Like Blackheaded Fireworm and Tipworm, the Cranberry Girdler can cause significant damage in cranberry bogs. Adult moths appear in June, flying at night near the surface of the bog. They have long mouthparts which give them the appearance of having an extended “snout”. Girdler also causes damage in turf, forage grass stands and fir tree species. In cranberries, the damage from chewing on the vines can result in large, irregular patches of dead plants. Adults are active for almost two months, laying up to several hundred eggs into the leaf litter. The larvae cause damage, then pupate and overwinter in a cocoon that develops in September or October.
Cranberry Girdler can be managed in an integrated program. It is best to hire the services of a consultant to monitor Girdler population dynamics. Sand can be top-dressed before eggs are laid by the adults in June, which is believed to cover fungi and moss that the young larvae feed on. Larvae can also be drowned by flooding for up to two days in late August, however keep in mind that if water is left on the bog too long it can cause an increase in fruit rot.
The most common entomopathogenic nematode for use against Girdler is Steinernema carpocapsae, but Heterorhabditis bacteriophora can also be used. A rate of 3 billion nematodes per acre is recommended to achieve firm control. Nematodes can be applied by spraying or chemigation. It is best to apply during cool conditions and to follow application with irrigation, to avoid the nematodes drying out and to rinse the nematodes off the foliage and into the leaf litter.
If you plan on using entomopathogenic nematodes this season, please help us secure your supply by planning ahead. If you do not have the contact information of one of our Sales Representatives, ask for it from either the Abbotsford or Delta offices. To have your nematodes in hand by application time in the summer, Spring is the best time to get on this.