PROJ00188

• Contract/PO #: FS0030X
• Contractor Name: Dolores Project USBR 1963
• Contract Type: Miscellaneous
• Water District: 0
• County: Montezuma
• Loan Projects - Doc Type: Feasibility Study

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PUELI C HEALTH SERVI CE

and in the bottoms of ravines and swales which dissect the higher irri-
gated lands al1d form natural drainage'''SYs. Farm ponds, some of which
are formed by low dams across the ravines, also were found to be impor-
tant sources of mosquitoes during late season. The September larval
collections from marshy seeps showed Culex tarsal~ and Anopheles ~
~ present in proportions of 74 percent and 26 percent, respectively;
the co:1lections from farm ponds showed the same species present but the
proportions reversed with A. freeborni comprising 91 percent and C. tar-
salis 9 percent of the total la.rvae. - -

In JUl1e 1960, prolific production of mosquitoes waS found at many
localities within the area of the proposed project. Heavy production
of ~ vexans was noted in floodwater pools in the bottomland along the
Dolores River between the town of Dolores and the mouth of Beaver Creek.
Larvae of C. tarsalis. ~uliseta inornata and Culiseta incidens also were
found in the floodwater pools but in smaller numbers than were the larvae
of !. vexans. Roadside ditches, pools on irrigated pastures. marshy
seeps, and alkaline marshes were found to be important sources of
!. vexans, Aedes dorsalis, Aedes melani mon . and f. tarsalis.

",'

The larvae collected, type of larval habitat, and the percent com-
position by species in each habitat are sho"ll in Table 6.

Table 6
Hos quit 0 Larvae Collected in Project Area
Percentage ComDosition
g rJJ ttl oj
tf) ~1! Ul '" rJJ
.... ..-1 +>" ~~
Total .... ..-l tf) 1!o .... 01 01
Ul '" ~ 1ii rJJ ~ >4 ttl Ul'O .~ ~
Type of Specimens 01 "' .g p,.g '" Ul ......rl
"'$.< 'O"" o ~ ,Hl g g ;.1 g
Habitat Identified ~,g .1i ~ ~ 01 .'i!... <3 'M
> u+> O'M
Roadside ditches
and borrow pits 290 8 36 56

Marshy seeps. along
sides or in bottoms
of ravines and swales 119 26 74
Farm ponds 136 91 9
Pools on irrigated
pastures 143 40 45 15
Floodwater pools along
Dolores River 404 63 26 6 6

Adult mosquito collections.--In the June 1960 survey, adult mosqui-
toes were encounteTed in large numbers attwo localities within the proj-
ect area. Adults of A. vexans were highly annoying in the cultivated

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