Growers who utilize strip tillage and a winter cover crop can utilize seed treatments for mitigation of early-season thrips infestation.

Identifying effective weed control regimes for organic peanut is paramount for improving the feasibility of organic production. Tine cultivation is a proven effective method for reducing in-row weed populations in several crops. Field trials were therefore conducted in 2008 and 2009 to assess the effects of tine cultivation combined with sweep cultivation and supplemental hand-weeding on weed control and overall productivity of two peanut cultivars under organic management. Tine cultivation regimes consisted of two frequencies (once per week or twice per week) for three durations (3 wk, 4 wk, or 5 wk). All cultivation treatments were also cultivated with flat sweeps at least once and hand-weeded periodically during the growing season. A non-cultivated, nonweeded control was included for comparison. All cultivation treatments significantly reduced annual grass populations in 2008 and Florida pusley populations both years. Cultivated treatments also resulted in denser plant stands for peanut (9.2 plants/m to 13.2 plants/m) than the noncultivated control (5.9 plants/m to 7.9 plants/m). Pod yields in cultivated treatments ranged from 3502 kg/ha to 3823 kg/ha and were all significantly greater than yields in the non-cultivated control (1630 kg/ha). Also, net revenues generated by cultivated treatments ranged from ($3333/ha to $3637/ha) and were greater than that of the control ($1795/ha). Cultivation frequency had little effect on weed control and peanut productivity. However, the 4-and 5-wk durations displayed potential for improving peanut yield, grade, and net revenue over the 3-wk duration, especially when annual grass weeds were predominant. Cultivating once weekly for 4 or 5 wk with a tine cultivator, along with at least one sweep cultivation and supplemental hand-weeding, is a viable, economical option for providing adequate weed control and maximizing productivity of organically-managed peanut at current market premiums.

Peanut smut is an emergent soilborne disease of peanut in South America that has significantly impacted the commercial peanut industry in Argentina. In response, plant breeders are in need of information about potential sources of smut resistance in cultivated germplasm for the rapid development of resistant cultivars. Available U.S. peanut mini-core accessions were evaluated under naturally-infested soil conditions in 2016-2019 near General Cabrera, Córdoba, Argentina, in addition to three susceptible breeding lines and four local commercial controls. Over three years, 18 mini-core accessions and two germplasm collection accessions exhibited no smut incidence in a 100-pod sample. Of those, 12 mini-core accessions and one germplasm collection accession (PI 153323) exhibited no smut incidence when all available pods were opened and examined in the 2016-2017 and 2017-2018 crop years. These 13 accessions were collected from a variety of origins across the Americas, Africa, and Asia; only three were collected from origins in South America. These results suggest that resistance mechanisms may be well-conserved across various groups within Arachis hypogaea L. The 13 identified accessions appear to be sources of resistance to peanut smut in A. hypogaea and would likely be good parent material for the development of new, resistant commercial peanut cultivars.

Previous research has shown that mechanical cultivation is the most effective and affordable method of weed control in organic peanut production. However, growers are in need of more information on specific integrated cultivation regimes for effective season-long weed control with minimal hand-weeding requirements. Therefore, field trials were conducted in 2010–2012 to evaluate the effects of various tine and sweep cultivation treatments combined with or without hand-weeding on season-long weed control, stand establishment, and yield and grade of an organically-managed peanut crop. Tine cultivation treatments consisted of no cultivation or weekly cultivations for 5 wks after planting (WAP). Sweep treatments consisted of no cultivation, weekly cultivations (for 5 WAP), cultivations at 2 and 5 WAP only, or cultivation at 5 WAP only. Hand-weeding treatments were no hand-weeding or hand-weeding of the entire plot. There were numerous significant interactions among tine and sweep treatments on weed control. Initial weed species composition greatly affected cultivation effects on overall weed control. Tine cultivation was most effective at controlling annual grass weeds. Sweep cultivation was effective at reducing weeds (Amaranthus spp., southern crabgrass, and Florida pusley), but primarily when tine cultivation was absent. Hand-weeding significantly improved weed control for every weed species every year. Additionally, inclusion of certain cultivation regimes significantly reduced the hand-weeding time requirement over the control. However, cultivation treatments did not improve pod yield or grade in any year. The most significant benefit in cultivation from these data is in the reduction in hand-weeding requirements. Based on this research, a regime consisting of weekly tine cultivations for 5 WAP, combined with two timely sweep cultivations provided the best overall balance of weed control and minimization of hand-weeding. Hand-weeding is the most critical weed control method, followed by tine cultivation, and finally sweep cultivation, which primarily served as an aid in the event of missed tine cultivations or failure.

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