- Author: C. Scott Stoddard
- Posted by: Gale Perez
Last summer, I was called out to view what appeared to be a herbicide drift incidence in a commercial tomato field. The leaves of affected plants were distorted with cupping and twisting that is characteristic of the growth regulator herbicides such as 2,4-D and dicamba (Figure 1). Cattails and mustard weeds growing in an adjacent drainage ditch appeared as though they had been recently sprayed with a herbicide, however, the symptoms looked to be more like that from glyphosate. (Figure 2). If these tomatoes were the unlucky recipient of drift from a Roundup application, they certainly were not expressing typical symptoms (Figure 3). Additionally, there had been no recent sprays of any herbicide made to the ditch, at least according to...
- Author: Brad Hanson
It's that time of the year when we're planning preemergence (aka "residual") herbicide programs for orchard and vineyard crops in California. Typically, these are the herbicides that are applied in the fall, winter, or early spring BEFORE weeds emerge (preemergence) and they usually affect weeds as they germinate or are just beginning to emerge from the soil. [often, people mistakenly think these herbicides kill seeds or sterilize the soil which is not actually the case].
As you're planning the specific program for the weed problems in your orchards and vineyards (or any site, really), I thought it would be a good time to review some of the...
- Author: Richard Smith
Each of the past several years, we have received samples of tomato plants from small growers and homeowners that have severe leaf deformity. The leaves of affected plants have the following symptoms: the leaves are distorted with cupping and twisting (Photos 1 & 2), as well as strapping or shoe string symptoms (Photo 3); the leaves can also have distinctive flaring along the edges (Photo 4). In addition, the leaves can be tightly curled (Photo 5). We examined these samples for the presence of viruses, but have never found viruses associated with these symptoms. In addition, the symptoms do not fit classic virus symptoms such as mottling (blending of dark green and yellowing). The symptoms on these tomatoes most closely fit with...