Tuesday, December 4, 2012
Maine Wild Blueberries Is Moving!
The Maine Wild Blueberries blog is moving. Visit Cooperative Extension: Maine's Native Wild Blueberries to view mummyberry and insect updates, or subscribe to the Wild Blueberry Blog RSS feed. Past posts from this blog will be archived at the new location.
Wednesday, November 28, 2012
WBANA' s "Wild About Health" Blog
Please be sure to check out WBANA's "WILD ABOUT HEALTH" blog where you will find many delicious wild blueberry recipes, videos and articles.
Thursday, October 25, 2012
WILD BEE POLLINATORS: THE GENUS Andrena
In
May and June of 2010 and 2011, I collected wild bees from 24 blueberry fields
in Hancock County in the towns of Orland, Penobscot, Sedgwick and Blue
Hill. By "wild" bees I
mean any bee that is not a honeybee or a commercial bumblebee. Most of the wild bees are native,
occurring naturally in Maine, but a few are not native and have been brought
here by humans at some point in time.
The wild bees are generally small- the size of a honeybee or less. The wild bees are mostly solitary,
living individually or maybe in aggregations, but never forming the large
colonies seen with honeybees.
Naturally occurring bumblebees are wild, and they live in fairly large,
social colonies, but I did not collect bumblebees. In the spring the only bumblebees that are out in the
blueberry fields are the queens that are foraging for nectar and pollen before
starting to lay eggs. If I collect
a queen, I prevent the founding of an entire large colony of bumblebees. I did not want to do this, so I avoided
collecting bumblebees whenever possible.
I
used two methods of capture. The
first method involved placing small, colored cups filled with soapy water in
the fields for 24-48 hours. This
method catches anything attracted to the cup, including plenty of insects that
are not bees (and unfortunately slugs like the cups as well). Many of the bees I've caught have come
from these cup traps, but just because I catch a bee in a blueberry field
doesn't mean that that bee pollinates blueberry flowers. So, I also caught individual bees found
foraging on blueberry flowers. From
these bees I have made a list of possible wild bee blueberry pollinators.
A field assistant shows how to hand-catch bees on blueberry
flowers- taken in Addison ME, 2012.
This list includes 223 individual bees from 34 species
caught on blueberry flowers.
More than half of these 223 bees come from only three species:
Andrena carlini
Andrena
vicina
Andrena
carolina
The Andrena are
ground-nesting bees. The adults
dig a main burrow and create lateral burrows for the cells. They coat the walls of the cells with a
waterproof lining to protect the eggs and larvae. In each cell they place a food mass (mostly pollen, but some
nectar drops might be included) and one egg. The pollen is the food for the growing larva and sustains
the bee until it reaches adulthood.
Almost all Andrena overwinter
in their cells as adults. Most Andrena make individual nests and don't
share entrances with other adults.
They may place their nests near others. I have seen this in one blueberry field that had a southern-facing,
sandy slope. Early in May when the
blueberry flowers were just opening but no leaves were out, I came upon an
aggregation of Andrena nests on this
slope.
Below
is a bee at the entrance to a nest.
It is not one of the three species listed above, but it is a similar
size. The bee is about 3/4 an inch
long and the hole not much more than 1/2 inch in diameter. This nest was located in a small, sandy bare
patch in the middle of the blueberry field.
These
three species of Andrena might be
quite important for blueberry pollination. In general, in 2011, in the fields where I caught the
greater number of the Andrenid bees, the fruit set also was higher.
Tuesday, October 16, 2012
Blueberry Flamer Demonstration
Steve Koch, Director of Agriculture Division of Flame
Engineering, Inc., demonstrated a propane burner that can be used both to prune
and sanitize your fields for insects and disease at the Blueberry Hill Farm in
Jonesboro on Tuesday, October 2, 2012.
The machine has been used to kill potato tops, but he demonstrated its use to prune wild blueberries (see http://www.flameengineering.com/Potato_Vine_Flamers.html).
The flamer uses both vaporized and liquid propane gas to
produce a flame of 2050 degrees F. It has a 250 gallon propane tank with 8 nozzles
that burn a 10-foot swath. The cost of the unit delivered is about $12,000, but would be less if multiple orders were made. They have kits that will cover 6’ at $2700.00 and the flamer can be constructed to cover up to a 65’ width.
The local distributor will be No Frills Oil Company in Hancock, Maine. For more information, please contact Bill Birdsall at 422-3581.
The local distributor will be No Frills Oil Company in Hancock, Maine. For more information, please contact Bill Birdsall at 422-3581.
15 growers attended the demonstration where the flamer did an excellent job despite the moist condition's from
the previous day's 4.5 inch rainfall..
Tuesday, September 18, 2012
Bumblebee disease and diversity
Welcome to the Pollinator Posts!
Posted by Sara Bushmann, University of Maine
On these web pages I'll provide updates on some of the
pollinator research projects being conducted in (mostly) Hancock and Washington
Counties. Look for two more posts
this year on or around Oct. 15 and Nov.15, and then again in April and May for
updates on pollinator activity in the spring.
DISEASE IN MAINE BUMBLEBEES AND THE USE OF COMMERCIAL
BUMBLEBEES (Part One)
(I gave a quick report of this study at the Blueberry Hill
Farm Day gathering in July, 2012.)
This project sprang out of concerns voiced by bee
researchers throughout Europe and North America that some bumblebee species are
declining. Some of the ideas as to why there are declines include habitat loss,
pesticide exposure, and disease. But one suggestion particularly relevant to
Maine blueberry agriculture is the idea that commercial bumblebees of the
species Bombus impatiens (usually purchased in Maine from Koppert
Biological Systems) are transmitting diseases to the wild bees. The suggestion
is grounded on the concern that lab-reared bees could build up virulent strains
of pathogens that they pass to other bees when they infect a shared resource
such as a flower.
I decided to look at one pathogen, Nosema bombi, that infects bumblebees. This pathogen is of the group Microsporidia that are highly
modified forms of fungi. In bees, these are parasites of the gut tract.
I asked these questions:
1. What is the
prevalence of Nosema bombi infections in wild bumblebees in
Maine blueberry fields?
2. Is the
prevalence higher in areas where commercial bumblebees have
been used?
Over two years I dissected 767 bumblebees caught in and
around 25 blueberry fields. I found a total of 42 bees infected with Nosema,
which means 5.47% of the wild bumblebees- a little less than six out of
every 100- are infected. I looked at several factors that might explain why the
infection occurred where it did. I looked at pruning methods, pesticide use or
non-use, types of pesticides, field size, rotational stage (fruit-bearing year
or not), and whether or not the field ever used commercial bumblebees for
pollination.
None of these things offered an explanation for the
occurrence of the disease.
According to other studies from other researchers, it is not out of the
ordinary to see about 5% of the population infected with Nosema. So, based on
my study, I cannot support the suggestion that commercial bumblebees have
passed the disease agent Nosema to
wild bumblebees.
___________________________
DISEASE IN MAINE BUMBLEBEES AND THE USE OF COMMERCIAL BUMBLEBEES (Part Two)
I did not find evidence of commercial bees transmitting Nosema to wild bumblebees. However, I did find that disease
occurrence is not the same for the different species of bumblebees. One bumblebee that used to be common in
Maine blueberry fields, Bombus terricola, is in serious decline
throughout its range, which includes the northern US westward to the Plains. In
a nationwide study this bee was associated with high levels of Nosema bombi.
In my study I caught 13 B.
terricola in three years and 6 of these (almost half) were infected!
Compared to all the other species of bees, that is a huge percentage of infected
bees.
I knew that B.
terricola used to be common in Maine fields. So, I decided to see how bumblebee species in blueberry
fields have changed over several years.
I found that B. terricola has greatly declined in abundance in blueberry fields, but that B. impatiens and B. ternarius have increased. Bombus vagans has remained a common bumblebee in blueberry fields since the 60's. But, again, only B. terricola shows a high prevalence of Nosema infection.
(The data from the 1990's is provided by Frank Drummond, and
the data from the 1960's is from Boulanger et al. 1967, University of Maine
Technical Bulletin No. 26 which is available online.)
The increase of B.
impatiens could mean that commercial colonies produce queens that
overwinter and add to the wild populations.
I have found five other bumblebee species in blueberry
fields, all of which occur in 10% or less of the population.
Bombus
griseocolis
Bombus
fervidus
Bombus
borealis
Bombus
perplexus
Bombus
bimaculatus
For more
information about commercial and wild bumblebees in Maine blueberry production,
please see Maine Cooperative Extension Fact Sheets no. 302 and 630.
_____________________________________
Monday, August 13, 2012
URGENT: Spotted Wing Drosophila Update
The state of Maine
has secured a Section 18 “Crisis Exemption” registration for a higher rate of
Malathion 8Fl that is more effective for the SWD than the lower rate on the
existing label. This higher rate is in EFFECT on August 13 and only lasts for
15 days (August 13-28). If you decide to use this material at the higher rate
very strict reporting is required by the US EPA. The forms for reporting can be acquired from
the Maine Board of Pesticide Control.
Last week (Aug 10) spotted wing drosophila (SWD) showed up
in a few more blueberry fields. We have found adult male flies in traps in TWO
fields in Franklin (Hancock Co.), one field in Surrey, two fields in Ellsworth,
one field in Harrington, and one field in Jonesboro. I (Frank Drummond) have also
confirmed trapping of adult flies from several fields in Deblois (Washington
Co.). Thirty wild blueberry fields are being monitored by the Maine Dept. of
Agriculture and the University of Maine and many additional fields are being
monitored by growers and so far the picture is that SWD appears very spotty
across our blueberry growing areas. But, please be vigilant and continue to
trap for SWD in fields that you have not harvested yet.
What to do if you do
find flies? Well, there are several approaches, NONE of which are based
upon experimental evidence from wild blueberry research in Maine.
Conservative and
most safe approach: as soon as 1 fly is trapped and confirmed apply a
suitable insecticide at an interval that reflects the average persistance of
kill (residual in table) of the material (see list of insecticides below).
Liberal approach:
Coninue to trap after you catch your first fly and when fly numbers START to
increase from 1 fly in a trap to 3, 5, 10, etc., then consider applying an
insecticide.
Whatever strategy you pick, consider the following before
applying an insecticide:
1. If
you sell to a processor, check with them
to see what material can be used.
2. Make
sure that the PHI for the material that you choose is in accordance with your
harvest schedule.
3. A
PLANNED harvest 1-2 days after a confirmed trap capture may allow you to
harvest the crop withpout making an application if you feel that you can get
the berries out of the field immediately.
Currently
Available Products for SWD Control:
(Click here to enlarge table)
(Click here to enlarge table)
Chemical Class
|
Active Ingredient
|
Trade Name
|
PHI
|
Days of Residual
|
Comments
|
MRL for Canada (Yes/No)
|
Organophosphate
|
malathion
|
Malathion
|
1
|
5-7
|
Yes
|
|
phosmet
|
Imidan
|
3
|
7
|
Long
PHI
|
Yes
|
|
Pyrethroid
|
zeta-cypermethrin
|
Mustang-Max
|
1
|
7
|
No
|
|
bifenthrin
|
Brigade
|
1
|
7
|
No
|
||
zeta-cypermethrin+
bifenthrin
|
Hero
|
1
|
7
|
No
|
||
esfenvalerate
|
Asana
|
14
|
7
|
Very
long PHI
|
No
|
|
fenpropathrin
|
Danitol
|
3
|
7
|
Long
PHI
|
Yes
|
|
Carbamate
|
methomyl
|
Lannate
|
3
|
3-5
|
Short
lives, long PHI
|
Yes
|
carbaryl
|
Sevin
|
7
|
5-7
|
Long
PHI, Not as effective as others
|
Yes
|
|
Spinosyn
|
spinetoram
|
Delegate
|
3
|
7
|
Long
PHI
|
Yes
|
spinosad
|
Entrust
|
3
|
3-5
|
Short
lived, Long PHI
|
Yes
|
|
Pyrethrum
|
pyrethrum
|
Pyganic
|
0.5
|
2-3
|
Very
short lived
|
Yes
|
Posted by Frank Drummond
Tuesday, July 31, 2012
Spotted Wing Drosophila Alert
Dear Blueberry Growers,
Many of you have started harvesting. The spotted wing drosophila has been found strawberry and raspberry fields in southern Maine so far, especially in the vicinity of Warren, where one trap in a strawberry field contained 98 SWD flies.
We are trapping 30 blueberry fields and found 1 SWD fly in a trap in a Franklin blueberry field, in the forest edge.
So, please be vigilant and keep trapping for this potentially devastating pest. I will provide an update when we trap more flies.
Frank Drummond
Many of you have started harvesting. The spotted wing drosophila has been found strawberry and raspberry fields in southern Maine so far, especially in the vicinity of Warren, where one trap in a strawberry field contained 98 SWD flies.
We are trapping 30 blueberry fields and found 1 SWD fly in a trap in a Franklin blueberry field, in the forest edge.
So, please be vigilant and keep trapping for this potentially devastating pest. I will provide an update when we trap more flies.
Frank Drummond
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