Combined Toxicity of Insecticides and Fungicides Applied to California Almond Orchards to Honey Bee Larvae and Adults
Beekeepers providing pollination services for California almond orchards have reported observing dead or malformed brood during and immediately after almond bloom—effects that they attribute to pesticide exposure. The objective of this study was to test commonly used insecticides and fungi...
Main Authors: | , , , , |
---|---|
Format: | Article |
Language: | English |
Published: |
MDPI AG
2019-01-01
|
Series: | Insects |
Subjects: | |
Online Access: | http://www.mdpi.com/2075-4450/10/1/20 |
id |
doaj-42eea883cfa147f684cebd5813881d34 |
---|---|
record_format |
Article |
spelling |
doaj-42eea883cfa147f684cebd5813881d342020-11-24T22:05:37ZengMDPI AGInsects2075-44502019-01-011012010.3390/insects10010020insects10010020Combined Toxicity of Insecticides and Fungicides Applied to California Almond Orchards to Honey Bee Larvae and AdultsAndrea Wade0Chia-Hua Lin1Colin Kurkul2Erzsébet Ravasz Regan3Reed M. Johnson4Department of Biochemistry and Molecular Biology, College of Wooster, Wooster, OH 44691, USADepartment of Entomology, The Ohio State University, Columbus, OH 43210, USADepartment of Microbiology, The Ohio State University, Columbus, OH 43210, USADepartment of Biochemistry and Molecular Biology, College of Wooster, Wooster, OH 44691, USADepartment of Entomology, The Ohio State University, Wooster, OH 44691, USABeekeepers providing pollination services for California almond orchards have reported observing dead or malformed brood during and immediately after almond bloom—effects that they attribute to pesticide exposure. The objective of this study was to test commonly used insecticides and fungicides during almond bloom on honey bee larval development in a laboratory bioassay. In vitro rearing of worker honey bee larvae was performed to test the effect of three insecticides (chlorantraniliprole, diflubenzuron, and methoxyfenozide) and three fungicides (propiconazole, iprodione, and a mixture of boscalid-pyraclostrobin), applied alone or in insecticide-fungicide combinations, on larval development. Young worker larvae were fed diets contaminated with active ingredients at concentration ratios simulating a tank-mix at the maximum label rate. Overall, larvae receiving insecticide and insecticide-fungicide combinations were less likely to survive to adulthood when compared to the control or fungicide-only treatments. The insecticide chlorantraniliprole increased larval mortality when combined with the fungicides propiconazole or iprodione, but not alone; the chlorantraniliprole-propiconazole combination was also found to be highly toxic to adult workers treated topically. Diflubenzuron generally increased larval mortality, but no synergistic effect was observed when combined with fungicides. Neither methoxyfenozide nor any methoxyfenozide-fungicide combination increased mortality. Exposure to insecticides applied during almond bloom has the potential to harm honey bees and this effect may, in certain instances, be more damaging when insecticides are applied in combination with fungicides.http://www.mdpi.com/2075-4450/10/1/20synergismApis melliferaAltacorIntrepidDimilinPristineTiltRovralpollination |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Andrea Wade Chia-Hua Lin Colin Kurkul Erzsébet Ravasz Regan Reed M. Johnson |
spellingShingle |
Andrea Wade Chia-Hua Lin Colin Kurkul Erzsébet Ravasz Regan Reed M. Johnson Combined Toxicity of Insecticides and Fungicides Applied to California Almond Orchards to Honey Bee Larvae and Adults Insects synergism Apis mellifera Altacor Intrepid Dimilin Pristine Tilt Rovral pollination |
author_facet |
Andrea Wade Chia-Hua Lin Colin Kurkul Erzsébet Ravasz Regan Reed M. Johnson |
author_sort |
Andrea Wade |
title |
Combined Toxicity of Insecticides and Fungicides Applied to California Almond Orchards to Honey Bee Larvae and Adults |
title_short |
Combined Toxicity of Insecticides and Fungicides Applied to California Almond Orchards to Honey Bee Larvae and Adults |
title_full |
Combined Toxicity of Insecticides and Fungicides Applied to California Almond Orchards to Honey Bee Larvae and Adults |
title_fullStr |
Combined Toxicity of Insecticides and Fungicides Applied to California Almond Orchards to Honey Bee Larvae and Adults |
title_full_unstemmed |
Combined Toxicity of Insecticides and Fungicides Applied to California Almond Orchards to Honey Bee Larvae and Adults |
title_sort |
combined toxicity of insecticides and fungicides applied to california almond orchards to honey bee larvae and adults |
publisher |
MDPI AG |
series |
Insects |
issn |
2075-4450 |
publishDate |
2019-01-01 |
description |
Beekeepers providing pollination services for California almond orchards have reported observing dead or malformed brood during and immediately after almond bloom—effects that they attribute to pesticide exposure. The objective of this study was to test commonly used insecticides and fungicides during almond bloom on honey bee larval development in a laboratory bioassay. In vitro rearing of worker honey bee larvae was performed to test the effect of three insecticides (chlorantraniliprole, diflubenzuron, and methoxyfenozide) and three fungicides (propiconazole, iprodione, and a mixture of boscalid-pyraclostrobin), applied alone or in insecticide-fungicide combinations, on larval development. Young worker larvae were fed diets contaminated with active ingredients at concentration ratios simulating a tank-mix at the maximum label rate. Overall, larvae receiving insecticide and insecticide-fungicide combinations were less likely to survive to adulthood when compared to the control or fungicide-only treatments. The insecticide chlorantraniliprole increased larval mortality when combined with the fungicides propiconazole or iprodione, but not alone; the chlorantraniliprole-propiconazole combination was also found to be highly toxic to adult workers treated topically. Diflubenzuron generally increased larval mortality, but no synergistic effect was observed when combined with fungicides. Neither methoxyfenozide nor any methoxyfenozide-fungicide combination increased mortality. Exposure to insecticides applied during almond bloom has the potential to harm honey bees and this effect may, in certain instances, be more damaging when insecticides are applied in combination with fungicides. |
topic |
synergism Apis mellifera Altacor Intrepid Dimilin Pristine Tilt Rovral pollination |
url |
http://www.mdpi.com/2075-4450/10/1/20 |
work_keys_str_mv |
AT andreawade combinedtoxicityofinsecticidesandfungicidesappliedtocaliforniaalmondorchardstohoneybeelarvaeandadults AT chiahualin combinedtoxicityofinsecticidesandfungicidesappliedtocaliforniaalmondorchardstohoneybeelarvaeandadults AT colinkurkul combinedtoxicityofinsecticidesandfungicidesappliedtocaliforniaalmondorchardstohoneybeelarvaeandadults AT erzsebetravaszregan combinedtoxicityofinsecticidesandfungicidesappliedtocaliforniaalmondorchardstohoneybeelarvaeandadults AT reedmjohnson combinedtoxicityofinsecticidesandfungicidesappliedtocaliforniaalmondorchardstohoneybeelarvaeandadults |
_version_ |
1725825473516142592 |