Master Gardener News Blog
Ants And Honeydew
By Linda Lewis Griffith UCCE Master Gardener
There are about 200 species of ants in California. The vast majority are harmless. In fact, many ants are considered beneficial because they feed on termites, fleas and other pests in the garden. But Argentine ants are one of the state's most serious ant pests, infesting homes, backyards and agricultural settings.
Argentine ants are dull brown in color. They move rapidly in long, distinct trails, usually travelling from their nests to a favored food source, such as honey, syrup, fruits or other sweets. In hot, dry weather, trails will also lead to water.
They live in shallow nests just below the surface of the soil. Colonies are linked together to form a large “supercolony” with multiple queens. When newly mated queens disperse to find new colonies, they are accompanied by workers from the existing colony, rather than going out on their own as most other species do.
Argentine ants are often found in trees and shrubs where they feed on honeydew excreted by small, soft-bodied, phloem-feeding insects, such as aphids, mealybugs, whiteflies, and soft scale. Honeydew is rich in sugar and a favorite food for the ants. The ants protect honeydew producing insects from natural enemies, allowing the pest population to increase and weaken the plant. Honeydew can also lead to sooty mold that blackens foliage, stems and fruit.
Ants can be kept out of trees by banding the trunks with a sticky substance, such as Tanglefoot. Circle the trunk securely with a collar of heavy paper, duct tape or fabric tree wrap. Then apply a layer of Tanglefoot completely around the collar. Inspect the coating every one or two weeks and reapply as necessary. Trim away branches that touch the ground, other plants or structures as these may provide other routes for ants to access the tree.
For more information on managing ants, go to: www.ipm.ucanr.edu/ants.
Lady Beetle: Beneficial or Invasive?
By Andrea Peck
It's hard to imagine that a ladybug could be threatening. Maybe annoying or even irritatingbut
only if you haven't had your morning cup of coffee and you've just recovered from the flu or
something like that. Even then, it's more likely that you would just refrain from getting excited
over the sight of one. In our family, we usually point them out, “there's a lady bug!” For some
reason they attract inordinate attention. I blame it on the kindergarten curriculum.
The real term is lady beetle, by the way. You probably know this. The lady beetle is not a bug at
all, she is a beetle according to the people involved in Scientific Categorization and
Organization. For some reason, she has always reminded me of Mary Poppins, but there is no
line item for that, so we are stuck with lady beetle. There are many kinds of lady beetles, but it
is the harlequin lady beetle ( Harmonia axyridis) that seems to be overstaying it's welcome and
giving the beetle the name, ‘bug.'
Since 1910, the Harlequin lady beetle, also called the Asian lady beetle, has been introduced into a number of countries as a biological warfare against the much maligned terrorist group: aphids. A bit dramatic, I know. But, technically, if you are a farmer, aphids may pose a very real threat to your income and ability to bring home the bacon and fry it up in the pan.
Unfortunately, this particular breed of lady beetle is becoming invasive. Let's just say that one
reason is that this girl doesn't know when to step away from the aphid buffet table. Of course,
this is why she was selected for the job. The problem comes when there are no aphid
delectables left for the native or local lady beetles.
But, we cannot blame the healthy appetite of the harlequin lady beetle entirely. In fact, other
evidence suggests that “alien” insects, those that are introduced to an area, are far less likely to
be predated upon by native predators. In fact, one study showed that where 1 in 9 native lady
beetles were predated upon, only 1 in 100 of the Harlequin beetles were subject to the same
fate. Predators included any type of insect or animal, including parasites or pathogens.
Another study noted that the Harlequin lady beetle preferred warm weather locales and urban areas. Seems snooty to me, but the researchers conjectured that the weather, combined with the ability to overwinter inside buildings, was less lifestyle choice and more about proliferation of
the species. They added that the lady beetle has had difficulty establishing itself in coniferous
woodland, which has allowed the native species a respite from the dominant Harlequin.
Combine the above with the usual suspects the ability to reproduce with abandon and eat a
wide variety of foods and you've got trouble.
The scientific community is involved in the situation at this point the Harlequin has become
problematic across the globe. The situation may ride on the head of a red, flying pin like
creature, but nevertheless, researchers have found a silver lining in it all. By studying the lady
beetle and considering what has led to its overpopulation, scientists may gain insight into the
“how” of invasives in any form plant, animal or insect. Additionally, researchers exuberantly
noted the usefulness of the public in gaining concrete data.
That means you!
By Leslie E. Stevens UCCE Master Gardener
What can I do to reduce weeds in my landscape? Carol K. SLO
Rainfall's welcome return brings lusher landscapes and spring blossoms to our gardens. It also spawns a bumper crop of noxious invaders commonly known as weeds. Left unattended, these uninvited guests can overwhelm your prized plantings, sucking up more than their share of water and nutrients, and otherwise damaging your garden's health and appearance.
Weeds by nature tend to be highly tenacious and adaptable, requiring a multi-pronged and ongoing effort to control and eradicate. Primary tools for home gardeners include cultural practices, mechanical and physical methods, and chemicals as a last resort.
Cultural: Proper soil preparation, irrigation methods, suitable plant selections and timing are examples of cultural considerations that can have big impacts on your garden's overall success and ability to outcompete weeds. Consider laying sod rather than planting seed for a new lawn. Choose plants that fill in quickly and are well adapted to your environment. Plant more densely to discourage weed growth. Avoid sprinklers where feasible. Instead, install drip irrigation to direct water to desirable plants' roots where it's needed, thereby reducing water consumption and minimizing damp ground where weeds easily can take root.
Mechanical: Time-tested methods of eliminating existing weeds include hoeing, hand-pulling, rototilling, mowing and chopping.
Physical: Soil sterilization prior to planting provides a head-start in preventing existing seeds from germinating. Likewise, spreading mulches around existing plants makes it more difficult for weed seeds to germinate by blocking sunlight and preventing seedlings from growing through the mulch barrier. Mulches also have the added benefits of conserving moisture and moderating soil temperature.
Your best chance of combating weeds is to inspect your landscape regularly and attack the intruders before they get a chance to become established. Good hunting.
UCCE Weed Research & Information Center, http://wric.ucdavis.edu/information/info_spec_weed.htm
Weed Management in Landscapes, http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7441.html
Weed Management in Lawns, http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn74113.html
Why Plant Lavender?
By Jackie Woods UCCE Master Gardener
Spring is in the air! Giddy gardeners everywhere are day-dreaming of what plants to add to their gardens this year. Despite the glorious rain, many gardeners here on the Central Coast are leaning towards transforming their water-loving gardens into drought-tolerant ones. While researching drought-tolerant plants, why not consider the ever-versatile herb that is lavender?
There are many varieties of lavender to choose from (English vs. hybrids) but one thing is certain: they will all look magnificent in any garden. Lavender planted close together in a row will easily form a beautiful, tidy hedge; planted next to a decorative boulder, lavender looks classy and aesthetically pleasing to the eye. And, who can resist a beautiful ceramic pot with a fragrant lavender plant growing inside of it?
Lavender is a wonderfully versatile plant. There are varieties for culinary use (lavender shortbread cookies? Oh my!) as well as for essential oil production which has many applications. Lavender plants can have sweet, floral aroma or have a more intense, camphor-like smell which naturally repels mosquitoes and other bugs. Deer steer clear of it, too. When the buds are dried, they can be used in sachets to store in clothing drawers or to use in clothes dryers for fragrance. Dried lavender on stems are used dried flower arrangements. Lavender in any form is a wonderful aromatherapy tool and has a natural calming effect.
While there are many drought-tolerant plants to choose from, lavender is a very popular choice for a low maintenance and low-water use garden. Lavender prefers soil that has higher pH or alkaline soil (sandy-loam) with excellent drainage. Because of its evergreen status, lavender plants look great all year round but are especially magnificent to look at when their various shades of blue-purple blooms are on display during the late spring and summer months. When the blooms are done, simply cut the stems off where they meet the plant and you'll have an eye-pleasing, neatly-groomed plant on display.
With its sublime, relaxing fragrance, hardiness in dry conditions and extreme versatility, why not add a few lavender plants to your garden?
Irrigating With Graywater
By Andrea Peck UCCE Master Gardeners
How does recycled water affect plants? Lynn, Los Osos
The drought has a powerful effect on us all, causing us to reduce and reuse where we can. But what effect does “already used” water have on your plants? Researchers continue to look at the long-term consequences of graywater on plants and the environment, but one thing remains clear: what you use to water your plants matters.
Graywater includes water from the bathroom sink, bathtub, shower and clothes washer. Black water, which should not be recycled for home use, includes water that comes from the toilet, kitchen sink and dishwasher. Studies indicate that black water may contain high levels of contaminants that can be hazardous to humans and pets.
Graywater, on the other hand, is a little bit of both. Some elements of graywater are actually beneficial--healthy microbes nourish the soil and the phosphates that make up soaps and detergents serve as a plant fertilizer.
However, graywater often contains salts, particularly if your home has a water softener. Salts can build up in the soil and create a barrier that reduces the ability of the plant to take up water.
Boron is another unfriendly addition that often flows with your graywater. Boron is commonly used in laundry detergents and though it is a necessary mineral, it can quickly become toxic. Plants with excessive boron may develop burned spots.
Chlorine bleach kills whatever you throw in its path and will definitely take its toll on your plants.
Despite these roadblocks, there are a number of ways in which you can get the most for your efforts. Make sure you set up your washing machine properly. A basic laundry-to-landscape system is not complicated, but it should include a valve that allows you to switch from sewer or septic and back to landscape. When using detergents, you may choose to use only the ‘rinse' portion of your wash. Refrain from using graywater on potted plants, root vegetables and the edible portion of the plant. Finally, keep a close eye on your plants--you may be the best judge!
For more information about greywater in the landscape visit http://ucanr.edu/sites/mgslo/files/230135.pdf