Week 25 – June 17 – 18

2008 Mosquito Report: Week 25

Report based on data collected from traps deployed on Tuesday, June 17, 2008 and retrieved on Wednesday, June 18, 2008. Report prepared by John Smith, Chan Suom, M.S., and Nate Boonisar.

1. Current mosquito activity/trend

CDC Light Traps:
CDC light traps for this week show a predominance of Ochlerotatus canadensis. The numbers collected remains below the average for this species at this time of year. Ocherlotatus excrucians and Ochlerotatus abserratus numbers continue to decline as would be expected with these spring brood species. Coquillettidia perturbans were collected in a few traps indicating the beginning of their emergence. The emergence of the adults of this species seems a little later than previous years and in lower numbers relative to the average. Small numbers of Anopheles punctipennis and walkeri continue to be collected. Culiseta melanura numbers remain low in those traps which collect them in any numbers. Well below the average for this species.

Gravid Traps:
Most of the gravid trap collections have increased from last week. The trend of higher numbers of Culex pipiens/restuans collected in the eastern (more urban) trap sites continued for this week. Culex pipiens/restuans collections in traps located in Dover, Milton, Needham, Norwood, Quincy and Walpolewere higher than their averages. In some cases several times higher than their average. Most noticeable was the Town of Dedham where collections have approached the highest level ever collected since the trap site was established in early 2000. This trend most likely will continue especially given the fact that frequent thunderstorms with their accompanying heavy rain and street run off continues to replenish rain basins and above ground containers.Ocherlotatus japonicus collections remain low relative to the average.

2. Current Predominant Species

The predominant species this week were Oc. canadensis and Culex pipiens/ restuans.

3. Comparison to previous season

Compared to last season, activity of the predominant species Oc. canadensis in light traps is below average. Above average collections of Culex pipiens/restuans have occurred in gravid traps especially in eastern locations of the county. Coquillettidia perturbans collections seem late and below normal for this year.

4. Weather Summary

The weather pattern turned fairly unsettled this week. Temperatures started the week on the cool side for mid June, then gradually warmed to normal or slightly above normal by the end of the week. Widespread showers and thunderstorms affected the area early in the week, with more scattered thunderstorms, especially in the eastern part of the county later in the week. A fairly widespread 1.0-1.5 inches of rain fell county-wide, with amounts closer to 2 inches in eastern sections. Despite this rainfall, totals for the month, and for the past 90 days remain between 50-75% of normal. Over the next 6-10 days, temperatures are forecast to be above normal with above normal precipitation. Temperatures remain above normal 8-14 days out with normal precipitation expected.

Total weekly rainfall: 1.14 inches (+0.49 in.)
Total Monthly rainfall: 1.77 inches (-0.50 in.)
Total Yearly rainfall: 22.89 inches (+2.46 in.)

5. Number of requests for service

Year to date NCMCP has received 1,151 calls for service as of 6/21/08. This represents a total of 274 calls for the week. This shows a decrease of over 100 calls from last week which is a further reflection of declining spring brood activity. Last year at this time the calls for service (year to date) were 2,532. Most likely the higher number of calls last year (year-to-date) was due to heavy summer reflood populations and higher Coquillettidia perturbans numbers.

6. MCP/Commission response

In general our response has been to continue ground ULV applications targeting areas of high public demand although this demand has declined. Due to this decline in surveillance numbers and calls for service the number of areas treated has also declined. NCMCP continues to treat rain basins in highly urban areas where Culex pipiens/restuans activity is highest based on gravid trap collections.


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Walpole, MA 02081

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