Pine Weevil

What it looks like

In the US, the pine weevil is the pales weevil. Adults are reddish-brown to black weevils about 1/3 inch long with a snout and small yellowish hair patches. Grubs are legless, white, curled, with a brown head.

Damage

Adults feed at night on the tender bark of seedlings, often girdling and killing them. Damage is worst on land where pines were recently cut or burned. Large outbreaks can kill over half the seedlings.

How nematodes help

The eggs, grubs, and pupae live in the roots of freshly cut stumps, below ground where nematodes can reach them. Adults hide during the day in the soil and leaf litter at the base of seedlings.

In Irish field trials on pine stumps against the European pine weevil (Hylobius abietis), a close relative, Heterorhabditis downesi (a species BioLogic doesn't sell) worked best, about twice as well as S. carpocapsae (the nematode in Ecomask). S. carpocapsae still infected the grubs and lasted in the stumps for up to 2 years. Trials in Poland found that every commercial nematode tested worked to some degree.

In university research, the timing that worked best was late spring to summer (May to August), when the grubs are feeding in the stump roots.

How to apply

Treat with Scanmask. Ecomask also works.

When: April to August.

Where: Drench the soil around and over freshly cut pine stumps, and the soil at the base of young seedlings nearby.

See How to apply for step-by-step directions, or use the calculator on the Scanmask Spray page to see how much you need.