Q. My apple tree has some kind of bug that has infected the fruit and as a result it has worms in the apples. What can I use to get rid of these unwelcome visitors? August 2014
A.
The worms are probably the larvae of the codling moth.
Here is an article from Planet Natural (www.planetnatural.com) on non-toxic control of this pest. It’s not quick or easy, but with persistence should be effective.
The Monterey Bay chapter of the California Rare Fruit Growers recently organized a members-only tour of a local citrus nursery’s growing grounds, in Watsonville.
Aaron Dillon, our tour guide, shared the history of Four Winds Growers, which was started by his great grandparents. He described the current operations and the pests and diseases that are challenging the entire citrus business.
One threat to citrus trees is the citrus leafminer (Phyllocnistis citrella), a very small Asian moth that lays its eggs in the tissue of citrus leaves. The eggs hatch into larva that feeds on the leaf, leaving a clearly visible, serpentine trail just below the surface of the leaf. Leafminers disfigure the leaves but rarely cause serious damage.
A greater threat is the Huanglongbing disease (HLB), which is known by the common names “citrus greening disease” and “yellow shoot disease.” HLB kills citrus trees.
A tiny insect, the Asian citrus psyllid, transfers this disease from tree to tree as it feeds. Because there is no cure for HLB, the control strategy is to find and stop the insect from spreading the disease. This pest has greatly reduced southern California’s citrus nursery industry, and has very recently been spotted in the San Jose area.
The citrus industry has developed regulations and procedures for propagating citrus trees in greenhouses, while keeping Asian citrus psyllids outside. The tour group entered an enormous greenhouse through an antechamber, in which a large fan produced positive air pressure to exclude any psyllids. The outer door closed, the fan was turned off, and an inner door opened to allow the group to enter the working area of the greenhouse.
Inside, a greenhouse worker, Alicia, expertly demonstrated the process of grafting a citrus scion to a robust rootstock. A skilled worker can graft 1,000 plants in a single day.
Aaron Dillon engaged the interested visitors with a wide-ranging presentation of many aspects of growing citrus trees. He demonstrated the extensive facilities in a large greenhouse where roses had been grown previously, and proudly showed an even larger new greenhouse now being readied for an expansion of propagation activities.
Now Amazon has a new line of products made of citrus, specific for eye care, a example is amazon eye masks.
Four Winds Growers propagates popular varieties of orange, mandarin, lemon, lime, grapefruit, and kumquat. For details, visit the nursery’s website <wwwlfourwindsgrowers.com> and click on “Our Citrus Trees.” Dillon listed three interesting varieties that consumers will enjoy in the future:
For information on these and many other varieties, browse to the amazing Citrus Variety Collection website, maintained by the University of California, Riverside <http://www.citrusvariety.ucr.edu/>.
Many varieties of citrus trees grow well in the Monterey Bay area, and local nurseries have many choices in stock currently. Growing information is readily available on the websites of the California Rare Fruit Growers < www.crfg.org/> and Four Winds Growers. Pest control advice for home gardeners is offered by the Citrus Pest & Disease Prevention Program www.californiacitrusthreat.org/.
Autumn in the garden is a good time to prepare for relocating shrubs or trees that would look or grow better in a different location.
If the thought of moving a shrub or tree troubles you, recognize that even good plants need not be permanent. Here are some reasons for moving a healthy shrub or tree.
When preparing to relocate a plant, first decide on where it will go. Examine the new location to ensure that it is the right place for this particular plant. Confirm that the soil is suitable, the drainage is good, and the exposure it right for the plant. Finally, make certain that the new spot could accommodate the plant when it is fully grown. Then, dig a hole twice the width of the intended root ball.
Ideally, prune the roots to protect against transplant shock. This involves digging a trench around the plant, outside the intended root ball, refilling the trench and watering to settle the soil. Root-prune in March for plants to be moved in October, and in October for plants to be moved in March.
Then, plan how to move the plant, taking its size into consideration.
Small Shrubs and Trees
For a shrub less than three feet tall, or a tree with a trunk is less than one inch wide, you could move it bareroot, i.e., without digging up a root ball. To move such a smaller plant bareroot, dig a trench around it, cutting the longer roots, wash the soil off the lateral roots, and use a flat shovel to remove the soil under the plant. Keep the roots moist until you are ready to transplant.
Not-so-small Shrubs and Trees
If you are preparing to move a plant that is between three and five feet high, decide how large a root ball to provide. For industry standards for transplanting different plants of various sizes, visit the website, americanhort.org and search for “root ball.” For example, moving a five-foot tree or shrub requires an eighteen-inch wide root ball. A root ball of that size could weigh 250 pounds, so plan for the appropriate equipment and helpers.
Larger Shrubs and Trees
Most gardeners will hire a tree service to move a tree or shrub that is larger than five feet high. If you prefer to do such work yourself, I will say “best wishes,” and predict that you will have professionals do your next transplant.
Really Large Trees
Even very large trees—up to forty-five feet high—can be moved successfully, if not cheaply. The widely available tree spade uses an array of large shovels to dig a conical divot to pluck a plant from the ground, and deposit it in a matching hole. For video clips of tree spades in various sizes, browse to YouTube.com and search for “tree spade.” To see an interesting DIY device, search YouTube for “Tree Toad 24 inch Tree Transplanter.”
A mechanized tree spade makes transplanting large bushes and small or medium trees a much easier proposition. Photo: Dutchman Industries
A newer technology for moving larger plants is the “air tool,” which uses compressed air to blow soil away from a tree’s roots. This bareroot method avoids pruning or breaking the roots, so the plant experiences little trauma and quickly resumes its usual growth cycle. To see a brief video demo of the air tool, visit growingwisdom.com, click on “Trees & Shrubs” and scroll to the link, “How to Move Large Trees Using an Air Tool.”
After moving a tree or shrub, transplanting herbaceous perennials is easy!
Codling moths are serious insect pests of apples. If your apples have “worms,” you probably have codling moths.
Life Cycle of the Codling Moth
The codling moth’s life cycle has an important stage in the soil or organic debris around the base of your apple tree. The full-grown larvae of the moth, in silken cocoons, overwinter in this environment, and develop into adult moths around mid-March to early April.
The moths fly into the tree to mate and deposit their eggs on the leaves, spurs or immature fruit. They are one-half to three quarters inch long, with a dark band at their wingtips. They can be difficult to spot because their colors blend with the tree’s bark, and they are active for only a few hours before and after sunset.
The eggs hatch in early to mid-May, and the young larvae tunnel into the core of the fruit and eat their fill, leaving behind reddish-brown frass (insect waste).
After they develop fully, the larvae drop from the fruit and tree to continue their life cycle in the soil or debris at the base of the tree.
A second generation often occurs in cooler coastal environments such as the Monterey Bay area, with the new group of young larvae attacking the fruit in mid-July.
Management of the Codling Moth
Organic pesticides for home gardeners are CYD–X Insecticidal Virus, which infects and kills the larvae of codling moths, and Spinosad, which is a nerve and stomach poison derived via fermentation from naturally occurring bacterium. These products might be found in a garden center; or can be ordered from GrowOrganic.com or other online sources.
Apply insecticide sprays as the eggs hatch and the larvae begin to attack the fruit and make the first “sting” (a tiny mound of frass on the fruit, marking a larva’s entry). Timing can be tricky, because temperature and other factors affect the moths’ schedule. For example, mating occurs only when sunset temperatures exceed 62 degrees Fahrenheit.
A Good Reference
The primary source of information for today’s column is the University of California publication, “Codling Moth: Integrated Pest Management for Home Gardeners and Landscape Professionals.” For additional approaches to management of these pests, download this free publication at www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7412.html.
Managing an established population of codling moths will require both insecticide sprays and additional methods. For example, sanitation, always a good practice, involves promptly removing infested and dropped fruit.
Eating a fresh apple from your own tree can be delightful, but you might have to compete with the wildlife.
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Here is one of several Spinosad products that have been formulated and packaged for home gardening. This products is available in gardens centers and online from Peaceful Valley ,
Monterey Garden Spray Concentrate – Spinosad (Pint)
$19.99 + $9.99 shipping
Spinosad for home gardeners Use on vegetable and fruit crops, ornamentals, and turf to control caterpillars as well as beetles, leafminers, thrips, Colorado potato beetles, fire ants and more! Use 4 Tbs/gal water. Spinosad insecticides are nerve and stomach poison derived via fermentation from naturally occurring bacterium Saccharopolyspora spinosa. New chemistry represents an alternative to Bt for worm control and offers excellent control of targeted pests and low toxicity to non-target organisms, including most beneficial insects. Low mammalian toxicity, helps conserve beneficials.
Each year, around now, I plan to spray my four small apple trees and indulge my optimistic vision of harvesting apples that are beautiful, tasty and—most of all—free of worms.
My apple trees include a small Fuji, a Gala espalier, a second espalier with eight familiar varieties of apple and my prize: a dwarf Cox’s Orange Pippin, originally from England. Here is Wikipedia’s description:
“Cox’s Orange Pippin is highly regarded due to its excellent flavour and attractive appearance. The apples are of medium size, orange-red in colour deepening to bright red and mottled with carmine over a deep yellow background. The flesh is very aromatic, yellow-white, fine-grained, crisp and very juicy. Cox’s flavour is sprightly sub-acid, with hints of cherry and anise, becoming softer and milder with age…One of the best in quality of the English dessert apples; Cox’s Orange Pippin may be eaten out of hand or sliced.”
The worms that ruin these great apples annually are the larvae of the codling moth (Cydia pomonella).
My usual plan of attack has been to spray the tree three times with horticultural oil, before it sets buds, to smother insects as they hatch. I have never accomplished this task in a timely and thorough manner, and never had satisfactory results.
This year, I learned that horticultural oil treatment can eliminate aphids, but has no impact on codling moths or other pests that attack the fruit. A fruitless strategy!
I mentioned my concern this week to a member of the California Rare Fruit Growers, who said he has a detailed regimen for treating the soil around his trees, has never sprayed and has no pest problems. At the moment, I couldn’t write down his method and it seemed like a long-term process anyway, so I researched the issue.
Valuable advice is available from Michael Phillips’ highly regarded book, The Apple Grower: A Guide for the Organic Orchardist (2nd edition, 2005). He advocates treating the soil to promote the development of fungi that help trees to deal with pests and diseases. This might be the method practiced by my CNGF contact.
Apple farmers use two effective new organic products: Surround, a spray that coats apples with insect-repelling kaolin clay, and Entrust, based on Spinosad, a poison that is derived from naturally occurring bacterium. These products are sold in commercial quantities for licensed users.
Spinosad is also available in smaller quantities for usage by unlicensed home gardeners, in Captain Jack’s Dead Bug Brew, Green Light Lawn & Garden Spray with Spinosad 2, Monterey Garden Insect Spray and other products.
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Entrust, a Spinosad product, is available only in larger quantities for commercial fruit growers. Here is an example of one such product, Entrust.
Entrust 80 WP – Spinosad (1 LB) – PBI400
$599.00 This product qualifies for $9.99 flat rate shipping in the Continental US.
This is a special order item. Please call 888-784-1722 to place an order.
This product is not registered for sale in the following states: PR
Pesticide ID # is required for all CA commercial growers AND all Nevada County, CA residents
Spinosad insecticides are nerve and stomach poison derived via fermentation from naturally occurring bacterium Saccharopolyspora spinosa. New chemistry represents an alternative to Bt for worm control and offers excellent control of targeted pests and low toxicity to non-target organisms, including most beneficial insects. Low mammalian toxicity, helps conserve beneficial insects.
Dry formulation of spinosad labeled for cole crops, corn, cucurbits, fruiting and leafy vegetables, pome fruits, potatoes, stone fruits, strawberries, bushberries and cranberries. Controls caterpillars, certain beetles, thrips and leafminers, including many pests prone to resistance problems such as diamondback moth, cabbage looper, fall armyworm and Colorado potato beetle. For Colorado potato beetle, use only every other year to help prevent resistance.
Apply .5 – 2 oz per acre.
Note: At the recommended application rate, one pound of Entrust would be enough for on treatment for between eight and thirty-two acres of crops. Other information sources indicate that multiple treatments may be required, because the coating can be rubbed or washed off easily.
Happily, Spinosad products are available in both commercial quantities and smaller quantities for home gardens. See the following essay: “Apples Without Worms, Part 2”
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Surround, a spray based on kaolin clay, seems interesting for commercial fruit growers, but appears not to be available (yet) in quantities that are appropriate for small orchards in a residential garden. Here is an example of a commercial product:
Surround WP (Kaolin Clay)
$37.50/25 lb. bag at Planet Natural.
Made from modified kaolin clay, Surround WP Crop Protectant is sprayed on as a liquid, which evaporates leaving a protective powdery film on the surfaces of leaves, stems and fruit. Controls a long list of insect pests on vegetables, fruit trees, ornamental plants s and more. OMRI Listed for use in organic production.
Surround works to protect plants and deter insects in three specific ways:
DIRECTIONS FOR USE: Application rates are dependent on the amount of foliage
that needs to be covered. Mix 1/4 to 1/2 lb. per gallon of water (25 to 50 lb. per 100 gallons of water per acre). May be applied up to the day of harvest.
Active Ingredient: Kaolin ….. 95.0%
Inert Ingredients: 5.0%
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Surround WP Kaolin Clay – Insect Repellent
Description Surround W. P. is made from 95% kaolin clay, a naturally occurring mineral. When applied to fruit trees, crops, and other plants, it forms a white film. Surround suppresses a wide range of pests, especially those that damage fruit crops including pears, apples, grapes, berries, and some vegetables. It can be applied up to day of harvest and is easily rubbed off when the fruit or produce is ready to eat.
Surround can help control pests such as: pear psylla, cutworms, pear midge, pear slug, apple sucker, climbing cutworm, eastern tent caterpillar, gypsy moth, Japanese beetle, June beetle, grasshoppers, green fruit worm, leafrollers, lygus bug, Mormon cricket, cicada, stink bug, tarnished plant bug, thrips, fabria leafspot, apple maggot, codling moth, plum curculio, rose chafer, aphids, naval orangeworm, husk fly, blueberry maggot, blackberry psyllid, flea beetles, orchards, grape leaf skeletonizer, bean leaf beetle, Mexican bean beetle, powdery mildew, cucumber beetle, boll weevil, armyworm, black vine weevil, and fruit flies.
How it works Insects are repelled by Surround. It sticks to their body parts and encourages them to move on elsewhere. At harvest time, the white film can be removed simply by rubbing off.
General usage: Use in orchards, fields, vegetable gardens.
Advisories Do not apply directly to water, or to areas where surface water is present or to intertidal areas below mean high water mark.
Application rates General rate varies between 25 – 50 pounds per 100 gallons of water. Amount of water used will depend on amount of foliage to be treated.
Apple half-treated with kaolin clay
Some might regard November as the beginning of the dormant season, with little or nothing for gardeners to do until spring. Not true!
Beginning now, we can pursue selected gardening projects will pay off later in the year. Still, the garden does not demand intensive work and daily dedication by the gardener during this season. It’s quite all right to take time off to celebrate the holidays, avoid nasty weather, and otherwise enjoy life’s many pleasures out of the garden.
There are many good gardening projects to do now in the garden; let’s consider three projects that are worth attention during November.
Plant Cool-season Ornamentals and Edibles
Visit your local nursery for cool-season flowers, e.g., pansies, calendula, candytuft, foxgloves, snapdragons, stock, sweet peas, and sweet alyssum.
Plant seedlings of cool season vegetable such as broccoli, carrots, cauliflower, chard, lettuces and greens, cabbage, potatoes, radishes, peas, bunching onions, and spinach.
Look for six-packs of seedlings at garden centers or farmer’s markets.
Plant Pacific Coast Irises
Several beardless iris species are native to the Pacific coast. Because they cross with each other freely, they are often referred to either as PCIs or Pacific Coast Hybrids (PCHs). Most common locally is the Douglas Iris (I. Douglasiana), named for David Douglas (1799-1834), who was the first botanist to describe this plant as it grew in the Monterey Bay area.
PCIs can be grown from seed, but more often from divisions. After listing a mature PCI clump, pull the stalks apart and store them in water for a few days as they develop white roots at least a half-inch long. Then, plant the divisions and keep them moist until four new leaves appear. Seasonal rains could be sufficient to establish the divisions.
Move Perennials and Shrubs
Plants vary in their ability to tolerate relocation. Roses and hydrangeas, for example, adapt quickly and easily to being moved, although they appreciate careful handling: lifted without being damaged, moved to a hospitable location (full sun for roses; morning sun and afternoon shade for hydrangeas), and watered in.
Generally, it is easy to move plants that tolerate rejuvenation pruning, e.g., abelia, dogwood, honeysuckle, hydrangea, lilac, mallow, penstemon, rose, Rose-of-Sharon, salvia, spirea and many others.
Shrubs with fine root systems, e.g., azaleas and rhododendrons, do not respond well to being moved.
For information on specific plants, search the Internet using the plant’s common or botanical name. Visit ongardening.com for successful search methods.
At this time of the year, plants are dormant, but not gardeners!
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The Yerba Buena Nursery website has a helpful pruning calendar for California native plants.
The National Gardening Association has brief but solid advice on dividing perennials.
SF Gate has suggestions for adding edible perennials to your garden. Right now is a good time. Some recommended plants might be unfamiliar: tree kale, yacon, ground cherries, chayote and banana passionfruit (Passiflora mollissima). Still, they might be turn out to be welcome new “friends.”
Master Gardener Marie Iannotti, writing on Ask.com, offers a good overview of pruning for several categories of garden plants.
To find information about specific plants in your garden, start by learning their botanical names. (Search ongardening.com for more information on botanical names.)
Then, using Google or another search engine search for the botanical name of the plant, plus “cultivate” or a more specific verb representing want you want to know. Include the variety name, when you know it. Examples:
Rosa minutifolia transplant
Hydrangea paniculata divide
Salvia greggii ‘Heatwave Glimmer’ prune
Spring has arrived! Our days grow longer from the Vernal Equinox (March 20) until the Summer Solstice on June 21. This season inspires gardeners to focus anew on their gardens.
To be sure, avid gardeners have diligently pursued dormant-period priorities and planted before the rainy season, and their landscapes are now in good condition. But many have taken a break during recent months.
This is the time when gardeners aspire to planting vegetables mostly for the pleasure of seeing edibles develop in their gardens. A vegetable patch might or might not save money, depending on how it is planned and implemented, but it reliably satisfies gardeners of any age and is particularly gratifying for kids.
For novice gardeners, however, creating a vegetable garden can be a daunting prospect. It often seems like a lot of work and mysterious requirements, and the impulse evolves quickly to “maybe next year.”
Fortunately, we have great new resource for just this situation: the 2nd edition of Mel Bartholomew’s classic garden book, “All New Square Foot Gardening.” Earlier versions were published in 1981 and 2007, and this new edition expands upon those bestsellers.
The result is an exceptionally clear and complete explanation for an efficient, cost-effective method for growing vegetables in the home garden.
The insight for square-foot gardening is while growing vegetable in rows works well for commercial farmers, home gardeners could use their space better and meet their food needs more accurately and efficiently with modular “square-foot” gardening.
The basic plan is a raised bed, four-feet square, with sixteen planting beds. Each one-foot square can be planted with one large vegetable, such as broccoli or cabbage, or up to sixteen smaller vegetables, e.g., onions or carrots.
The book includes multiple variations: repeating the basic plan as needed for a large family, adding a trellis for vining plants, planting on a patio or balcony, etc.
Bartholomew describes each step of garden development in detail, with lucid photographs. The process is easily applied by most gardeners, and the author’s website www.squarefootgardening.org/ offers more information and a range of useful products.
If you have postponed your desire to grow vegetables, this book will help you to discover a satisfying and successful adventure with edible gardening. If you are already gardening in rows, square-foot gardening will help you to create a more efficient, more manageable approach.
Enjoy your garden!
Gardening is usually an individual, contemplative activity. Sometimes, we engage in planting, pruning, weeding and other tasks with a friend or a group of friends.
Countless gardeners have pursued this satisfying work for millennia, unconcerned by the larger context of advances in agricultural technology, political and economic struggles and growing concerns over sustainability.
Such issues abound in the world of ornamental horticulture, but are more intense and consequential in commercial farming.
These issues are the focus of the 33rd Annual Eco-Farm Conference, which happens next week at the Asilomar Conference Grounds in Pacific Grove. This event, organized by the non-profit Ecological Farming Association, is about educating, networking and celebrating. It combines joyful commitment to farming organically, sharing ideas and successes in the field, and exploring concerns over policies and practices that favor so-called “conventional” farming.
In fact, “conventional” farming depends on synthetic chemical fertilizers and pesticides, and employs practices that have been introduced since World War II. Many advances have made large-scale agriculture more efficient and productive, but too often those advances also generate social impacts: fewer natural food choices, declines of taste and nutrition and long-term damage to the environment.
Such alleged problems of course are debatable. We cannot treat them fully in this brief essay, but the Eco-Farm Conference supports valuable in-depth discussions.
Many of the Conference’s sixty workshops are designed for professional farmers, but here are some sessions that relate most directly to consumers.
The Eco-Farm Conference runs from Wednesday, January 23rd to Saturday, January 26th. For more information, visit the conference website: http://ecofarm2013.org/.
This conference presents a positive vision of the future for all consumers and home gardeners. It is gratifying that it happens in the Monterey Bay area.
Yes, even weeds can be interesting. Here are two examples.
First, I’ve written about the “weed seed bank” that exists in all gardens. This inventory of dormant seeds lurks in the top few inches of soil, waiting for life-giving sunlight, air and moisture.
The weed seed bank results from earlier generations of weeds that dropped their seeds under the plant, projected them a few feet away or cast them to the winds for wider distribution. Such seeds might also be brought to the garden as the undigested part of a bird’s meal, tracked in on a visitor’s clothing, or imported with a plant from a friend or the local nursery. Whatever the source, they are part of every garden.
The weed seed bank might be called simply the seed bank, because it includes wildflowers and other garden-worthy plants as well as weeds. Abandoned gardens eventually sprout their hidden wealth of weeds and wildflowers.
Weed seeds can remain in the soil, ready for germination, for several years. Gardeners are wise to use mulch to discourage the germination of weeds and help realize “low maintenance” gardening.
Dormant seeds can be amazingly long-lived under the right conditions. Earlier this year, Russian scientists reported their discovery in Siberia of seeds that a squirrel had buried in the Early Pleistocene era, about 31,800 years ago. The seeds soon were frozen in permafrost and didn’t thaw until retrieved by the research team. With great care, scientist Svetlana Yashina cared for the seeds, which germinated and produced a flowering plant and a new generation of seeds.
The plant is the Narrow-leaved Campion (Silene stenophylla), once known by mammoths and wooly rhinos. An evolved form of this plant grows today in Arctic regions. The genus Silene includes many species, including several wildflowers of Europe and elsewhere in the Northern Hemisphere.
The story of bringing this prehistoric plant into blossom raises the possibility that more plants could be recovered from frozen seeds in Siberia, the Arctic and the Yukon, and the intriguing prospect for the gardeners to grow prehistoric weeds and other plants. Examples of other specimens include the Sago Cycad (Cycas revoluta) and the Maidenhair Tree (Ginkgo biloba). Both of these plants, which are distant relatives, have fossil histories from more than 250 million years ago, and are available today as young plants.
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A second example of interest in these lowly plants involves harvesting them for the dinner table. Dandelions and purslanes are only a beginning. A new cookbook, Foraged Flavor: Finding Fabulous Ingredients in Your Backyard or Farmer’s Market, by Tama Matsuoka Wong, with chef Eddy Leroux, describes many culinary and nutritional benefits of several common weeds. Ms. Wong’s website, Meadows and More, offers more details and an extensive weed identification section.
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For more about the prehistoric Narrow-leaved Campion (Silene stenophylla), including pictures, browse to the article in Discover magazine.
Another interesting ancient plant is the Amborella trichopoda (no common name), which has been called “the most primitive living flowering plant.” It may be the earliest of the angiosperms: flowering plants that emerged about 130,000,000 years ago. A useful article about this plant is available on Wikipedia. This Arboretum at the University of California, Santa Cruz is the only place in the United States that is growing this plant for botanical study. For a 1999 article on the Arboretum’s work with this plant, click here.
For more information on the book, Foraged Flavor, browse to the New York Times article.
Ms. Wong’s website, Meadows and More, has a wealth of information on culinary uses of common weeds, and an extensive series of weed photographs, with expert identifications.
For identification of weeds that are common in California, visit the Weed Photo Gallery on the University of California’s Integrated Pest Management website.
