- Author: Help Desk Team
Now that the leaves have fallen, or mostly fallen, from your backyard fruit trees, are you wondering whether you should apply dormant sprays?
“Dormant sprays” or “delayed dormant sprays” are terms used for the application of pesticides when the tree is dormant or just coming into bud swell. The pesticide could be a fungicide used to help manage fungal disease or a horticultural oil or oil in combination with insecticides to kill insects.
Don't assume that you need dormant spray. Before reaching for the spray, first determine whether your trees have previously had a disease or serious insect pest problem that can be managed with dormant sprays. Have you already tried all non-chemical recommendations for lessening the problem? Finally, evaluate the amount of damage from the disease or insect pest you experienced in the prior growing season to decide whether a pesticide is really needed.
Fruit tree diseases that can be managed by applying a fungicide dormant spray include peach leaf curl, brown rot, and shot hole disease.
Peach leaf curl affects only peach and nectarine trees. It shows up in spring after the tree has leafed out. Leaves are thickened, curled, and colored red or yellow instead of normal green.
If your tree has had significant peach leaf curl in prior years, dormant spraying with a fixed copper spray just after all the leaves have fallen from the tree (usually December to January in our County) may prevent or reduce the severity of the disease. For information on managing peach leaf curl, see https://ipm.ucanr.edu/PMG/PESTNOTES/pn7426.html/
Brown rot (Monilinia) is a fungal disease that can affect peaches, plum, cherries, apricots, and nectarines. In the spring blossoms on infected trees shrivel and die, often clinging to the twigs. Leaves at the base of infected twigs may also turn brown and die. Fungal spores attach themselves to developing fruit and show up as brown or tan spots on the surface of the fruit.
If your trees had significant fruit loss from brown rot in the prior growing season, a dormant spray of a copper-based fungicide may help. Apply it at the pink bud stage while flower buds are still tightly curled and pink in color. For more information on brown rot, see http://ipm.ucanr.edu/PMG/GARDEN/FRUIT/DISEASE/aprbrownrot.html.
Shot hole (coryneum blight) can affect plums, nectarines, peaches, cherries, and especially apricots. It shows up as small reddish holes on leaf surfaces. Often the holes turn brown and drop out. Fruits may also be infected. Where disease has been severe and cultural steps haven't helped, a fungicide spray following complete leaf drop may be needed. See http://ipm.ucanr.edu/PMG/GARDEN/FRUIT/DISEASE/shothole.html.
Insects that can be managed with dormant sprays of horticultural oils or oils mixed with insecticides include scale, aphids and spider mites. Don't spray unless you have confirmed that the insects are present in damaging numbers and cannot be controlled by other means. Keep in mind that spraying may also kill beneficial insects which are the first line of defense against insect pests. More information on controlling these insect pests can be found at these UC websites: http://ipm.ucanr.edu/QT/scalescard.html, http://ipm.ucanr.edu/QT/aphidscard.html and http://ipm.ucanr.edu/QT/spidermitescard.html.
Before spraying, read and carefully follow the label instructions on the pesticides you use, including wearing recommended protective gear.
If you want to add another fruit tree to your home orchard, stay tuned for an upcoming Blog article on Selecting and Planting Bare Root Fruit Trees to be published in December. If you want to be sure you can get a specific variety of fruit tree, contact your local nursery. The nursery may be able to reserve it for you, or if necessary, special order it for you.
Help Desk of the UC Master Gardener Program of Contra Costa County (TKL)
- Author: Help Desk Team
Christmas cactus will be in bloom soon, available at your local nursery and home and garden store, in many stunning colors to brighten our shorter days. Their bloom time can range from November to January, just when we could use that emotional lift the most.
Many people purchase these beautiful plants for themselves or receive them as gifts. They keep them during their bloom time to brighten their home, and then dispose of them once the bloom is gone. This time, this year, seriously consider caring for them during their off season. It will reward you this time next year with a bigger plant and no new purchase necessary.
Christmas cactus is the common term that nurseries use for any variety of Schlumbergera truncata or Schlumbergera x buckleyi. Plant breeders in their quest for more unique colors have created so many varieties of each that nurseries typically no longer provide the scientific names. One can tell the genetic lineage of their plant though by the shape of the stem segments.
S. truncata has a crab claw-like shape to its flat, fleshy stems which have ‘teeth' along the edges and at the tips of the branches. These are also known as Thanksgiving cacti because they bloom earlier than S. x buckleyi, the true Christmas cactus. S. x buckleyi stems are also flat and fleshy but with smooth scalloped edges.
While the lineage is interesting, the care and maintenance is the same for all varieties. The name ‘cactus' gives one the image of a plant that lives in desert sand; this is not that kind of plant. Its native origins are the tropical rainforests of Brazil, where it lives not in soil but in plant debris on other plants, where it would get its water and nutrients from the humidity around it. Due to its native habitat, one would think that caring for it here in our climate would be close to impossible, but not true!
In the home, these cacti require bright but filtered light near a south-facing window. They do best in 50–70 degrees F. During warmer months they can live on a sheltered patio. In order to mimic their native growing conditions, the potting soil should be loose and fast draining (for example, 40% perlite and 60% coconut coir). They like air around their roots, so it should dry out a bit between waterings. To induce bloom for the next holiday season, starting in mid-September, give it cool nighttime temperatures (50–55 degrees F), 12–14 hours of darkness, and reduce watering to compensate for slowed growth.
Schlumbergera species can be quite long lived. Given the right care they can brighten your living space for decades. Detailed care and reblooming instructions can be found at the link below in the UC publication titled Holiday Cacti. If you give one as a gift, include the publication below and hopefully the recipient will be able to enjoy it for years.
https://anrcatalog.ucanr.edu/pdf/8114.pdf
Help Desk of University of California Master Gardener Program of Contra Costa County (EDC)
- Author: Help Desk Team
It's time to get ready for cold winter temperatures and to start preparing protection for citrus trees and other frost-sensitive plants. Depending on where you live in Contra Costa County, your first frost date may be as early as Halloween. However, November 15 is often thought of as a first frost date in much of our County, with slightly earlier in the eastern portion and later in the more temperate West County areas. Because significant climate variation can occur, it's good to start thinking of frost protection early, before you need it.
Frost can start to occur when the temperature gets below 36°F and is sure to happen at 32°F. When temperatures drop below 32°F, it becomes a freeze, and if it drops below 28°F, it's a hard freeze.
Protecting plants when temperatures drop in the Bay Area can be done using three simple elements:
Water: It may seem counter intuitive, but water can provide protection from freezing temperatures. When dry soil freezes, moisture is pulled from the roots, causing damage. If the soil is moist, it can freeze without harming roots. Wet soil also holds more heat than dry soil. When the forecast calls for 32°F or below at night, water the ground around your plants lightly in the late afternoon or early evening. The exceptions to watering plants before frosty temperatures are succulents. They need to be kept dry when a freeze is expected if you can't move them into a warmer spot.
Frost Covers: Protect tender plants and trees with frost covers either purchased or homemade. Sheets, blankets, tarps, or burlap can be used, but these need to be propped up above the leaves and removed in the morning. These materials can become wet with dew and damage sensitive leaves. Commercial frost cloth comes in several weights and can provide up to 4°F protection (find it at your local nursery or home and garden store). It can float over the top of the plants and can be left on for several days since light can pass through it. For very sensitive plants, make sure the cover goes all the way to the ground. If very cold temperatures are forecast, also wrap the trunk of a young citrus tree with cardboard to protect the bud union and above.
Covering or tenting should be done in the late afternoon or early evening when freezing temperatures are predicted, then removed in the morning after frost has thawed to allow for healthy air circulation and to allow the soil to warm in the sun.
Heat: Moving potted plants indoors, into a greenhouse, or even grouping them together under a tree or house eaves to conserve heat will give enough protection for many plants. A light bulb (100-watt designed for outdoor use) or Christmas lights (old-fashioned incandescent type lights—LED lights do not emit enough heat to help) under a frost cover can add additional heat. Make sure you use extension cords and lights rated for outdoor use.
If plants have suffered damage from frost, wait to prune until spring. Frost-damaged areas on plants can add protection to parts below if there is another freeze. You also don't want to stimulate the plant to put out new tender growth that would surely be damaged in another frost.
Following is a link to a UC publication titled Frost Protection for Citrus and Other Subtropicals: https://anrcatalog.ucanr.edu/pdf/8100.pdf
Help Desk of University of California Master Gardener Program of Contra Costa County (SEH)
- Author: Help Desk Team
Garlic has been part of agriculture for at least 5000 years and is thought to have been brought to the Americas by Columbus. There is much folklore associated with it, from treating warts to fighting off vampires! Garlic, leeks, and shallots are members of the onion family (alliums) and are great cool-weather crops for winter gardens in our area. They are easy to grow and do not take up a great deal of garden space.
Growing conditions are similar for most members of the Allium family. They need reasonably fertile soils (amend with compost), but must have good drainage as bulbs may rot in soggy soils. They also like a sunny spot. The links given below each variety give more information on how to grow them.
Garlic
Garlic is best planted in October or November and will be ready to harvest in June or July. It is started from ‘seed garlic', individual cloves separated from a garlic bulb. Good quality disease-free seed garlic from a nursery should be used, rather than grocery-store garlic. You can also use bulbs saved from last year's crop. There are many different varieties of garlic, with varying degrees of flavor and spiciness.
These fall into two main types: Softnecks are the ones found in grocery stores and have a flexible stem which can be incorporated into braids. California Late White and Early White are examples of softneck garlic. They store well. Hardnecks or Rocambole tend to have larger cloves and more flavor variations. They have a stiff central stem between the cloves, hence the name! They are better suited to a colder climate than ours in the Bay Area, and do not store as long as softneck garlic. Nonetheless, many of us grow hardneck garlic successfully.
http://ipm.ucanr.edu/home-and-landscape/onions-and-garlic/cultural-tips/
https://vric.ucdavis.edu/veg_info/garlicprodtips.htm
https://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=43862
Elephant Garlic
This looks like a giant garlic bulb but is actually closely related to leeks. It has a milder flavor, with big flower heads and foliage reaching to 4 feet tall. Fun to grow with kids!
Shallots
Shallots are mild-tasting onion relatives and are much-used in gourmet cooking! They can be grown from seed, but often the individual bulbs are planted in a similar fashion to garlic and will form a new cluster as they grow. Drainage is especially important for shallots, as the bulbs will rot if they remain too wet. https://ucanr.edu/sites/mgscc2016/files/333041.pdf
Leeks
Leeks may be planted from seed, but also seedlings can be very economically purchased from a nursery. Leeks like regular water, but as with their relatives, good drainage is essential. They are often planted in a trench with soil being gradually added as they grow to create the blanched stems usually associated with leeks.
https://sonomamg.ucanr.edu/Vegetable_of_the_Month/Leeks/
Conclusion
Growing alliums in winter is a great way to keep your garden producing during the cooler months. If we end up having a good rainy season, these plants will be watered with free water. If not, keep watering during the dry spells so the plants continue to grow.
Help Desk of University of California Master Gardener Program of Contra Costa County (SMW)
- Author: Help Desk Team
For most of the Bay Area we had an unexpected but wonderful seasonal surprise – RAIN. This blessing provided a drink of water to plants that we have had to ignore due to water rationing.
We were not the only ones waiting for that first seasonal rain. Subterranean termites were waiting for that cue to emerge from the soil and party. Winged reproductives leave the underground nest in swarms to seek out a mate and then search for a new nest site. You may have seen them flying in swarms or on the ground exiting or landing on the soil.
They generally fly less than 300 feet from their emergence point. Their goal may be thwarted though, as this ritual exposes them to predation by birds, reptiles, spiders, and other insects. Most of the reproductives don't survive the feeding frenzy.
The most common subterranean termites, Reticulitermes, can be encountered in nearly all regions of the state. It can swarm in fall or spring and both situations are warm days following rain. They are not very big, less than one-half inch long including the wings, which are silvery-gray and twice the length of the body itself.
When not involved in the mating ritual, they live in the soil. Subterranean termites require a moist environment, and living in the soil and feeding in dead and decaying wood meets that need.
Termites are decomposers which benefit the environment. Unfortunately for us, dead wood includes structural lumber of which our homes or outdoor structures are made.
Since most soil around a home has buried wood debris (roots, stumps, or fence posts), finding swarming termites in your yard doesn't necessarily mean your house is infested. If you see a swarm on your property, do you have a problem? Possibly.
Andrew Sutherland, University of California's Urban Integrated Pest Management Advisor for the Bay Area, wrote in his blog: “If observing a swarm on your property, especially if near your home or other structures, you can hire a professional termite company for a detailed inspection. Make sure to photograph or otherwise note the swarm location so that the inspector can start there.”
If you would like additional information on subterranean termites, including recognizing their activity in and around the home and management options, check out the following link to UC IPM's Pest Note titled Subterranean and Other Termites.
http://ipm.ucanr.edu/PMG/PESTNOTES/pn7415.html
Help Desk of University of California Master Gardener Program of Contra Costa County (EDC)