Week 28 – July 12 – 16

2010 Mosquito Report: Week 28

Report based on data collected from traps deployed the week of July 12, 2010 through July 16, 2010. Report prepared by John Smith, Chan Suom, M.S., and Nate Boonisar.

1. Current mosquito activity/trend

CDC Light Traps:
There was a dramatic decrease of host-seeking mosquito activity throughout Norfolk County. The only towns that reported average levels of activity include Foxboro, Plainville, Quincy, parts of Walpole, and parts of Wrentham.

Gravid Traps:
As with the CDC light trap collections, gravid traps also reported a significant decrease in gravid mosquito activity when compared with the historical average. Only Norfolk 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 although Culex pipiens/restuans populations are higher than average in Canton and Franklin. 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 Ochlerotatus japonicus populations are higher than average in Avon, Milton, and Stoughton.

3. Comparison to previous season

Compared to previous seasons, mosquito activity was significantly lower for this week. The nature of which was primarily due to intense bouts of rainfall followed by a cooling effect throughout the county during the trapping and collection period. This translated to lower than average mosquito populations collected in our CDC light traps. The disturbance on the water surface by heavy and sporadic rainfall also negatively affected our gravid mosquito collections and dilution of the “swill” may have reduced the attractiveness of the trap to Culex species.

4. Weather Summary

Weather conditions continued to be the same as previous weeks (hot, humid) but with somewhat more frequent, although scattered, rainfall provided by weak cold frontal passages. The most widespread fell on Tuesday night into Wednesday as a tropical airmassbrought showers and thunderstorms to the area. Heaviest amounts of ¼ to ½ inch fell across central parts of the county with lesser amounts to the north and east. Weakening thunderstorms associated with another cold front on Friday night brought a trace to ¼ inch of rain with highest amounts in the west. Longer term rainfall continues below normal county-wide.

Total weekly rainfall: 0.47 inches (-0.21 in.)
Total Monthly rainfall: 0.63 inches (-1.05 in.)
Total Yearly rainfall: 30.28 inches (+7.33 in.)

5. Number of requests for service

NCMCP received 3,960 calls year to date for service as of 7/16/10. NCMCP received 312 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. Calls for service this year are the highest they have been at this point in the past three years. Complaint calls are up slightly this week versus last week. NCMCP continues to treat rain basins using a pouch with Bs as the active ingredients. NCMCP also treated salt marshes in both Quincy and Weymouth as a result of the monthly high tide which peaked @ July 14th. NCMCP continues to work on several water management projects during this “low flow” period.


144 Production Rd, Suite C

Walpole, MA 02081

Office: (781) 762-3681
Fax: (781) 769-6436