- Author: Rachael Freeman Long
It’s that time of year again when we need to start thinking about controlling weevils in alfalfa hay production. Egyptian alfalfa weevils are the most damaging insect pests of alfalfa in California, as the larvae feed on the foliage, causing yield and quality losses if left untreated.
The life cycle of the Egyptian alfalfa weevil is predictable. Adults spend the summer outside fields in protected areas, such as behind tree bark (for example, eucalyptus trees) and in crevices. In late fall or early winter, adults emerge and migrate into alfalfa stands. Soon after entering fields, they begin laying eggs in new and old or dead alfalfa stems. Hatching larvae make their way to the terminal buds and feed on the developing...
- Author: Steve Orloff
Dodder is a troublesome annual parasitic weed that infests alfalfa fields. Initial infestations are usually caused by sowing dodder infested seed (a good reason to purchase Certified seed) and by “sheeping off” fields with sheep that came from an infested field. Perhaps no weed problem is worse than an alfalfa field heavily infested with dodder. As a parasite, it lives at the expense of the alfalfa plant and literally sucks the vigor and life out of the plant. If left uncontrolled it can actually kill the alfalfa plant. It emerges as a rootless shoot and must attach itself to a suitable host within a few days or it dies. After it embeds its sucker-like structures (called...
- Author: Eric T. Natwick
The UC Statewide IPM Pest Management Guidelines lists many insecticides as effective for Alfalfa (http://www.ipm.ucdavis.edu/PMG/r1300511.html). However, these are not the only insecticides registered for control of Egyptian alfalfa weevil on alfalfa grown for hay in California. Some newer products have been evaluated for Egyptian alfalfa weevil control and are mentioned in this report. Most of those newly registered insecticides are formulations of two different insecticides in the same container and are referred to as ‘in-the-can-mixtures’. An important question that PCA’s and alfalfa growers should be asking is: “What are the potential benefits and/or...
- Author: Vonny M. Barlow
The alfalfa weevil complex, comprised of the Egyptian alfalfa weevil, Hypera brunneipennis, and alfalfa weevil, Hypera postica, is the most damaging arthropod complex in California alfalfa (Medicago sativa). If populations of alfalfa weevil are left unchecked, the larvae can cause severe defoliation, significantly reducing yields. Repeated use of insecticides such as organophosphates and carbamates has resulted in these insecticides being detected in surface waters, providing incentives to find alternative means to manage this pest. The alfalfa weevil is susceptible to the biological control agent Bathyplectes curculionis in many alfalfa-growing regions in the United States. Work...
- Author: Rachael Freeman Long
- Author: Daniel H Putnam
There is no question that managing pests in alfalfa is a challenge. But it’s even more of a challenge considering that we need to consider how our chemical tools impact our environment. Why is this is important? Two reasons: 1) no grower wants to pollute our natural waterways or wells, 2) ultimately unwanted environmental impacts will cause the loss of these pesticide tools over time. This became evident last year when the detection of the herbicide Velpar (hexazinone) in wells caused DPR to threaten to pull the registration. After hearings with members of the California Alfalfa & Forage Association and scientists in Sacramento, ultimately growers were able to keep Velpar, but it should have been a wake-up...