Progress 05/01/08 to 04/30/13
Outputs
Progress Report Objectives (from AD-416): To evaluate the the toxicity of a new pesticide, Rimon, on the alfalfa leafcutting bee. Rimon is a growth regulator inhibitor and is suspected by some beekeepers to be affecting the growth of bee larvae. The pesticide is used in alfalfa seed fields to control lygus bugs. The two main goals of this project are to assess egg mortality when adult bees are treated with Rimon, and evaluate the mortality dose response of eggs and larvae when pollen provisions are treated. Approach (from AD-416): Rimon� is a chitin inhibitor insecticide used for the suppression of lygus bug, the most damaging insect in Utah alfalfa seed fields. The active ingredient in Rimon interferes with insect pest development and successful molting, but is supposed to be safe on beneficial and pollinating insects. In the fall of 2007, several Idaho alfalfa seed growers noticed a greater percentage of leafcutting bee cells containing pollen/nectar provisions with no live bee brood from fields that were treated with Rimon. Growers questioned if Rimon could be lethal or sublethal to leafcutting bee eggs or larvae. The potential negative health effects of Rimon on leafcutting bees are valid concerns for growers who will have to purchase more new bees each growing season. This project will provide basic information on the lethal or sublethal effects of Rimon on adult and immature alfalfa leafcutting bees used to pollinate alfalfa using controlled exposures in the laboratory. ARS will provide a supply of bees and expertise in bee biology and how to handle the bees for development and mortality studies. The University will conduct the experiments, analyze the data, and write up the reports. Alfalfa leafcutting bees are the most common alfalfa pollinator in the Pacific Northwest. People managing alfalfa leafcutting bees in Idaho, Utah and Colorado reported unusually low numbers of bees being produced in fields that had been treated with novaluron, an insecticide used to control Lygus bugs. Novaluron is an insect growth regulator. We evaluated novaluron toxicity to immature leafcutting bees using two exposure methods: by directly applying pesticides to eggs and bee larvae (and their food provision), or by feeding the insecticide to adult females before releasing them in field cages with blooming alfalfa where nesting and immature mortality were observed. When immature bees were treated, mortality was significantly higher than in both the water-treated and untreated controls, providing evidence that novaluron is toxic to bee offspring in nest cells. The eggs and young larvae were more susceptable than older larvae. When adult female bees were fed the insecticide, nesting was similar to the controls; however, offspring mortality was greater in those treatments where females were fed sugar-water + novaluron compared to sugar-water only. Although novaluron-fed females provided adequate provisions for their offspring, there was a low percentage of egg hatch or larval development. Novaluron could be contributing to poor bee return in alfalfa grown for seed. This agreement was also used to provide chemical analayses of pesticide levels in bee nests from agricultural fields, for honey bees, alfalfa leafcutting bees, and blue orchard bees. Analysis of the results is underway.
Impacts
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Publications
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Progress 10/01/11 to 09/30/12
Outputs
Progress Report Objectives (from AD-416): To evaluate the the toxicity of a new pesticide, Rimon, on the alfalfa leafcutting bee. Rimon is a growth regulator inhibitor and is suspected by some beekeepers to be affecting the growth of bee larvae. The pesticide is used in alfalfa seed fields to control lygus bugs. The two main goals of this project are to assess egg mortality when adult bees are treated with Rimon, and evaluate the mortality dose response of eggs and larvae when pollen provisions are treated. Approach (from AD-416): Rimon� is a chitin inhibitor insecticide used for the suppression of lygus bug, the most damaging insect in Utah alfalfa seed fields. The active ingredient in Rimon interferes with insect pest development and successful molting, but is supposed to be safe on beneficial and pollinating insects. In the fall of 2007, several Idaho alfalfa seed growers noticed a greater percentage of leafcutting bee cells containing pollen/nectar provisions with no live bee brood from fields that were treated with Rimon. Growers questioned if Rimon could be lethal or sublethal to leafcutting bee eggs or larvae. The potential negative health effects of Rimon on leafcutting bees are valid concerns for growers who will have to purchase more new bees each growing season. This project will provide basic information on the lethal or sublethal effects of Rimon on adult and immature alfalfa leafcutting bees used to pollinate alfalfa using controlled exposures in the laboratory. ARS will provide a supply of bees and expertise in bee biology and how to handle the bees for development and mortality studies. The University will conduct the experiments, analyze the data, and write up the reports. Research was initiated this year to look at pesticides in pollen provisions from blue orchard bees that had been used for pollinating almond orchards. Pollen provisions were collected and chemical analyses conducted. The results are being analyzed and interpreted.
Impacts
(N/A)
Publications
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Progress 10/01/10 to 09/30/11
Outputs
Progress Report Objectives (from AD-416) To evaluate the the toxicity of a new pesticide, Rimon, on the alfalfa leafcutting bee. Rimon is a growth regulator inhibitor and is suspected by some beekeepers to be affecting the growth of bee larvae. The pesticide is used in alfalfa seed fields to control lygus bugs. The two main goals of this project are to assess egg mortality when adult bees are treated with Rimon, and evaluate the mortality dose response of eggs and larvae when pollen provisions are treated. Approach (from AD-416) Rimon� is a chitin inhibitor insecticide used for the suppression of lygus bug, the most damaging insect in Utah alfalfa seed fields. The active ingredient in Rimon interferes with insect pest development and successful molting, but is supposed to be safe on beneficial and pollinating insects. In the fall of 2007, several Idaho alfalfa seed growers noticed a greater percentage of leafcutting bee cells containing pollen/nectar provisions with no live bee brood from fields that were treated with Rimon. Growers questioned if Rimon could be lethal or sublethal to leafcutting bee eggs or larvae. The potential negative health effects of Rimon on leafcutting bees are valid concerns for growers who will have to purchase more new bees each growing season. This project will provide basic information on the lethal or sublethal effects of Rimon on adult and immature alfalfa leafcutting bees used to pollinate alfalfa using controlled exposures in the laboratory. ARS will provide a supply of bees and expertise in bee biology and how to handle the bees for development and mortality studies. The University will conduct the experiments, analyze the data, and write up the reports. Alfalfa leafcutting bees are the most common pollinators of alfalfa seed in the western U.S. Beekeepers in Idaho, Utah and Colorado reported that bees from fields treated with novaluron (to control lygus) reproduced poorly. The toxicity of novaluron to immature alfalfa leafcutting bees was tested using two different possible mechanisms of exposure. Immature mortality was assessed when nectar and pollen in the nest (the food of immature bees) were contaminated, and when the adults were exposed to novaluron. Mortality of the immature bees was significantly higher in all the novaluron treatments than in the water or blank controls, providing evidence that novaluron is toxic to progeny in bee nest cells. More eggs and young larvae died, as compared to older larvae. Novaluron did not affect female nesting in field cages; however, there was greater immature mortality in cages where females were fed sugar-water that was contaminated with novaluron as compared to sugar-water only. Although adult female bees provided adequate pollen and nectar provisions to their offspring, a low percentage of the eggs hatched and larval development was poorer when females ingested novaluron before mating and nesting. When the plants in the cages were sprayed to treat the adults, Novaluron was also present in the pollen and nectar provisions from the nests. At least 84 percent of progeny died when the mother bees were allowed to mate and nest 24 hours after a novaluron application. Novaluron could be contributing to poor bee production in alfalfa grown for seed. Timely insecticide applications to suppress lygus is an important consideration to improve ongoing bee health. ADODR monitoring is done by site visits and meetings, phone calls, and email.
Impacts
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Publications
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Progress 10/01/09 to 09/30/10
Outputs
Progress Report Objectives (from AD-416) To evaluate the the toxicity of a new pesticide, Rimon, on the alfalfa leafcutting bee. Rimon is a growth regulator inhibitor and is suspected by some beekeepers to be affecting the growth of bee larvae. The pesticide is used in alfalfa seed fields to control lygus bugs. The two main goals of this project are to assess egg mortality when adult bees are treated with Rimon, and evaluate the mortality dose response of eggs and larvae when pollen provisions are treated. Approach (from AD-416) Rimon� is a chitin inhibitor insecticide used for the suppression of lygus bug, the most damaging insect in Utah alfalfa seed fields. The active ingredient in Rimon interferes with insect pest development and successful molting, but is supposed to be safe on beneficial and pollinating insects. In the fall of 2007, several Idaho alfalfa seed growers noticed a greater percentage of leafcutting bee cells containing pollen/nectar provisions with no live bee brood from fields that were treated with Rimon. Growers questioned if Rimon could be lethal or sublethal to leafcutting bee eggs or larvae. The potential negative health effects of Rimon on leafcutting bees are valid concerns for growers who will have to purchase more new bees each growing season. This project will provide basic information on the lethal or sublethal effects of Rimon on adult and immature alfalfa leafcutting bees used to pollinate alfalfa using controlled exposures in the laboratory. ARS will provide a supply of bees and expertise in bee biology and how to handle the bees for development and mortality studies. The University will conduct the experiments, analyze the data, and write up the reports. Chemical analyses were conducted from previous experiments, data were analyzed, and a manuscript was drafted and submitted to a peer-reviewed scientific journal for publication. ADODR monitoring is done via e-mail, on-site visits, and phone calls.
Impacts
(N/A)
Publications
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Progress 10/01/08 to 09/30/09
Outputs
Progress Report Objectives (from AD-416) To evaluate the the toxicity of a new pesticide, Rimon, on the alfalfa leafcutting bee. Rimon is a growth regulator inhibitor and is suspected by some beekeepers to be affecting the growth of bee larvae. The pesticide is used in alfalfa seed fields to control lygus bugs. The two main goals of this project are to assess egg mortality when adult bees are treated with Rimon, and evaluate the mortality dose response of eggs and larvae when pollen provisions are treated. Approach (from AD-416) Rimon� is a chitin inhibitor insecticide used for the suppression of lygus bug, the most damaging insect in Utah alfalfa seed fields. The active ingredient in Rimon interferes with insect pest development and successful molting, but is supposed to be safe on beneficial and pollinating insects. In the fall of 2007, several Idaho alfalfa seed growers noticed a greater percentage of leafcutting bee cells containing pollen/nectar provisions with no live bee brood from fields that were treated with Rimon. Growers questioned if Rimon could be lethal or sublethal to leafcutting bee eggs or larvae. The potential negative health effects of Rimon on leafcutting bees are valid concerns for growers who will have to purchase more new bees each growing season. This project will provide basic information on the lethal or sublethal effects of Rimon on adult and immature alfalfa leafcutting bees used to pollinate alfalfa using controlled exposures in the laboratory. ARS will provide a supply of bees and expertise in bee biology and how to handle the bees for development and mortality studies. The University will conduct the experiments, analyze the data, and write up the reports. Significant Activities that Support Special Target Populations Caged bee release studies were used to evaluate whether Rimon could affect the health of eggs and bee larvae produced by mother bees exposed to the insecticide. Four field cages were placed over alfalfa in bloom at the Utah State University Greenville Farm in Logan, Utah. A small ALCB nesting block was placed in the center of each cage, and 15 female bees were released into each cage on 16 July, 22 July, and 3 August; 18-23 males were released in each cage one day prior to the female releases. Two cages had females feeding on sugar-water for 24 hours prior to release, and the other two cages had females feeding on sugar-water + field-rate Rimon for 24 hours prior to release. For each replication, females foraged and nested within their respective cages for 7-9 days. Each nesting block was replaced between replications. Percent mortality of the progeny was evaluated, and for the first replication, there was 100% progeny mortality for the two cages where ALCB female adults were fed sugar-water + Rimon. These results can be compared to 12 and 20% progeny mortality for the two cages where ALCB females were fed sugar- water but no pesticide. Decreasing flower availability and increasing pest pressure over time in all cages likely reduced optimal nesting during the second and third replications. In all four cages of the first replication, females produced similar number of eggs; although most were not viable in the sugar-water + Rimon treatment. Most of the progeny were dead eggs or young larvae. It appears that when ALCB females feed on Rimon, it affects the health of their progeny. The direct effects of Rimon on alfalfa leafcutting bee larvae and eggs was evaluated in laboratory bioassays. The insecticide was applied directly to eggs in the bee cells with natural provisions. Rimon was tested at 4 rates, and 2 controls were used (a water-treated and an untreated control). The experiment was replicated 4 times over the season. Percent mortality for the four Rimon treatments ranged from 79 � 98%. For all replications, the 4 Rimon treatments were significantly more lethal than the water and blank controls, but mortality in the controls was greater than desired (mean of 56%). Cell handling, chalkbrood, and other environmental factors caused control mortality. ADODR monitoring included on-site visits, phone calls, and e-mail.
Impacts
(N/A)
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