Week 24 – June 14 – 18

2010 Mosquito Report: Week 24

Report based on data collected from traps deployed the week of June 14, 2010 through June 18, 2010. Report prepared by John Smith, Chan Suom, M.S., and Nate Boonisar.

1. Current mosquito activity/trend

CDC Light Traps:
Many of the towns in Norfolk County experienced average mosquito activity for this time of year although the towns of Avon, Bellingham, Canton, Franklin, Medway, Millis, Milton, Norfolk, Sharon, Walpole, and Weymouth recorded higher than average mosquito activity due to an early emergence of Coquillettidiaperturbans populations. Canton, Dedham, Franklin, Needham, Sharon, Walpole, and Weymouth report lower than average populations of Ochlerotatus canadensisand/or Aedes vexans activity.

Gravid Traps:
Gravid traps have not been deployed still, and there is very little Culex spp. activity in CDC light traps as well.

2. Current Predominant Species

CDC Light Traps:
The most predominant CDC trapped mosquitoes in Norfolk County this week were Co. perturbans. Oc. canadensis collections were lower compared to last week’s numbers and the historical average. Oc. triseriatus and Psorophora ferox have made their first appearance in the county traps, albeit in very small numbers.

Gravid Traps:
Gravid trap figures are not available thus far. NCMCP will begin deploying gravid traps Epi Week 25.

3. Comparison to previous season

Co. perturbans populations have literally exploded all over the county. Usually their peak activity is expected around Week 26 and this week’s observations have corroborated with many MCP’s line of thinking that mosquito activity has been accelerated by two weeks. Ae. vexans may start to appear sporadically within a week or two if thunderstorms flood their habitats. In general wetlands are in a drying down phase. This is also the case with river floodplains.

4. Weather Summary

This week featured generally low amounts of rainfall with the passage of some weak fronts. Weekly rainfall was generally under 0.25” county-wide. Temperatures averaged close to normal with increasing heat and humidity towards the end of the week. So far this month, rainfall has been near to slightly below normal across the county.

Total weekly rainfall: 0.16 inches (-0.60 in.)
Total Monthly rainfall: 2.14 inches (+0.09 in.)
Total Yearly rainfall: 29.57 inches (+9.46 in.)

5. Number of requests for service

NCMCP received 2,612 calls year to date for service as of 6/19/10. NCMCP received 152 calls for service this week. This is considerable less than EpiWeek 23.

6. MCP/Commission response

NCMCP has been conducting “area wide” ground ULV applications when and where necessary. Large area larval control interventions were conducted using aircraft in mid April and small area larval control has been on going since early April. NCMCP personnel treated salt marshes with Bti granular following flooding of the marshes on the month’s highest tide (June 15th). Rain basin monitoring with a Landers Ladles indicated Culex larvae presents in many of the basins sampled. As a result NCMCP has begun rain basin treatments using a briquette with both Bti and Bs as the active ingredients (Fourstar).


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Walpole, MA 02081

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