- Author: Lynn M. Sosnoskie
Floral terminology: Perfect vs imperfect, monoecious vs dioecious
Perfect flowers: contain both male parts (stamens, the male fertilizing organ of a flower, typically consisting of a pollen-containing anther and a filament) and female parts (pistils, the female organs of a flower, comprising the stigma, style, and ovary) in the same flower.
Imperfect flowers: have either male parts (which are called staminate flowers), or female parts (which are called pistillate lowers), but not both. Imperfect flowers can be found on either the same plant (which is defined as being monoecious) or on separate plants (which is defined as being dioecious). Consequently, dioecious species have separate male and female plants.
Waterhemp (Amaranthus tuberculatus) produces male (left) and female (right) flowers on separate plants
- Author: Kathy Keatley Garvey
Not so with the Biological Orchard and Gardens (BOG) on the University of California, Davis, campus. It's a 24,000-square foot treasure, a living museum planted not only with several dozen species of heritage fruit trees, but landscaped with colorful mini-gardens.
This spring scores of wildflowers bloomed in awe-stopping glory, prompting passersby to pull out their cell phones and take selfies.
“The project began in 2010 when a group of students raised the money to convert an under-utilized lawn into a working orchard with fruits free for everyone to enjoy,” related former student project manager and now BOG volunteer Emily Dorrance. She recently graduated with a bachelor of science degree in environmental policy analysis and planning.
“Since then, the team has grown to involve many other UC Davis faculty, staff, and student groups," Dorrance said. ”Ernesto Sandoval, manager and curator of the UC Davis Botanical Conservatory, has been an advisor to the BOG student leadership for many years now and continues to be an important partner!”
At its core, BOG is a collaboration of students, staff and academic programs and an outdoor ecological laboratory that directly supports the university's popular Introduction to Biology course. Or, as the BOG Facebook page indicates: "An agro-biodiverse collaboration between students, staff, academic specialists and programs at UC Davis!"
BOG is located in front (or back) of the Mann Laboratory on Kleiber Hall Drive, depending on which way you're going! If you park in Lot 26, off Kleiber Hall Drive, it's a short walk down the sidewalk to BOG.
"The orchard you see today was planted two years ago," Dorrance noted. "The wildflowers were seeded four years ago and continue to self-seed, with some supplementation.We're planning on planting some more permanent plantings in the fall. The Mediterranean plots surrounding the orchard will have some more seasonal variety as well! I don't think we have any major planting plans for this summer but that could change!"
Among the flowers blooming in the Bog in the early spring, by color:
- Red: European red flax, Linum grandiflorum rubrum, an annual that's native to Algeria
- Yellow: tidy tips, Layia platyglossa, an annual that's native to California
--The seep monkey flower, Mimulus guttatus, native to California
--Lupine, Lupinus, native to North America. - Blue: Desert bell, Phacelia campanularia, an annual herb that is native to California and endemic (limited) to California.
- Lavender: Phacelia, also called Lacy phacelia, blue tansy or purple tansy (Phacelia tanacetifolia), native to the southwestern United States
--Lupine: Lupinus, native to North America - Red-Orange-Yellow: Blanket flower or Gaillardia (Gaillardia × grandiflora), native to North and South America
- Orange: California golden poppies, Eschscholtzia californica
The orchard contains heritage fruit tree varieties threatened with commercial extinction. They include the Gravenstein and Johnathan apples; the Suncrest peach; the Bleinheim apricot, the Mariposa plum and the Meyer lemon. See the full list of trees as well as some fun facts here: https://thebogatucd.wixsite.com/bogucd/single-post/2017/07/18/BOG-Fruit-Trees.
In 2013 BOG received a "Go Green" grant from the UC Davis Dining Services. Then last month, the Green Initiative Fund (TGIF) awarded $19,934 to the BOG for final site development. It was a major effort. (On its Facebook page, BOG thanks Kelly Richmond and Andra George for help on the grant and supporters Geoffrey Benn, Ivana Li, Pat Randolph, Lee Anne Richmond, and Peter Hartsough.)
Future plans? According to the website: "The BOG is joining the campuswide effort in transitioning towards a landscaping genre that embraces lawn reduction and plantings more suitable for the teaching, outreach and research mission of the university and sustainability practices. The motivation for the BOG is to serve as a teaching garden for multiple university courses and provide a relaxing space to enjoy the outdoors and simply delicious fruit. The BOG's main function is to serve a demonstration of and test site for plants more suitable to the region's hot dry summers and cool wet winters, with a focus on drought tolerant plants less commonly available in the Sacramento Valley."
When we stopped by the BOG in mid-April, the Phacelia tanacetifolia proved to be a favorite: honey bees (Apis mellifera), male and female Valley carpenter bees (Xylocopa varipuncta) and yellow-faced bumble bee (Bombus vosnesenskii) were all over it. It's fairly uncommon to see male Valley carpenter bees--"teddy bear bees" or green-eyed blonds--foraging, but there they were, along with the female of the species. "The girls" are solid black in a clear-cut case of sexual diphormism.
Want to get involved? The BOG seeks volunteers, interns and donors. See its website at https://thebogatucd.wixsite.com/bogucd or its Facebook page at www.facebook.com/ucdBOG or email "thebogatucd@gmail.com."
You can even adopt a tree!
Or become buddies with a bee!
(Note: Most of the annual wildflowers have "passed" since our visit in mid-April, but the orchard is thriving with newly formed fruit.)
/span>/span>- Author: Surendra K. Dara
Male spotted wing drosophila adult. Photo by Gevork Arakelian, Los Angeles County Ag Commissioner's Office
Spotted wing drosophila (SWD), Drosophila suzukii is a pest of several small fruit in California and other states. SWD belongs to the group of flies that are generally known as vinegar flies or lesser fruit flies. It was initially known as cherry fruit fly in 1930s and is now referred to as spotted wing drosophila. SWD can be distinguished from other Drosophila spp. based on the following traits:
- Females have a hard and dark (sclerotized) ovipositor with prominent serrations or saw-teeth that enable the fly to lay eggs in intact ripening fruit.
- Antennae with branched bristle-like part called arista.
- Males have a distinctive dark spot at the tip of each wing.
- Males also have two dark bands (combs) of 3-6 teeth on each front leg.
Sclerotized ovipositor of SWD (right) compared to the normal ovipositor of a vinegar fly (left).
Distinctive combs on the front legs of male spotted wing drosophila. Photo by Gevork Arakelian.
Origin and distribution: It is traditionally known to be a pest in Asia, but it is now reported in Neotropics, North America, and Europe. In the US, it has been reported in Hawaii, Washington, Oregon, California, Utah, Minnesota, Michigan, Missouri, Louisiana, West Virginia, Pennsylvania, North Carolina, South Carolina, and Florida.
Host range: They generally infest thin-skinned fruit and prefer temperate climate. Host range includes apple, blackberry, blueberry, cherry, dogwood, grape, mulberry, peach, persimmons, plum, raspberry, and strawberry. Non-crop hosts that support SWD populations include barberry, brambles (wild raspberry and blackberry), buckthorn, cotoneaster, currant, dogwood, elderberry, fig, honeysuckle, laurel, mulberry, nightshade, oleaster, orange jasmine, pin cherry, pokeweed, purple flowering raspberry, spicebush, sweet box, and yew.
Biology: SWD prefer 68-86 oF and overwinter as adults. Various sources suggested 5-10 generations per year. Eggs are translucent to milky-white. Females lay an average of 384 eggs at 7-16 per day and there can be 1-3 eggs per oviposition site. Multiple females may deposit eggs in the same fruit. Eggs hatch in 2-72 hours and larval stage lasts for 3-13 days. Larvae milky-white with a legless body tapering towards the anterior end (towards the head). Mouthparts are dark and sclerotized. Pupation takes place inside the fruit or in the soil and lasts for 3-15 days. Pupae are reddish brown and have two spiracles (breathing tubes) at the anterior end. Adults are small (2-3 mm) flies. Life cycle takes anywhere from 21-25 days at 59 oF to 7 days at 82 oF. Females can start laying eggs within 1 day after their emergence and can lay more than 400 eggs in their lifetime. Based on the degree day (DD) calculations, egg, larval, and pupal stages require 20.3, 118.1, and 200 DD.
Damage: Other fruit flies usually infest overripe and fallen fruit, but SWD infests fresh fruit because of its powerful ovipositor. Adults feed on fallen fruit but lay their eggs under the skin of intact fruit. Softening and collapse of the tissue results from larval feeding inside the fruit. Oviposition holes can be seen on the fruit with close observation. In addition to the direct damage, SWD makes the infested fruit vulnerable to other pests and diseases. Monitoring SWD is very important to avoid harvesting and marketing infested berries.
Monitoring: Use traps made with apple cider vinegar or yeast-sugar solutions for early detection of SWD. There are numerous studies using a variety of containers and attractants. Pherocon traps and lures are commercially available for SWD monitoring.
Management: A variety of organic and conventional management options are available.
Cultural – Discard fallen and unmarketable fruit in the field to prevent infestation. Remove wild hosts in the vicinity that might harbor SWD populations.
Botanical – Pyrethrins and azadirachtin products are used in multiple studies.
Chemical – Research indicates that organophosphates, pyrethroids, and spinosyns are among the chemicals that can be used against SWD. Remember to rotate chemicals among different mode of action groups to reduce the risk of resistance development.
Microbial – Entomopathogenic fungi (Beauveria bassiana or Isaria fumosorosea) and bacteria-based products such as Grandevo (Chromobacterium subtsugae) and Venerate (Burkholderia rinojensis) against adults, and entomopathogenic nematodes (Heterorhabditis spp. and Steinernema spp.) against pupae that form outside the fruit can be used.
Additional resources:
http://ipm.ucanr.edu/PMG/PESTNOTES/pn74158.html
http://www.omafra.gov.on.ca/english/crops/facts/swd-wildhosts.htm
http://www.ipm.msu.edu/uploads/files/SWD/em9113.pdf
http://entnemdept.ufl.edu/creatures/fruit/flies/drosophila_suzukii.htm
http://pest.ceris.purdue.edu/map.php?code=IOAPAUA
http://www.ipm.msu.edu/invasive_species/spotted_wing_drosophila/factsheets
- Author: Ben Faber
There are 4,000 species of earthworms grouped into five families and distributed all over the world. Some grow uo to 3 feet long, while others are only a few tenths of inches. We call them nightcrawlers, field worms, manure worms, red worms and some people call them little diggers.
In California, we have some native species of earthworms, but in many cases non-native introduced species have come to dominate. The predominant native species belong to the Argilophilus and Diplocardia while many of the non-native are of European in origin in the Lumbricidae family. Many of these non-natives were probably introduced by settlers bringing plants from home, which had soil containing the worms. A survey of California earthworms by the US Forest Service can be found at:
https://www.fs.fed.us/psw/publications/documents/psw_gtr142/psw_gtr142.pdf
This is a wonderful description of earthworm biology and their occurrence in the landscape.
When digging in citrus orchards, it is common to find earthworms in the wetted mulch under tree canopies. Many of our citrus orchards were initially established by “balled and burlap” nursery trees that brought worms along with the soil. In the case of many avocado orchards, on the other hand, it can be rare to find earthworms in orchards. Most avocado orchards have been established since the 1970s when potting mixes and plastic liners were the standard practice and worms were not part of the planting media. Even though there is a thick leaf mulch in avocado orchards, the worms have not been introduced, and it is rare to find them.
Numerous investigators have pointed out the beneficial effects of earthworms on soil properties. One of the first of these observers was Charles Darwin who published Earthworms and Vegetable Mould in 1881. He remarked on the great quantity of soil the worms can move in a year. He estimated that the earthworms in some of his pastures could form a new layer of soil 7 inches thick in thirty years, or that they brought up about 20 tons of soil per acre, enough to form a layer 0.2-inch-deep each year.
Earthworms, where they flourish, are important agents in mixing the dead surface litter with the main body of the soil. They drag the leaves and other litter down into their burrows where soil microorganisms also begin digesting the material. Some earthworms can burrow as deeply as 5 to 6 feet, but most concentrate in the top 6 to 8 inches of soil.
The worm subsists on organic matter such as leaves and dead roots near the soil surface. The earthworm ingests soil particles along with the organic matter and grinds up the organic matter in a gizzard just as a chicken does. This is excreted in what we call worm casts. The castings differ chemically from the rest of the soil, as they are richer in nitrogen, potassium and other mineral constituents.
Castings are a natural by-product of worms. When added to normal soils in gardens or lawns, they provide the same kinds of benefits as other bulky organic fertilizers. Castings today are not commonly used as fertilizer by commercial plant growers because of their cost relative to other fertilizers. However, castings are used by some organic growers and are sold commercially as a soil amendment or planting medium for ornamental plants grown in pots.
The physical soil churning process also has several important effects:
-Organic residues are more rapidly degraded with the release of elements such as nitrogen, sulfur and other nutrients.
-Some of the inorganic soil minerals tend to be solubilized by the digestive process.
-Extensive burrowing improves soil aeration.
-Burrowing can improve water penetration into soils
-The earthworm carries surface nutrients from the soil surface and imports them into the root zone of the plant.
Although earthworms are considered beneficial to soil productivity, few valid studies have been made to determine whether their presence will significantly improve plant growth. This may seem odd since many of us have learned from childhood that worms are good. It is something like the chicken and the egg analogy. The conditions that are conducive to earthworms are also ideal for plants. Both plants and worms need temperatures between 60 and 100 degrees F for good growth; both need water, but not too much or little; they both require oxygen for respiration; and they do not like soils that are too acid or basic or too salty. By correcting soil conditions that are unfavorable for one will also improve the outlook for the other. The earthworm is a natural component of the soil population. If the soil is properly managed this natural population will thrive. In this sense, the presence or absence or earthworms can be an indicator of the "fertility" of one's soil.
- Author: Katherine E. Kerlin
It's no big surprise that humans are impacting the planet. But a new study pinpoints a sobering connection.
As human life expectancy increases, so does the percentage of invasive and endangered birds and mammals, according to a study by the University of California, Davis.
The study, published in the September issue of Ecology and Society, examined a combination of 15 social and ecological variables — from tourism and per capita gross domestic product to water stress and political stability. Then researchers analyzed their correlations with invasive and endangered birds and mammals, which are two indicators of what conservationist Aldo Leopold termed “land sickness,” the study said.
Human life expectancy, which is rarely included among indexes that examine human impacts on the environment, surfaced as the key predictor of global invasions and extinctions.
“It’s not a random pattern,” said lead author Aaron Lotz, a postdoctoral scholar in the UC Davis Department of Wildlife, Fish and Conservation Biology when the study was conducted. “Out of all this data, that one factor — human life expectancy — was the determining factor for endangered and invasive birds and mammals.”
The study analyzed data from 100 countries, which included roughly 87 percent of the world’s population, 43 percent of global GDP per capita, and covered 74 percent of the Earth’s total land area. Additional factors considered were agricultural intensity, rainfall, pesticide regulation, energy efficiency, wilderness protection, latitude, export-import ratio, undernourishment, adult literacy, female participation in government and total population.
The findings include:
- New Zealand, the United States and the Philippines had among the highest percentages of endangered and invasive birds.
- New Zealand had the highest percentage of all endangered and invasive species combined, largely due to its lack of native terrestrial mammals. The study said that in the past 700 to 800 years since the country was colonized, it has experienced massive invasion by nonindigenous species, resulting in catastrophic biodiversity loss.
- African countries had the lowest percentage of invasive and endangered birds and mammals. These countries have had very little international trade, which limits opportunities for biological invasion.
- As GDP per capita — a standard measure of affluence — increased in a country, so did the percentage of invasive birds and mammals.
- As total biodiversity and total land area increased in a country, so did the percentage of endangered birds. (Biodiversity in this context is not a measure of health but refers to the number of species in an area.)
Lotz said the study’s results indicate the need for a better scientific understanding of the complex interactions among humans and their environment.
“Some studies have this view that there’s wildlife and then there’s us,” said Lotz. “But we’re part of the ecosystem. We need to start relating humans to the environment in our research and not leave them out of the equation. We need to realize we have a direct link to nature.”
The study was featured in the Los Angeles Times, Wired, and the U.K.'s Daily Mail among other media.
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