Field Corn, Corn Rootworm Rescue with Center Pivot Applications of Insecticides in South Dakota, 1986-1978

In 1986, a corn rootworm rescue trial was established at Armour. Dekalb 1100’ was planted on 4 May 86. Lorsban 4E (1.0 lb [AI]/acre) was injected with a Northern chemigation unit into a Zimmatic low-pressure system on 26 Jun 87. In 1987, tests were conducted at Armour and Onida. At Armour, Lorsban 4E (1.0 lb [AI]/acre) was injected 17 Jun 87 and compared to a planting time (28 Apr 87, ‘Dekalb 1100’) application of Counter 15G (1.0 lb [AI]/ acre). At Onida, corn (‘Pay Master 2990’) was planted on 12 May 87. Lorsban 4E (1.0 lb [AI]/acre) was injected into a center pivot unit on 19 Jun 87 and contrasted with Furadan 15G (1.0 lb [AI]/acre) delivered aerially with a fixed wing aircraft on 28 Jun 87. In late July of each year, rootworm injury was evaluated by randomly digging 10 root systems/treatment from each of 4 separate areas within a treated section of the pivot. Roots were rated on the Iowa 1-6 scale (1, no noticeable feeding damage; to 6, 3 nodes of roots pruned).