For the past several years, California rice has been dealing with a pesky new weed, weedy rice aka “red” rice. Weedy rice is a difficult pest to manage, because it is the same species as rice (both are Oryza sativa L.), rendering herbicide use next-to-impossible. In the southern US rice-growing region (Texas, Louisiana, Mississippi, Missouri, Arkansas), they utilize two rice varieties (in rotation) that have been conventionally bred to tolerate the use of two herbicides: Clearfield (imazamox) and Provisia (quizalofop). Since weedy rice is susceptible to these chemicals, the entire field can be sprayed with these herbicides: the rice varieties survive, and the weedy rice is controlled. In California, these varieties...
- Author: Whitney Brim-DeForest
The 2019 Rice Weed Course will take place:
Friday, September 6, 2019
from 8:00AM to 4:10PM (Registration begins at 7:30AM)
Hamilton Road Field (on West Hamilton Rd. between Hwy. 99 & Riceton Hwy.)
Diamondback moth (DBM) is a persistent pest in the Salinas-Castroville area. We were able to find late instar caterpillars in several spots along Blackie road on Tuesday, January 22nd. Basically, these caterpillars were feeding on brassica weeds, located along the side of the road (Fig. 1). This is an example of how insects exploit weeds as alternative hosts when there is a lack of a preferred and abundant host plant in the landscape. DBM will continue feeding on these weeds, while increasing their numbers. These DBM adults, originated from weeds, have the potential to infest any commercial cole crop during the upcoming weeks and months. Based on our observations, most of these caterpillars were close to pupate. Within the...
- Author: Sarah Light
In March of this year I traveled to Chimoio, Mozambique to provide an Integrated Pest Management training to a group of farmers through the USAID Farmer-to-Farmer program. On my first day at the farm, we toured the farm and discussed their worst pest issues. One of the farmers brought a red flowering weed to show me, which he said it caused major issues in corn and was very difficult to control.
We continued on our way and it became clear that the biggest pest issue they were facing was the fall armyworm, an invasive species that spread to Mozambique in 2017 and can decimate a corn field. Since chemical inputs aren't always economically feasible for low-input systems like the one I was working in, I was interested learning about...
- Author: Guy B Kyser
This has been a big year for purslane at the UC Davis farm. Common purslane (Portulaca oleracea) is a succulent summer annual weed with fleshy leaves and rubbery-looking stems. Native to Eurasia, or maybe Africa, purslane arrived in the Americas with the first Europeans to settle here. It is a common weed in row crops worldwide.
Purslane is a tasty vegetable, either raw or cooked, and sometimes appears in farmer's markets and grocery stores. It is reported to be high in omega-3 fatty acids.
It's also a royal pain in the neck as a crop weed. Each plant produces thousands of tiny, long-lived seeds. The brittle stems make it difficult to pull or hoe, and stem fragments left on the soil will readily re-root. I once...