Issue link: https://www.e-digitaleditions.com/i/1099801
11 8 Johnson, Reed. 2017. Effects of Insecticide-Fungicide-Adjuvant Combinations Commonly applied during bloom on Honey Bee Development and Survival. Almond Board of California 2017 Research Update, p. 47. The University of California recommends avoiding the use of fungicides containing iprodione, captan or ziram during almond bloom, and research performed in response to field observations of brood effects confirms that these fungicides can affect brood development. These compounds, however, do provide effective fungal control outside of bloom. As previously noted, controlled studies 8 demonstrate that some insecticides are known to result in greater than additive toxicity when combined with certain fungicides such that when the insecticide and fungicide are tank-mixed, the combination can be more toxic to bees than either chemical used alone. Until more is known, avoid tank-mixing insecticides with fungicides during the almond pollination season, the only exception being mixing Bt with a fungicide. USE INTEGRATED PEST MANAGEMENT TO MINIMIZE SPRAYS Following a monitoring-based integrated pest management (IPM) program in every season enhances pest control, protects water and air quality, and minimizes exposure of bees and pollen to pesticide sprays. Sources of information on developing and implementing an IPM program in almonds include the "UC Statewide IPM Pest Management Guidelines" and "Year-Round IPM Program for Almonds," which are available at IPM.UCANR.edu under Agricultural Pests and Almond. HONEY BEES AND SELF-COMPATIBLE ALMOND VARIETIES Self-compatible (or self-fertile) varieties do require bees for pollination, although the number of bees required to pollinate the blossoms is reduced. A number of factors — genetic, environmental and even the individual flowers — determine self-pollination and set. Even with self- compatible varieties, honey bees can ensure maximum set because bees consistently transfer pollen within the same flower from the anthers to the stigma of the pistil, where fertilization is initiated (see Fig. 1, Page 18). However, with self-compatible varieties, because pollen no longer needs to be transferred between different varieties, the number of hives needed is reduced. UC IPM online provides many resources to almond growers. BE CAUTIOUS ABOUT ADJUVANTS The University of California recommends adjuvants should not be used with fungicides during bloom, unless specified otherwise on the label. Most fungicides are already formulated with adjuvants, including wetting agents, spreaders and stickers. With few exceptions, additional adjuvants do not statistically improve the efficacy of fungicides for managing diseases. Although there is limited information on the interaction of adjuvants and fungicides with honey bees, it is best to take a precautionary approach because adjuvants may increase the wettability of bees and subsequently the potential toxicity of fungicides to bees. For more detail, see "Fungicides, Bactericides, and Biologicals for Deciduous Tree Fruit, Nut, Strawberry, and Vine Crops," available at Almonds.com/UCPollination.