Mechanical Control

Mechanical Control: Prune out, bag up and throw infected plant materials in the trash. Some arborists suggested cutting down the Myoporum and letting it re-sprout, it grows back vigorously and in some cases can be healthier.

It has been observed that in situations where older bushes had recently had been heavily pruned back (assuming because of thrips damage as there were plants in the nearby landscapes that had major damage) that were flourishing with unaffected to minorly effected new and semi-new growth. This appears to be good control method if one does not mind hacking back their myoporum every time they get bad thrips. It seems that younger shoots are more resistant to thrips, probably due to the hardy nature of Myoporum that has made it such an invasive weed as well as a desired landscape plant.

Cultural Control

Cultural Control:

Keep plants healthy by giving them adequate water and fertilizer, however do not over water, or apply too much fertilizer as you may encourage thrips populations. In extreme cases you could put insect screens over smaller plants, or put down reflective mulch, which may repel thrips.

Reflective Mulch or mesh confuses and repels certain flying insects searching for plants, apparently because reflected ultraviolet light interferes with the insects’ ability to locate plants. Most uses of reflective mulch have been against winged aphids, but infestation of young plants by other pests including leafhoppers, thrips, and whiteflies has also been prevented or delayed.

Various materials, such as polyethylene plastic film, can be used. Silver or gray is the most effective color for reflective mulch or mesh, but white also works. Commercially available products include aluminum-metalized polyethylene and silver-embossed polyethylene from suppliers. Aluminum foil may be used on a small scale, such as for a home garden.

Chemical Control

Chemical Control:

Horticultural oils and insecticidal soaps are recommended, but have not been proven to control the Myoporum Thrips. Pesticides containing spinosad, (Conserve), or imidacloprid, (Merit), provide the best control and significantly reduce the number of thrips. However pesticides containing abamectin, (Avid), provide some control over time, but does not dramatically reduce populations.*

*With all of these options large reductions in predatory insects occurred. The plant material must be sprayed at least twice per season to get noticeable control, and the spray coverage must be very good. May not be the most cost effective option.

Alternative Plantings to Myoporum

Syzygium paniculatum

Brush Cherry

Queensland Native

Height 30ft

Spread 10-30ft

Light Full sun or partial shade

Moisture Medium, well-drained soils,

Tolerance Drought

Zones 10-11

Uses Erect to spreading, bushy, large shrub or small tree

Traits Reddish-bronze young leaves

Leaves Lanceolate, shiny, deep green

Flowers Small white with many yellow stamens in summer

Fruit Ovoid, pink, red, purple, or white pear-shaped berries after flowering

Alternative Plantings to Myoporum

Xylosma congestum

Shiny Xylosma

East Asia Native

Height 20ft

Spread 15ft

Light Full sun

Moisture Medium, well-drained soil

Tolerances Drought, heat, most soil types

Zones 8-24

Uses Evergreen shrub or small tree

Leaves Evergreen, shiny, light green

Flowers None

Fruit None

Alternative Plantings to Myoporum

Myrtus Communis

Common Myrtle

Mediterranean Native

Height 10ft

Spread 10 ft

Light Full sun to partial shade

Moisture Medium to low

Tolerance Drought

Zones 8-9

Uses Upright, bushy, evergreen shrub, mixed border, hedge, specimen

Traits Somewhat fragrant, solitary flowers

Leaves Ovate, dark green, glossy

Flowers White, little fragrance, tufts of white stamens; midsummer through fall

Fruit Purple-black berries in fall

Alternative Plantings to Myoporum

Callistemon salignus

White or Willow Bottlebrush

South Australia Native

Height 15-50ft

Spread 10-15ft

Light Full sun

Moisture Medium

Tolerance Drought, hardy at low temperatures

Zones 9-11

Uses Erect to spreading shrub or small tree

Traits Papery white bark, attracts butterflies

Leaves Narrow, lanceolate, pale green

Flowers Long, green or white, sometimes red pom-poms; spring to midsummer

Fruit None

Alternative Plantings to Myoporum

Fremontodendron californicum

California Flannel Bush

California Native

Height 20ft

Spread 12 ft

Light Full sun

Moisture Low

Tolerance Drought

Zone 8-10

Uses Upright evergreen, semi-evergreen shrub

Traits Showy flowers, windbreak, mixed borders

Leaves Lobed, dark green, long, hairy

Flowers Bright yellow through Spring and Fall

Fruit None

Alternative Plantings to Myoporum

Heteromeles arbutifolia

Toyon, Christmas Berry, California Holly

California Native

Height 15-30ft

Spread 15-30ft

Light Full sun to partial shade

Moisture Dry to medium dry

Tolerance Drought

Zones 8-10

Uses Hedge, showy flowers and fruit

Traits Attracts birds, butterflies; native

Leaves Evergreen narrowly ovate

Flowers White clusters through summer

Fruit Red berries in fall and winter

Alternative Plantings to Myoporum

Laurus nobilis

Common Name: Bay Laurel, Sweet Bay

Mediterranean Native

Height 40ft

Spread 30ft

Light Full sun to partial shade

Moisture Medium

Tolerance Drought

Sones 8-10

Uses Cone-shaped tree or large shrub

Traits Spice used in cooking

Leaves Evergreen, narrowly ovate

Flowers Inconspicuous yellow; male and female flowers on different plants

Fruit None

Alternative Plantings to Myoporum

Griselinia littoralis

Common Name: Griselinia

New Zealand native

Plant Characteristics:

Height 25ft

Spread 15ft

Light Full sun to partial shade

Moisture High to medium

Tolerance High salts

Zones 7-9

Uses Dense shrub border, hedging

Traits Excellent windbreak

Leaves Evergreen, broad, leathery, bright green

Flowers Inconspicuous yellow-green; late spring

Fruit Purple berries if both sexes present

Damage Caused by Myoporum Thrips

Healthy Myoporum laetum

Leaf curling and galling;

damage caused by

Myoporum thrips.

Damage has been seen all over the Central Coast of California. It was found that there was minor correlation between coastal regions and thrips damage. In coastal areas (within about 1 mile of coast) damage was present, though generally less harsh than more inland. This correlation did not hold strong in Avila, CA, though, (as some plants within 200 yards of the ocean were very heavily effected). It is postulated that this is due to the protected environment and warmer, less foggy conditions (on average) that Avila exhibits that the thrips are able to flourish. It is either the colder coastal conditions, the presence of moisture or a combination of the two that is the reason that unprotected coastal areas generally see less severe Myoporum thrips damage.

It has been observed that in situations where older bushes had recently had been heavily pruned back (assuming because of thrips damage as there were plants in the nearby landscapes that had major damage) that were flourishing with unaffected to minorly effected new and semi-new growth. This appears to be good control method if one does not mind hacking back their myoporum every time they get bad thrips. It seems that younger shoots are more resistant to thrips, probably due to the hardy nature of Myoporum that has made it such an invasive weed as well as a desired landscape plant.

Also of note, it seems that there is a minor correlation in shaded plants

exhibiting less severe thrips damage than those in full sun. This seems to be

truer when numerous plants were in close proximity; some would be shaded by others and some would be exposed to the sun. Those plants in full sun tended to have worse damage, even though in contact with other plants. This was observed in coastal areas but needs to observed inland. Also, there seems to be a minor, though visible difference in damage levels between these adjacent North and South-facing plantings.

Along with leaf curling and leaf galls, K. myopori can also cause a streaking of the leaves so much so that a heavily infested plant will seem to look variegated (white and green foliage).

What is a Myoporum Thrips?

The County of Los Angeles’ Agricultural Comminssioner/Weights and Measures Department has declared Myoporum Thrips (Klambothrips myopori) a new agricultural pest for Southern California, though the pest has been found as north as the Bay Area in 2008. This new pest has been a problem in San Luis Obispo county and the surrounding areas. Damage to the myoporum shrubs, trees, and groundcovers can be seen throughout the coastal areas of California as the pest and infested plant material spreads via human interaction.

You can identify this particular thrips because it will be present on Myoporum only (as far as recent data has shown). The adults are like the above picture: 2-2.5mm, shiny brown to dark brown, with wings and long posterior tube. The larvae vary from white to orange and are wingless.

There has not been much research on this pest because in some areas the plant species that K. myopori damages is considered a weed. Myoporum has been placed on the invasive species list in some areas of California. Myoporum can be considered invasive because it is drought tolerant, generally pest free, and they tolerate pollution and disturbance well and have competitively spread into native environments. Paradoxically, for those who consider Myoporum to be a weed in most situations, this pest may be the exact answer to your prayers to control the spread of this invasive weed in a no-spray effort. The same characteristics that make it a competitive weed are exactly what makes Myoporum an ideal ornamental plant. However, the Thrips do not differentiate between species of Myoporum and can invade a homeowners' garden easily if their host plant is available.