Week 30 – July 22-28

2012 MOSQUITO REPORT: WEEK 30

Report based on data collected from traps deployed the week of July 22, 2012 through July 28, 2012. Report prepared by Chan Suom, M.S., Dave Lawson, and Nate Boonisar.

1. CURRENT MOSQUITO ACTIVITY/TREND

CDC Light Traps:
Most host-seeking light traps returned lower than average to average collections of mosquitoes this week. Only Canton, Dedham, Foxborough, Norfolk, and Quincy reported higher than average collections.

Gravid Traps:
This trapping interval indicates that the population abundance of gravid mosquitoes continues to be lower than average all throughout Norfolk County. Only Medfield indicated an increase, albeit the Ochlerotatus japonicus species once again.

 2. CURRENT PREDOMINANT SPECIES

CDC Light Traps:
The most predominant CDC trapped mosquitoes in Norfolk County this week were Coquillettidia perturbans once again, with populations higher than average in Canton, Dedham, Foxborough, and Norfolk.  Culex pipiens/restuans numbers are higher than average in Quincy. Aedes vexans has made an appearance once more due to the recent rain events and we can expect many more in the coming weeks after this past weekend’s torrential downpours.

Gravid Traps:
Though their populations are low, Culex pipiens/restuans are the most predominant species in gravid traps throughout Norfolk County.

3. COMPARISON TO PREVIOUS SEASON

The mixed collections for host-seeking mosquitoes and really low abundance of gravid mosquitoes appear to be a factor of low abundance as the phenology would suggest. Overall, mosquito collections returned lower numbers than average. This week’s thunderstorm and rain events may produce a new emergence of flood-dependent mosquito species, of which we should encounter within 2 weeks.

4. WEATHER SUMMARY

Temperatures were generally above normal this week, but closer to normal towards the end of the week. There were two rounds of precipitation. On Wednesday, thunderstorms in the early morning, then again in the evening gave rain to southwest and northeast sections. Amounts were around ¼ inch in the southwest and northeast sections, with lighter amounts in between. More significant rain occurred on Saturday evening as an area of heavy rain moved across the area bringing a widespread 1-2 inches. This rainfall caused increases on our rivers, however not enough to cause any flooding since the rivers were running well below normal prior to the rain. Likewise, this rainfall certainly added to soil moisture levels, but it was unlikely to have caused significant recharge of area wetlands. The Norfolk USGS groundwater gauge showed this rainfall bringing groundwater levels to near normal for late July after being below normal for most of the month.

Total weekly rainfall: 1.89 inches (+1.20 in.)
Total Monthly rainfall: 2.52 inches (-0.24 in.)
Total Yearly rainfall: 17.32 inches (-6.71 in.)

5. NUMBER OF REQUESTS FOR SERVICE

NCMCD has received 5,340 calls year to date for services as of 7/27/12. The NCMCD received 652 calls for service this week.

6. MCP/COMMISSION RESPONSE

The NCMCD continues to respond to ULV requests by residents. With the recent finding of multiple EEE positive pools of Cq. perturbans in Canton, the District has stepped up additional ULV applications in Canton and Randolph. Basin treatments have been completed in some communities and continue in other municipalities. Very few larvicide requests are being initiated at this time.

Contact

144 Production Rd, Suite C

Walpole, MA 02081

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