Interactions among weed, insect, and common rust treatments in sweet corn

Abstract

Treatment interactions affecting endemic populations of annual grass and broadleaf weeds, corn rootworm larvae (CRW), corn earworm (CEW), European corn borer (ECB), and common rust in sweet corn were investigated in three field studies near Arlington, WI, in 1996 and 1997. In all environments, weed biomass was affected only by the weed control treatments with cultivation resulting in the highest weed biomass. Corn root damage was affected only by the CRW insecticide treatments in the early- and late-planted environments in 1997 (E97 and L97). Both weed control and ear insect (CEW and ECB) control treatments affected corn ear damage by CEW and ECB. In E97 and L97, more insect ear damage occurred in plots with 1× herbicide treatments than in cultivation treatments. In L97, the ear insect treatment decreased ear damage 55% compared to untreated plots. The interaction between ear insect and weed control treatments affected the number of CEW found per 10 ears in L97. The interaction between hybrid rust and weed control treatments influenced common rust severity in all environments. A hybrid rust by CRW by ear insect treatment interaction also affected common rust severity in E97 and L97. ‘Jubilee’ hybrid (rust-susceptible) corn treated with both insecticides had greater common rust severity than nontreated Jubilee corn. Sweet corn yield was affected most by weed control in all environments, with the lowest yields occurring in cultivated plots. Sweet corn yield did not differ between the 1× and ⅓× herbicide treatments in all environments. The interaction among hybrid rust by CRW by ear insect treatments also affected yield in E97 and L97. An important component of this interaction was the CRW treatment, as sweet corn yield was higher in treated than nontreated plots. The interactions in this study indicate that the best chances for developing comprehensive thresholds for sweet corn pests in the Midwest are for CEW, ECB, and common rust.

Predominance of Metabolic Resistance in a Six-Way-Resistant Palmer Amaranth (Amaranthus palmeri) Population

“…Palmer amaranth ( Amaranthus palmeri S. Watson) is a top-ranked troublesome weed in the United States ( Van Wychen, 2019 ). It is a summer annual C 4 eudicot species, with a fast growth rate and ability to accumulate biomass ( Horak and Loughin, 2000 ; Sellers et al, 2003 ).…”

Weed control by 2,4-D dimethylamine depends on mixture water hardness and adjuvant inclusion but not spray solution storage time

“…Experiment 1 was conducted in the Purdue University Horticulture greenhouses in West Lafayette, IN (40.421°N, 86.914°W) to determine the influence of water hardness level on the efficacy of 2,4-D dimethylamine. Dandelion, a common weed in turf and right-of-ways (Beck and Patton 2015; Van Wychen 2016), and horseweed, a troublesome weed among terrestrial crop and noncrop areas (Van Wychen 2016), were used to bioassay the effects of water hardness and adjuvant treatments on 2,4-D dimethylamine efficacy.…”

Effect of Bicyclopyrone on Triploid Watermelon in Plasticulture

“…A 2016 survey determined that the most common weeds in North Carolina watermelon fields were Palmer amaranth, carpetweed ( Mollugo verticillata L.), goosegrass [ Eleusine indica (L.) Gaertn. ], large crabgrass, and yellow nutsedge (Van Wychen 2016). The same survey reports Palmer amaranth, yellow nutsedge, and wild radish ( Raphanus raphanistrum L.) as the most troublesome weeds in North Carolina watermelon fields (Van Wychen 2016).…”

“…], large crabgrass, and yellow nutsedge (Van Wychen 2016). The same survey reports Palmer amaranth, yellow nutsedge, and wild radish ( Raphanus raphanistrum L.) as the most troublesome weeds in North Carolina watermelon fields (Van Wychen 2016). Registration of bicyclopyrone for use in watermelon would provide extended residual control of many of these common and troublesome weeds and would provide an additional herbicide MOA, allowing growers to rotate MOAs and reduce selection pressure for herbicide resistance (Norsworthy et al 2012).…”