2022 Pre-Hatch Larval Control

Purpose:

Larval control at CMMCP is typically done in wetlands after confirmation of sufficient larval presence (1+ per 5 dips per GEIR). Pre-hatch control is performed using slow release products in areas of historical larval activity, before larvae hatch and become airborne. Low water temperatures and slow feeding patterns of early instar larvae are barriers to early-season treatments, but one bacterial product has shown success.

In 2014 CMMCP investigated efficacy for pre-hatch control of mosquito larvae using slow release formulations of Bti and combination Bti/Bs product in wetlands, with poor results.

From 2015-2020, we tested an organically-certified, 30-day slow release formulation of the bacterial product Natular G30, active ingredient spinosad. These applications showed good results, and in 2021 we went fully operational treating 61 acres (157 applications). This program was expanded in 2022 targeting 200+ acres.

2022 Application:

Dates: March 9-28, 13 application days

430 applications, 214.6 acres treated in total in all member communities.

4.9 acres per community average – 9.8 lbs. per community average

Cost:

(53) 40 lb. bags, $32,838 - cost to CMMCP: $0. 23 bags from previous rebate, 30 bags from 2021 SRB aerial program.

Monitoring:

~20% sites for efficacy and NPDES adverse impacts. Results: 89 sites were rechecked (21%), 4 were found to have 1st or 2nd instar larvae, these 4 sites will be checked again. No adverse impacts noted for NPDES permit.

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2022 prehatch acres
 # applicationsamount appliedacres treated
Acton7474.7
Ashland11404.35
Auburn19525.2
Ayer642.54.25
Berlin1655.55.55
Billerica1053.55.35
Blackstone1045.54.55
Bolton6545.4
Boxborough1050.55.05
Boylston1670.957.89
Chelmsford973.257.375
Clinton1042.54.25
Devens7323.2
Dracut932.53.25
Fitchburg1044.54.45
Gardner13565.6
Grafton9414.1
Holliston9393.9
Hopedale844.754.47
Hopkinton9394.2
Hudson7444.4
Lancaster1083.58.35
Leominster12454.5
Littleton8484.8
Lowell5303
Lunenburg7474.7
Marlboro981.358.13
Milford9585.8
Millbury1434.53.45
Millville10393.9
Natick10414.02
Northboro1159.255.92
Northbridge1152.55.2
Sherborn7414.1
Shrewsbury10535.3
Southboro949.754.97
Stow15535.3
Sturbridge6434.3
Tewksbury10373.7
Webster11414.6
Westboro1265.756.67
Westford5444.4
Wilmington10434.3
Worcester8373.7
    
TOTALS4302,126.55214.60
    
    
    
average # applications:9.8 
    
average amount applied:48.3 
    
average acres: 4.9 
    
    

 

graph

Efficacy graphs going back to 2016 available here: https://www.cmmcp.org/larval-control-program/pages/pre-hatch-larval-cont...