- Author: Lynn M. Sosnoskie
There is still time to register for the April 11th SJV Weed Science Extension Day at the Westside Research and Extension Center in Five Points (17353 West Oakland Avenue, Five Points, CA 93624).
The meeting at the Westside Center will focus on agronomic crops, ROWs, and tree and vine systems. The session will also include hands-on weed ID and nozzle selection/drift management training.
The meeting has been approved for 3.5 CDPR continuing education credits (other).
These presentations are free to attend although we do request that you register by calling the UCCE Merced County office at 209-385-7403 to reserve your spot. The agenda is listed below (a pdf flyer is also attached).
Our programs are open to all potential participants. If you require special accommodations, please contact the UCCE Merced County office at 209-385-7403. Thank you and we hope to see you at the meeting!
San Joaquin Valley Weed Science Day at the WSREC
Thursday, April 11, 2019, 8:00 a.m. – 12:15 p.m.
Westside Research and Extension Center
17353 West Oakland Avenue, Five Points, CA 93624
8:00 a.m. Registration and Welcome (Refreshments provided)
8:30 a.m. Concurrent Sessions (attendees will be split into two groups and will rotate between the weed ID and spray drift demonstrations at 45-minute intervals)
Session 1: Identification of Common Weeds of Agricultural Cropping Systems and Non-Crop areas of the Southern San Joaquin Valley.
Anil Shrestha, Chair: Department of Viticulture & Enology and Professor: Weed Science, CSU Fresno
Session 2: Nozzle Selection and Proper Use and Spray Drift Management
James Schaeffer, Staff Research Associate, UCCE – Fresno County
10:00 a.m. Break (Refreshments provided)
10:15 a.m. The Biology and Management of Alkaliweed
Kurt Hembree, Weed Science Advisor, UCCE – Fresno County
10:45 a.m. Managing tough weeds in the right-of-way (ROW), landscape and other non-crop sites
Rick Miller, Corteva Agrisciences
11:15 a.m. Pre- and Post-Herbicide Performance on Threespike Goosegrass in Tree Nut Orchards
Drew Wolter, UC Davis
11:45 a.m. Breaking Bindweed: What Controls the Species and What Doesn't Work
Lynn Sosnoskie, Agronomy and Weed Science Advisor, UCCE – Merced and Madera Counties
12:15 p.m. Adjourn
SJV Weed Day April 11 2019 at WSREC Flyer
- Author: Lynn M. Sosnoskie
There are TWO upcoming weed science extension days in the San Joaquin Valley this April.
The first will be held on the 2nd of April at the Kearney Agricultural Research and Extension Center in Parlier (9240 South Riverbend Road, Parlier CA 93648) and the second will be held on April 11th at the Westside Research and Extension Center in Five Points (17353 West Oakland Avenue, Five Points, CA 93624).
The meeting at the Kearney Center will focus on rangeland, turf, and tree and vine systems while the meeting at the Westside Center will focus on agronomic crops, ROWs, and tree and vine systems. Both meetings will open with hands-on weed ID and nozzle selection/drift management training.
The Kearney meeting has been approved for 3.5 CDPR continuing education credits (other); an application for 3.5 credits is currently pending for the Five Points meeting.
Both meetings are free to attend although we do request that you register by calling the UCCE Merced County office at 209-385-7403 to reserve your spot. Agendas are listed below (pdf flyers are also attached).
Our programs are open to all potential participants. If you require special accommodations, please contact the UCCE Merced County office at 209-385-7403. Thank you and we hope to see you at the meeting!
San Joaquin Valley Weed Science Day at the KARE
Tuesday, April 2 2019, 8:00 a.m. – 12:15 p.m.
Kearney Agricultural Research and Extension Center
9240 South Riverbend Road, Parlier CA 93648
8:00 a.m. Registration and Welcome (Refreshments provided)
8:30 a.m. Concurrent Sessions (attendees will be split into two groups and will rotate between the weed ID and spray drift demonstrations at 45-minute intervals)
Session 1: Identification of Common Weeds of Agricultural Cropping Systems and Non-Crop areas of the Southern San Joaquin Valley.
Anil Shrestha, Chair: Department of Viticulture & Enology and Professor: Weed Science, CSU Fresno
Session 2: Nozzle Selection and Proper Use and Spray Drift Management
James Schaeffer, Staff Research Associate, UCCE – Fresno County
10:00 a.m. Break (Refreshments provided)
10:15 a.m. Post-Emergence Herbicides for Use in Orchards
Kurt Hembree, Weed Science Advisor, UCCE – Fresno County
10:45 a.m. Turfgrass Weeds in the Central Valley
Maggie Reiter, Environmental Horticulture Advisor, UCCE – Fresno, Madera, Tulare and Kings Counties
11:15 a.m. Post-fire Rangeland Weed Management: A Critical Component of Land Stewardship
Rebecca Ozeran, Livestock and Natural Resources Advisor, UCCE – Fresno and Madera Counties
11:45 a.m. Glyphosate for Weed Control: How it Works, Why it Fails, and What we can do to Maximize Efficacy
Lynn Sosnoskie, Agronomy and Weed Science Advisor, UCCE – Merced and Madera Counties
12:15 p.m. Adjourn
San Joaquin Valley Weed Science Day at the WSREC
Thursday, April 11, 2019, 8:00 a.m. – 12:15 p.m.
Westside Research and Extension Center
17353 West Oakland Avenue, Five Points, CA 93624
8:00 a.m. Registration and Welcome (Refreshments provided)
8:30 a.m. Concurrent Sessions (attendees will be split into two groups and will rotate between the weed ID and spray drift demonstrations at 45-minute intervals)
Session 1: Identification of Common Weeds of Agricultural Cropping Systems and Non-Crop areas of the Southern San Joaquin Valley.
Anil Shrestha, Chair: Department of Viticulture & Enology and Professor: Weed Science, CSU Fresno
Session 2: Nozzle Selection and Proper Use and Spray Drift Management
James Schaeffer, Staff Research Associate, UCCE – Fresno County
10:00 a.m. Break (Refreshments provided)
10:15 a.m. The Biology and Management of Alkaliweed
Kurt Hembree, Weed Science Advisor, UCCE – Fresno County
10:45 a.m. Managing tough weeds in the right-of-way (ROW), landscape and other non-crop sites
Rick Miller, Corteva Agrisciences
11:15 a.m. Pre- and Post-Herbicide Performance on Threespike Goosegrass in Tree Nut Orchards
Drew Wolter, UC Davis
11:45 a.m. Breaking Bindweed: What Controls the Species and What Doesn't Work
Lynn Sosnoskie, Agronomy and Weed Science Advisor, UCCE – Merced and Madera Counties
12:15 p.m. Adjourn
- Author: Lynn M. Sosnoskie
You just KNOW that some plants are considered weeds. Their common names give them away. They sound awful. Giant hogweed (Heracleum mantegazzianum). Ripgut brome (Bromus diandrus). Devil's claw (Proboscidea lutea). Smellmelon (Cucumis melo). Itchgrass (Rottboellia cochinchinensis). Dog-strangling vine (Cyanthum rossicum).
Others...well, others seem more benign. Even sweet. For Valentine's day I present to you nine weedy plants with lovely names. Enjoy...
1. Tree-of-Heaven (Ailanthus altissima). How celestial (Sigh...). How divine (Sigh...). How invasive (sigh...wait, what?). Tree-of-heaven is a deciduous tree, native to China, in the Simaroubaceae. It has been used, extensively, as a street tree; in fact it is the subject of A Tree Grows in Brooklyn by Betty Smith. But it suckers. A lot. And it stinks. A lot. And it spreads, rapidly, by seeds (lots and lots of seeds!) and root-sprouts. Some people living in urban areas have renamed it 'Tree-of-Hell'.
Tree of Heaven - Ailanthus altissima
2. Baby's breath (Gysophila paniculata). Baby's breath?!?!? Baby's breath?!?!? That delicate plant in the Pink family that is beloved by florists? You would have to work REALLY hard to make up a sweeter sounding name for a pest! Like 'Fuzzy kitten herb' or 'Baby giraffe weed'. Or 'Mouse ear chickweed' (That last one is real...). But baby's breath has become invasive in certain habitats, like Sleeping Bear Dunes in Michigan, where it escaped from gardens.
3. Amaranthus spp. The genus name is derived from two Greek words: amarantos (unfading) and anthos (flower). There it is. Unfading flower. A perfect metaphor for love, no? Well, I've got two words of my own for you: PALMER AMARANTH. Enough said. (To be fair, many Amaranths are used worldwide as food sources, either leaves or seeds...but my animosity isn't directed at them.)
Palmer amaranth - Amaranthus palmeri
4. Love-apple (Solanum capsicoides). Sounds delicious, right? If you are talking about a tomato (Lycopersicon lycopersicum), sure. If you are talking about red soda apple (a.k.a. devil's apple and cockroach berry), not so much. The fruits are toxic and have been/are being used in many countries for rodent and insect control.
5. Multiflora rose (Rosa multiflora). A 'rose with many flowers', how can that be bad? HA! The intentions were good when this species was being promoted in the 19th and 20th centuries (ornamental shrub, erosion control, living livestock fence, wild-life food source), but things have gone terribly wrong since then. This shrub forms dense stands that can displace native vegetation.
6. Love leaves (Arctium minus). It sounds like you could brew up a nice aphrodisiac from this species. Although parts of the plant are said to be edible, love leaves, better known as common or lesser burdock, is also listed as being toxic in many weed guides. However, burdock doesn't make this list because of its questionable medicinal or culinary virtues, but rather for its seed. The tiny hooks on the seeds of this plant were the inspiration for velcro. Try pulling them out of the fur of a long-haired dog...
7. Heart's ease (Polygonum persicaria). Better know as smartweed or ladysthumb. This weed can grow everywhere, it seems. Seriously. It is even found in Greenland.
8. Love vine (Convolvulus arvensis). Love may keep us together, but you don't want to be in a relationship with this plant, which is better known as field bindweed. This perennial species is listed as one of the most noxious weeds in the WORLD. It has roots that can grow to depths of >10', it reproduces by seed and rhizomes, infrequent tillage just makes it mad, and repeated applications of herbicides are needed to suppress it. This plant also goes by the name possession vine...and you're nobody's property.
Field Bindweed - Convolvulus arvensis
9. Bouquet-violet (Lythrum salicaria). People love getting flowers on Valentine's day, right? Maybe you shouldn't send this 'bouquet', though, which you probably know better as purple loosestrife. This plant was introduced, intentionally, to North America as an medicinal herb, but it has since escaped from our gardens and become naturalized. Large infestations can alter water flow in streams and rivers, reduce native plant species diversity and negatively impact macrofauna, such as amphibians and waterfowl, that rely on wetlands for food and shelter.
This post was originally published on the UC Weed Science Blog in 2014
https://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=12890
- Author: Lynn M. Sosnoskie
A drive around parts of the San Joaquin Valley revealed some fields with Palmer amaranth (Amaranthus palmeri) rising above the crop canopy (See image below).
A male Palmer amaranth in a corn field in Merced County
Palmer amaranth is a tall (growing up to 10 feet in height), dioecious (male and female flowers develop on separate plants), summer annual that grows rapidly and produces significant amounts of seed (upwards of 400,000-1,000,000 per female plant). The species is extremely competitive with many crops, including corn and cotton. In the United States, Palmer amaranth populations with resistances to the ALS inhibitors (WSSA 2), EPSPS inhibitors (WSSA 9), HPPD inhibitors (WSSA 27), micotubule inhibitors (WSSA 3), PPO inhibitors (WSSA 14), and PSII inhibitors (WSSA 5) have been documented; this includes populations with resistances to two or more sites of action (http://weedscience.org/). In California (CA), glyphosate resistance has been confirmed, although the geographic distribution of the trait is largely unknown.
Hand-weeding is a common strategy for weed management in many CA crops. However, Palmer amaranth plants that have survived hand-weeding attempts have been known to re-grow and produce seed, sometimes in significant quantities. In 2014, my colleagues at the University of Georgia and I published a paper specifically looking at the intensity of defoliation on subsequent Palmer amaranth development (Sosnoskie et al. 2014 Ann Appl Biol 165:147-154) to address concerns that growers were having with late-season seed set following management efforts. With respect to the methodology: when Palmer amaranth began to flower (which was 8 weeks after cotton planting (PHY 375)), 10 pigweed plants per 25 feet of row were cut back to 1) the soil line, 2) ~1 inch above the soil line, and 3) ~6 inches above the soil line; a set of plants were left untreated as a control population. Weed heights were measured for up to 6 weeks following cutting. At cotton defoliation, seed was collected from the surviving female Palmer amaranth plants and the amounts and viability were quantified.
Plant survival, re-growth, and seed production were directly affected by the cutting height. 95% of the plants that were cut back to ground level died as compared to 64% of the plants cut back to 1 inch above the soil line and 35% of the plants cut back to 6 inches above the soil line. Palmer amaranth plants that survived the cutting treatments grew (from adventitious stem buds) to final heights of 40 inches (6 inch cutting treatment), 15 inches (1 inch cutting treatment) and <1 inch (cut to ground level). Comparatively, the untreated plants grew to heights of 86 inches. With respect to seed production, female plants in the control plots produced, on average, 400,000 seeds per plant; surviving plants cut back to 6 inches, 1 inch, and to the soil line produced approximately 100,000 seeds per plant, 35,000 seeds per plant, and 700 seeds per plant, respectively. Seed viability was not affected by cutting treatments (Mean germination = 76%).
While cotton yield can directly benefit from the removal of Palmer amaranth plants, the intensity of defoliation and stem removal could also have an impact future weed populations. To reduce the potential for competitive interference in subsequent crops, care must be taken to prevent as many seeds as possible from returning to the seed bank. Similarly, to minimize the risk of developing herbicide-resistant weeds and to manage existing populations, soil seed bank populations must also be addressed. Growers, farm managers, and crop advisors should be aware that hand-weeding failures can and do occur and that viable seed production can occur from Palmer amaranth plants that survive defoliation attempts.
Literature Cited:
Sosnoskie, L.M., T.M. Webster, T.L. Grey, and A.S. Culpepper. 2014. Severed stems of Amaranthus palmeri are capable of regrowth and seed production in Gossypium hirsutum. Annals of Applied Biology 165:147-154.
For more information about identifying commonly occurring pigweeds in California, please refer to this blog post: http://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=27501
This post is also hosted at the Agronomy and Weed Science Blog
which is an extension of the Agronomy and Weed Science program at UCCE Merced County