Week 29 – July 19 – 23

2010 Mosquito Report: Week 29

Report based on data collected from traps deployed the week of July 19, 2010 through July 23, 2010. Report prepared by John Smith, Chan Suom, M.S., and Nate Boonisar.

1. Current mosquito activity/trend

CDC Light Traps:
Decreased host seeking mosquito activity continues from last week’s lower than average numbers. Only Bellingham and Milton reported higher than average activity whereas Foxboro, Medfield, Millis, Plainville, Quincy, parts of Walpole, parts of Weymouth, and parts of Wrentham indicated average mosquito populations.

Gravid Traps:
As with the CDC light trap collections, gravid traps continued with a decrease in gravid mosquito activity when compared with the historical average. OnlyFranklin reported an average collection.

2. Current Predominant Species

CDC Light Traps:
The most predominant CDC trapped mosquitoes in Norfolk County this week was once again Coquillettidia perturbans, especially in Belllingham and Milton . Culexpipiens/restuans populations are higher than average in Canton, Franklin, and Medway even thought these towns collected fewer mosquitoes than the historical average. Aedes vexans and Psorophora ferox populations are starting to become more numerous, especially in Canton.

Gravid Traps:
Culex pipiens/restuans continue to dominate gravid traps, although their populations are low this week. Ochlerotatus japonicus numbers are down from last week also.

3. Comparison to previous season

Host seeking and gravid mosquito activity is significantly lower than average for this past week throughout Norfolk County at our historical trap sites. This observation contradicts the current outbreak of salt marsh Ochlerotatus sollicitans mosquitoes all over eastern Quincy as indicated by heavy service call volumes, landing counts, and site visitations conducted by field personnel.

4. Weather Summary

It was somewhat cooler weather this week, but still a bit above normal, with increased coverage of showers and thunderstorms. The northern fringe of an area of thunderstorms to the south brought up to ¼ inch of rain across our southern areas on Monday. A cold front and associated rainfall mainly missed Norfolk County on Wednesday except for a lone shower across Dover and Needham that brought a localized tenth to ¼ inch of rain. On Friday, a warm front brought heavy showers to the area in the evening. A widespread ¼ to ¾ of an inch of rain fell. Finally, thunderstorms associated with a cold front on Saturday brought localized heavy rainfall across southwest sections, with over an inch falling along a line from Medway to Foxborough. For the week, county wide rainfall was above normal in the southwest sections, but a bit below normal across the remainder. The US Dept of Agriculture has placed most ofNorfolk County and points north into an “Abnormally Dry” category based on longer term precipitation trends. The extreme southern section, (and points south) are not included in this. This map can be seen here: http://www.drought.unl.edu/dm/monitor.html. The reasoning behind this is based on 30 and 60 day rainfall deficits which can be seen here: http://water.weather.gov/precip/.

Total weekly rainfall: 0.63 inches (-0.05 in.)
Total Monthly rainfall: 1.26 inches (-1.10 in.)
Total Yearly rainfall: 30.91 inches (+7.27 in.)

5. Number of requests for service

NCMCP received 4,482 calls year to date for service as of 7/23/10. NCMCP received 522 calls for service this week.

6. MCP/Commission response

NCMCP continues to conduct “scattered and isolated” ground ULV applications when and where necessary. ULV applications (both frequency and area covered) have steadily decreased over the past several weeks due to lowering populations of human biting mosquito species with the exception of Quincyand North Weymouth. In these areas calls have increased significantly especially in the Merrymount, Adams Shore, Germantown and Houghs Neck area of Quincy. ULV activities have increased in these areas. This is due to a rain induced emergence of salt marsh mosquitoes (Oc. sollicitans) from the Broad Meadows marsh restoration area. Unfortunately, due to safety and security concerns, NCMCP was not able to access the site to conduct larval control operations. NCMCP personnel met with members of the Corp. of Engineers to set up a process which would allow for future access to the site. NCMCP personnel also treated remaining active breeding sites on Broad Meadows. Calls for service this year are the highest they have been at this point in the past three years. Complaint calls are up this week due to the Oc. sollicitans outbreak in Quincy. Calls have also increased in response to the media coverage of EEE/WNv activity. NCMCP continues to treat rain basins using a pouch with B. sphaericus as the active ingredient.


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Walpole, MA 02081

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