Issue link: https://www.e-digitaleditions.com/i/1099801
10 Label language will continue to evolve as more information becomes available on the effects of pesticides on bee brood. However, until more is known about the effect of insecticides on bee brood, growers and their applicators should avoid applying any insecticide, except Bt, during almond bloom in order to protect bee brood, and instead should consider other effective timing options for applications outside of the bloom period. Before making insecticide applications during the delayed-dormant, bloom or post bloom periods, the appropriate individual (i.e., applicator) should visit BeeWhereCalifornia.com or contact their county agricultural commissioner to locate hives within a 1-mile radius of the spray site. They should also notify the beekeeper of the upcoming spray. The University of California Statewide Integrated Pest Management Guidelines for almonds provide insecticide application and timing options at IPM.UCDavis.edu under the Agricultural Pests section. The UC Statewide IPM site also has an interactive tool for determining bee precaution pesticide ratings. Another valuable resource is "How to Reduce Bee Poisoning from Pesticides," a Pacific Northwest Extension publication, PNW 591. Toxicity ratings in this publication focus on acute contact toxicity to adult foraging bees, and new information on additional risks to bee brood in the hive are included when available. A free downloadable version is available at Almonds.com/BeeBMPs and a free app is available at Almonds.com/OSUBeeApp. The University of California Statewide Integrated Pest Management Program provides guidance on bee precaution pesticide ratings at IPM.UCANR.edu/BeePrecaution. Delayed dormancy is the period of time from the resumption of growth after dormancy — indicated by bud swell, up until green tip — which occurs around Feb. 1, depending on region, variety and weather. This period is followed by bloom. Post bloom begins after petal fall, which is typically in late March but may vary based on region, variety and weather. As shown in this image, bloom sprays made at night will minimize the exposure of bees and pollen to spray chemicals. HONEY BEES AND FUNGICIDES All parties involved in almond pollination or pesticide applications should only apply fungicide(s) deemed necessary and, during bloom, should only apply those fungicides in the late afternoon or evening when bees and pollen are not present. Fungicide applications are needed in many situations as disease protection during almond bloom is key. However, fungicides may negatively impact pollination. For example, spraying while bees are foraging weakens the floral-scented chemicals that draw the bees to the blossom. In fact, there is also research that shows some fungicides, while fairly safe for use around adult honey bees, may contribute to brood losses in larval and pupal stages. 7 7 Mussen, E.C., J.E. Lopez, C.Y.S. Peng. 2004. Effects of selected fungicides on growth and development of larval honey bees, Apis mellifera L. Environ. Entomol. 33(5):1151–1154.