Nosema and pesticides-

Discussion in 'Bee News' started by Ray, Jul 25, 2013.

  1. Ray

    Ray Member

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    "One pathogen of major concern to beekeepers is Nosema spp. The endoparasitic fungal infections of N. apis and N. ceranae adversely affect honey bee colony health, and can result in complete colony collapse
    [30]. Infection with Nosema in the autumn leads to poor overwintering and performance the following spring [31], and queens can be superseded soon after becoming infected with Nosema [32]. We chose Nosema as a model pathogen because earlier work [13],[14] had demonstrated an interaction with pesticide exposure."

    "In blueberry, cranberry, cucumber, pumpkin and watermelon bees collected pollen almost exclusively from weeds and wildflowers during our sampling. Thus more attention must be paid to how honey bees are exposed to pesticides outside of the field in which they are placed. We detected 35 different pesticides in the sampled pollen, and found high fungicide loads. The insecticides esfenvalerate and phosmet were at a concentration higher than their median lethal dose in at least one pollen sample. While fungicides are typically seen as fairly safe for honey bees, we found an increased probability ofNosema infection in bees that consumed pollen with a higher fungicide load."

    "Third, two fungicides (chlorothalonil and pyraclostrobin), and two miticides used by beekeepers to control varroa infestation (amitraz and fluvalinate) had a pronounced effect on bees’ ability to withstand parasite infection."