Week 36 – Sept 4-10

2011 MOSQUITO REPORT: WEEK 36

Report based on data collected from traps deployed the week of September 4, 2011 through September 10, 2011. Report prepared by John Smith, Chan Suom, M.S., and Nate Boonisar.

1. CURRENT MOSQUITO ACTIVITY/TREND

CDC Light Traps:
Host-seeking activity this week is evenly split between lower than average and higher than average activity throughout the county. Franklin, Holbrook, Medway, Millis, Needham, Plainville, Sharon, parts of Walpole, and Wrentham collected higher than average numbers of mosquitoes whereas Avon, Bellingham, Canton, Dedham, Medfield, Milton, Quincy, parts of Walpole, and Weymouth returned lower than average collections. The remaining towns reported average activity levels.

Gravid Traps:
Gravid trap collections are lower than average for almost all towns in our service area. Only Dover, parts of Quincy, and Wrentham had average levels of oviposition activity.

2. CURRENT PREDOMINANT SPECIES

CDC Light Traps:
Aedes vexans continues to be the most active mosquito species in our county as a result of the previous rain events; and their activity levels are high in Franklin, Medway, Millis, Needham, Plainville, parts of Walpole, and Wrentham. Culex pipiens/restuans host-seeking activity is high in Medway and Millis. Culiseta melanura continues to be a big presence in Holbrook, whereas Sharon is now experiencing an abundance of newly emerged Ochlerotatus canadensis. The Broad Meadows area of Quincy is experiencing a higher abundance of Oc. cantator than the typical Oc. sollicitans that we collect from the site.

Gravid Traps:
Gravid Culex pipiens/restuans mosquito populations are extremely low this week.

3. COMPARISON TO PREVIOUS SEASON

The continued weekly rain events have created and maintained plenty of habitat for flood-type mosquitoes as seen from this week’s Ae. vexans and newly emerged Oc. canadensis and Oc. cantator populations . Culiseta melanura populations have gone back up higher than normal in Holbrook. The rain events from the remnants of Tropical Storm Lee have put a damper on gravid mosquito activity as it was extremely low compared to historical records. Host-seeking activity fared better, but was visibly affected by the rain as collections were lower than average in half of our trap sites. The upcoming week should provide better data as the weather is predicted to be clear during our trapping and collecting schedule. The only deterrent to mosquito activity appears to be cooler evenings that are becoming more common as the summer season draws to a close.

4. WEATHER SUMMARY

After a dry start, a stalled front combined with tropical moisture to create periods of rain in the middle to end of the week. Some of the rain was very heavy, especially on Thursday. Amounts were over two inches county-wide, with more than three inches in central and western areas. With the prior wet conditions, this caused both the Charles and Neponset to rise to well above normal levels, and to keep ground water levels well above normal.

Total weekly rainfall: 2.71 inches (+1.91 in.)
Total Monthly rainfall: 2.71 inches (+1.57 in.)
Total Yearly rainfall: 36.15 inches (+7.31 in.)

5. NUMBER OF REQUESTS FOR SERVICE

NCMCP received 7,315 calls year to date for service as of 9/9/11. NCMCP received 253 calls for service this week.

6. MCP/COMMISSION RESPONSE

NCMCP continues ground ULV applications in high request areas and in areas where collection data indicate a need. Forecasted might time temps in the 40’s and 50’s starting this Thursday night and following will likely end the ULV program at the end of this week. Rain basin treatments continue with a concentration in urban areas where West Nile virus (WNV) has been collected. These treatments will be coming to end as well this week. NCMCP continues some groundlarviciding in certain areas in response to flooding due to frequent rain events. Due to the positive WNV isolates in mosquitoes collected in multiple communities, NCMCP has conducted localized (focused) applications of both ULV and rain basin treatments. Boards of Health in all communities have stepped up public outreach using all available local media outlets. EEE has also now been identified in pools of Culiseta melanura in the towns of Holbrook and Sharon. AppropriateULV applications have been conducted in these towns.

Contact

144 Production Rd, Suite C

Walpole, MA 02081

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