Greetings
I have written to the Ithaca Times objecting to the City of Ithaca's proposal to inject Ash trees with emamectin as a "preventative" against Emerald Ash Borer, which has not yet been found in this area. I have suggested that an environmental impact study be done to ascertain the potential impact on insects that collect pollen from the ash tree (Fraxinus).
I have looked into some aspects of the issue and have learned that there is indeed a risk posed to pollinators by this course of action. Emamectin is *Highly toxic to bees* [Apis mellifera (honey bee) LD50 (24 h) oral = 0.0036 μ g/bee].
Do bees collect pollen from ash trees? The following study seems to indicate conclusively that they do, in addition to dandelion (Taraxacum), willow (Salix), and poplar (Populus) which bloom at the same time.
* * *
The most important pollen plants (in northeastern Italy) were identified at the end of March 2003. In this period pollen loads were collected, grouped according to colour and 142 slides prepared. Using an optical microscope, the different plant pollens were identified. The relationship between pollen load colours and pollen plants was studied; pollen plants that were preferentially visited by honey bees were identified. Taraxacum officinale Weber, Fraxinus, Salix, Liliaceae races and Populus resulted the most important pollen plants, in this area. Bee crops often consisted of different pollen types.
Bees often visited Fraxinus, Salix and Taraxacum for pollen. In particular Fraxinus seems to be very important in Cornino and San Daniele; there on the 23rd of March, this species was *the only plant* from which bees gathered pollen. Moreover Fraxinus pollen was collected by bees in all four places on the 27th of March, and on that day pollen loads were made up almost entirely by this pollen.
The data allow to draw some conclusions:
- the polliniferous plants always harvested by bees, in the beginning of the spring in the studied area, are Taraxacum officinale Weber, Fraxinus, Salix, Liliaceae and Populus;
- this study shows pollen types which honey bees gathered at the beginning of the active season when a lot of energy is needed. It is not know why honey bees have chosen them, a study of grains composition will be useful to identify the factors (i.e. protein contents) which influence forager’s choices.
A study on the pollen sources for honey bees in Udine province (northern Italy)
Laura FORTUNATO, Federica GAZZIOLA, Renzo BARBATTINI, Franco FRILLI
Dipartimento di Biologia applicata alla Difesa delle Piante – Entomologia, Università di Udine, Italy
Bulletin of Insectology 59 (1): 39-43, 2006 ISSN 1721-8861
Peter L Borst
128 Lieb Road
Spencer, NY 14883
42.35°N 76.50°W
***********************************************
The BEE-L mailing list is powered by L-Soft's renowned
LISTSERV(R) list management software. For more information, go to:
http://www.lsoft.com/LISTSERV-powered.html
Guidelines for posting to BEE-L can be found at:
http://honeybeeworld.com/bee-l/guidelines.htm
|
