March 18, 2026
Bee Science: Varroa Mites with Dewey Caron (BSD-3)
Varroa mites are the most destructive parasite affecting honey bee colonies worldwide. In this Bee Science Short, Dr. Dewey Caron explains how Varroa destructor reproduces, spreads within colonies, and why understanding the mite’s biology is essential for modern beekeeping.
Female Varroa mites enter brood cells shortly before they are capped and reproduce alongside the developing bee. Inside the sealed cell, mites feed on the developing bee and produce offspring that emerge with the young adult bee. Because the mite’s reproductive cycle is closely tied to brood production, populations can increase rapidly during the active season.
Beyond direct feeding damage, Varroa mites also spread viruses that weaken colonies and shorten the lifespan of worker bees. Dewey explains why unchecked mite populations can quickly overwhelm a colony if they are not monitored and managed.
For beekeepers, the key is awareness. Regular monitoring allows beekeepers to track mite levels and respond before populations reach damaging levels. Understanding the biology of Varroa helps beekeepers make informed decisions about management strategies and colony health.
This episode is part of the Bee Science with Dewey series, where Dr. Caron shares practical explanations of honey bee biology to help beekeepers better understand what is happening inside their colonies.
Links and references mentioned in this episode:
-
Lundin, Ola. Et. al. 2021. Integrated pest and pollinator management – expanding the concept. Frontiers Ecol & Environ. https://doi.org/10.1002/fee.2325
-
Caron, Dewey and review committee. Tools for Varroa Management. Honey Bee Health Coalition https://honeybeehealthcoalition.org/resources/varroa-management/ (you want to get the 9th edition (available soon)
-
Bruckner, Selina, et.al. 2025. Let’s not sugar coat it: the powdered sugar shake is Published online: https://doi.org/10.1080/00218839.2025.2550855
-
Caron, D.M. and L. J. Connor. 2025. Honey bee Biology and Beekeeping. Wicwas Press.
______________
Brought to you by Betterbee – your partners in better beekeeping.
Betterbee is the presenting sponsor of Beekeeping Today Podcast. Betterbee’s mission is to support every beekeeper with excellent customer service, continued education and quality equipment. From their colorful and informative catalog to their support of beekeeper educational activities, including this podcast series, Betterbee truly is Beekeepers Serving Beekeepers. See for yourself at www.betterbee.com
_______________
We hope you enjoy this podcast and welcome your questions and comments in the show notes of this episode or: questions@beekeepingtodaypodcast.com
Thank you for listening!
Podcast music: Be Strong by Young Presidents; Epilogue by Musicalman; Faraday by BeGun; Walking in Paris by Studio Le Bus; A Fresh New Start by Pete Morse; Wedding Day by Boomer; Christmas Avenue by Immersive Music; Red Jack Blues by Daniel Hart; Bolero de la Fontero by Rimsky Music; Perfect Sky by Graceful Movement; Original guitar background instrumental by Jeff Ott.
Beekeeping Today Podcast is an audio production of Growing Planet Media, LLC
** As an Amazon Associate, we may earn a commission from qualifying purchases
Copyright © 2026 by Growing Planet Media, LLC
WEBVTT
00:00:00.880 --> 00:00:02.400
Hi, I'm Dr.
00:00:02.400 --> 00:00:04.160
Dewey Kerr.
00:00:04.640 --> 00:00:07.920
I come to you from Portland, Oregon.
00:00:07.920 --> 00:00:14.960
I present another audio postcard in my new series of once-monthly Beekeeping Today mini-series podcasts.
00:00:15.080 --> 00:00:16.360
Bee Science with Dr.
00:00:16.360 --> 00:00:17.800
Dewey Karen.
00:00:17.800 --> 00:00:20.920
This is the third installment in this series.
00:00:20.920 --> 00:00:26.119
Each episode seeks to blend research, field experience, and seasonal context
00:00:26.140 --> 00:00:30.539
Focusing on the why behind honeybee biology and behavior.
00:00:30.539 --> 00:00:34.620
I welcome your suggestions for timely topics.
00:00:34.200 --> 00:00:38.040
The miniseries topic this month is mites.
00:00:38.040 --> 00:00:41.960
Yes, I know you have heard a lot about mites found in Dives.
00:00:41.960 --> 00:00:45.000
Certainly trophylaps and bromites.
00:00:44.820 --> 00:00:51.940
less perhaps about raw tracheal mites, and hardly nothing about common pollen mites.
00:00:51.940 --> 00:00:59.460
We are most interested in understanding how mites are so threatening to beekeeping success.
00:00:59.020 --> 00:01:01.100
My message is simple.
00:01:01.100 --> 00:01:06.140
If you don't get anything else from this episode, remember have a plan
00:01:06.740 --> 00:01:17.540
For this episode, I will be discussing boroamite, a formidable foe to colony survival due to its involvement in spreading virus epidemics in our colonies.
00:01:17.520 --> 00:01:31.360
We are well aware that our beehives are an ideal environment for harboring the growth of pathogens with abundant, highly concentrated, stored carbohydrates, like you know, honey, and protein, bee bread.
00:01:31.160 --> 00:01:45.560
Additionally, their social organization, which fosters behavior such as food exchange and thermal regulation, among others, also aids in rapid and possible rapid possibilities passage and growth and spread.
00:01:45.439 --> 00:01:49.920
Your plan for Vroomites should be an IPM-based one.
00:01:49.920 --> 00:01:54.720
IPM is the acronym for Integrated Pest Management.
00:01:54.920 --> 00:02:03.080
Which is sometimes you might see that as IPPM for Integrated Pest and Pollinator Management
00:02:03.580 --> 00:02:11.340
The IPM mantra is one, know your enemy, two, monitor its population, three
00:02:11.860 --> 00:02:24.420
Determine the threshold level for damage the pest may cause to plant crop or host, and four, determine how best to control the pest if it exceeds an economic entry level.
00:02:24.160 --> 00:02:34.000
IPM for varroa mite means using tools designed to kill mites in or flatten the varroa mite population growth curve.
00:02:34.040 --> 00:02:43.000
A fifth tenant is when selecting a control method, pesticides should be the last tool considered for control of the pest.
00:02:43.340 --> 00:02:56.220
But in practice, in crop and animal pest control, certainly, practitioners, practitioners being homeowners, farmers, pest control companies, beekeepers, anyone doing battle with a pest
00:02:56.620 --> 00:02:59.340
usually often reach for the bottle.
00:02:59.340 --> 00:03:08.860
The pesticide, the method that quickly and usually pretty efficient effectively will neutralize the pest, at least until pest resistance builds
00:03:08.760 --> 00:03:18.520
While we want to flatten mite population increase, we do not want to flatten the bee growth when we are using a mite control pest tool.
00:03:18.260 --> 00:03:23.700
We want the bee colony to grow and expand five to sixfold from its overwintering size.
00:03:23.700 --> 00:03:32.820
The exception is that in later spring we may need to slow colony growth if the bees start preparing to divide via swarming.
00:03:32.440 --> 00:03:36.040
That's the topic for an upcoming bee science podcast.
00:03:36.040 --> 00:03:45.319
The better we are able to flatten mite population growth in the hive, the greater our chances that we will be able to successfully meet our beekeeping objectives
00:03:45.520 --> 00:03:55.040
More honey, more efficient pollination, more potential economic return, and especially improving overwintering success
00:03:55.420 --> 00:04:01.340
Success can be broadly or narrowly defined as meeting both short and long-term beekeeping objectives.
00:04:01.340 --> 00:04:04.700
I'll not be going into the level of B losses in this podcast.
00:04:04.700 --> 00:04:06.860
Thankfully, so far this winter.
00:04:07.140 --> 00:04:20.019
The extremely heavy colony losses experienced the last three to five years by USB keepers, generally above 50% annual colony loss levels, seems to be lower
00:04:20.220 --> 00:04:26.940
Still too high, and especially for some individual beekeepers, it remains elusively high.
00:04:26.940 --> 00:04:33.580
Heavy overwintering and annual losses tells us that we are not apparently using the best bee stock, nor
00:04:33.860 --> 00:04:40.020
Correctly mixing the number of tools that we have available to flatten mic growth expansion in RB hives.
00:04:40.020 --> 00:04:41.860
That is where your plan comes in.
00:04:41.860 --> 00:04:45.060
Develop a plan that will reduce mic numbers in a hive.
00:04:45.260 --> 00:04:51.900
I suggest your plan, in broad terms, might be something like improve bee health for better high survival.
00:04:51.900 --> 00:04:53.660
The devil is in the details.
00:04:53.660 --> 00:04:57.180
You'll need to have a more refined plan to succeed.
00:04:57.320 --> 00:04:59.800
So let's look at the IPM approach.
00:04:59.800 --> 00:05:03.240
First thing I said is we need to know the enemy.
00:05:03.240 --> 00:05:06.040
So let's talk a bit about the bromite.
00:05:05.940 --> 00:05:14.980
The scientific name, Veroa Destructor, the species name is very apt as this might, if left unchecked, will destroy a hive.
00:05:14.780 --> 00:05:16.940
The vrroamite was discovered in the U.
00:05:16.940 --> 00:05:17.100
S.
00:05:17.180 --> 00:05:24.140
in 1987 after accidental introduction, probably by a beekeeper illegally bringing queens into the U.
00:05:24.140 --> 00:05:24.300
S.
00:05:24.380 --> 00:05:25.100
from Europe.
00:05:25.460 --> 00:05:28.979
The original host of Broa is an Asian honeybee.
00:05:28.979 --> 00:05:35.460
Sometime, maybe 50 to 70 years ago, it changed host to our apus mellifera.
00:05:35.260 --> 00:05:43.420
And then in the early 1970s, it was transported, again, likely by gek beekeepers, from Asia to Europe.
00:05:43.160 --> 00:05:54.200
It has found the European honeybee, the way we keep colonies close together in similar boxes, as both being very favorable for meeting its life's necessities
00:05:54.420 --> 00:06:03.860
Asian bee groom it more effectively, uncapp and remove infested brood, and the mites can only develop in drone brood
00:06:04.340 --> 00:06:07.300
The Asian bee has the mite under control.
00:06:07.300 --> 00:06:09.220
Our European bee does not.
00:06:09.220 --> 00:06:18.900
Either directly or indirectly, various mites annually killed twenty five to fifty percent of beekeeper colonies, lately greater than fifty percent.
00:06:18.440 --> 00:06:25.160
When it first arrived, it killed an estimated ninety percent of non-managed feral colonies in the US.
00:06:25.160 --> 00:06:31.080
Broa is such a threat to European honeybees because they are are a new they are a new threat
00:06:31.139 --> 00:06:36.100
European honeybees haven't had enough time to develop resistance to them.
00:06:36.100 --> 00:06:43.460
European honeybee colonies infected with VROA that are not treated will die within one to three years
00:06:43.800 --> 00:06:47.960
Severamide has two components to its annual life cycle.
00:06:47.960 --> 00:06:51.880
During the dispersal, formerly labeled the pharetic,
00:06:52.220 --> 00:07:02.860
Sometimes labeled the traveling phase, it switches from one adult bee host to another for an estimated average of seven days on host.
00:07:02.740 --> 00:07:10.980
It feeds primarily on the host bee's fat body, bedding itself in the first couple of intersectional membrane regions
00:07:11.039 --> 00:07:14.159
of the lower abdomen of its host adult.
00:07:14.159 --> 00:07:18.560
Nurse age bees are preferred as they have larger amounts of fat body.
00:07:18.560 --> 00:07:23.680
During spring, however, the dispersal phase is mostly spent on drones.
00:07:23.720 --> 00:07:28.600
Because they exist in defined areas of the brood where drone brood occurs.
00:07:28.600 --> 00:07:34.040
The second phase of the mite life cycle is the reproductive phase.
00:07:33.740 --> 00:07:44.300
During this phase, a dispersal mite on a nurse bee or drone drops into a cell 15 to 18 hours prior to the cell being capped.
00:07:44.039 --> 00:07:48.599
This mite is termed a foundress or sometimes mother mite.
00:07:48.599 --> 00:07:58.599
The foundrous female mite can apparently tell the bee larvae has just about finished feeding on its food provisioned in her cell.
00:07:57.860 --> 00:08:02.660
and is about to go to the next stage, what we call the prepupa.
00:08:02.660 --> 00:08:10.660
The bee prepupa spins a thin silken cocoon within her cell, while the cell is covered with a beeswax capping by adult bees
00:08:10.740 --> 00:08:17.540
Slightly older than the nurse age bees, what we call the so-called middle-aged bees, adult bees.
00:08:17.540 --> 00:08:23.220
The founders mite hides in and consumes the leftover larval food at the bottom of the cell.
00:08:22.960 --> 00:08:26.800
to avoid getting trapped in the silk cocooning of the prepupa.
00:08:26.800 --> 00:08:36.640
After the prepupa completes her cocoon, it transfers into the pupil stage, and then the founder Smite climbs onto her body
00:08:36.740 --> 00:08:46.900
then opens a feeding hole in the pupal body of that worker or drone bee near the fifth abdominal segment of the B pupa.
00:08:46.900 --> 00:08:51.460
This is needed before the B pupa exoskeleton hardens.
00:08:51.339 --> 00:08:57.579
Only a single feeding site is open, even if multiple founders mites invade a brood cell.
00:08:57.579 --> 00:09:02.459
The founder starts feeding on a brood within six hours of the cell being sealed.
00:09:02.259 --> 00:09:05.220
And she feeds irregularly thereafter.
00:09:05.220 --> 00:09:11.300
She feeds on fat body, which will suppress the immune system of the developing bee.
00:09:11.520 --> 00:09:20.880
This will allow for rapid development of certain viruses, which she also, in feeding, introduces into that developing bee.
00:09:20.500 --> 00:09:25.460
The founder's mite defecates on a beeswax cell wall close to the feeding hole.
00:09:25.460 --> 00:09:30.500
This helps ID the feeding site location for her offspring.
00:09:30.160 --> 00:09:36.800
and also it becomes the place where the male mite will mate with the mature female offspring's mites.
00:09:36.800 --> 00:09:44.160
It takes sixty to seven hours after capping for that founders mite's body to mature the first egg
00:09:43.959 --> 00:09:45.320
Which is a male egg.
00:09:45.320 --> 00:09:52.680
All remaining eggs are laid at approximately 26 to 32 hour intervals and are female eggs
00:09:52.540 --> 00:09:58.940
Five to seven eggs total may be produced within a cell by a single foundrous mite.
00:09:58.940 --> 00:10:05.420
The immature mite has two immature life stages termed protonymph and deudonymph
00:10:05.560 --> 00:10:15.320
It takes about five to six days for male buromites to develop and seven to eight days for female mites to develop from that egg stage to a mature adult.
00:10:15.320 --> 00:10:18.600
Mating occurs in the brood self itself
00:10:18.759 --> 00:10:24.199
The male viromite dies inside the shell cell shortly afterwards.
00:10:24.199 --> 00:10:30.199
And during this time it has not fed as it uses its mouth parts in mating.
00:10:29.759 --> 00:10:31.199
and so does not feed.
00:10:31.199 --> 00:10:36.480
Reproductive output depends upon the cell entered by the founderous female.
00:10:36.480 --> 00:10:39.680
Drone brood is preferred for reproduction.
00:10:39.540 --> 00:10:50.820
And due to that two-day longer development time of the drone pupa, 14 days, compared to the 12-day capping duration of a worker cell,
00:10:50.800 --> 00:10:59.839
A drone cell yields an average of three female offspring versus a single adult female offspring
00:11:00.140 --> 00:11:03.020
That can be produced in a worker cell.
00:11:03.020 --> 00:11:12.460
Founders mites gradually change from drone brood of early spring to worker brood as fewer drone cells become available
00:11:12.620 --> 00:11:17.260
after the summer solstice, basically the end of June, early July.
00:11:17.260 --> 00:11:24.140
Fromites usually live for two months and reproduce an average of three to four times
00:11:24.420 --> 00:11:29.300
A single foundress can produce up to 30 offspring in her lifetime.
00:11:29.300 --> 00:11:36.500
They live longer over winter, where they're between the sclerites, those hardened plates of the exoskeleton and the doubt worker bees
00:11:36.820 --> 00:11:46.260
Varroa mite population growth is determined by the number of female mites in the honeybee colony and the reproductive rate of female mites.
00:11:46.140 --> 00:11:51.500
As well as the availability, of course, of brood and type of brood that is available.
00:11:51.500 --> 00:11:57.580
Four very important factors that are all hard to try to put together and uh compute together
00:11:58.440 --> 00:12:09.000
A second aspect that I indicated for an IPM approach to mic control was monitoring the pest population.
00:12:09.040 --> 00:12:20.320
The traditional means of monitoring how many mites are present in the bee colony is washing of a sample of typically 300 adult worker bees collected from the brood area.
00:12:20.160 --> 00:12:32.480
Which helps us helps ensure most bees in your sample container are nurse age bees, or counting mites falling onto a debris sticky board.
00:12:32.440 --> 00:12:41.720
Using the debris board, and many of us have purchased at one point or another or can a high bottom board that is available
00:12:42.020 --> 00:12:50.020
that uh makes use of a debris board very effectively, very efficiently, that you can remove it and do your counting, reinsert it, etc.
00:12:50.260 --> 00:12:52.900
But that means tedious counting of mics
00:12:53.040 --> 00:13:03.519
An alternative is to make a quick analysis of the level of mites that are falling onto the debris or sticky board.
00:13:03.600 --> 00:13:13.840
For example, saying one, there essentially I don't see any mites, two, there are some mites, or three, I see way too many mites.
00:13:13.740 --> 00:13:22.780
the three part evaluation and use that in a decision as to how to take how our present
00:13:23.380 --> 00:13:31.940
ongoing at the present time when we use the when we count to look at the sticky board, how that is doing and controlling uh our mites
00:13:32.320 --> 00:13:40.240
or using that debris, that fall of mites onto the debris board to evaluate post-treatment
00:13:40.640 --> 00:13:45.680
how a particular uh control might have been, how effective it might have been.
00:13:45.680 --> 00:13:52.160
Destruct washing agents include alcohol or non-sudzing soap
00:13:52.240 --> 00:14:00.720
While non-destruct sampling methods to separate mites from their adult host are powdered sugar or CO2.
00:14:00.720 --> 00:14:03.760
There are a few others, but those are the four majors.
00:14:03.720 --> 00:14:12.760
Although these latter two do not immediately kill bees, that's the powdered sugar or CO2 sampling, they are still harmful adults
00:14:12.740 --> 00:14:24.580
I have a report by Sarah Bruckner and co-authors in Endnotes that describes how sugar shake or use of CO2 significantly shortens the lifespan of adult bees.
00:14:24.620 --> 00:14:36.300
Looking and counting the number of mites in drone brood or on adult bee bodies are so highly unreliable as to be essentially worthless means of monitoring mite numbers
00:14:36.720 --> 00:14:51.360
We'd like to be able to develop drone brood sampling as a means of monitoring reproduction of raw mites in the spring, since founders mites are highly likely to use drone brood for the reproductive mice cycle phase.
00:14:51.320 --> 00:15:00.200
But the non-random, highly clumped distribution of cells used by phylondrous mites means such sampling is unreliable.
00:15:00.200 --> 00:15:04.680
We don't have a technique to get around those negative aspects
00:15:04.400 --> 00:15:08.000
The gold standard is washing the B bodies in alcohol.
00:15:08.000 --> 00:15:14.160
Any type of uh alcohol, such as rubbing alcohol to more concentrated alcohol, can be used.
00:15:14.160 --> 00:15:18.160
And the sample agitated for several min minutes
00:15:18.579 --> 00:15:22.339
as in use of a shaking device, for example.
00:15:22.339 --> 00:15:29.779
Repeated washings of the B sample until no further mites are noted adds to accuracy
00:15:30.100 --> 00:15:32.820
But a precau precautionary note.
00:15:32.820 --> 00:15:38.820
Study by an Oregon master beekeeper for his capstone research project collected adult workers
00:15:39.040 --> 00:15:53.760
and did three three hundred bee samples as three separate washes, one collection of the bees into a uh white container, and then took out three separate three hundred samples.
00:15:53.720 --> 00:16:02.600
He found the number of mites recovered varied widely, sometimes as much as a threefold difference
00:16:02.640 --> 00:16:06.560
Just from the same sample, but three different samples taken.
00:16:06.560 --> 00:16:15.440
So, although there are alternative ways to monitor a pest as serious as bromite, some are easier and more accurate than others
00:16:15.720 --> 00:16:19.320
Your plan should include how you will monitor.
00:16:19.320 --> 00:16:21.720
That brings up a major issue.
00:16:21.720 --> 00:16:28.040
How should we monitor for mites considering seasonal and life cycle differences of broa?
00:16:28.220 --> 00:16:36.300
In the spring, the majority of varomites, up to 70% in some estimates, will occur in drone brood.
00:16:36.140 --> 00:16:48.060
Using a sample of 300 adult worker bees does not reliably sample nor adequately represent the mite population in your beehive.
00:16:47.800 --> 00:16:53.080
We get lots of zeros or one to two mites washing adult bees in March through June.
00:16:53.080 --> 00:17:01.000
Likewise, uncapping drone brood using a capping scratcher yields highly variable resul
00:17:00.860 --> 00:17:10.540
Once drone brood rearing slows and the reproductive mites move to worker brood, for example, in June and July after the summer solstice.
00:17:10.720 --> 00:17:23.760
Reproducing mites may be only around 50% of the total mite population, so sampling of the nurse-age worker bees is a better means of estimating the mite population size
00:17:24.120 --> 00:17:26.840
Not necessarily great, but at least better.
00:17:26.840 --> 00:17:31.320
Now we may recover more than three mites in a 300B sample
00:17:31.760 --> 00:17:35.760
Three mites equals a one percent infestation level.
00:17:35.760 --> 00:17:41.360
Higher mites then give us a fair approximation of percent infestation level
00:17:41.540 --> 00:17:44.100
of the adult bee population.
00:17:44.100 --> 00:17:49.140
The acceptable level to use in making a decision has come down over the years.
00:17:49.140 --> 00:17:55.140
At one time, 10% was considered acceptable, 10% level of might.
00:17:55.140 --> 00:17:57.380
Then it was lowered to 5%.
00:17:57.380 --> 00:18:04.820
Our tools for Varroa for Varroa Management Guide has documented this lowering acceptance over the eight editions.
00:18:05.040 --> 00:18:06.720
we have put out of the guide.
00:18:06.720 --> 00:18:12.560
The ninth edition, now being formatted and ready for publication, lists 1%
00:18:13.419 --> 00:18:18.940
Or when colonies are large in late summer, a 2% mite level.
00:18:18.940 --> 00:18:26.220
That would be with the range of 3 to no more than 6 mites recovered in alcohols in the alcohol sample
00:18:26.500 --> 00:18:28.419
are our target goals.
00:18:28.419 --> 00:18:35.860
Colonies with these minimal levels are considered at less risk of dying in the later fall or winter period.
00:18:35.860 --> 00:18:39.140
The colonies are keeping the mites below
00:18:39.460 --> 00:18:43.860
uh a harmful level, the colonies or our control methods.
00:18:43.860 --> 00:18:45.700
This is a bit of a misnomer.
00:18:45.700 --> 00:18:51.540
It is is in reality not to number the percent of mites that is what is important.
00:18:51.620 --> 00:18:54.420
Because the mites don't kill bees.
00:18:54.420 --> 00:19:00.980
It is the viruses of, for example, the DWB and paralys viruses complexes that are the killers.
00:19:00.980 --> 00:19:06.100
By washing bee bodies of mites, we are not measuring virus levels.
00:19:05.940 --> 00:19:10.179
We are only looking at the percentage of host bees that have mites.
00:19:10.179 --> 00:19:17.380
During the winter, how might we monitor mite numbers on the overwinter adult host?
00:19:17.519 --> 00:19:24.720
Open and colony collect bees can be harmful, and debris boards are not reliable as mites are not moving host to host.
00:19:24.720 --> 00:19:29.200
They remain over the winter embedded in the abdominal sclerites of hosts
00:19:29.419 --> 00:19:35.100
So we opt to treat prophylactically, without knowing mite population levels.
00:19:35.100 --> 00:19:44.059
We even have a special tool, oxalic acid, applied as drizzle or by our vaporization, that is when we heat the crystals to the gaseous form.
00:19:43.660 --> 00:19:45.580
That can be used.
00:19:45.580 --> 00:19:51.260
Taking advantage of the lack of, or because there is a reduced breeching at this time.
00:19:51.820 --> 00:19:58.620
Our rationale is we want to get the number of mites to be as low a number as possible
00:19:59.519 --> 00:20:08.880
So the surviving founders mite numbers are really low as they start the colony expansion in the spring.
00:20:08.660 --> 00:20:16.740
When these low numbers start reproducing, it will take longer for the mites to build up their population numbers.
00:20:16.740 --> 00:20:17.060
I.
00:20:17.060 --> 00:20:17.300
e.
00:20:17.380 --> 00:20:20.340
, we're planning to flatten the mite growth curve.
00:20:20.340 --> 00:20:21.460
Low as we can go
00:20:22.120 --> 00:20:28.280
Likewise, what should we use to sample early season mite numbers and the level of reproductive success?
00:20:28.280 --> 00:20:33.800
We would want to determine how rapidly they are reproducing and expanding their population.
00:20:33.740 --> 00:20:40.140
At this time, washing adult bodies is not reliable, nor is sampling drone brewed.
00:20:40.140 --> 00:20:44.700
Could we look on drone adults and count how many drones have a mic?
00:20:44.500 --> 00:20:47.620
Or how many mites are present on the average drone?
00:20:47.620 --> 00:20:54.900
If say 2 or 5% of a sample of 100 adult drones have one or more mites,
00:20:55.320 --> 00:21:07.080
Could that help us determine a risk where higher numbers would key a management decision and a lower number would help reassure us that things are progressing okay?
00:21:06.840 --> 00:21:11.320
At least until next time we sample, which might be next week, next month.
00:21:11.320 --> 00:21:20.520
We would need to look very carefully because on adult bodies the dispersal bites embed between those ventral abdominal sclerites
00:21:20.440 --> 00:21:26.840
Sometimes only a tiny sliver of their abdomen may protrude, so we may see and count them.
00:21:26.840 --> 00:21:33.240
At this point, truth in advertising, we don't have such a percentage or average number per drone
00:21:33.340 --> 00:21:37.179
that we might use as a population monitoring tool.
00:21:37.179 --> 00:21:39.740
That might be very handy if we did.
00:21:39.740 --> 00:21:45.820
Therefore, once again, we are often will apply a control without first monitoring
00:21:45.840 --> 00:21:49.039
our prophylactic approach to mic control.
00:21:49.039 --> 00:21:51.919
That's not an IPM approach.
00:21:51.919 --> 00:21:58.400
On to the third aspect of I indicated the tenets of IPM
00:21:58.640 --> 00:22:01.760
And that is determining a threshold.
00:22:01.760 --> 00:22:11.200
IPM seeks to determine a threshold, an EIL, which stands for economic injury level of a pest infestation.
00:22:11.320 --> 00:22:18.760
The EIL threshold is the point at which the pest causes an economic difference in yield
00:22:19.240 --> 00:22:25.880
for example, for a crop, or stress that might affect livestock animal production.
00:22:25.880 --> 00:22:33.960
If the pest numbers are below this number, any negative effects of the pest infestation would not be measurable.
00:22:33.519 --> 00:22:43.440
Does not mean there would not be a negative effect, but any effect would be within a normal level that yield negative is would not be measurable.
00:22:43.060 --> 00:22:50.660
Once this threshold is reached, it will then cost time and money to negate economic injury.
00:22:50.660 --> 00:22:55.620
Cost and time to reduce the pest population below the EIL
00:22:56.040 --> 00:23:02.280
will obviously be relative, depending on what and how control is performed.
00:23:02.280 --> 00:23:05.720
So we have a new population level, an EIT
00:23:06.940 --> 00:23:12.460
EIT stands for economic injury threshold, would be of importance.
00:23:12.460 --> 00:23:21.659
For very minor damage above the in in injury level, it might not be worth the time or cost to implement a control.
00:23:21.220 --> 00:23:34.420
If the pest population is exploding, increasing in an exponential fashion, rapid control implementation, and using a highly effective means to quickly reduce that
00:23:34.840 --> 00:23:39.320
hu the exponentially growing pest population would be called for.
00:23:39.320 --> 00:23:44.200
Crop growers employ pest control technicians to monitor pest populations.
00:23:44.620 --> 00:23:56.620
visually, using traps, computer models, or their intuition to know how rapidly to apply a control and what tools might be best to use.
00:23:56.720 --> 00:24:08.160
The tool is usually a pesticide, but remember IPM should mean other controls might be utilized and pesticides used only as a last resort.
00:24:07.800 --> 00:24:13.960
So what are the threshold numbers beekeepers might use in their decisions on control?
00:24:13.960 --> 00:24:17.080
Now we get into murky territory.
00:24:17.019 --> 00:24:27.740
You'll read that numbers that exceed 1, 2, 3%, not so many years ago, 5, 10%, can be a used to measure risk, i.
00:24:27.740 --> 00:24:27.899
e.
00:24:28.059 --> 00:24:29.980
, they've been called a threshold.
00:24:29.940 --> 00:24:32.419
But how did we come up with these numbers?
00:00:00.880 --> 00:00:02.400
00:00:02.400 --> 00:00:04.160
00:00:04.640 --> 00:00:07.920
00:00:07.920 --> 00:00:14.960
00:00:15.080 --> 00:00:16.360
00:00:16.360 --> 00:00:17.800
00:00:17.800 --> 00:00:20.920
00:00:20.920 --> 00:00:26.119
00:00:26.140 --> 00:00:30.539
00:00:30.539 --> 00:00:34.620
00:00:34.200 --> 00:00:38.040
00:00:38.040 --> 00:00:41.960
00:00:41.960 --> 00:00:45.000
00:00:44.820 --> 00:00:51.940
00:00:51.940 --> 00:00:59.460
00:00:59.020 --> 00:01:01.100
00:01:01.100 --> 00:01:06.140
00:01:06.740 --> 00:01:17.540
00:01:17.520 --> 00:01:31.360
00:01:31.160 --> 00:01:45.560
00:01:45.439 --> 00:01:49.920
00:01:49.920 --> 00:01:54.720
00:01:54.920 --> 00:02:03.080
00:02:03.580 --> 00:02:11.340
00:02:11.860 --> 00:02:24.420
00:02:24.160 --> 00:02:34.000
00:02:34.040 --> 00:02:43.000
00:02:43.340 --> 00:02:56.220
00:02:56.620 --> 00:02:59.340
00:02:59.340 --> 00:03:08.860
00:03:08.760 --> 00:03:18.520
00:03:18.260 --> 00:03:23.700
00:03:23.700 --> 00:03:32.820
00:03:32.440 --> 00:03:36.040
00:03:36.040 --> 00:03:45.319
00:03:45.520 --> 00:03:55.040
00:03:55.420 --> 00:04:01.340
00:04:01.340 --> 00:04:04.700
00:04:04.700 --> 00:04:06.860
00:04:07.140 --> 00:04:20.019
00:04:20.220 --> 00:04:26.940
00:04:26.940 --> 00:04:33.580
00:04:33.860 --> 00:04:40.020
00:04:40.020 --> 00:04:41.860
00:04:41.860 --> 00:04:45.060
00:04:45.260 --> 00:04:51.900
00:04:51.900 --> 00:04:53.660
00:04:53.660 --> 00:04:57.180
00:04:57.320 --> 00:04:59.800
00:04:59.800 --> 00:05:03.240
00:05:03.240 --> 00:05:06.040
00:05:05.940 --> 00:05:14.980
00:05:14.780 --> 00:05:16.940
00:05:16.940 --> 00:05:17.100
00:05:17.180 --> 00:05:24.140
00:05:24.140 --> 00:05:24.300
00:05:24.380 --> 00:05:25.100
00:05:25.460 --> 00:05:28.979
00:05:28.979 --> 00:05:35.460
00:05:35.260 --> 00:05:43.420
00:05:43.160 --> 00:05:54.200
00:05:54.420 --> 00:06:03.860
00:06:04.340 --> 00:06:07.300
00:06:07.300 --> 00:06:09.220
00:06:09.220 --> 00:06:18.900
00:06:18.440 --> 00:06:25.160
00:06:25.160 --> 00:06:31.080
00:06:31.139 --> 00:06:36.100
00:06:36.100 --> 00:06:43.460
00:06:43.800 --> 00:06:47.960
00:06:47.960 --> 00:06:51.880
00:06:52.220 --> 00:07:02.860
00:07:02.740 --> 00:07:10.980
00:07:11.039 --> 00:07:14.159
00:07:14.159 --> 00:07:18.560
00:07:18.560 --> 00:07:23.680
00:07:23.720 --> 00:07:28.600
00:07:28.600 --> 00:07:34.040
00:07:33.740 --> 00:07:44.300
00:07:44.039 --> 00:07:48.599
00:07:48.599 --> 00:07:58.599
00:07:57.860 --> 00:08:02.660
00:08:02.660 --> 00:08:10.660
00:08:10.740 --> 00:08:17.540
00:08:17.540 --> 00:08:23.220
00:08:22.960 --> 00:08:26.800
00:08:26.800 --> 00:08:36.640
00:08:36.740 --> 00:08:46.900
00:08:46.900 --> 00:08:51.460
00:08:51.339 --> 00:08:57.579
00:08:57.579 --> 00:09:02.459
00:09:02.259 --> 00:09:05.220
00:09:05.220 --> 00:09:11.300
00:09:11.520 --> 00:09:20.880
00:09:20.500 --> 00:09:25.460
00:09:25.460 --> 00:09:30.500
00:09:30.160 --> 00:09:36.800
00:09:36.800 --> 00:09:44.160
00:09:43.959 --> 00:09:45.320
00:09:45.320 --> 00:09:52.680
00:09:52.540 --> 00:09:58.940
00:09:58.940 --> 00:10:05.420
00:10:05.560 --> 00:10:15.320
00:10:15.320 --> 00:10:18.600
00:10:18.759 --> 00:10:24.199
00:10:24.199 --> 00:10:30.199
00:10:29.759 --> 00:10:31.199
00:10:31.199 --> 00:10:36.480
00:10:36.480 --> 00:10:39.680
00:10:39.540 --> 00:10:50.820
00:10:50.800 --> 00:10:59.839
00:11:00.140 --> 00:11:03.020
00:11:03.020 --> 00:11:12.460
00:11:12.620 --> 00:11:17.260
00:11:17.260 --> 00:11:24.140
00:11:24.420 --> 00:11:29.300
00:11:29.300 --> 00:11:36.500
00:11:36.820 --> 00:11:46.260
00:11:46.140 --> 00:11:51.500
00:11:51.500 --> 00:11:57.580
00:11:58.440 --> 00:12:09.000
00:12:09.040 --> 00:12:20.320
00:12:20.160 --> 00:12:32.480
00:12:32.440 --> 00:12:41.720
00:12:42.020 --> 00:12:50.020
00:12:50.260 --> 00:12:52.900
00:12:53.040 --> 00:13:03.519
00:13:03.600 --> 00:13:13.840
00:13:13.740 --> 00:13:22.780
00:13:23.380 --> 00:13:31.940
00:13:32.320 --> 00:13:40.240
00:13:40.640 --> 00:13:45.680
00:13:45.680 --> 00:13:52.160
00:13:52.240 --> 00:14:00.720
00:14:00.720 --> 00:14:03.760
00:14:03.720 --> 00:14:12.760
00:14:12.740 --> 00:14:24.580
00:14:24.620 --> 00:14:36.300
00:14:36.720 --> 00:14:51.360
00:14:51.320 --> 00:15:00.200
00:15:00.200 --> 00:15:04.680
00:15:04.400 --> 00:15:08.000
00:15:08.000 --> 00:15:14.160
00:15:14.160 --> 00:15:18.160
00:15:18.579 --> 00:15:22.339
00:15:22.339 --> 00:15:29.779
00:15:30.100 --> 00:15:32.820
00:15:32.820 --> 00:15:38.820
00:15:39.040 --> 00:15:53.760
00:15:53.720 --> 00:16:02.600
00:16:02.640 --> 00:16:06.560
00:16:06.560 --> 00:16:15.440
00:16:15.720 --> 00:16:19.320
00:16:19.320 --> 00:16:21.720
00:16:21.720 --> 00:16:28.040
00:16:28.220 --> 00:16:36.300
00:16:36.140 --> 00:16:48.060
00:16:47.800 --> 00:16:53.080
00:16:53.080 --> 00:17:01.000
00:17:00.860 --> 00:17:10.540
00:17:10.720 --> 00:17:23.760
00:17:24.120 --> 00:17:26.840
00:17:26.840 --> 00:17:31.320
00:17:31.760 --> 00:17:35.760
00:17:35.760 --> 00:17:41.360
00:17:41.540 --> 00:17:44.100
00:17:44.100 --> 00:17:49.140
00:17:49.140 --> 00:17:55.140
00:17:55.140 --> 00:17:57.380
00:17:57.380 --> 00:18:04.820
00:18:05.040 --> 00:18:06.720
00:18:06.720 --> 00:18:12.560
00:18:13.419 --> 00:18:18.940
00:18:18.940 --> 00:18:26.220
00:18:26.500 --> 00:18:28.419
00:18:28.419 --> 00:18:35.860
00:18:35.860 --> 00:18:39.140
00:18:39.460 --> 00:18:43.860
00:18:43.860 --> 00:18:45.700
00:18:45.700 --> 00:18:51.540
00:18:51.620 --> 00:18:54.420
00:18:54.420 --> 00:19:00.980
00:19:00.980 --> 00:19:06.100
00:19:05.940 --> 00:19:10.179
00:19:10.179 --> 00:19:17.380
00:19:17.519 --> 00:19:24.720
00:19:24.720 --> 00:19:29.200
00:19:29.419 --> 00:19:35.100
00:19:35.100 --> 00:19:44.059
00:19:43.660 --> 00:19:45.580
00:19:45.580 --> 00:19:51.260
00:19:51.820 --> 00:19:58.620
00:19:59.519 --> 00:20:08.880
00:20:08.660 --> 00:20:16.740
00:20:16.740 --> 00:20:17.060
00:20:17.060 --> 00:20:17.300
00:20:17.380 --> 00:20:20.340
00:20:20.340 --> 00:20:21.460
00:20:22.120 --> 00:20:28.280
00:20:28.280 --> 00:20:33.800
00:20:33.740 --> 00:20:40.140
00:20:40.140 --> 00:20:44.700
00:20:44.500 --> 00:20:47.620
00:20:47.620 --> 00:20:54.900
00:20:55.320 --> 00:21:07.080
00:21:06.840 --> 00:21:11.320
00:21:11.320 --> 00:21:20.520
00:21:20.440 --> 00:21:26.840
00:21:26.840 --> 00:21:33.240
00:21:33.340 --> 00:21:37.179
00:21:37.179 --> 00:21:39.740
00:21:39.740 --> 00:21:45.820
00:21:45.840 --> 00:21:49.039
00:21:49.039 --> 00:21:51.919
00:21:51.919 --> 00:21:58.400
00:21:58.640 --> 00:22:01.760
00:22:01.760 --> 00:22:11.200
00:22:11.320 --> 00:22:18.760
00:22:19.240 --> 00:22:25.880
00:22:25.880 --> 00:22:33.960
00:22:33.519 --> 00:22:43.440
00:22:43.060 --> 00:22:50.660
00:22:50.660 --> 00:22:55.620
00:22:56.040 --> 00:23:02.280
00:23:02.280 --> 00:23:05.720
00:23:06.940 --> 00:23:12.460
00:23:12.460 --> 00:23:21.659
00:23:21.220 --> 00:23:34.420
00:23:34.840 --> 00:23:39.320
00:23:39.320 --> 00:23:44.200
00:23:44.620 --> 00:23:56.620
00:23:56.720 --> 00:24:08.160
00:24:07.800 --> 00:24:13.960
00:24:13.960 --> 00:24:17.080
00:24:17.019 --> 00:24:27.740
00:24:27.740 --> 00:24:27.899
00:24:28.059 --> 00:24:29.980
00:24:29.940 --> 00:24:32.419