Integrating cultivation using a tine weeder with herbicides in conventional peanut production

Authors: Johnson, Wiley - Carroll; LUO, XUELIN - University Of Georgia

Submitted to: Weed Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/17/2018
Publication Date: 3/14/2019
Citation: Johnson, W.C., Luo, X. 2019. Integrating cultivation using a tine weeder with herbicides in conventional peanut production. Weed Technology. 33(2):374-379. https://doi.org/10.1017/wet.2018.114.
DOI: https://doi.org/10.1017/wet.2018.114

Interpretive Summary: Previously, sweep cultivation was commonly used in conventional peanut production to supplement herbicides. However, sweep cultivation is now rarely used due to improved herbicides. Repeated cultivation with a tine weeder is commonly used in organic peanut production and this form of mechanical weed control may be useful in conventional peanut production. Studies were conducted in Tifton, GA from 2014 through 2017 to determine if tine weeding can be integrated with herbicides in conventional peanut production to supplement herbicides. Experiments evaluated eight herbicide combinations and two levels of cultivation with a tine weeder. Herbicides were labelled rates of ethalfluralin PRE, S-metolachlor PRE, imazapic POST, ethalfluralin PRE/S-metolachlor PRE, ethalfluralin PRE/imazapic POST, S-metolachlor PRE/imazapic POST, ethalfluralin PRE/S-metolachlor PRE/imazapic POST, and a nontreated control. The herbicides chosen were based on knowledge of the weed species composition at the research sites. Cultivation regimes were cultivation with a tine weeder (six times at weekly intervals) and a non-cultivated control. Annual grasses were effectively controlled by treatments that included ethalfluralin and/or S-metolachlor and did not need cultivation to supplement control provided by the herbicides. However, imazapic alone did not effectively control annual grasses and needed supplemental control from cultivation with the tine weeder. Treatments that included imazapic effectively controlled smallflower morningglory and did not require cultivation to supplement control from the herbicide. However, cultivation with the tine weeder improved smallflower morningglory control from ethalfluralin and/or S-metolachlor. Peanut yields did not respond to any of the herbicide combinations integrated with cultivation using the tine weeder. Peanut were cultivated with the tine weeder in May through July, with 2014 and 2017 having more total rainfall and days of rainfall events during that time period compared to the other years. Rainfall and wet soils lessened the performance and weed control benefits of the tine weeder. This highlights the risk of depending on cultivation for weed control.

Technical Abstract: Previously, sweep cultivation was commonly used in conventional peanut production to supplement herbicides. However, sweep cultivation is now rarely used due to improved herbicides. Repeated cultivation with a tine weeder is commonly used in organic peanut production and this form of mechanical weed control may be useful in conventional peanut production. Studies were conducted in Tifton, GA from 2014 through 2017 to determine if tine weeding can be integrated with herbicides in conventional peanut production to supplement herbicides. Experiments evaluated eight herbicide combinations and two levels of cultivation with a tine weeder. Herbicides were labelled rates of ethalfluralin PRE, S-metolachlor PRE, imazapic POST, ethalfluralin PRE/S-metolachlor PRE, ethalfluralin PRE/imazapic POST, S-metolachlor PRE/imazapic POST, ethalfluralin PRE/S-metolachlor PRE/imazapic POST, and a nontreated control. The herbicides chosen were based on knowledge of the weed species composition at the research sites. Cultivation regimes were cultivation with a tine weeder (six times at weekly intervals) and a non-cultivated control. Annual grasses were effectively controlled by treatments that included ethalfluralin and/or S-metolachlor and did not need cultivation to supplement control provided by the herbicides. However, imazapic alone did not effectively control annual grasses and needed supplemental control from cultivation with the tine weeder. Treatments that included imazapic effectively controlled smallflower morningglory and did not require cultivation to supplement control from the herbicide. However, cultivation with the tine weeder improved smallflower morningglory control from ethalfluralin and/or S-metolachlor. Peanut yields did not respond to any of the herbicide combinations integrated with cultivation using the tine weeder. Peanut were cultivated with the tine weeder in May through July, with 2014 and 2017 having more total rainfall and days of rainfall events during that time period compared to the other years. Rainfall and wet soils lessened the performance and weed control benefits of the tine weeder. This highlights the risk of depending on cultivation for weed control.