Annual Bluegrass Weevil Optimum Control Strategy

With the documentation of pyrethroid resistance in certain ABW populations – primarily in southern New England – this program incorporates a range of insecticides with different MOAs. The program anticipates the worst-case scenario of a prolonged period of egg-laying by overwintered ABW adults and recognizes that, under some circumstances, even high levels of control of first generation larvae will not completely prevent damage by summer generations of ABW.

Optimum Control Strategy Summary (for First Generation ABW Control)

Optimum Control Strategy Summary (for Second Generation ABW Control)

First Generation Control

The treatment schedule below is for the first generation of ABW activity on golf courses. Subsequent ABW generation treatment recommendations are based on first generation tracking by WeevilTrak researchers.

FIRST APPLICATION (Stage 1): The first application uses Scimitar GC as an adulticide at a recommended rate of 10 fl. oz./A in late March to early May. Timing of this application will be based on GDD and refined according to observations on plant phenology and ABW activity. Be sure to carefully monitor for adults and check WeevilTrak.com for proper timing in your area.

The adulticide application accomplishes three important tasks:

1. Reduces overall ABW pressure by killing adults on contact as they move from overwintering sites into areas of highly managed annual bluegrass. Roughs that are adjacent to ABW overwintering sites can also be treated, so they act as buffer zones.
2. Prevents early egg-laying by overwintered ABW females.
3. Allows Acelepryn to be applied slightly later in the season so you have insecticide protection for roughly two months.

SECOND APPLICATION (Stage 2): Although Acelepryn is highly active against ABW larvae, timing is critical because effective control depends on the systemic uptake of Acelepryn by the plant. It is important to have Acelepryn moving in the transpiration stream of the plant when the ABW larvae hatch and begin to chew their way into the stem in late April to mid-May.

Evidence shows Acelepryn will provide high levels of ABW control when applied three weeks before hatch. The timing of this application will be made roughly two to three weeks after the first application of Scimitar GC and will be based on GDD monitoring (check WeevilTrak.com for proper timing in your area).

Applying Acelepryn at 12 fl. oz./A is critical and provides:

1. About three weeks of ABW larval control.
2. Season-long control of white grubs.
3. Season-long control of caterpillars.

THIRD APPLICATION (Stage 3): The third treatment needed to target first generation ABW larvae is an application of Ference during mid-May to early June to control all first through fifth instar larvae. This application is critical because June is often when the first period of notably hot weather occurs in the Northeast, which makes annual bluegrass exceptionally vulnerable to damage. Ference is highly effective against asynchronous ABW populations, making it the best choice to round off first generation applications.

Applying Ference at 12 fl. oz./A is important to:

1. Provide systemic control of ABW at all larval stages (first through fifth instar).
2. Control asynchronous larval populations that may be present.

Summer Generation Control

First generation ABW populations may reach more than 300 larvae per square foot of turfgrass if left uncontrolled. Under such extreme population pressure, even programs that provide exceptionally high levels of control will allow a certain number of ABW to survive and produce second and third generations throughout the summer.

FOURTH APPLICATION (Stage 4): The first generation adults that generally appear in mid- to late June are prime targets for another adulticide application using Scimitar GC. As the adults reproduce, ABW populations usually become asynchronous, meaning that all life stages are present at the same time and there often is no single dominant stage.

FIFTH APPLICATION (Stage 5): For further control of second generation adults and late instar, the Optimum Control Strategy recommends the first application of Provaunt WDG.

Applying Provaunt WDG at 18 oz./A is important to:

1. Target early third instar larvae as they emerge from the stem and move to feed on the crown of the plant.
2. Provide two to three weeks of residual control, which will strengthen the management program for the second generation larvae.

It is recommended to water-in Provaunt WDG applications with .05 - .10 inches of water immediately after application.

SIXTH APPLICATION (Stage 6): Late July through early August is prime time for another insecticide application to reinforce control of instar larvae ABW. Ference is recommended for this application because it is highly effective against asynchronous larval populations that may be present in the first, second and/or third generation from July to September.

An application of Ference at the rate of 12 fl. oz./A in this time period should carry most courses through to the end of the year.

SEVENTH APPLICATION (Stage 7 if needed): If a third generation of ABW larvae becomes present and increases the asynchronous summer population in late August and early September, Provaunt WDG can be applied at a rate of 18 oz./A, 21 to 28 days after the Ference application to extend control of the asynchronous larvae population.