Rossland, BC, V0G1Y0 - Columbia Shuswap Regional District Golden, Electoral Area A Mosquito Control Program Mid-Season Update July 2021
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Columbia Shuswap Regional District
Golden, Electoral Area A
Mosquito Control Program
Mid-Season Update
July 2021
Submitted by:
Morrow BioScience Ltd.
2197 Columbia Avenue
Rossland, BC, V0G1Y0
Golden, Electoral Area A - Mosquito Control Program Executive Summary The 2021 snowpack within the Upper Columbia Basin contributes to the regional Columbia River and Kicking Horse River. The snowpack in that basin was 108 percent of normal immediately prior to the mosquito season. Warmer-than-normal weather in mid-April slowly brought out some low elevation snow. Strong high-pressure ridges were also present in the Golden and Electoral Area A region in mid-May and mid/late June, further reducing the regional snowpack. However, most of the high- elevation snowmelt occurred in mid/late-June as a result of record-setting high ambient temperatures throughout much of B.C. The highest seasonal peaks for the Kicking Horse River occurred on 29 June (5.25 m) and for the Columbia River on 2 July (4.95 m) and 3 July (3.863 m) at the Donald and Nicholson gauges, respectively. The Columbia River at Donald peak was higher than those recorded in, at least, the last 11 years. By the end of June, the snowpack in the Colpitti Creek snow station was depleted. Regional rivers are receding, but may remain elevated beyond normal levels through late August. Since April, local precipitation accumulation has been below normal, although considerable station malfunctioning occurred in April. It is likely that precipitation accumulation did not measurably augment mosquito development sites this season. Environment Canada probabilistic weather forecasts show a likelihood for below- normal precipitation accumulation and 40-50 percent likelihood that ambient temperatures will be higher-than-average for the Golden and Electoral Area A region from July-September. Site monitoring began on 19 April and treatments commenced on 21 April. High regional river levels resulted in a need for five (5) aerial treatment days, thus far. The aerial campaigns occurred on 4 May, 11 June, 24 June, 30 June, and 7 July. Ground treatments at snowmelt mosquito development sites were clustered from 21 April – 10 May and at floodwater mosquito development sites from 21 May – 5 July; additional ground treatments may be required this season. A bacterial larvicide, AquabacÒ (active ingredient - Bacillus thuringiensis var israelensis) was used to treat a total of 1,847 ha (10,542 kg granules) required for floodwater mosquito control within Golden and Electoral Area A, as of 9 July. Post-treatment monitoring of both ground and aerial treatments revealed high efficacy. Provincial COVID-19 guidelines against large gatherings resulted in adjusted education outreach strategies for 2021. MBL dispensed information on social media platforms and the MBL website. Two FAQ documents focused on mosquito biology, disease transmission, and Bacillus thuringiensis var. israelensis were sent directly to the CSRD program manager in late April. A disease transmission blog focused on COVID-19 has also been posted on the MBL website. Following CSRD approval, a media release was sent to 104.3 EZ (Bell Media) on 7 June highlighting field activities, mosquito biology, and personal protective tips. A brief interview was conducted with a station DJ on 7 June and details of the press release were aired during the week of 7 Morrow BioScience Ltd. ii
Golden, Electoral Area A - Mosquito Control Program June. MBL will continue to update social media sites in an effort to inform residents of monitoring, control activities, and outreach events throughout the height of the season. One inquiry-based call was received on 4 May. No complaint calls or emails were received as of 9 July. Morrow BioScience Ltd. iii
Golden, Electoral Area A - Mosquito Control Program Table of Contents EXECUTIVE SUMMARY .........................................................................................................................II LIST OF FIGURES .................................................................................................................................... V INTRODUCTION ...................................................................................................................................... 1 SIGNIFICANT REGIONAL ENVIRONMENTAL CONDITIONS ....................................................... 1 SNOW LEVELS ............................................................................................................................................................ 1 RIVER LEVELS ............................................................................................................................................................ 3 PRECIPITATION .......................................................................................................................................................... 6 AMBIENT TEMPERATURE RECORDS ...................................................................................................................... 7 NUISANCE CONTROL .......................................................................................................................... 10 PROGRESS TO DATE ............................................................................................................................................... 10 GROUND APPLICATION SUMMARY ...................................................................................................................... 11 AERIAL APPLICATION SUMMARY ........................................................................................................................ 12 PUBLIC RELATIONS (DONE) ............................................................................................................ 14 ANNOYANCE REPORTS/INQUIRIES (DONE)...................................................................................................... 14 EDUCATION OUTREACH (DONE) ......................................................................................................................... 14 PROJECT CONTACTS AT MORROW BIOSCIENCE LTD.............................................................. 16 REFERENCES ......................................................................................................................................... 16 Morrow BioScience Ltd. iv
Golden, Electoral Area A - Mosquito Control Program
List of Figures
Figure 1. Columbia River (Donald gauge - ID: 08NB005, Nicholson gauge - ID:
08NA002) and the Kicking Horse River (ID: 08NA006) levels (m) from 1 April –
9 July 2021. ......................................................................................................................................... 4
Figure 2. 2018 – 2021 river levels (April – August; m) as recorded at the Columbia
River (Donald gauge - ID: 08NB005) from 1 April – 31 August. 2021 data are
current through 9 July. .................................................................................................................. 5
Figure 3. 2021 precipitation values (rainfall and snow accumulation; mm) recorded
at the Golden Airport weather station (ID: 1173210) for 01 April 1 – 8 July
(blue). Average station precipitation values (1981-2010) are shown in orange. 7
Figure 4. Maximum daily ambient temperatures (C) as recorded at the Golden
Airport weather station (ID: 117321001 April 1 – 8 July 2021. Lower black line
illustrates threshold at which Ae. sticticus eggs commence hatching; upper
black line illustrates threshold at which most Ae. sticticus eggs hatch. ................... 9
Figure 5. Ground application events (purple; ha) with Columbia River levels at
Donald gauge (green; m) and Columbia River at Nicholson gauge levels (blue;
m). Data presented are from 1 April – 9 July 2021. Treatment areas are
represented on the secondary y-axis. ...................................................................................12
Figure 6. Aerial application events (black; ha) with regional Columbia River levels
(green, blue; m). Data presented are from 1 April – 9 July 2021. Treatment area
is represented on the secondary y-axis................................................................................13
Morrow BioScience Ltd. vGolden, Electoral Area A - Mosquito Control Program Introduction This report summarizes the mosquito control program activities for Golden and Electoral Area A within the Columbia Shuswap Regional District (CSRD) for the 2021 season through 9 July. Specifically, this report will include current environmental conditions affecting mosquito populations and monitoring efforts, outline the progress to date for the proposed deliverables, present preliminary data, and identify potential issues for the duration of the mosquito season. The information presented herein is meant to provide a snapshot of the season, thus far. An in-depth review of each reporting category will be included in the 2021 final report, to be submitted by November. Significant Regional Environmental Conditions Snow Levels Floodwater mosquito abundance within Golden and Electoral Area A is primarily governed by the regional Columbia River (i.e., Donald and Nicholson gauges). The Kicking Horse River also contributes water to the Columbia River near the Town of Golden, affecting down-stream flows in the Donald area. The water levels of those systems are governed by the freshet released from the Upper Columbia snow basin (Image 1). Frequent and large amounts of local precipitation can also affect river levels. However, in normal years, localized precipitation accumulation typically affects river levels less than the Upper Columbia Basin – associated freshet during the late spring and early summer. Morrow BioScience Ltd. 1
Golden, Electoral Area A - Mosquito Control Program
Image 1. Upper Columbia Snow Survey Basin purview (https://www2.gov.bc.ca/gov/)
On 1 April 2021 the snowpack within the Upper Columbia Basin was 108 percent of
normal1. While the region received additional snow in the early half of April, a ridge
of high pressure settled over much of the province in mid-April resulting in
unseasonably warm ambient temperatures. The Upper Columbia regions received
very little precipitation toward the end of the month2.
The Colpitti Creek snow survey station (ID: 2A30P) is the closest station to the
program purview. It serves as a representative site for the regional snowmelt
trajectory. A short melting stint occurred toward the end of April, affecting low-
elevation snowpack (Image 2). However, he first measurable melting trend occurred
1 https://www2.gov.bc.ca/assets/gov/environment/air-land-water/water/river-forecast/2021_apr1.pdf
2 https://www2.gov.bc.ca/assets/gov/environment/air-land-water/water/river-forecast/2021_may1.pdf
Morrow BioScience Ltd. 2Golden, Electoral Area A - Mosquito Control Program in mid-May, with the lower and middle-elevation snow showing significant drops in Snow Water Equivalent (SWE; Image 2). The weather in May was considerably dry. Thus, the Upper Columbia Basin snowpack was not augmented. Continued warm weather in early June resulted in the further depletion of all middle-elevation and some high-elevation snow within the Upper Columbia Basin (Image 2). Following a brief stint of cool weather that slowed the regional snowmelt in mid-June, an additional high-pressure system settled over the region in late June. From late June through early July, the final high-elevation snowmelt came through the regional rivers. Other snow survey stations throughout the Upper Columbia Basin show similar trends3. Image 2. Colpitti Creek weather station (ID: 2A30P) Snow Water Equivalent trends (Upper Columbia Basin, 10 July 2021). The snowpack in the Colpitti Creek station was depleted in early July (Image 2). Given the lack of remaining snowpack in the Upper Columbia Basin, the freshet is unlikely to be the major contributor towards Columbia and Kicking Horse River levels for the rest of the 2021 mosquito season. The timing of the depletion of the regional snowpack was average. River Levels Floodwater mosquito eggs are laid on the damp substrate of areas that experience intra-annual flooding. Within Golden and Electoral Area A, floodwater mosquito development sites primarily exist along the flooding corridors of the Columbia River and, to a lesser degree, along the Kicking Horse River, including associated seepage sites. The presence of water is a hatching cue and, thus, tracking regional river levels provides predictive capabilities with regards to floodwater mosquito larval development. 3 https://governmentofbc.maps.arcgis.com/apps/webappviewer/index.html?id=c15768bf73494f5da04b1aac6793bd2e Morrow BioScience Ltd. 3
Golden, Electoral Area A - Mosquito Control Program
In mid-April 2021, unseasonably warm ambient temperatures resulted in a small
pulse of water that came through both river systems from the contributing Upper
Columbia snow basin (Figure 1). That pulse marked the consistent rise of the
Columbia River (Donald gauge – 08NB005; Nicholson gauge – 08NA002) and Kicking
Horse River (Golden gauge; 08NA006). Warming periods occurred throughout latter
April, generally resulting in increased river levels within the month. Floodwater
mosquito eggs laid on substrates at various river levels have optimal environmental
cues and adequate time within which to hatch when rivers rise at a slower rate. When
river levels rise at high rates, mosquito eggs typically lack sufficient environmental
cues due to the pulse of cold, highly oxygenated water moving through the system.
Both regional rivers rose at moderate rates in 2021. Thus, environmental cues were
present to trigger mass mosquito hatching events at near-peak river levels.
2021 Columbia River and Kicking Horse Levels
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Columbia River (Donald) Columbia River (Nicholson) Kicking Horse River
Figure 1. Columbia River (Donald gauge - ID: 08NB005, Nicholson gauge - ID: 08NA002) and the Kicking
Horse River (ID: 08NA006) levels (m) from 1 April – 9 July 2021.
Following a provincial warming trend in mid-May and again in late May/early June,
both river systems experienced initial peaks (Figure 1). Record high ambient
temperatures across the southern portion of B.C. in late June led to rapid snowmelt
that resulted in the highest seasonal peaks in the Kicking Horse River on 29 June (5.25
m) and the Columbia River 2 July (4.95 m) and 3 July (3.863 m) at the Donald and
Nicholson gauges, respectively (Figure 1). The 2021 peaks were approximately 2
weeks later than normal. Because the contributing snowpack has been depleted (see
‘Snow Levels’ above), it is unlikely that the peaks noted in June and July will be
surpassed this year.
Morrow BioScience Ltd. 4Golden, Electoral Area A - Mosquito Control Program
The Kicking Horse River feeds into the Columbia River at Golden. Thus, the Columbia
River at Donald gauge provides data for the Kicking Horse River and Columbia River.
Comparing data from the Donald gauge through various seasons provides a
representative understanding of relative flooding states. The 2021 Columbia River at
Donald peak was approximately 0.337 m higher than the 2020 peak (Figure 2). The
peak recorded in 2021 is the highest recorded in the previous 11 years. All floodwater
mosquito development sites were wet in 2021.
Columbia River Levels (2018-2021)
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2018 2019 2020 2021
Figure 2. 2018 – 2021 river levels (April – August; m) as recorded at the Columbia River (Donald gauge -
ID: 08NB005) from 1 April – 31 August. 2021 data are current through 9 July.
The current year’s peak in the regional Columbia River relative to those of recent
seasons is another predictive variable that may help explain a current year’s larval
abundance. If the current year’s peak river levels far exceeded those of the preceding
season, mosquito eggs laid between the high-water mark of both years could have
remained dormant until current-year flood waters trigger their hatching. Because the
peaks of the river levels in 2021 were higher than those of the preceding season’s, it
is likely that the peak levels noted in 2021 triggered a compound number of
floodwater mosquito eggs to hatch. As such, a higher-than-normal floodwater
mosquito larval abundance has been noted thus far.
Morrow BioScience Ltd. 5Golden, Electoral Area A - Mosquito Control Program The regional Columbia River and Kicking Horse River are slowly receding, given the lack of remaining snowpack at regional snow stations (see ‘Snow Levels’ above). Local precipitation accumulation can considerably augment regional river levels (see ‘Precipitation’ below). While the long-term forecast predicts lower-than-normal precipitation, it is difficult to ensure localized precipitation will not increase river levels. Given that regional river levels were still high as of 9 July, it is possible, though unlikely, that significant precipitation could result in higher peaks than those noted. It is reasonable to assume that regional river levels may be heightened water levels through August. Precipitation While not the primary contributor to Columbia River and Kicking Horse River levels within the CSRD, significant and concentrated local precipitation accumulation may temporarily elevate river levels. The precipitation received to the Golden Airport weather station (ID: 1173210) in April was only approximately 1 mm lower than the station average (1981-2010; Figure 3). However, data were missing from 20 days in April. Thus, it’s likely the April precipitation sum is an underestimate and difficult to determine its impact on regional rivers. Precipitation accumulation at the Golden Airport weather station in May and June also reflected the drier-than-normal season. The total precipitation received in May was approximately 13 mm less than the station average and the June precipitation was about 20 mm less than average (Figure 3). The low amount of precipitation received during the 2021 freshet indicate that peak flooding levels for the Columbia River and Kicking Horse River were primarily a result of regional snowmelt. The Golden Airport weather station provides data through 8 July. Thus, the precipitation accumulation noted in July is artificially low for this point in the season. July accumulation values will likely increase as the month continues. Historically, averages for this station show that precipitation accumulation increases in July (Figure 3). However, Temperature and Precipitation Probabilistic Forecasts for Canada4 for July – September show a 60-70 percent likelihood that precipitation for the Golden and Electoral Area A region will be below normal. Given this prediction, it is unlikely that significant precipitation events will prolong the presence of the mosquito development seepage sites noted at peak river levels. However, MBL technicians are aware of the potential development of new sites given localized precipitation events and will continue to monitor current and potential sites. 4 https://weather.gc.ca/saisons/prob_e.html Morrow BioScience Ltd. 6
Golden, Electoral Area A - Mosquito Control Program
60
Monthly Precipitation Accumulation
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Precipitation (mm)
30
20
10
0
April May June July August
Average (1981-2010) 2021
Figure 3. 2021 precipitation values (rainfall and snow accumulation; mm) recorded at the Golden Airport
weather station (ID: 1173210) for 01 April 1 – 8 July (blue). Average station precipitation values (1981-
2010) are shown in orange.
Ambient Temperature Records
Ambient temperature data provides information specific to the freshet timing,
floodwater mosquito larval development, and potential adult dispersal. The 2021
mosquito season began in April with generally average ambient temperatures across
the Upper Columbia Basin. According to the May 1st Snow Survey and Water Supply
Bulletin5, the weather in April was largely stable, with a strong high-pressure ridge
over much southern B.C. in mid-April. The high-pressure ridge resulted in relatively
high ambient temperatures, causing low-elevation snow to melt (Figure 4). The snow
came through the regional river systems around 18 April (Figure 4).
In general, ambient temperatures in May within the Southern Interior were also
higher-than-normal. A ridge of high pressure in mid and late-May aided in the
increased melting rate of the majority of middle elevation and some high-elevation
snowpack. Record-breaking high temperatures occurred at the end of June
throughout the Golden and Electoral Area A region. Ultimately, the increase in
ambient temperatures in late June brought out the final high-elevation snowpack and
led to the regional Columbia River and Kicking Horse River peaks in 2021.
5 https://www2.gov.bc.ca/assets/gov/environment/air-land-water/water/river-forecast/2020_may1.pdf
Morrow BioScience Ltd. 7Golden, Electoral Area A - Mosquito Control Program Temperature data are consistent with 2021 automated snow station data6 depicting snowmelt points correlating with regional ambient temperature spikes. Local ambient temperatures can be a predictive tool in understanding when floodwater eggs might begin to hatch. In a laboratory experiment, Trpis and Horsfall (1969) exposed submerged eggs of a common univoltine floodwater mosquito species, Aedes sticticus, to various constant air temperatures and recorded hatching success. Results revealed that eggs began to hatch at 8°C, although larval development was slow and survivorship was low. Eggs held at 21°C provided the optimal temperature, of the five temperatures tested, for hatching and larval development (Figure 4). While Ae. sticticus is not the sole floodwater species present in the Golden and Electoral Area A program, it serves as a representative species for our purposes and provide general developmental benchmarks. It should be noted that extrapolating laboratory results to the field is not always necessarily appropriate due to the considerable additional variables for hatching success in the field (e.g., natural predators, water depth, associated water temperature, organic matter, etc.). Thus, the benchmark noted here is meant to provide a conservative gauge for the commencement of mosquito larval monitoring and treatment. 6 https://www2.gov.bc.ca/gov/content/environment/air-land-water/water/water-science-data/water-data-tools/snow- survey-data/automated-snow-weather-station-data Morrow BioScience Ltd. 8
Golden, Electoral Area A - Mosquito Control Program
2021 Daily Maximum Ambient Temperature
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Figure 4. Maximum daily ambient temperatures (C) as recorded at the Golden Airport weather station (ID:
117321001 April 1 – 8 July 2021. Lower black line illustrates threshold at which Ae. sticticus eggs
commence hatching; upper black line illustrates threshold at which most Ae. sticticus eggs hatch.
April ambient temperatures were sufficient for large-scale floodwater mosquito egg
hatching if the eggs were exposed to flooding conditions (Figure 4). Mosquito egg
development at that time of the season would have likely been slow and hatching
success low. While temperatures in mid-April were past the threshold for a high rate
of mosquito egg hatching and survivorship, the regional river levels were low and,
thus, the floodwater mosquito eggs were not exposed to water.
Snowmelt mosquito eggs hatch earlier than floodwater mosquito eggs. Certain
snowmelt mosquito species begin to hatch at approximately 4°C water temperature
and can complete development to adult emergence at 10°C (Clements 1992). Thus,
snowmelt mosquito eggs laid along the mountain bench area were also likely
triggered to hatch in April as sites began to experience initial warming trends.
Local ambient temperatures in May and June were considerably warmer, with
favourable environmental cues for greater floodwater mosquito egg hatching success
(Figure 4). Thus, it was expected that hatching and larval development rates would
increase significantly within those timeframes. Appropriately, larval treatments
increased considerably in the beginning of May.
Temperature and Precipitation Probabilistic Forecasts for Canada 7 for July –
September show an 40-50% likelihood that ambient temperatures for Golden and
7 https://weather.gc.ca/saisons/prob_e.html
Morrow BioScience Ltd. 9Golden, Electoral Area A - Mosquito Control Program Electoral Area A will be above normal. At this point in the season, most floodwater larval mosquitoes have either hatched or been treated. The adult mosquitoes will experience an increased rate of development given higher temperatures. Above normal temperatures with a lack of precipitation also means that mosquito development sites may become dry sooner than normal. Nuisance Control Progress to Date Snowmelt mosquito monitoring begins in the early spring when consistent local snowmelt begins. Snowmelt mosquito development site monitoring began on 19 April. Floodwater mosquito monitoring begins when spring ambient temperatures start to rise steadily in the Upper Columbia Basin, followed by consistently increasing regional Columbia River and Kicking Horse River levels (Image 3). Consequently, floodwater mosquito development site monitoring began on 15 May. Image 3. MBL staff member assessing floodwater mosquito larval abundance (Electoral Area A seepage site) The unseasonably high ambient temperatures in mid-April led to melting of some low elevation snow within the Upper Columbia Basin, including mountain bench sites. This early melting trend was sufficient to activate snowmelt mosquito eggs in multiple mosquito development sites. Ambient temperatures remained consistent until late April, after which point ambient temperatures increased considerably. The higher-than-average ambient temperatures experienced from mid to late May Morrow BioScience Ltd. 10
Golden, Electoral Area A - Mosquito Control Program resulted in fast-paced floodwater mosquito larval development rates leading into June. Ground treatments have been required frequently since 21 April. The considerably high regional Columbia River levels resulted in a peak (Donald gauge) that exceeded those of the previous 11 years, at least. High water activated a compound number of floodwater mosquito eggs. Thus, in addition to the usual snowmelt mosquito development site aerial (April), numerous aerials targeting floodwater mosquito sites occurred from June – July. As of 9 July, a total of approximately 1,847 ha has been treated. Ground Application Summary Sites within Golden and Electoral Area A are visited on a weekly basis unless conditions required more frequent monitoring (i.e., above normal regional river levels, ambient temperatures > 20°C, large precipitation event). Sites are treated when a standard dip (350ml) collects 5 or more late instar (3rd or 4th instar) larvae per dip. All sites are checked within one or two days of the initial treatment to ensure treatment efficacy. If necessary, touch-up treatments are conducted. AquabacÒ is the product used for all larval mosquito treatments conducted by MBL. The active ingredient in AquabacÒ is a soil-borne bacterium, Bacillus thuringiensis var. israelensis (Bti). Bti has high target specificity and achieves 95% - 100% efficacy in typical field conditions (AquabacÒ Mosquito Biolarvicice - Technical Bulletin). Only the granular formulation has been used in 2021, but the liquid formulation may be used in the latter half of the season. The application rate for ground treatments can vary depending on the product formulation and the plant density in the target area. Using the granular product by ground, most sites in Golden and Electoral Area A require an application rate of 4 kg/ha. Ground treatments (i.e., hand, backpack blower treatments) are often applied at a lower rate than that of aerial treatments because a higher percentage of AquabacÒ (i.e., Bti) is expected to reach target areas when there is little canopy to take into consideration. MBL field staff monitored mosquito development sites starting on 19 April and first treated sites on 21 April (Figure 5). Additional treatments quickly became necessary following the initial treatment due to consistently increasing ambient temperatures, providing snowmelt mosquito eggs along mountain bench sites with sufficient environmental cues to hatch. The total area treated by ground as of 9 July was approximately 88 ha (350 kg granular Bti; Figure 4). Real-time data associated with each treatment are available through MBL’s client-registered program portal. Additional ground-based treatments Morrow BioScience Ltd. 11
Golden, Electoral Area A - Mosquito Control Program
will likely be required through July and into August if considerable local precipitation
occurs.
2021 River Levels and Ground Treatments
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Ground Treatments Columbia River (Donald) Columbia River (Nicholson)
Figure 5. Ground application events (purple; ha) with Columbia River levels at Donald gauge (green; m)
and Columbia River at Nicholson gauge levels (blue; m). Data presented are from 1 April – 9 July 2021.
Treatment areas are represented on the secondary y-axis.
Aerial Application Summary
The 2021 mosquito season is considered an exceptionally high-water year. All known
sites and some new sites have been wet this season. Aerial events are required when
access is challenged and when multiple large sites have concurrent hatches along
with high late-instar mosquito larval abundance. The number of aerial applications
required is directly proportional to the height of the water and how long peak levels
are sustained: low-water years require fewer treatments than high-water years.
Because the regional Columbia River peak levels in 2021 exceeded those of 2020,
flooding levels in 2021 triggered a compound number of mosquito eggs to hatch. The
high river level heights, coupled by the likelihood of compound mosquito eggs,
resulted in the requirement of five (5) aerial events, as of 9 July 2021. The aerial
campaigns occurred on 4 May, 11 June, 24 June, 30 June, and 7 July (Figure 6).
Morrow BioScience Ltd. 12Golden, Electoral Area A - Mosquito Control Program
The aerial event that occurred on 4 May was conducted at snowmelt mosquito
development sites (i.e., near Reflection Lake, near Nicholson wetlands, Palumbo
Heights Swamp, Mirage Swamp). Aerial events treating floodwater ideally take place
immediately after the regional rivers have peaked because AquabacÒ is able to reach
mosquito larvae before they disperse with rising water. As it is difficult to determine
when the peak will hit and whether it will be multi-modal, it is often the case that
aerial treatments book-end a peak. Additionally, when river levels rise relatively
slowly, as they did in 2021, there are sufficient cues for large-scale mosquito egg
hatching events while the rivers are rising. The aerial treatment in 2021 took place
following the second highest peak of the season on 11 June (Figure 6). The subsequent
three aerial campaigns book-ended the ultimate peak (Columbia at Donald, 2 July),
taking place on 24 June, 30 June, and 7 July. Because the peak river levels are
consistently receding and treatment efficacy was deemed high, an additional aerial
treatment is unlikely this season.
Aerial application rates vary between sites due to differences in site canopy cover.
Where canopy cover is greater, a higher granular application rate may be necessary.
This year, the aerial application rate for the snowmelt aerial treatment was an
average of 4 kg/ha. The aerial application rate for floodwater mosquito sites was 6
kg/ha. A total of 1,759 ha has been treated by air, as of 9 July. This total equates to
10,192 kg of granular AquabacÒ (Figure 5). Shapefiles of aerial treatments are
maintained by MBL and will be supplied to the CSRD.
2021 River Levels and Aerial Treatments
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Aerial Treatments Columbia River (Donald) Columbia River (Nicholson)
Figure 6. Aerial application events (black; ha) with regional Columbia River levels (green, blue; m). Data
presented are from 1 April – 9 July 2021. Treatment area is represented on the secondary y-axis.
Morrow BioScience Ltd. 13Golden, Electoral Area A - Mosquito Control Program Public Relations Annoyance Reports/Inquiries MBL has maintained a Mosquito Hotline for over a decade (1-877-986-3363). Messages left on the MBL Hotline are checked daily and recorded in a database. MBL also has a contact form on the MBL website (morrowbioscience.com) that is directed to staff inboxes. All calls and emails are returned within 24 hours. Additionally, all calls or emails received by the CSRD program manager are forwarded to MBL and recorded. In 2021, one call has been received as of 9 July. The call was classified as an inquiry- based call, notifying the MBL program manager that mosquito larvae were present in her pond and requesting a site visit. The call was received on 4 May. A return call was made within 24 hours and site visit was scheduled. As of 9 July, no emails have been received. For a high-water year, the call and email volume to date has been exceptionally low. However, the volume is expected to increase with the warming weather and as adult mosquitoes emerge from peak levels, likely between 18 and 25 July. Education Outreach Education outreach is a key aspect to each of MBL’s mosquito programs. The goals for this portion of the program are to increase awareness about personal protective measures, provide mosquito habitat reductive tips, and also to assure residents that Golden and Electoral Area A contractors are committed to providing mosquito control in their area. Outreach material can be presented in numerous forms: in person, through media interviews, and via social media sites. MBL has maintained a presence on social media for the last decade. MBL has a Facebook account (facebook.com/MorrowMosquito), Twitter account (@MorrowMosquito), and Instagram account (linked to Facebook) which are regularly updated. Each platform includes posts regarding where monitoring events are taking place, what the environmental conditions are, and general larval abundance. As of 9 July 2021, the MBL Facebook page was up to 347 followers, which is an increase of 29 followers since that date in 2020. Given the provincial restrictions placed on large gatherings to reduce the spread of COVID-19, MBL incorporated a company-wide policy to provide in virtually-available education outreach material instead of attending public events. As such, the new Morrow BioScience website (www.morrowbioscience.com) has highlighted two sets of FAQs focused on (1) mosquito biology and disease transmission and (2) the active ingredient used in control efforts (Bacillus thuringiensis var. israelensis). Additionally, a blog dedicated specifically to mosquitoes and COVID-19 was published on the MBL website. Morrow BioScience Ltd. 14
Golden, Electoral Area A - Mosquito Control Program A press release was provided to 104.3 EZ (Bell Media) on 7 June. The station has coverage in the Golden and Electoral Area A purview. An off-air interview was conducted with MBL staff and the DJ. The DJ committed to airing the details of the press release on air within the week of 7 June. If opportunities arise, MBL staff will ensure that the CSRD mosquito program manager is consulted prior to agreeing to additional interviews. Every effort will be made to accommodate interviews which assist in raising awareness about mosquito control efforts and personal protective measures. Morrow BioScience Ltd. 15
Golden, Electoral Area A - Mosquito Control Program
Project Contacts at Morrow BioScience Ltd.
Dirk Lewis
Owner/Biologist
dirk@morrowbioscience.com
604.317.1413
Morgan Sternberg
Research Manager
morgan@morrowbioscience.com
250.231.4455
Barry McLane
GIS Manager
barry@morrowbioscience.com
250.231-6934
References
Becker Microbial Products, Inc. Aquabac Mosquito Biolarvicide – Technical Bulletin.
Accessed 12 June 2019. Available online:
https://beckermicrobialproductsinc.com/PDF/bulletin.pdf
Clements, A. (1992). Biology of Mosquitoes. CAB International.
https://beckassets.blob.core.windows.net/product/readingsample/457488/9
783540928737_excerpt_001.pdf
Trpis, M. and Horsfall, W.R. (1969). Development of Aedes sticticus (Meigen)) in
Relation to Temperature, Diet, Density, Depth. Annals Zoologici Fennici, 6(2):
156-160.
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