Arnon Dag: How to Improve Cross-Pollination in Almond, Pear, Apple and Cherry Trees

How can you improve cross-pollination in such tree crops as almond, pear, apple and cherry?

Senior scientist Arnon Dag of the Agricultural Research Organization, Volcani Institute, Israel, will discuss his research at the UC Davis Department of Entomology and Nematology seminar at 4:10 p.m., Monday, Nov. 27 in 122 Briggs Hall.

His seminar, titled "Improving Cross-Pollination in Deciduous Fruit Trees," also will be on Zoom: The Zoom link:

"Tree crops belonging to the Rosaceae, such as almond, pear, apple, and sweet cherry, depend on cross-pollination by insects to set fruit," Dag says in his abstract. "The primary pollinator of the crops is the honey bee (Apis mellifera). However, due to harsh climatic conditions during flowering, limited movement of bees between cultivars, low preference of the bees for flowers of the target crop, and limited overlap in flowering between the cultivars, pollination is a primary factor limiting yield. Our group has tested multiple approaches to mitigate this problem: Using 'Pollen dispensers,' sequential introduction of beehives to the orchards, selection of honeybee strains with higher preference for the target crop, introduction of bumblebee (Bombus terrestris) colonies and phosphorous fertilization to increase nectar secretion and improve crop-flower attractiveness. I will summarize the effects of those methods on fruit set and yield in apples, almonds, and pears."

A native of Moshav Lachish, Israel,  Dag received his bachelor's degree (1990) and master's degree (1992)  in life sciences at the Faculty of Life Sciences, Tel Aviv University. His master's thesis: "Improving the Honey Bee Efficiency of Melon Pollination in Greenhouses." He obtained his doctorate in agriculture at the Horticulture, Faculty of Agriculture at Hebrew University of Jerusalem, completing his dissertation on "Pollenizers, Pollinators and Pollination in Mango." He held postdoctoral positions at both Tel Aviv University and the Hebrew University of Jerusalem.

Dag's research interests include fruit tree physiology, olive biology and cultivation, reproductive biology of fruit trees, crop pollination, pomology in semi-arid conditions and "developing guava as an export crop."

He served as an Extension specialist in beekeeping from 1991 to 2003 for the Israeli Ministry of Agriculture.

Seminar coordinator is Brian Johnson, associate professor, UC Davis Department of Entomology and Nematology. For Zoom technical issues, he may be reached at The list of seminars is posted here.