Week 35 – Aug 27 – 28

2008 Mosquito Report: Week 35

Report based on data collected from traps deployed on Wednesday, August 27, 2008 and retrieved on Thursday, August 28, 2008. Report prepared by John Smith, Chan Suom, M.S., and Nate Boonisar.

1. Current mosquito activity/trend

CDC Light Traps:
CDC activity this week has declined from last week in nearly all towns except for Canton, Holbrook, Medfield, Millis, Milton, and Plainville. In these towns the most active species is Aedes vexans followed by Ochlerotatus canadensis. Salt marsh mosquitoes are still active along the coast although calls for service have declined in most coastal areas.

Gravid Traps:
Gravid traps showed an increase in activity from last week to this week in the towns of Bellingham, Dedham, Foxboro, Franklin, Holbrook, Medway, Millis, Milton, Norfolk, Norwood, Plainville, Randolph, Stoughton, Weymouth, and Wrentham. Several of these trap sites showed a marked increase, in some cases several times the multi year average. At most trap sites collections remain at or above the multi year average. Ochlerotatus japonicuspopulations are declining.

2. Current Predominant Species

Aedes vexans continues to be the most predominant species collected in CDC traps, especially in the above mentioned towns. We are still seeing some Ochlerotatus canadensis activity at some trap sites, Holbrook and Millis showing the highest activity. We have noted that some Culex salinarius were present in some of the traps also. Gravid traps are dominated by Cx. pipiens/restuans. Ochlerotatus japonicus populations are dwindling.

3. Comparison to previous season

CDC activity remains steady with noted increased activity in the above-mentioned towns. Gravid mosquito activity is higher this year and it has also increased from the previous week’s catch. In general, we are seeing more activity later this season when compared to the end of the 2007 season.

4. Weather Summary

The dry weather pattern continued this week with only sprinkles or very light rain on Monday and Saturday. Amounts were a trace to a few hundredths of an inch. Temperatures averaged near to slightly below normal. Despite the recent dry conditions (most of the county has not had appreciable rainfall since Aug 15th), August monthly rainfall across the county averaged between 90-110% of normal, with a swath of 200% of normal in central sections. 60-day rainfall amounts were slightly above normal (100-150% of normal) county-wide, while 90-day rainfall was 90-125% of normal. This puts meteorological summer’s (June-July-Aug) rainfall near to slightly above normal across the county.

Total weekly rainfall: 0.00 inches (-0.78 in.)
Total Monthly rainfall: 4.93 inches (+1.56 in.)
Total Yearly rainfall: 33.02 inches (+5.46 in.)

5. Number of requests for service

Year to date NCMCP has received 4,034 calls for service as of 8/30/08. This represents a total of 261 calls for the week. Numbers of calls dropped this week versus the last few weeks. Last year at this time the calls for service (year to date) were 5,328.

6. MCP/Commission response

In general our response has been to continue ground ULV applications targeting areas of high public demand and areas of positive WNv mosquito pools.Additional trapping of gravid Culex pipiens/restuans has taken place in areas active for WNv. Coordination between NCMCP and the local Boards of Health is ongoing relative to control/surveillance options in the vicinity of WNv positive birds/mosquito pools.


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Walpole, MA 02081

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