Posts Tagged: Weeds
Weed Day 2018 comes to UC Davis July 12 You can read about the latest weed-science research being...
press release WeedDay2018
A recent blog by Farm Advisor Rachel Freeman Long in Yolo/Solano/Sacramento Counties alerted me to a weed that I thought was mainly a northern California plant.
But according to Calflora it's been found in Agoura Hills and Moorpark with two sightings in San Luis Obispo County.
Spiny buttercup (Ranunculus muricatus) is a non-native plant, that is fairly common, especially in wet areas such as meadows. We also find it in crops, including orchards, pastures, and cereal grain fields. It's both an annual and perennial plant that blooms from March to May, with seed pods that are large and prickly. Though it's pretty with the bright yellow flowers, don't be fooled, as it has a dark side, so should be controlled.
First, according to Dr. Birgit Puschner, UC Davis Vet Med Toxicologist, all buttercups contain ranunculin, though there are differences in species in terms of toxin levels. In pastures, because the plant is bitter, animals simply eat around it. But if ingesting the fresh plant, they can develop blisters. The toxin degrades in hay; thus, it's only a problem in grazing and fresh exposures.
Second, according to Dr. Gilbertson, UC Davis Plant Pathologist and Ozgur Batuman, former UCD Post Doc, buttercup is a significant host of tomato spotted wilt virus (TSWV). Other important weed hosts for TSWV include cheeseweed (Malva parviflora), sowthistle (Sonchus oleraceus), and prickly lettuce (Lactuca serriola). TSWV crop hosts include peppers, tomato, lettuce, and bell beans (fava).
The primary vector of TSWV is the western flower thrips, a tiny insect that feeds on the plant foliage. Immature thrips pick up this pathogen from infected plants and transmit it to healthy ones when they become adults and disperse to new host plants. TSWV is not transmitted via seed.
Symptoms of TSWV typically include necrotic spots, often with tip or leaf dieback that looks like drift from a contact broadleaf herbicide. However, there is a lot of variability in the symptoms of TSWV depending on the host that could be confused with other problems. As such, if you suspect TSWV in your crop, the best way to positively identify it is by using on-site tools to test for this disease, such as ImmunoStrip® tests. A good resource for TSWV in tomatoes is: Tomato spotted wilt disease in tomatoes.
Watch for spiny buttercup and control this weed to keep it from spreading. We need to keep our pastures safe and TSWV out of our crops.
UCIPM and California Department of Pesticide Regulation are holding Weed Management...
Occasionally plants show up in our office for identification and no one in the office knows what it...
Occasionally plants show up in our office for identification and no one in the office knows what it is. So it's sent off to to others who might know. This was the case of a perennial amaranth, also called goosefoot for some reason. The is Chenopodium californicum, also know as Blitum californicum.
Like other amaranths, it can be upright to 3 feet in height, or if mowed or grazed be more flattened or decumbent. It has a thick, fleshy stem that along with the leaves can be eaten. I guess pigs like it, because it's also called pigweed.
The leaves look sort of lettuce like, which gives it another name - Indian Lettuce.
The stem has also been used for making soap, which gives it another name of soaproot. Which is not to be confused with another soaproot, Chloragulum. Plant names can be confusing.
Chenopodium californicum, Blitum,goosefoot, pigweed, soaproot grows in the chaparral on slopes and in foothill woodlands, mainly along the coast.
Plants for a Future: https://www.pfaf.org/USER/Plant.aspx?LatinName=Chenopodium+californicum