Italian Ryegrass Control Research Articles

Wheat (Triticum aestivum) Cultivar Tolerance and Italian Ryegrass (Lolium multiflorum) Control with Diclofop, BAY SMY 1500, and Metribuzin

In the field, 14 soft red winter wheat cultivars responded differently to 1.1 kg ai ha–1diclofop, 1.7 kg ai ha–1BAY SMY 1500, and 0.42 kg ai ha–1metribuzin applied POST. Diclofop and metribuzin did not injure any cultivar more than 10% on a silty clay soil. However, BAY SMY 1500 injured ‘Pioneer 2551’ and ‘Coker 983’ 39 and 21%, respectively, in March. All other cultivars were injured less than 10% by BAY SMY 1500. Early injury did not translate into yield loss in the cultivar tolerance study. In an application timing study for Italian ryegrass control, late-season ratings indicated better control with two-leaf applications than with PRE applications for all treatments. Delaying application to the three-tiller stage reduced control with BAY SMY 1500 or metribuzin, but not with diclofop. On the sandier soil at this location, wheat injury with 0.28 or 0.43 kg ha–1metribuzin or 2.2 kg ha–1BAY SMY 1500 was sufficient to reduce wheat yield compared with other treatments, despite good Italian ryegrass control.

Soil as Herbicide Carrier for Italian Ryegrass (Lolium multiflorum) Control in Wheat (Triticum aestivum)

The efficacy of herbicides applied broadcast by hand with a soil carrier or sprayed with water carrier were compared for Italian ryegrass control in winter wheat in central Oklahoma. Italian ryegrass was controlled 77 to 100% with BAY SMY 1500, chlorsulfuron, and CGA-131036 applied with both carriers. Metribuzin applied POST with 187 L ha–1water was less phytotoxic to Italian ryegrass and wheat than with 200 kg ha–1soil. All herbicides applied with 200 kg ha–1silt loam soil as carrier at two locations controlled Italian ryegrass 96 to 100%. Increasing herbicide rate, soil carrier quantity, or broadcasting soil-carried herbicide in two directions rather than one did not significantly improve herbicide efficacy over that of conventional spraying.

Control of Italian Ryegrass and Wild Oats in Winter Wheat with HOE 234081

AbstractItalian ryegrass (Lolium multiflorum Lam.) and wild oats (Avena fatua L.) are widespread and competitive weeds in winter grain fields of western Oregon and Washington. A new herbicide, HOE 23408 {methyl 2‐[4‐(2,4‐dichlorophenoxy) phenoxy] propanoate}, has shown promise for selective control of both species. Field studies were conducted at 12 locations in 1974–75 and 1975–76 to evaluate the effectiveness and consistency of weed control with HOE 23408 in winter wheat (Triticum aestivum L.) and to measure the influence of removing ryegrass and wild oats on wheat grain yields. HOE 23408 was applied preemergence, early postemergence (two to three‐leaf stage), and late postemergence (tillering stage) at rates from 0.84 to 2.24 kg/ha. When applied preemergence, HOE 23408 gave adequate control of ryegrass when the seedbed was relatively free of clods and plant residues but wild oat control was erratic. Nearly complete control of both species was obtained from all postemergence treatments at rates as low as 0.84 kg/ha. Increases in wheat grain yield were often dramatic; in one case, the increase over the untreated control was 6,000 kg/ha from treatment at 1.12 kg/ha applied early postemergence. Average yields from this treatment exceeded yields from plots treated with diuron [3‐(3,4‐dichlorophenyl)‐1,1‐dimethylurea], barban (4‐chloro‐2‐butynyl m‐chlorocarbanilate), and triallate [S‐(2,3,3‐trichloroallyl) diisopropylthiocarbamate] by 2,170, 1,280, and 1,580 kg/ha, respectively. Results indicate that HOE 23408 has considerable potential for control of ryegrass and wild oats and that large increases in yield of wheat grain can be expected when severe infestations of these weeds are controlled.