Some follow-up or additional thoughts re: NOI thresholds for mosquitocide use 

Meredith William H. (DNREC) 

to: 

Allison Wiedeman 

03/03/2010 01:14 PM 

Cc: 

Linda Boornazian, Jack Faulk, William Jordan, Susan Lewis 

Show Details 

ALLISON – here are some more thoughts regarding acreage amounts when mosquito control spraying that would trigger

the need for filing NOIs, regarding some things that I either want to confirm or clarify associated with our meeting in

Dallas this past January, or to now newly mention or propose.   

  

1) The working document we used at the Dallas meeting indicated NOI thresholds for mosquitocide use of 160 acres

for a “Water‐Treatment Area Annual Threshold”, and 640 acres for a “Treatment Area Annual Threshold,” per the

table in Section 1.2.2:   

  

• The first threshold above termed “Water‐Treatment Area Annual Threshold” could benefit by some

additional description or clarification that this applies to larviciding, which of course is only done over or

into water (and hence results in “water‐acres”).   

• The second threshold above termed “Treatment Area Annual Threshold” could benefit by some

additional description or clarification that this applies to adulticiding, whether done over wetland or

upland/terrestrial areas (with the thinking here for upland/terrestrial areas that given how mosquito

control adulticides are purposely applied to favor long‐distance spray drift, in many cases adulticide

product will eventually settle out into waters of the U.S., albeit at very low densities).

         

2) It should be clarified that “Water‐Treatment Area” annual acreages should not also be considered as part of

“Treatment Area” annual acreages, to be sure to avoid having larvicide acreage mistakenly also be “double

counted” as part of adulticide acreage.  By making the clarifications recommended in #1 above for larviciding vs.

adulticiding, this should help prevent such “double counting,” but you nonetheless might still want to additionally

spell this out.   

  

3) I believe that as was discussed in Dallas, the EPA will now view both of these annual acreage figures (160 or 640)

as being “aggregate” acres as opposed to consisting of “discrete” or distinct acres, with the former being the way

that most mosquito control programs tally their annual acreage spray figures (since “aggregate” accounting also

helps to more accurately reflect the amount of mosquitocide product that was used) – for example with the

“aggregate” approach, you could hit the NOI threshold when larviciding if you treated 160 acres only once per

year for each acre, or alternatively via treating 40 acres four times per year for each acre.  This would be in

contrast to your having to larvicide 160 or more “discrete” or distinct acres per year (without any accounting for

repetitive treatments on any given acre) before the NOI threshold would be exceeded.  The same type of thinking

about “aggregate” accounting also applies here when adulticiding.  All this needs to be better clarified in the draft

permit.

  

4) Finally, you might soon be seeing a letter from CropLife America recommending that the mosquito control NOI

threshold acreages be increased from the 160/640 acres up to what would become 250/1000 acres, done to help

ensure that truly “small time” mosquitocide applicators don’t get caught‐up in having to file NOIs.   This increase

in acreage thresholds would seemingly be a good thing to now allow or accommodate, especially given an

“aggregate” approach to calculating annual treatment acreages versus taking a “discrete” or distinct acreage

approach.

  

Much thanks for considering this input!

  

Cheers, BILL    

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