- Author: Laura Lukes
If you seek a peaceful place to explore nature and local history on foot or by bicycle, it may be time to explore Verbena Fields. This 20-acre site was historically a floodplain for Lindo Channel and later became used as a gravel mine for road construction.
The area was restored in partnership with state and local agencies, including the California Water Resources Board (a major funder), the CSU, Chico Research Foundation, Big Chico Creek Watershed Alliance, Streaminders, and the Mechoopda tribe. The restoration plan included input from neighbors, along with experts in wetland restoration, urban runoff mitigation, native plants, and local fauna. Together, these entities transformed a pile of rocks, broken asphalt, and noxious weeds into a natural refuge for humans, animals, and plants.
A wide, level path of crushed gravel (handicap accessible and suitable for small children and strollers) meanders along the perimeter of Verbena Fields. A second path bisects the site approximately at its midsection. We enter at the southwest corner, where Verbena Lane and East First Avenue intersect. Signage lets you know that your dog is welcome, on a leash, and at this corner there is a drinking fountain and a dog bag dispenser. To the left, a level strip of small trees, shrubs, and wildflowers borders the backyard fences that make up the western boundary of the site. To the right, desire lines (informal paths) lead from level ground to the Mechoopda Gathering Circle, a lowland area that features a beautiful tile mosaic depicting aspects of tribal life.
To the right is the open grassy area that comprises the bulk of the site and surrounds the wetland expansion portion of the project. The bisecting trail runs through the lupine and poppy (and also star thistle) that grow among the grasses. This middle trail affords access to a heavily shaded grove in which someone has fashioned a 10 to 12-foot- tall teepee from lumber scraps. An old rug has been placed inside, and it looks like a peaceful place to meditate, or the perfect place to play a game of fort.
Springtime at Verbena Fields is particularly beautiful: grasses are green and supple, redbuds, poppies, and lupines combine to make a palette of bright color, and fresh leaves bud from the limbs of the deciduous trees. Summer is dryer and crisper, but the shady groves of large trees and the low-lying cool spots offer respite from the heat. Fall brings the changing of colors when the grasses mellow to shades of heather, and in winter (if we are lucky with the rains) one can appreciate the value of the bioswales and wetlands features, as well as the view of the foothills to the east.
Whatever the season, Verbena Fields is a delightful place to visit. Just follow East First Avenue eastward, away from the busy bustle of traffic, to find it.
A virus can reduce a plant's growth, lower its yield, and result in inferior fruit, vegetables and flowers. Viruses are often very host specific. Recognizing symptoms can help you take appropriate action, where possible, to manage a virus and hopefully prevent its spread. The following are several viruses that can plague the home garden.
Viruses of this type can be identified by green and yellow mottling (“mosaic”) symptoms. In addition to the common Tomato Mosaic Virus (TMV) discussed in the previous article, mosaic viruses can affect cucumber, cauliflowers and lettuces. Choose resistant plants when available for your garden. Mosaic viruses are mostly spread by insects, especially aphids and leafhoppers. Try covering your plants with a floating row cover or use aluminum foil mulches to prevent these insects from infecting your plants. Some types of weeds may serve as hosts of the virus, so controlling weeds may be a deterrent.
Cucumber Mosaic Virus (CMV) is one of the most common mosaic viruses. It is usually spread by aphids. It was first found on cucumbers, hence its name; but it can affect many other woody and herbaceous plants, including tomato, melon, and squash. Symptoms include leaves mottled with yellow and/or light and dark green spots or streaks. Young plants may have twisted leaves and become stunted.
Tomato plants infected with CMV are stunted and exhibit “shoestring syndrome,” in which the edges of the leaves fail to develop. Leaf veins appear as long, narrow strips. Tomatoes are small and misshapen, and yield is reduced.
Once plants are infected with CMV, there is no control. Remove and destroy all the infected plants. Disinfect gardening tools that have come into contact with infected plants.
Cauliflower Mosaic Virus (CaMV) primarily infects plants such as cabbage, brussels sprouts, cauliflower, broccoli, rape seed and turnip. It is transmitted in a non-circulatory manner by aphids, which can acquire this virus within one minute of feeding on an infected plant and can transmit the virus to a healthy plant just as quickly. Systemic symptoms include vein clearing – a condition in which the veins on a plant's leaves become translucent. Later, a striking mosaic pattern may develop. Plants can be stunted, and infected cabbage heads develop internal brown flecks and spots when stored in the refrigerator.
Temperatures between 61 and 68 degrees favor symptom expression in plants. CaMV is often found as a mixed infection along with Turnip Mosaic Virus, resulting in more severe symptoms than when either virus is present alone.
Eradicate cruciferous weed hosts (such as wild mustard, wild radish and wintercress) and incorporate crop debris immediately after harvest.
Infected plants may reach full size, but the older outer leaves will be yellow, twisted, and otherwise deformed. On head lettuce, the plant may not form heads or the wrapper leaves may curve away from the head. Developing heads may be deformed or brown, necrotic black or brown flecks occur on the wrapper leaves.
Plant resistant lettuce varieties when available and use certified seed that has been tested for the virus. Control weeds to remove potential virus sources and destroy post-harvest residue from crucifers, broccoli, cabbage, cauliflower, Chinese cabbage, and mustard.
Practice good aphid management. Control aphid-protecting ants, knock off aphids with a stream of water, or use a silver-reflective mulch to repel the aphids. Apply fertilizer only as necessary.
To determine the difference between wilting from lack of water and wilting from curly top virus, soak the soil around plants in the early evening. If the plant doesn't revive overnight, it's likely the plant has Curly Top Virus.
There is no cure or chemical control for curly top. Shade cloth can be placed over plants using stakes to discourage leafhoppers and to help tomato and pepper plants grow better and produce more fruit during the hottest summer months. Remove and destroy diseased plants.
Viruses that affect ornamental plants
Some viruses have actually been encouraged for their aesthetic effect on flowers or leaves. The most famous example of this is the Tulip Breaking Virus which can create flame patterns on tulip flowers and led to the speculative market in tulip bulbs that gripped much of Dutch society in the early 17th century. Today, “broken” tulips with patterns on the flowers are the result of breeding, not viral infection.
There is a virus that affects Abutilon spp. (flowering “maple” or Indian mallow) and is considered desirable. Abutilon Mosaic Virus (AMV)is transmitted by infected sap moved on cutting tools and through grafting. This virus causes yellow to whitish blotches on leaves. It causes no apparent harm and propagators select infected plants to sell.
Much less attractive and desirable is the Rose Mosaic Virus Complex (RMVc), which is one of the most widespread rose diseases in the United States. This virus may be a complex of more than one pathogen. Symptoms in leaves include yellow line banding in a zigzag or “oak leaf” pattern, mosaic, and watermarking (characterized by faint yellow swirls or squiggles). In vein banding, the veins are yellow, and the leaf is green. This virus may also cause distorted or stunted blooms.
Symptoms of Rose Mosaic Virus are more pronounced in spring and fall. In summer heat, growth appears normal and the virus seems to disappear. A plant may be several years old before showing any symptoms. Damage can range from mild and easily overlooked to seriously stunting. Virus-infected plants may grow more slowly, produce delayed or fewer flowers, and become more susceptible to frost damage.
The UC Master Gardeners of Butte County are part of the University of California Cooperative Extension (UCCE) system. To learn more about us and our upcoming events, and for help with gardening in our area, visit our website. If you have a gardening question or problem, call the Hotline at (530) 538-7201 or email mgbutte@ucanr.edu.
Most gardeners are aware of plant diseases that can wreak havoc in their gardens. If you grow fruit trees, you may be confronted with curled, reddened peach leaves (peach leaf curl fungus). If you grow apples or pears, your trees may sometimes look like they were scorched with a blow torch (fire blight bacterium). But did you know that viruses can also lurk in the leaves, stems, and fruit of your garden vegetables and flowers? A virus infection can reduce a plant's growth, lower its yield, and/or result in inferior fruit, vegetables, or flowers.
Viruses attach to cells, penetrate, uncoat, replicate, assemble, and then are released. The time between initial introduction and systemic plant infection varies from a few days to a few weeks. Transmission to other plants completes a virus's life cycle.
History
The first plant virus to be discovered was found on the leaves of tobacco plants in the late 19th century. Researchers found that sap from infected tobacco leaves caused green and yellow mottling (“mosaic”) symptoms in healthy plants. Unlike bacteria, this virus could not be filtered out, but boiling the sap destroyed the infectiousness. Tobacco Mosaic Virus (TMV), the first plant virus discovered, remains one of the most common plant viruses. It attacks not just tobacco but also other members of the nightshade family (Solanaceae), including eggplant, cucumber, pepper, potato, tomato, petunia, snapdragon, delphinium, and marigold.
Virus Transmission
Transfer of virus-infested sap may occur during agricultural practices (through damage caused by tools or hands) or naturally (by an animal feeding on the plant). Plant viruses can also be transmitted by insects, nematodes, fungi, and through pollen, seed, or vegetative propagation from infected parent plants.
There are many, many plant viruses that collectively have the potential to infect virtually all species of plants. Fortunately, host ranges of individual viruses vary from very narrow to very broad. Plants can prevent viral infection through either passive or active defenses. In passive defenses, some plants simply don't produce one or more of the factors required for a particular virus to reproduce and spread within that species. Active defenses detect and destroy or wall off virus-infected cells by the action of resistant genes in the plant.
Virus Symptoms
Viruses typically spread throughout the whole plant and cause a systemic infection. A plant's response to infection can range from completely symptomless to severe disease and plant death, depending on the host and the particular virus.
Typical leaf symptoms of a plant virus include mosaic patterns, chlorotic (yellow) or necrotic (brown) lesions, yellowing, stripes or streaks, vein clearing (becoming translucent), vein banding (where bands of a lighter or darker color occur alongside veins), and leaf rolling and curling. Flower symptoms include deformation and changes in the color and pattern of the flowers. Fruit and vegetable symptoms may include mosaic patterns, stunting, discoloration or malformation, and chlorotic ringspots. Stems may develop stem pitting and grooving or tumors in response to virus infection.
Disease Management
Understanding a virus disease is the first step. Consult the UC IPM website to help identify virus disease possibilities that might infect the plant species of concern. There is no cure for a virus disease once a plant is infected. Prevention or reducing spread between plants is the only possibility. Some viruses are spread by aphids and other insects that suck plant juices so controlling them on vegetables can be helpful.
Herbaceous ornamentals and certain vegetables are generally more susceptible to serious injury or death from viruses, especially when plants are young. Prevention includes using certified virus-free seed or plant material and elimination of virus reservoirs in surrounding vegetation. Grow virus resistant cultivars when available. Provide proper cultural care to improve plant vigor. Management depends on how a virus enters the plant, how it is transmitted between plants, and where it survives when susceptible vegetables are not present. Dig out and destroy virus-infected plants.
Tobacco mosaic virus (TMV) is also known as tomato mosaic virus. It commonly appears at this time of year. TMV infects a plant by entering a break in the cell walls caused by insects or other physical damage. Leaves infected with this virus become mottled with yellow and green spots. The dark green spots often appear thicker and somewhat raised, giving the leaves a blister-like appearance. Mottled areas may turn brown and wither. Plants infected with TMV may be stunted and produce very little fruit.
To manage TMV, remove and destroy any symptomatic plants. Avoid use of tobacco around tomato plants. Use only certified virus-free seed. Sanitation is the single most recommended practice to control TMV, because transmission of the virus from plant to plant usually occurs from contaminated tools or hands. The most common sources of infection are the debris of infected plants that remains in the soil. After removing diseased plants, wash your hands and decontaminate tools. Surface sterilize seeds with bleach before planting. There are no chemical sprays that will prevent, control or eradicate viruses.
Viruses rarely kill woody plants but may alter their appearance with line patterns or ring spots on their leaves. When available, planting certified virus-free stock is the best approach. Rose mosaic virus, is a common example that often has clear visual symptoms in the leaves, especially in cool spring weather. Controlling insects is not an effective method of preventing virus infection in woody ornamentals since low densities of pests can spread viruses throughout the life of perennial shrubs and trees. Virus infected ornamentals should be removed if severe stunting compromises the value of the plant in the landscape. Locally, many very productive almond orchards continue to be hosts of a mild plant virus. There is some debate in the commercial nursery industry as to whether or not this needs to be addressed with certified virus clean stock when trees are propagated for new orchards.
Several other viruses that affect garden plants and vegetables will be discussed in the next Real Dirt column.
The UC Master Gardeners of Butte County are part of the University of California Cooperative Extension (UCCE) system. To learn more about us and our upcoming events, and for help with gardening in our area, visit our website. If you have a gardening question or problem, call the Hotline at (530) 538-7201 or email mgbutte@ucanr.edu.
Record numbers of people are gardening this spring and victory gardens are rapidly sprouting across the nation. Now is a better time than ever to learn how to save seeds.
Some vegetables, like beans and peas, are self-pollinating. These are less likely to cross with other related varieties through insect pollination. Self-pollinating varieties are excellent choices for the beginning seed saver, as some pods can simply be left on the vine to dry out. Once completely dried, remove seeds from pods, place them in envelopes labeled with the variety and date and store them in an airtight container in a dry dark place. A mason jar placed in the refrigerator or freezer makes a good receptacle for seed packets. Properly stored bean and pea seeds should remain viable for three years.
Peppers cross easily due to pollination. You may notice your sweet bell peppers suddenly take on a spicy hot pepper quality if you don't separate pepper varieties by at least 100 feet or plant barrier crops in between varieties. But pepper seeds are some of the easiest to save; just remove seeds from the fruit and dry them for two to three days on a plate or paper towel. Properly stored pepper seeds remain viable for up to two years.
Some vegetables require much more care to ensure that seeds do not carry mixed or unexpected character traits. While corn is an American staple in the garden and whole cobs are easily dried, wind pollination leads to easy crossing between different varieties. If you want to save corn seed, grow only one variety in a large patch (or in patches of different varieties separated by 1,000 feet, if you have that much space). Members of the squash family within the same species readily cross and must be separated by a half mile or hand-pollinated to ensure a pure strain. Similarly, cole crops are all varieties of a single species, Brassica oleracea. Cauliflower, broccoli, Brussels sprouts, kale, cabbage, turnips, collard and bok choy will all cross with one another; therefore, growing only one variety at a time is recommended if you plan to save the seed.
For more information on saving seeds of all types, consult The Complete Guide to Saving Seeds by R. E. Gough and C. Moore-Gough, Seedsavers Exchange at www.seedsavers.org, your local seed lending library, or Beginner's Guide to Seed Saving” by Paul McCollum, UC Master Gardener of Monterey Bay.
You say you don't have a green thumb, or you don't have a yard for gardening? No problem! You can easily grow fresh, nutritious microgreens all year long in a sunny window in your home. All you need is soil, seeds, a container, and water.
Microgreens are larger than sprouts and smaller than baby lettuces. They can be grown from almost any vegetable or herb seed. You can find microgreen seed packets at most nurseries and online through seed catalogues. You can use single packets of seeds or make your own mix. When mixing a variety of seeds, make sure that the germination time for each type is about the same, so they can be harvested together. That information will be on the outside of the seed packet.
Experiment to find a flavor or combination of flavors that you enjoy. Try growing some spicy herbs and vegetables like radishes, mustards, arugula, or basil. Other good options for this method of growing are beets, broccoli, kale, peas, chard, cress, and sunflowers (sunflower sprouts have a nutty flavor and crunchy texture).
To grow microgreens indoors start with preparing a container. Re-purpose an old plastic lettuce container or a plastic ‘flat' that came from the garden center. Kits that include a container, a soil mix, and seed are available online. Whatever you use for a container, make sure it has drainage holes and a soil mix that drains well. If you are using a plastic ‘flat' cover the bottom with burlap or weed cloth. Choose a soil mix or seed starting mix that is labeled organic or free of chemicals. The microgreens will draw most of their nutrition from the soil and water. Their green leaves manufacture carbohydrates using sunlight and carbon dioxide from the air.
Fill the container with moistened soil mix to within one inch from the top. Sprinkle seeds generously over the entire area. Cover very lightly with soil and use a spray bottle to moisten the top. You want to moisten, but not drench, the soil. Place the container in a sunny window.
Growing microgreens is a simple way to add fresh, nutritious produce to your diet. They taste great and have a quick turn-around time. If you have children at home this is a fun project to do together. You can introduce the kids to the satisfaction of growing some of their own food and the fun of experimenting with their microgreens in everyday dishes.