are affected, it has been reported that M. laetum 'Compactum' is resistant to the Myoporum thrips. However, it is a lower growing cultivar with much smaller leaves. Until more suitable resistant cultivars are available, we believe that treatment applications will be necessary for survivorship of this popular plant as a tree or ground cover. Another less popular alternative is to replace Myoporum with an alternate plant type, one that is similar to the qualities of Myoporum. A difficult task, to say the least.

VOLUME 4 , ISSUE 2 RETAIL NURSERY NEWSLETTER PAGE 3

Big Bad Grass continued from page 1

residential landscapes can help protect our native environment. The plant can be replaced with other ornamentals that have a simi-lar appearance: blue oat grass (Helictotrichon sempervirens), Cali-fornia fescue (Festuca californica), deer grass (Muhlenbergia rigens), San Diego sedge (Carex spissa), and giant wild rye (Leymus conden-satus).

Clumps of pampas and jubatagrass can be physically re-moved, chemically treated or con-trolled with a combination of both methods. Mechanical removal:

Large plants can be dug out with hand tools. You can use a Pulaski (axe on one end and hoe on the other), Mattock (pick on one end and hoe on the other), or a long-bladed shovel. To prevent re-sprouting it is important to remove

the entire crown and top section of the roots. Re-growth from lower roots is unlikely.

Removing the large mass of stems and foliage with a chain saw or weed eater can expose the base of the plant and allow better access for removal of the crown. This also makes disposal of the removed plant more manageable. If a plant has produced flowers, it is important to, first, cut and remove the flower stalks to prevent seed dispersal during the removal proc-ess. Chemical treatment:

Spot treatment with the her-bicide glyphosate (Roundup) can be used to control existing plants. Dust on foliage reduces the herbi-cide’s effectiveness. Where feasi-ble, first wash foliage with a forceful spray of water to remove dust. Use the concentration listed on the label for difficult to control weeds. Be careful not to spray desirable plants.

Plants should be sprayed to just-wet foliage, but not to the point of run-off. Glyphosate is absorbed by green foliage and moves down-ward into underground stems and roots. This occurs at a faster rate late in the growing season so fall application usually results in better control than summer.

Combination: In some situations, spray-

ing a large clump may damage nearby desirable plants. This can be avoided by using a combination of mechanical and chemical meth-ods. First cut and remove the top foliage of a large clump. When new foliage has regrown to a length of about 2 feet, spray it with gly-phosate. Less herbicide is required with this method but more than one application may be required for good control. Monitor the clump for several months and retreat if new growth develops.

For a limited time, you can order any publication from the UC Agriculture and Natural Resources on-line catalog, and receive a 20% discount. How to Order: 1. Go to http://anrcatalog.ucdavis.edu

2. Select Publications and add to Cart 3. At check-out, Enter Promotion Code “PRSAN37” to receive 20% discount 4. Publications will be shipped directly to you If you have a problem using the Discount Code, please contact Chiquita Taylor, telephone (800) 994-8849.

20% Off University of California Agriculture and Natural Resources Publications!

SAMPLE PUBLICATIONS

Jubatagrass

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Recommended Alternatives

California Fescue Photo by Ellen Zagory, UCD Arboretum

Deer Grass Photo by Nikhil Joshi, UCD Arboretum

HEALTHY GARDEN—HEALTHY HOME

University of California Cooperative Extension Farm and Home Advisors Office 5555 Overland Avenue, Building #4, Suite #4101 San Diego, CA 92123

Phone: 858-694-2184 Fax: 858-694-2849 E-mail: saparker@ucdavis.edu Web Site: www.cesandiego.ucdavis.edu

FREE Point-of-Purchase Educational Materials and Training Workshops Available for Local Nurseries and Garden Centers!

The University of California prohibits discrimination against or harassment of any person on the basis of race, color, national origin, religion, sex, physical or mental disability, medical condition (cancer related or genetic characteristics), ancestry, marital status, age, sexual orientation, citizenship, or status as a covered veteran (special disabled veteran, Vietnam-era veteran or any other veteran who served on active duty during a war or in a campaign or expedition for which a campaign badge has been authorized). University policy is intended to be consistent with the provisions of applicable State and Federal laws. Inquiries regarding the University’s non-discrimination policies may be directed to the Affirmative Action/Staff Personnel Services Director, University of California, Agriculture and Natural Resources, 300 Lakeside Drive, 6th Floor, Oakland CA 94612-3560. (510) 987-0096. University of California, County of San Diego, and the United States Department of Agriculture cooperating.

As part of the Healthy Gar-den – Healthy Home Integrated Pest Management (IPM) outreach effort, research based educational materials, and the fixtures necessary to display them, are available to nursery and garden centers throughout San Diego County. Materials include water re-sistant pest cards and informational tear-off sheets. Pest Card topics in-clude; Ants, Aphids, Cockroaches, Earwigs, Fleas, Giant Whitefly, Go-phers, Head Lice, Rats, Snails & Slugs, Spiders, Termites, Safe Use & Disposal of Pesticides, Lawn Insects, and Gardening with Good Bugs.

Tear-Off Sheet topics include; Gen-eral IPM Information, Ants, Snails & Slugs, Aphids, and Preventing Irriga-tion Runoff. In addition to these Point-Of-Purchase items, several educational videos ranging in length from 15 sec-onds to 3 minutes are available for use in your store. Both DVD and video format are available. Workshops for nursery staff focus-ing on topics related to IPM and Wa-ter Quality are also available for book-ing. For more information about any of these opportunities or to make

arrangements for your nursery or gar-den center to participate in this pro-gram please contact Scott Parker by phone, 858-694-2184, or email, saparker@ucdavis.edu.

Sample Pest Cards Display Racks

Touch-Screen IPM Kiosks Available Nurseries and Garden Centers The Healthy Garden/Healthy Home Program, in collaboration with the UC Statewide IPM Program, has developed an interactive Information Kiosk. The touch-screen units, which provide the consumer with UC generated IPM information, are available for use for 45-day periods during the initial test year. The IPM Kiosk provides the consumer with management tips related to irriga-tion, fertilization, pest identification, pest management, least toxic control tips, safe use and disposal of chemi-cals, and runoff prevention. Each unit also has printer capabilities so that the user can print out useful management tips and contact infor-

mation for the Cooperative Exten-sion and Master Gardener program. Retail nursery and garden centers can use these units as part of their customer education efforts. Each unit is self-contained and only requires a simple electrical outlet for operation. We are looking for addi-tional retailers to help in the evalua-tion of this outreach tool by placing a kiosk in their store, nursery or gar-den center. Interested managers should contact Scott Parker, saparker@ucdavis.edu 858-694-2184, at the UC Cooperative Extension Office to arrange for the placement of a unit in your establishment.

IPM Touch-Screen Kiosk