Shannon Mueller

Foraging range of honey bees, Apis mellifera, in alfalfa seed production fields

Abstract A study was conducted in 2006 and 2007 designed to examine the foraging range of honey bees, Apis mellifera (Hymenoptera: Apidae), in a 15.2 km2 area dominated by a 128.9 ha glyphosate-resistant Roundup Ready® alfalfa seed production field and several non-Roundup Ready alfalfa seed production fields (totaling 120.2 ha). Each year, honey bee self-marking devices were placed on 112 selected honey bee colonies originating from nine different apiary locations. The foraging bees exiting each apiary location were uniquely marked so that the apiary of origin and the distance traveled by the marked (field-collected) bees into each of the alfalfa fields could be pinpointed. Honey bee self-marking devices were installed on 14.4 and 11.2% of the total hives located within the research area in 2006 and 2007, respectively. The frequency of field-collected bees possessing a distinct mark was similar, averaging 14.0% in 2006 and 12.6% in 2007. A grand total of 12,266 bees were collected from the various alfalfa fields on seven sampling dates over the course of the study. The distances traveled by marked bees ranged from a minimum of 45 m to a maximum of 5983 m. On average, marked bees were recovered ∼ 800 m from their apiary of origin and the recovery rate of marked bees decreased exponentially as the distance from the apiary of origin increased. Ultimately, these data will be used to identify the extent of pollen-mediated gene flow from Roundup Ready to conventional alfalfa.

A method for distinctly marking honey bees, Apis mellifera, originating from multiple apiary locations.

Abstract Inexpensive and non-intrusive marking methods are essential to track natural behavior of insects for biological experiments. An inexpensive, easy to construct, and easy to install bee marking device is described in this paper. The device is mounted at the entrance of a standard honey bee Apis mellifera L. (Hymenoptera: Apidae) hive and is fitted with a removable tube that dispenses a powdered marker. Marking devices were installed on 80 honey bee colonies distributed in nine separate apiaries. Each device held a tube containing one of five colored fluorescent powders, or a combination of a fluorescent powder (either green or magenta) plus one of two protein powders, resulting in nine unique marks. The powdered protein markers included egg albumin from dry chicken egg whites and casein from dry powdered milk. The efficacy of the marking procedure for each of the unique markers was assessed on honey bees exiting each apiary. Each bee was examined, first by visual inspection for the presence of colored fluorescent powder and then by egg albumin and milk casein specific enzyme-linked immunosorbent assays (ELISA). Data indicated that all five of the colored fluorescent powders and both of the protein powders were effective honey bee markers. However, the fluorescent powders consistently yielded more reliable marks than the protein powders. In general, there was less than a 1% chance of obtaining a false positive colored or protein-marked bee, but the chance of obtaining a false negative marked bee was higher for “protein-marked” bees.

Strip Cutting Alfalfa for Lygus Management: Forage Quality Implications

Strip cutting is used to limit lygus migration from alfalfa into susceptible neighboring crops. Hay growers are concerned that the uncut strips negatively impact quality and marketability of alfalfa from subsequent cuttings. The objective of this trial was to determine if blending the hay from the uncut strips with the new growth could mitigate reductions in quality and improve marketability. There were negative impacts of mixing old hay with the new growth alfalfa in both 2000 and 2001. As old growth was added in 25% increments to the new forage in the bale, crude protein values declined by 1 to 2% and ADF values increased by 1 to 3.5%. Since ADF is used to calculate TDN, increases in ADF will have a significant impact on the value of the forage. There was no significant reduction in crude protein value when 7 or 14% old growth alfalfa was present in bales as compared to bales containing 100% new growth. With respect to ADF, the only significant difference was between the new hay and the hay containing 14% old growth. When visually evaluating hay, there appear to be subtle changes in appearance when old growth is blended with new growth that can be detected. The most sensitive characteristics are color and overall quality. Growers need to assess the requirements of their market, and determine the best strategy for managing the alfalfa strips left in fields for the purpose of lygus management based upon the expected reductions in quality reported here.

Review of Roundup Ready Alfalfa

Roundup Ready (RR) alfalfa is the first perennial forage species commercially released with a genetically modified trait (GMO). While not needed by all farmers who grow alfalfa, RR alfalfa may allow some farmers to more effectively establish alfalfa and control certain weed problems.

Sclerotinia Stem Rot of Garbanzos

Author(s): Frate, Carol A; Mueller, Shannon C; Temple, Steve R; Davis, R Michael | Abstract: Sclerotinia rot (white mold) is a fungal disease of garbanzos and other crops in California. While much remains unknown about Sclerotinia rot, this publication will help you identify it and manage its severity and spread.

Ascochyta Blight of Garbanzos

Author(s): Frate, Carol A; Mueller, Shannon C; Temple, Steve R | Abstract: Ascochyta blight is a major disease of garbanzos in California. Learn how to control of the disease after harvest in infected fields and prevent its spread into new areas.