Week 32 – Aug 5 – 6

2009 Mosquito Report: Week 32

Report based on data collected from traps deployed on Wednesday, August 5, 2009 and retrieved on Thursday, August 6, 2009. Report prepared by John Smith, Chan Suom, M.S., and Nate Boonisar.

1. Current mosquito activity/trend

CDC Light Traps:
Host-seeking mosquito activity was higher than average in most parts of Norfolk County, with only Franklin reporting lower than average mosquito activity. The towns of Bellingham, Holbrook, Weymouth, and Wrentham experienced average levels of host-seeking mosquito activity.

Gravid Traps:
For the third week in a row, all of the towns in Norfolk County experienced yet another lower than average trap collection. Canton, Foxboro, Franklin,Norfolk, and Wrentham reported average numbers but these collections were also low in mosquito abundance.

2. Current Predominant Species

CDC Light Traps:
The most predominant CDC trapped mosquitoes this week were Aedes vexans and Coquillettidia perturbans. Culex pipens/restuans populations are high and spread throughout the county. Oc. canadensis populations continue to be high in the towns of Foxboro, Plainville, and Sharon. Psorophora feroxpopulations have dropped drastically across the county. Oc. sollicitans has been very active in Quincy. The town of Norfolk experienced an unusually high population of Oc. trivittatus. The Franklin traps collected mixed numbers, with higher Ae. vexans populations and lower Co. perturbanspopulations. Dedham showed a dramatic increase in Ae. vexans numbers. The Charles and Neponset River flood plains have dried down to more normal non-flooded conditions. The good news, as detailed in the weather report below, shows no additional rainfall recently. Site visits continue to show high levels of human biting mosquito activity with landing rates remaining unchanged from Epi Week 30.

Gravid Traps:
Gravid trap collections remain predominately Culex pipiens/restuans.

3. Comparison to previous season

Host-seeking mosquito activity this week was mostly higher than average due to the continued, staggered emergence of Co. perturbans, and the recent emergences of Ae. vexans, and Oc. canadensis populations. In general, gravid trap activity for Norfolk County was lower than average continuing with last week’s low collection trend.

4. Weather Summary

A warm and humid weather pattern continued during early parts of the week, however precipitation was fairly scarce across the county compared to previous weeks. A cold frontal passage on Wednesday brought thunderstorms to southern sections of the county, however rainfall was generally no more than ¼ inch. Cooler and less humid weather returned for the end of the week.

Total weekly rainfall: 0.00 inches (-0.73 in.)
Total Monthly rainfall: 0.00 inches (-0.83 in.)
Total Yearly rainfall: 26.81 inches (+1.64 in.)

5. Number of requests for service

NCMCP received 4,110 calls for service as of 8/08/09. NCMCP received 525 calls for service this week.

6. MCP/Commission response

NCMCP continues to conduct “area wide” ground ULV applications in many areas of the county due to high numbers of calls as a result of these large populations of human biting mosquitoes. Due to an increase in demand these ULV activities have been expanded across the county again this week. NCMCP continues treatments to rain basins in high density basin areas such as centers of towns. NCMCP deployed additional gravid traps and CDC light traps in select areas of Walpole proximate to the DPH site. NCMCP conducted area wide ULV applications in areas proximate to this positive WNv collection. Coordination between NCMCP and all local Boards of Health is ongoing relative to interpretation of surveillance data and how best to get the word out to the public relative to avoidance of mosquito bites. NCMCP remains prepared to conduct additional ground adulticide, ground larvicide and aerial larvicide control activities as required.


144 Production Rd, Suite C

Walpole, MA 02081

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