Week 27 – July 1 – 2

2008 Mosquito Report: Week 27

Report based on data collected from traps deployed on Tuesday, July 1, 2008 and retrieved on Wednesday, July 2, 2008. Report prepared by John Smith, Chan Suom, M.S., and Nate Boonisar.

1. Current mosquito activity/trend

CDC Light Traps:
Generally, activity level for CDC traps declined this week compared to the average, whereas the towns of Millis (PER), Canton (CAN), and Wrentham (PER) have seen an increase in activity. CDC light traps for this week show a predominance of Ochlerotatus canadensis and Coquillettidia perturbansalthough at all sites except the Millis site the numbers remain low for all human biting species. Millis showed a spike in Coquillettidia perturbans. Culiseta melanura numbers remain low in those traps which collect them.

Gravid Traps:
Mosquito activity in gravid traps remains up in most trap sites with most collections at or above the average. The most eastern (urban) sites are still showing the highest levels. Specifically the trap sites located in Avon, Milton, Quincy and Randolph which are collecting high numbers compared to their averages. Ocherlotatus japonicus collections remain low.

2. Current Predominant Species

The most predominant CDC trapped mosquitoes were Coquillettidia perturbans followed by Ochlerotatus canadensis. Culex pipiens/restuans is the most abundant species collected in gravid traps.

3. Comparison to previous season

Compared to last season, activity of the predominant species Coquillettidia perturbans in light traps is well below average. Above average collections ofCulex 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. Ochlerotatus canadensis numbers are declining fairly rapidly in most cases and remain below their averages.

4. Weather Summary

The stretch of active weather continued this week, with the focus shifting into Norfolk County on Wednesday. Much of the county, especially central sections, was hit by thunderstorms with very heavy rain and hail causing localized flooding and sharp, yet brief, rises on the Neponset River. Some widespread light rain fell on the 4th giving around ¼ inch to the region. Weekly rainfall throughout the county averaged between 1 and 2 inches with a bit more in the far north due to continued frequent thunderstorm activity in this area. With the antecedent dry conditions, and the very intense yet brief duration of this rainfall, this precipitation simply halted any further drying, with the possible exception of the far north (Needham and Dover) which has received repeated thunderstorms over the past few weeks and is contributing to larger longer term rainfall amounts. Otherwise, moderately humid and near to slightly above normal temperatures prevailed.

Total weekly rainfall: 1.85 inches (+1.24 in.)
Total Monthly rainfall: June: 1.85 inches (-1.37 in.), July: 1.85 inches (+1.45 in.)
Total Yearly rainfall: 23.75 inches (+1.97 in.)

5. Number of requests for service

Year to date NCMCP has received 1,797 calls for service as of 7/5/08. This represents a total of 245 calls for the week. This shows a slight decrease in calls from last week. Last year at this time the calls for service (year to date) were 3,204 almost double the calls so far this year. No doubt this is due to the lack of summer refloods and the lower than usual Coquillettidia perturbans numbers. Media coverage of EEE and WNv has been less this year as well which may have contributed to the spike in calls early last season.

6. MCP/Commission response

In general our response has been to continue ground ULV applications targeting areas of high public demand. 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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