Week 29 – July 13-19

2014 MOSQUITO REPORT: WEEK 29

Report based on data collected from traps deployed the week of July 13-19, 2014. Report prepared by Chan Suom, Dave Lawson, and Nate Boonisar.

1. CURRENT MOSQUITO ACTIVITY/TREND

CDC Light Traps:
CDC light trap activity has decreased by a small margin as half of the towns are reporting lower than average levels of host-seeking mosquito activity. Avon, Holbrook, Norwood, and Stoughton collected an average number of mosquitoes in their respective traps, whereas Braintree, Dedham, Dover, Foxborough, Medfield, Milton, Needham, Randolph, and Weymouth returned higher than average mosquito collections.

Gravid Traps:
Gravid trap activity remains lower than the historical average. Only Braintree, Norfolk, and Wrentham reported an average population of ovipositing mosquitoes.

 2. CURRENT PREDOMINANT SPECIES

CDC Light Traps:
The most abundant mosquito species this week are Coquillettidia perturbans of which over 5,500 were collected from across the county. This was followed by Aedes vexans (which increased to over 1,100 specimens). Ochlerotatus taeniorhynchus has made a small emergence in Holbrook whereas Oc. canadensis has dropped in abundance compared to last week’s figures.

Gravid Traps:
Culex pipiens/restuans are the main species in these traps and their overall population is lower than average for this time of the season.

3. COMPARISON TO PREVIOUS SEASON

The overall mosquito population for host-seeking mosquitoes in CDC light traps is mixed whereas gravid trap activity is lower than average when compared to historical data (2007-2013). Coquillettidia perturbans populations are higher than average for the most part, but their numbers are lower this week than previous. This may have to do with the string of heavy rainstorms during the week, which affects mosquito host-seeking activity.Aedes vexans populations may have gotten a boost (from 468 to 1,172 specimens) from Hurricane Arthur’s rainfall as numbers have increased from last week’s collection. A recent emergence of Ochlerotatus taeniorhynchus in Holbrook suggests that these species benefitted from Hurricane Arthur’s precipitation also.

Please refer to our surveillance charts for detailed trap collection data.

4. WEATHER SUMMARY

Temperatures this week averaged slightly above normal to start the week, then dropped below normal following a cold front. This slow moving front brought two rounds of showers and thunderstorms on Monday and again on Wednesday. Rainfall ranged from as low as a half inch along the southern border of the district to localized amounts over 1.5 inches in western and northern sections. So far this month, rainfall has been above normal across the entire district, however 60 and 90-day rainfall deficits remain.

Total weekly rainfall: 1.18 inches (+0.50 in.)
Total Monthly rainfall: 2.80 inches (+0.93 in.)
Total Yearly rainfall: 22.21 inches (-0.94 in.)

5. NUMBER OF REQUESTS FOR SERVICE

We received 503 calls for service this week. We have recorded a total of 5,500 service requests for the year.

6. MCP/COMMISSION RESPONSE

The District is currently responding to requests for spraying with our evening ULV application program. Catch basins continue to be treated in the District’s towns with a majority of the towns’ treatments having been completed at this point. A small number of larvicide requests from residents continue to be checked as needed. In response to a finding of WNV in a pool of mosquitos in Canton, the district urged the town to post notifications warning residents, and especially the elderly, to take precautions to avoid mosquito bites.

Contact

144 Production Rd, Suite C

Walpole, MA 02081

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