Thursday, June 18, 2009
Wireworms in Small Grains
I've received reports of wireworms in small grains this season - not surprising this year given that wireworm tend to be more active in cooler conditions. There are several species of wireworms in the Red River Valley and although they're usually neither a frequent nor wide-spread problem in the RRV, when they do occur, damage can be quite significant even leading to a total field loss.
Wireworms are difficult to control and rescue treatments are ineffective, if not impossible. Seed treatments and at-plant insecticides can be used as a preventative, but there's little that can be done after symptoms become apparent. Because wireworms live as larvae in the soil for 3-4 years, wireworm populations tend to build over time if not treated. Consequently, areas that were in non-rotated or non-tilled cropping systems tend to have higher wireworm populations (e.g. CRP or any field in which grasses were growing). Preventive measures should be taken if there was evidence of wireworm populations in a field the previous year or if the field is coming out of an at-risk system (e.g. CRP). If re-planting a damaged field, seed treatments or at-plant insecticides should definitely be considered.