PestHigh Severity

Black Vine Weevil Larvae

Otiorhynchus sulcatus

Off-white grubs with brown heads in characteristic C-shape, black vine weevil larvae are the most damaging stage of this widespread weevil. They tunnel through soil to feed on roots and can cause significant damage including plant death, especially in spring before pupation.

Peak Season: Egg hatch: Mid to late summerActive feeding: Summer through fall, then springOverwintering: As pre-pupae in soilSpring feeding: Late May to early JunePupation: Spring, lasting about one month
Black vine weevil adult and larvae

Identification & Symptoms

What to Look For

Yellowing leaves indicating root damage
Stunted plant growth
Wilting despite adequate moisture
Plant decline or death in severe cases
Stem girdling when larvae forced to surface in wet conditions

Potential Damage

Root feeding by larvae causing primary damage
Bark feeding on larger roots by mature larvae
Stem girdling leading to plant death
Most extensive damage occurs in spring before pupation
High populations can kill entire plants

Lifecycle

Larvae emerge from eggs in 10-14 days as small grubs. They tunnel through soil feeding on roots, growing to 5/8 inch by summer's end. Larvae overwinter in soil as pre-pupae, resume feeding in late May/early June before pupating in spring. One generation per year.

Professional Treatment Approach

1

Systemic soil treatment with Imisol for root zone protection

2

Spring applications before peak larval feeding resumes

3

Arborfos treatments for comprehensive root protection

4

Apply treatments in early spring when larvae become active

5

Focus on preferred hosts showing decline symptoms

Recommended Mauget Products

Imisol

Professional-grade treatment specifically effective against black vine weevil larvae.

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Arborfos

Professional-grade treatment specifically effective against black vine weevil larvae.

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