Talking Points:

Weed control failures can and do occur.

Weed control failures occur for many reasons, including improper treatment applications and plant size and development at the time of treatment.

Plants that aren't completely controlled can produce viable seed and re-infest fields.

Insufficient control of herbicide-resistant weeds could facilitate the establishment and spread of undesirable traits.

Introduction:

Weed pressure, and the resulting competition for water and nutrients, can significantly impact crop establishment, growth, yield and harvest. Furthermore, there is some concern among growers that non-managed weeds may support...

Onionweed (Asphodelus fistulosus) is an attractive but very difficult to control weed that is relatively common along highways, some irrigation right of ways and other areas in Southern California. It likely came to our area as an ornamental plant, maybe as part of a seed mix or used (I was told) in reclamation projects in the north county area of San Diego. Once you learn to recognize it, it is easy to spot in spring and summer, especially along interstate 5 from La Jolla and on north at least as far as San Luis Obispo County. Photo 2 is from a restoration site in San Diego...

Aquatic weed propagules pose a serious long-term management problem. Curlyleaf pondweed (Potamogeton crispus) produces numerous asexual propagules that make traditional management difficult. We initially compared the effect of three benthic barrier materials (jute, polyethylene and rubber) on the control of curlyleaf pondweed turions (see Fig. 1 for example of bottom barriers) in both laboratory bench studies and studies using larger mesocosms. After the bottom barriers covered the turions for eight weeks we then determined the viability of the turions by allowing them to sprout. Our results showed that the jute and polyethylene did not give any control of curlyleaf pondweed sprouting, but the rubber barrier, which blocks both...

Based on the bestselling Weeds of California and Other Western States, the Weed Pest Identification and Monitoring Cards is the perfect pocket-sized companion for anyone working in the field.

These 48 cards cover the most common weeds, grouped into 8 categories for easy identification.

• Broadleaf annuals, erect
• Broadleaf annuals, low growing
• Broadleaf annual, scrambling
• Broadleaf perennials, not viney
• Broadleaf perennials, viney
• Grass annuals
• Grass perennials
• Sedges

Each weed is identified by a description and excellent close-up color photographs of...