Chemical Weed Control in Wheat, Barley, Oats, Rye, and Triticale

Transcription

1 Chemical Weed Control in Wheat, Barley, Oats, Rye, and Triticale W. J. VRMA, Crop Science Department OT: A mode of action code has been added to the Herbicide and mulation column of this table. Use MOA codes f herbicide resistance management. See Table 710, Herbicide Resistance Management, f details. TABL 78A. CHMICAL WD COTROL I WHAT, BARLY, OATS, RY, AD TRITICAL Code 1, and mulation mulation per ounds Active recautions and Remarks WHAT replant otill, merged annual broadleaf and grass weeds, volunteer cn, topkill of perennials (ramoxone Inteon) 2 SL (ramoxone Max) 3 SL 2 to 4 pt 0.5 to 1 Rate depends upon weed size; see label. Apply befe crop emerges. Add nonionic surfactant at per 100 gal spray solution crop oil concentrate at 1 gal per 100 gal spray solution. See application directions on label. May be tank mixed with Hoelon. eneric fmulations of paraquat containing 3 lb active per gal are available. Apply these products at 1.3 to 2.7 pt. WHAT replant otill, merged annual broadleaf and grass weeds, control suppression of perennial weeds See label 0.38 to 1.13 WHAT replant otill reemergence, Broadleaf weeds saflufenacil, MOA 14 (Sharpen) 3.42 flumioxazin, MOA 14 (Val SX) 51 WD (ramoxone Inteon) 2.5 SL OR lyphosate is available as an isopropylamine salt and a potassium salt. lyphosate fmulations and and per acre, respectively. Rate in the preceding column is expressed as a.e. See TABL 710 f glyphosate Rate depends upon weed species and size; see label. Apply befe crop emergence. Adjuvant recommendations vary by glyphosate brand; see label of brand used f details. Select Select Max may be mixed with glyphosate to control volunteer Roundup Ready cn. cn up to 12 in. tall, apply 4 to 6 fl oz of Select 6 fl oz of Select Max. cn up to 24 in. increase Select rate to 6 to 8 fl oz Select Max rate to 9 fl oz. Select Select Max must be applied at least 30 days ahead of wheat planting. Val SX at 1 to 2 oz per acre will suppress ryegrass and bluegrass and controls several broadleaf weeds. Do not till after application and apply at least 30 days pri to planting. 1.0 to 2.0 fl oz to See label f broadleaf weeds controlled. Sharpen does not control grasses. Apply with amonium sulfate (1 to 2 gal/100 gal) and methylated seed oil (1 gal/100 gal). Do not apply if wheat has germinated. See label f tank mixtures. 2.0 oz 2 to 4 pt See label 0, to to 1.13 WHAT replant otill reemergence, merged annual broadleaf weeds pyraflufenethyl, MOA 14 (T) 1 SL 0.5 to 2.0 fl oz to (lb a.i.) WHAT reemergence, Italian ryegrass and annual broadleaf weeds chlsulfuron, MOA 2 metsulfuron methyl, MOA 2 (inesse) 75 WD WHAT Spike Stage, Italian ryegrass flufenacet, MOA 15 metribuzin, MOA 5 (Axiom) 68 WD WHAT ostemergence, Italian ryegrass diclofopmethyl, MOA 1 (Hoelon) 3 C mesosulfuron, MOA 2 (Osprey) 4.5 WD pinoxaden, MOA 1 (Axial XL) 0.42 C 0.5 oz to 10 oz to to Use only on notill minimum till fields where stubble from the previous crop has not been incpated. Val SX must be applied at least 30 days ahead of planting wheat. Residual control of broadleaf weeds and Italian ryegrass. Apply with nonionic surfactant at 1 qt/100 gal. Can be applied with nitrogen carriers. Do no perfm tillage after application. Carefully follow label directions f sprayer cleaning after each day s use. T can be used f limited suppression of small emerged summer annual and winter weeds. See label f adjuvant and spray volume recommendations. Research with T is limited in th Carolina. Ryegrass control is variable; expect only suppression. May stunt wheat on sandy soils. Suggested primarily f fields with Hoelonresistant ryegrass. Also controls most annual broadleaf weeds. Do not use where a later application of Osprey owerlex is anticipated. lant only STS soybeans following wheat harvest. May cause severe injury in nonsts soybeans. Apply to wheat in the spike stage. reemergence application can cause severe injury on coarsetextured soils. Application rate depends on soil type; see label. In general, th Carolina research has shown best results with 6 to 7 oz on coarse soils and 8 to 9 oz on medium and heavy soils. If rainfall is received timely, Axiom controls ryegrass well. It also controls chickweed, henbit, and wild radish to 2.67 pt 0.5 to 1 Apply when ryegrass is in the one to fiveleaf stage. See label f specific rates depending upon weed size. Application to smaller ryegrass is me effective. Make only one application per season. Do not tank mix with broadleaf herbicides use liquid nitrogen as the carrier. Apply befe the first wheat node (joint) develops. May add per acre of crop oil concentrate under dry conditions when ryegrass is large. In most cases, crop oil is not necessary. See precautions on label concerning temperatures. Biotypes of ryegrass resistant to Hoelon are common within the state. Hoelon should not be applied to fields where resistance is suspected oz Apply when ryegrass is in oneleaf to twotiller stage. Add adjuvant as directed on label. In th Carolina, nonionic surfactant at 1 to 2 qt per 100 gal spray solution plus 1 to 2 qt of 30% liquid nitrogen per acre is preferred. See label f broadleaf weeds controlled. additional control, Osprey may be mixed with Harmony xtra. Do not tank mix with 2,4D dicamba. Do not apply using liquid nitrogen as the carrier. Do not topdress wheat within 14 days of Osprey application. In fields with Hoelonsusceptible ryegrass, it is recommended that Osprey owerlex and Hoelon Axial be used on an alternating basis (i.e., rotated) as part of a resistance management strategy. See comments f Axial. Ryegrass with multiple resistance to Axial, owerlex, Hoelon, Osprey, and owerlex occurs in th Carolina fl oz Apply to wheat with two me leaves when ryegrass has one to five leaves on the main stem. Me effective when applied to smaller ryegrass. May be tank mixed with Harmony xtra. When mixing, add Harmony xtra first, then Axial. o adjuvants are necessary. May be applied in waternitrogen mixtures containing up to 50% liquid nitrogen by volume. Add water to tank, then add Axial. Mix thoughly, and then add the nitrogen. Axial and Hoelon have the same mode of action. Ryegrass resistant to Hoelon may be crossresistant to Axial, although in some cases Axial will control Hoelonresistant ryegrass. If Hoelon resistance is expected, trial use of Axial on limited acreage is suggested to determine if the biotype is susceptible to Axial. 273

2 TABL 78A. CHMICAL WD COTROL I WHAT, BARLY, OATS, RY, AD TRITICAL Code 1, and mulation mulation per WHAT ostemergence, Italian ryegrass (continued) ounds Active recautions and Remarks pyroxsulam, MOA 2 (owerlex) 7.5 WD 3.5 oz Can be applied to wheat from the 3leaf stage until jointing. Apply after the majity of the ryegrass has emerged but befe it exceeds the 2tiller stage. Add nonionic surfactant at 1 to 2 qt/100 gal spray solution. See label f broadleaf weeds controlled. addiitional control, owerlex may be mixed with Harmony xtra. Do not mix with dicamba with amine fmulations of 2,4D MCA. Can be applied in waternitrogen mixtures containing up to 50% liquid nitrogen by volume, a maximum of 30 lb/acre. If applying in liquid nitrogen, reduce surfactant rate to /100 gal. Rainfast in 4 hours. Do not apply to wet foliage. Current labeling specifies a 5month rotation f soybeans. Limited research in th Carolina has shown no problems with soybeans doublecropped behind owerlextreated wheat. Cn, cotton, peanuts can be planted 9 months after application. See comments under mesosulfuron (Osprey) and pinoxaden (Axial) concerning resistance management. WHAT ostemergence, Cheat pyroxsulam, MOA 2 (owerlex) 7.5 WD 3.5 oz See comments f owerlex under Italian Ryegrass. WHAT ostemergence, Annual bluegrass mesosulfuron, MOA 2 (Osprey) 4.5 WD 4.75 oz See comments f Osprey under Italian Ryegrass. Apply to bluegrass from the 1leaf to 2tiller stage. Application when plants are about the size of a quarter coin has wked well. WHAT ostemergence, Wild garlic, curly dock, and most winter annual broadleaf weeds except cnflower and vetch thifensulfuronmethyl, MOA 2 tribenuronmethyl, MOA 2 (Harmony xtra S with TotalSol) 50 WD 0.45 to 0.9 oz to Apply after the twoleaf stage of wheat but befe flag leaf is visible. Use 0.45 to 0.6 oz f most winter annual weeds. Use 0.75 to 0.9 oz f wild garlic and wild radish. Wild garlic should be less than 12 in. tall and should have 2 to 4 in. of new growth. Control is enhanced when application is made during warm temperatures (50 o me) to actively growing garlic plants. Add 1 qt of nonionic surfactant per 100 gal of spray solution. Liquid nitrogen may be used as the carrier. May tank mix Harmony xtra with to lb active ingredient of 2,4D f improved control of wild radish. ollow mixing instructions on the label when using nitrogen as the carrier when mixing with 2,4D. Reduce surfactant rate accding to label instructions when using nitrogen as the carrier when mixing with 2,4D. Do not tank mix with Hoelon. May be tank mixed with Axial Osprey. WHAT ostemergence, Most winter annual broadleaf weeds except chickweed, henbit, and knawel 2,4D amine, MOA 4 2,4D ester, MOA 4 2,4D ester, MOA 4 2,4D acid/ester, MOA WHAT ostemergence, Most winter annual broadleaf weeds Apply after wheat is fully tillered (usually 4 to 8 in. tall; stages 4 and 5 on eekes scale) but befe jointing. Spraying wheat too young after jointing can cause defmed heads, reduced yields, and uneven ripening. Better results are obtained when daytime temperatures are above 50 degrees. Increase the rate of 2,4D by 50% to control cn cockle. Liquid nitrogen may be used as the carrier f 2,4D. ster fmulations can be added directly to the nitrogen. If using amine fmulation, premix in water (1 part 2,4D to 4 parts water) and add mixture to nitrogen with strong agitation. Amine fmulations give less burn than ester fmulations in nitrogen Apply after wheat is fully tillered but befe jointing. Better results will be obtained if applied when daytime temperatures are above 50 o. Liquid nitrogen may be used as the carrier. 2,4D amine, MOA 4 2,4D ester, MOA to 0.75 pt 0.5 to 0.75 pt to to 0.36 Apply after wheat is fully tillered (usually 4 to 8 in. tall; stages 4 and 5 on eekes scale) but befe jointing. Compared to dicamba alone, tank mixture is me effective on buttercup, cnflower, field pennycress, Virginia pepperweed, shepherdspurse, wild mustard, and wild radish. Use this tank mix only if both herbicides are necessary f weed control. Tank mix may injure wheat. pyraflufenmethyl, MOA 14 (T) 1 SL 0.5 to 2.0 fl oz to (lb a.i.) WHAT reharvest, Annual broadleaf and grass weeds, suppression of perennial weeds T can be used to suppress small annual winter weeds. Although application is registered to flag leaf appearance, coverage of small weeds is necessary but difficult when wheat is tall. See label f adjuvant and spray volume and carrier recommendations. Research with T is limited in th Carolina. See label 0.75 Apply after hard dough stage of grain (30% less grain moisture) and at least 7 days befe harvest. Do not apply to wheat grown f seed. lyphosate is available as an isopropylamine salt and a potassium salt. lyphosate fmulations and and per acre, respectively. Rate in the preceding column is expressed as a.e. See TABL 710 f glyphosate WHAT reharvest, Annual broadleaf weeds 2,4D amine, MOA 4 2,4D ester, MOA 4 2,4D ester, MOA 4 2,4D acid/ester, MOA 4 to 0.95 to 0.95 to to 0.7 BARLY replant otill, merged annual broadleaf and grass weeds, volunteer cn, topkill of perennials Apply when grain is in hard dough stage later. Do not allow drift to sensitive crops (be especially careful with ester. Amine fmulations strongly encouraged if sensitive crops are nearby, especially cotton and tobacco. (ramoxone Inteon) 2 SL 2 to 4 pt 0.5 to 1 Rate depends upon weed size; see label. Apply befe crop emerges. Add nonionic surfactant at per 100 gal spray solution crop oil concentrate at 1 gal per 100 gal spray solution. See application directions on label. eneric fmulations of paraquat containing 3 lb active per gal are available. Apply these products at 1.3 to 2.7 pt. 274

3 TABL 78A. CHMICAL WD COTROL I WHAT, BARLY, OATS, RY, AD TRITICAL Code 1, and mulation mulation per ounds Active recautions and Remarks BARLY replant otill, merged annual broadleaf and grass weeds, control suppression of perennial weeds BARLY ostemergence, Italian ryegrass diclofopmethyl, MOA 1 (Hoelon) 3 C pinoxaden, MOA 1 (Axial XL) 0.42 C 275 Chapter VII Chemical Weed Control lyphosate is available as an isopropylamine salt and a potassium salt. lyphosate fmulations and and per acre, respectively. Rate in the preceding column is expressed as a.e. See TABL 710 f glyphosate Rate depends upon weed species and size; see labels. Apply befe crop emergence. Adjuvant recommendations vary by glyphosate brand; see label of brand used f details. Select Select Max may be mixed with glyphosate to control volunteer Roundup Ready cn. cn up to 12 in. tall, apply 4 to 6 fl oz of Select 6 fl oz of Select Max. cn up to 24 in. increase Select rate to 6 to 8 fl oz Select Max rate to 9 fl oz. Select Select Max must be applied at least 30 days ahead of barley planting to 2.67 pt 0.5 to 1 Apply when ryegrass is in the one to fourleaf stage and after tiller initiation but pri to jointing of barley. Make only one application per year. Do not tank mix with broadleaf herbicides use liquid nitrogen as the carrier. Do not add crop oil. Apply only to the following varieties of barley: Anson, Boone, Henry, Milton, Molly Bloom, Mulligan, omini, ennco, Starling, Sussex, and Wys. Cold (lower than 40 degrees ) and/ prolonged wet conditions increase barley sensitivity to Hoelon. Biotypes of ryegrass resistant to Hoelon are becoming me common within the state. Hoelon should not be applied to fields where resistance is suspected fl oz Apply to barley with two me leaves when ryegrass has one to five leaves on the main stem. Me effective when applied to smaller ryegrass. May be tank mixed with Harmony xtra. When mixing, add Harmony xtra first, then Axial. May be applied in water/nitrogen mixtures containing up to 50% liquid nitrogen by volume. Add water to tank, then add Axial. Mix thoughly, and add the nitrogen. Axial and Hoelon have the same mode of action. Ryegrass resistant to Hoelon may be crossresistant to Axial, although in some cases Axial will control Hoelonresistant ryegrass. If Hoelon resistance is expected, trial use of Axial on limited acreage is suggested to determine if the ryegrass biotype is susceptible to Axial. BARLY ostemergence, Wild garlic, curly dock, and most winter annual broadleaf weeds except cnflower and vetch thifensulfuronmethyl, MOA 2 tribenuronmethyl, MOA 2 (Harmony xtra S with TotalSol) 50 WD 0.45 to 0.9 oz to BARLY ostemergence, Most winter annual broadleaf weeds except chickweed, henbit, and knawel 2,4D amine, MOA 4 2,4D ester, MOA 4 2,4D ester, MOA 4 2,4D acid/ester, MOA BARLY ostemergence, Most winter annual broadleaf weeds 2,4D amine, MOA 4 2,4D ester, MOA 4 Apply after the twoleaf stage of barley but befe flag leaf is visible. Use 0.45 to 0.6 oz f most winter annual weeds. Use 0.75 to 0.9 oz f wild garlic and wild radish. Wild garlic should be less than 12 in. tall and should have 2 to 4 in. of new growth. Control is enhanced when application is made during warm temperatures (50 degrees me) to actively growing garlic plants. Add 1 qt of nonionic surfactant per 100 gal of spray solution. Liquid nitrogen may be used as the carrier. May tank mix Harmony xtra with to lb a.i. of 2,4D f improved control of wild radish. ollow mixing instructions on the label when using nitrogen as the carrier when mixing with 2,4D. Reduce surfactant rate accding to label instructions when using nitrogen as the carrier when mixing with 2,4D. Do not tank mix with Hoelon. Apply after barley is fully tillered but befe jointing. Spraying barley too young after jointing can cause defmed heads, reduced yields, and uneven ripening. Better results are obtained when daytime temperatures are above 50 degrees. Increase the rate of 2,4D by 50% to control cn cockle. Liquid nitrogen may be used as the carrier f 2,4D. ster fmulations can be added directly to the nitrogen. If using amine fmulation, premix in water (1 part 2,4D to 4 parts water) and add mixture to nitrogen with strong agitation. Amine fmulations give less burn than ester fmulations in nitrogen Apply befe jointing stage of growth. Risk of crop injury is least if applied after winter dmancy and befe grain begins to joint. Better results will be obtained if applied when daytime temperatures are above 50 o. Liquid nitrogen may be used as the carrier. 0.5 pt 0.5 pt BARLY reharvest, Annual broadleaf weeds 2,4D amine, MOA 4 2,4D ester, MOA 4 2,4D ester, MOA 4 2,4D acid/ester, MOA to 0.95 to 0.95 to to 0.7 BARLY reharvest, Annual broadleaf and grass weeds, suppression of perennial weeds Apply after barley is fully tillered but befe jointing. Compared to dicamba alone, tank mixture is me effective on buttercup, cnflower, field pennycress, Virginia pepperweed, shepherdspurse, and wild mustard. Use this tank mix only if both herbicides are necessary f weed control. Tank mix may injure barley. Apply when grain is in hard dough stage later. Do not allow drift to sensitive crops (be especially careful with ester. Amine fmulations strongly encouraged if sensitive crops are nearby, especially cotton tobacco. See label 0.75 Apply after hard dough stage of grain (and 20% less moisture) and at least 7 days befe harvest. Do not apply to barley grown f seed. lyphosate is available as an isopropylamine salt and a potassium salt. Compare glyphosate fmulations and application rates on the basis of glyphosate acid equivalent (a.e.) per gallon and per acre, respectively. Rate in the preceeding column is expressed as a.e. See TABL 710 f glyphosate OATS replant otill, merged annual broadleaf and grass weeds, volunteer cn, control suppression of perennial weeds See label 0.56 to 1.13 (lb a.e.) lyphosate is available as an isopropylamine salt and a potassium salt. lyphosate fmulations and and per acre, respectively. Rate in the preceding column is expressed as a.e. See TABL 710 f glyphosate Rate depends upon weed species and size; see labels. Apply befe crop emergence. Adjuvant recommendations vary by glyphosate brand; see label of brand used f details. Select Select Max may be mixed with glyphosate to control volunteer Roundup Ready cn. cn up to 12 in. tall, apply 4 to 6 fl oz of Select 6 fl oz of Select Max. cn up to 24 in., increase Select rate to 6 to 8 fl oz Select Max rate to 9 fl oz. Select Select Max must be applied at least 30 days ahead of planting oats.

4 TABL 78A. CHMICAL WD COTROL I WHAT, BARLY, OATS, RY, AD TRITICAL Code 1, and mulation mulation per ounds Active recautions and Remarks OATS ostemergence, Wild garlic, curly dock, and most winter annual broadleaf weeds except cnflower and vetch thifensulfuronmethyl, MOA 2 tribenuronmethyl, MOA 2 (Harmony xtra S with TotalSol) 50 WD 0.45 to 0.6 oz to to OATS ostemergence, Most winter annual broadleaf weeds except chickweed, henbit, and knawel 2,4D amine, MOA 4 OATS ostemergence, Most winter annual broadleaf weeds Apply after the twoleaf stage of oats but befe flag leaf is visible. Wild garlic should be less than 12 in. tall and should have 2 to 4 in. of new growth. Control is enhanced when application is made during warm temperatures (50 degrees me) to actively growing garlic plants. Add 1 qt of nonionic surfactant per 100 gal of spray solution. Liquid nitrogen may be used as the carrier. May tank mix Harmony xtra with to lb a.i. of 2,4D f improved control of wild radish. ollow mixing instructions on the label when using nitrogen as the carrier when mixing with 2,4D. Reduce surfactant rate accding to label instructions when using nitrogen as the carrier when mixing with 2,4D. Oats are me sensitive to 2,4D than wheat. Apply after oats are fully tillered but befe jointing. Spraying oats too young after jointing can cause defmed heads, reduced yields, and uneven ripening. Also, oats are less tolerant of 2,4D than wheat. Better results are obtained when daytime temperatures are above 50 degrees. Liquid nitrogen may be used as the carrier f 2,4D. remix in water (1 part 2,4D to 4 parts water) and add mixture to nitrogen with strong agitation. OATS reharvest, Annual broadleaf weeds 2,4D amine, MOA 4 2,4D ester, MOA Apply befe jointing stage of growth. Risk of crop injury is least if applied after winter dmancy and befe grain begins to joint. Better results will be obtained if applied when daytime temperatures are above 50 o. Liquid nitrogen may be used as the carrier. to 0.95 Apply when grain is in hard dough stage later. Do not allow drift to sensitive crops, especially cotton and tobacco. Amine fmulations strongly encouraged if sensitive crops are nearby, especially cotton tobacco. RY replant otill, merged annual broadleaf and grass weeds, control suppression of perennial weeds RY ostemergence, Most winter annual broadleaf weeds except chickweed, henbit, and knawel 2,4D amine, MOA 4 2,4D ester, MOA 4 2,4D ester, MOA 4 RY reharvest, Annual broadleaf weeds 2,4D ester, MOA 4 2,4D ester, MOA 4 lyphosate is available as an isopropylamine salt and a potassium salt. lyphosate fmulations and and per acre, respectively. Rate in the preceding column is expressed as a.e. See TABL 710 f glyphosate Rate depends upon weed species and size; see labels. Apply befe crop emergence. Adjuvant recommendations vary by glyphosate brand; see label of brand used f details. Select Select Max may be mixed with glyphosate to control volunteer Roundup Ready cn. cn up to 12 in. tall, apply 4 to 6 fl oz of Select 6 fl oz of Select Max. cn up to 24 in., increase Select rate to 6 to 8 fl oz Select Max rate to 9 fl oz. Select Select Max must be applied at least 30 days ahead of planting rye. Apply after rye is fully tillered but befe jointing. Spraying rye too young after jointing can cause defmed heads, reduced yields, and uneven ripening. Better results are obtained when daytime temperatures are above 50 o. Increase the rate of 2,4D by 50% to control cn cockle. Liquid nitrogen may be used as the carrier f 2,4D. ster fmulations can be added directly to the nitrogen. If using amine fmulation, premix in water (1 part 2,4D to 4 parts water) and add mixture to nitrogen with strong agitation. Amine fmulations give less burn than ester fmulations in nitrogen. to 0.95 Apply when grain is in hard dough stage later. Do not allow drift to sensitive crops, especially cotton and tobacco. Amine fmulations are strongly encouraged if sensitive crops are nearby, especially cotton tobacco. TRITICAL replant otill, merged annual broadleaf and grass weeds, control suppression of perennial weeds TRITICAL reemergence, Italian ryegrass and annual broadleaf weeds chlsulfuron, MOA 2 metsulfuron methyl, MOA 2 (inesse) 75 WD 0.5 oz TRITICAL ostemergence, Wild garlic and annual broadleaf weeds thifensulfuronmethyl, MOA 2 tribenuronmethyl, MOA 2 (Harmony xtra S with TotalSol) 50 WD 0.45 to 0.9 oz to TRITICAL ostemergence, Annual broadleaf weeds 2,4D, MOA 4 (Amine 4 2,4D) 3.8 SL (Weedar 64) 3.8 L lyphosate is available as an isopropylamine salt and a potassium salt. lyphosate fmulations and and per acre, respectively. Rate in the preceding column is expressed as a.e. See TABL 710 f glyphosate Rate depends upon weed species and size; see labels. Apply befe crop emergence. Adjuvant recommendations vary by glyphosate brand; see label of brand used f details. Select Select Max may be mixed with glyphosate to control volunteer Roundup Ready cn. cn up to 12 in. tall, apply 4 to 6 fl oz of Select 6 fl oz of Select Max. cn up to 24 in., increase Select rate to 6 to 8 fl oz Select Max rate to 9 fl oz. Select Select Max must be applied at least 30 days ahead of planting triticale. See comments under WHAT, reemergence. Apply after twoleaf stage of triticale but befe flag leaf is visible. See comments f Harmony xtra under WHATostemergence. See comments f 2,4D under WHAT ostemergence oz See comments f dicamba under WHAT ostemergence. 1 Mode of Action (MOA) code developed by the Weed Science Society of America. See Table 710, Herbicide Resistance Management, f details. 276

5 Weed Response to Herbicides in Small rains W. J. VRMA, Crop Science Department Chapter VII Chemical Weed Control Ratings based upon average to good soil and weather conditions f herbicide perfmance and upon proper application rate, technique, and timing. TABL 78B. WD RSOS TO HRBICIDS I SMALL RAIS Species Annual bluegrass Annual ryegrass Buttercup Chickweed, common Cnflower Curly dock Cutleaf eveningprimrose ield pennycress Henbit Knawel Shepherd spurse Swinecress Vetch Virginia pepperweed Wild garlic Wild mustard Wild radish Herbicides Axial Axiom Banvel/Clarity inesse 2 2,4D Harmony xtra Hoelon Osprey owerlex 7 1 A biotype of ryegrass resistant to Hoelon is common in th Carolina, especially in the piedmont. If resistance is suspected, do not apply Hoelon. 2 Applied preemergence. 3 Rating assumes mustard radish is 1 to 2 in. Osprey is less effective on larger plants. 4 Assumes adequate rainfall f activation pri to weed emergence. 5 A biotype of ryegrass resistant to Osprey and owerlex has been found in the southern piedmont. 6 May not control Hoelonresistant ryegrass. See comments under Wheatostemergence. 7 Inadequate research has been conducted in th Carolina to determine response of most broadleaf weeds to owerlex. The label claims control of a number of broadleaf species, including Carolina geranium, chickweed, hairy bittercress, field pennycress, sheperdspurse, buttercup, Virginia pepperweed, and vetch. Key: = excellent control, 90% better = good control, 80% to 90% = fair control, 50% to 80% = po control, 25% to 50% = no control, less than 25%