In 2019, we reported that an alfalfa field was affected by crane flies in Muhlenberg County. Similar issues have been observed this year in the same field. Alfalfa plants showed signs of severe injuries to stems, foliage, and roots. A sample conducted at the Research and Education Center at Princeton showed the presence of this insect in an alfalfa field; however there was little damage to the plants. In Muhlenberg County, high numbers of crane fly larvae were found in the field, with plants completely defoliated, and stems, young foliage, and shoots completely damaged by crane fly larvae (Figures 1, and 2).
Warrior II with Zeon Technology® a group 3 pyrethroid insecticide with the active ingredient lambda-cyhalothrin (22.8%) was approved under FIFRA section 2(ee) (Warrior for crane flies) to be used for the control of crane fly larvae in alfalfa. The recommended rate is 1.92 fl. oz/A. As thresholds have not been established for this insect, scouting and crane fly larvae feeding should be observed before an application.
In order to use Warrior II with Zeon Technology® on alfalfa, the applicator will need to have a copy of this insecticide 2(ee) label, be a certified applicator, and check with the alfalfa clients to make sure this is acceptable. The label for Warrior II with Zeon Technology® can be reached through this link.
By Raul T. Villanueva and Ric Bessin, Extension Entomologists.