- (Public Value) UCANR: Promoting economic prosperity in California
- Author: John A Roncoroni
- Posted by: Gale Perez
There have been several recent questions about dealing with a plant floating in reservoirs. Here's Weed Scientist Emeritus John Roncoroni's response to them.
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Pacific Mosquitofern, (Azolla filiculoides) often referred to as Azolla, is native to California. It is considered a desirable component of natural habitats and an important food source for waterfowl. Azolla is a floating aquatic fern that spreads by stem fragments and spores. Azolla as being up to 5 cm (2 inches) long, but can be as small as ¼ to ½ inches.
Azolla is often misidentified as duckweed (Lemna spp), another common small floating aquatic plant. Azolla is initially green, like duckweed, but...
- Author: Sonia Rios
- Posted by: Gale Perez
From the Topics in Subtropics blog ¦ Oct. 21, 2022
Control of weeds has always been a major economic cost in subtropical fruit production because of favorable climate that allows for weed germination and year-round growth. The use of chemical weed control has increased dramatically due to labor costs, equipment costs, product costs and availability, the shift to more narrowly spaced tree rows, and installation of low volume irrigation systems that prohibit the operation of mowing or tillage equipment under the tree canopy area (Futch 2001).
However...
- Author: Thomas Getts
Winter annual grasses are one of the major invaders on rangelands in the intermountain region. They also can be problematic in a variety of systems from farm ground to forestry (cheatgrass in particular). Control options exist from physical means to chemistry but there doesn't appear to be any silver bullet. They can be suppressed, but typically rear their head reinvading the system within a few years. The impacts are far and wide, from creating fine fuels for wildfire, to being a poor source of forage for livestock on the range.
Picture one- Area to the left was treated with indaziflam in the fall of 2020, the area to the right was untreated and continued to be infested with non-desirable species like...
- Author: Whitney Brim-DeForest
- Author: Luis Espino
- Author: Troy Clark
- Posted by: Gale Perez
2020 Survey Update
Weedy rice was found in California on a large scale in 2016, over 8 counties, after having been only found in a few fields in one county prior to 2008. In 2020, University of California Cooperative Extension conducted a comprehensive survey. The objectives of this survey were to determine: 1) presence-absence of weedy rice, 2) to determine infestation level, and 3) to determine if there was any pattern to the distribution of weedy rice biotypes.
A survey was conducted from June thru September 2020 across eight counties (Glenn, Butte, Colusa, Sutter, Yolo, Yuba, Placer and Sacramento). Each field was surveyed on an individual basin level. Each basin was surveyed by...
- Author: Konrad Mathesius
- Contributor: Thomas Getts
- Contributor: José Luiz Carvalho de Souza Dias
- Editor: Brad Hanson
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Concerns about a growing resistance to herbicides
In Mediterranean or arid climates, particularly in areas with marginal soils, crop rotations are often limited to a narrow range of hay, pasture, a handful of winter legumes, or rainy-season grasses. Arid conditions and weathered soils drove Australia's rainfed grain growers to adopt no-till strategies earlier than their counterparts in California. While beneficial from a water use perspective, successful no-till systems depend on herbicides to control weeds that were traditionally kept in check with tillage.
Dependence on herbicides alone in these systems has resulted in weeds with resistance to multiple modes of action. In Australia, there is one...
