- Author: Kathy Keatley Garvey
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:
https://ucdavis.zoom.us/j/95882849672.
"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 brnjohnson@ucdavis.edu. The list of seminars is posted here.



- Author: Kathy Keatley Garvey
Have you ever asked Siri "How cold is it?"
Siri, a computer program known as Apple's "intelligent personal assistant" or "knowledge navigator," is part of Apple's Inc.'s iOS operating system. Folks usually ask Siri for directions. We ask about the weather AND directions.
So on Wednesday noon, Jan. 25, from our Vacaville "weather station," we picked up the Iphone and asked Siri: "How cold is it?'
"It's 53 degrees and I don't find that particularly cold," she said, maybe a little too fiesty. Siri is probably headquartered in Fairbanks, Alaska, where shivering residents experience -70 degrees in January. Or maybe she's based in Grand Forks or Fargo, N.D., where -40 degrees is considered a heat wave.
It's so cold in some of the cities in Alaska, North Dakota and Minnesota--how cold?--so cold that you have to open the refrigerator to heat the house. And, sometimes it's so cold that:
- you step outside and your shadow freezes
- you hear the police telling a robber to "freeze" and he does
- you bake a cake and set it out on the windowsill to cool and seconds later, it's frosted
- you talk to friends and your words freeze, so you have to pick up the letters and thaw them before continuing
- bees are begging to be smoked
So we walked outside to check the newly flowering oxalis for the presence of honey bees. Fifty-three degrees. Scientists tell us that honey bees don't usually fly when it's below 55 degrees, but we've seen bees flying at 50 degrees. So, between 50 and 55, that's a given.
The yellow oxalis seemed to be waiting. Any bees? Yes, one bee. She probably emerged from her hive, shivered a bit, and said to her fellow worker bees: "Let's go, girls!"--or something like that.
So we asked Siri "Do you like bees?"
"This is about you, Kathy, not me," she said.
Still feisty.


