Weed Control Recomendations for Commercial Vegetable Crops
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-er Weed Control Recomendations For Commercial Vegetable Crops Extension Circular 746 Revised July 1977 Oregon State University Extension Service Oregon Weed Control Recommendations for Commercial Vegetable Crops ACTIVE INGREDI- CROP CHEMICAL ENTS TIME REMARKS ARTICHOKES Sinuuine 4 lbs. Fall (Princep) Diuron 32 lbs. Fall ASPARAGUS Chloramben 3 lbs. Pre-emergence Needs moisture Seedbed (Amiben) Mineral spirits SO gals. Postemergence Apply before broadleaf weeds have more than 4 true leaves Parquat 1 to li lbs. Pre-emergence Effective only on emerged weeds Established fields Diuron 1.6 to 3.2 lbs. Spring Before spears emerge, or after cutting (Karmex) Simazine 1.6 to 3.2 lbs. Fall or spring After ferns die down, before spears emerge (Princep) or after cutting 2,4-D (sodium) 1.6 to 2 lbs. Spring For field bindweed control Dalapon 7.4 lbs. Spring Spot spray for grass control BEANS, snap and Dinoseb 3 to 6 lbs. Pre-emergence lima (Dinitro 11 to 4i lbs. Postemergence When most beans are in crook stage; use low amine) rate for high temperature Trifluralin 1 to 1 lb. Preplant Work into soil thoroughly (Treflan) Chloramben 3 lbs. Pre-emergence (Amiben) Profluralin i to 1.0 lbs. Preplant Work into soil immediately (Tolban) Snap beans only EPTC 3 lbs. Preplant Work into soil immediately (Incl. Romano) (Eptam) DCPA 9 lbs. Pre-emergence (Dacthal) BEETS Pyrazon 4 lbs. Pre- or (Pyramin) postemergence EPTC 2 lbs. Preplant Work into soil immediately (Eptam) Cycloate 3 to 4 lbs. Preplant Work into soil immediately (Ro-Neet) Phenmedipham 1 lb. Postemergence Apply when weeds are small, avoid high (Betanal) temperatures BROCCOLI Bensulide 5 to 6 lbs. Preplant or Not recommended for cabbage. Also incor- BRUSSELS (Prefar) pre-emergence porate by cross discing of PTO rotary tiller SPROUTS CDEC 4 lbs. Immediately When crop is grown by direct seeding CABBAGE (Vegadex) after seeding CAULIFLOWER 6 lbs. After transplanting Direct the spray to base of plants Trifluralin i to i lb. Before seeding or Work into soil thoroughly (Treflan) before transplant DCPA 9 lbs. After seeding (Dacthal) or transplanting Nitrofen 3 to 6 lbs. Pre-emergence or Use wettable powder formulation only (TOK) postemergence CANTALOUPES NPA 4 lbs. Immediately Requires soil surface moisture CUCUMBERS (Alanap after seeding WATERMELONS liquid) DCPA 9 lbs. 4 to 6 weeks after (Dacthal) seeding Bensulide 6 lbs. Preplant Incorporate shallowly (Prefar) Cantaloupes and CDEC 4 lbs. Immediately Cucumbers only (Vegadex) after seeding Chloramben 2 to 3 lbs. Pre-emergence (Amiben) Trifluralin 1 to i lb. Postemergence Directed spray, when cucumbers have 3 to 4 (Treflan) leaves Cucumbers only Dinoseb 3 lbs. Immediately after Do not use if temperatures above 80* F are (Dinitro planting expected amine) ACTICE INGREDI- CROP CHEMICAL ENTS TIME REMARKS CARROTS Mineral spirits 60 to 80 gals. Postemergence Apply when crop plants have 3 leaves and CELERY weeds have emerged DILL Linuron 2 lbs. Postemergence For carrots only. Use when carrots are 2"-6" PARSLEY (Lorox) tall but when weeds ar still small PARSNIPS Nitrofen 2 to 6 lbs. Pre- or post- Carrots, celery and parsley only (TOK) emergence Trifluralin i to i lb. Preplant Work into soil thoroughly (Treflan) Carrots and celery only Chloroxuron 3 to 4 lbs. Pre-emergence For carrots only. Apply when weeds have (Tenoran or emerged but are less than 2" tall. Norex) CORN, sweet Atrazine 1.6 lbs. Pre-emergence to Use shallow soil incorporation or follow ap- (AAtrex) weeds and within plication with light irrigation (1 inch) for 3 weeks of best results planting 4 lbs. For control of quackgrass or other peren- nials Atrazine plus 2 to 3 lbs. Preplant or Paraquat active Atrazine pre-emergence Follow tank mixing directions carefully plus J to J lb. Alachlor (Lasso) may be added where a active Paraquat grass problem is anticipated Atrazine 1 to 1.6 lbs. Postemergence When weeds are small plus oil or active Atrazine 0.5 to 1.0% plus 1 gal. oil surfactant Dinoseb 6 lbs. Pre-emergence May be delayed until just before corn (Dinitro emerges amine) U to 3 lbs. Postemergence When com is spike stage (1 to 2 inches tall) ; use low rates for high temperatures Propachlor S lbs. Pre-emergence Best used with atrazine or 2,4-D (Ramrod) Alachlor 2i lbs. Pre-emergence (Lasso) EPTC 2 to 4 lbs. Preplant Work into soil immediately plus safener (Eradicane) Butylate 4 lbs. Preplant Plant com shallowly. Not recommended for plus safener use in com planted for hybrid seed. For (Sutan +) control of nutgrass and bamyardgrass 2,4-D amine 4 lb. Postemergence After com is up and until lay-by time Direct spray to base of plants after com is 1 foot tall GARLIC Dinoseb 1 lb. Pre-emergence Before garlic is 6 inches high (Dinitro amine) DCPA 9 lbs. Pre-emergence (Dacthal) Paraquat i lb. Pre-emergence Apply on emerged weeds before garlic shoots appear. LEAF CROPS Trifluralin i to i lbs. Preplant Work into soil thoroughly Beet greens, Col- (Treflan) lards, Kale, Mus- Sulfallate 3 to 4 lbs. Postemergence Follow application immediately with light tard, Rape, Spinach, (Vegadex) irrigation (1 inch) Turnip greens Spinach CIPC 1 lb. Pre-emergence For fall plantings for spinach only (Chlorpro- pham) Collards, Kale and DCPA 9 lbs. Pre-emergence Mustard only (Dacthal) LETTUCE Sulfallate 4 lbs. Pre-emergence Follow application immediately with light (Vegadex) irrigation IPC 6 lbs. Preplant or (Propham) pre-emergence Benefin } to 1 lb. Preplant Work into soil thoroughly (Balan) Paraquat 1 lb. Preplant or pre- Postemergence on weeds emergence to crop Bensulide S to 6 lbs. Preplant or Incorporate preplant applications. Apply 1 (Prefar) active Pre-emergence inch of water by sprinkler irrigation for pre- emergence applications Pronamide 1 to 1.5 lbs. At planting time (Kerb) ACTIVE INGREDI- CROP CHEMICAL ENTS TIME REMARKS ONIONS CIPC 4 to 6 lbs. Pre-emergence Organic soil or postemergence CDAA 6 lbs. Pre-emergence Organic soils (more than 20% organic mat- (Randox) or postemergence ter) Do not use on green onions DCPA 6 to 9 lbs. Pre-emergence (Dacthal) Nitrofen 3 to 4 lbs. Postemergence When weeds are small and onions have (TOK) reached the two true leaf stage. If wettable powder formulation is used onions may be sprayed in flag leaf stage. PEAS MCPA i to i lb. Postemergence When peas are 4 to 6 inches tall amine salt MCPB 1 to 1 lb. Postemergence Use before flower buds form Dinitro amine 3 to 6 lbs. Pre-emergence i to li lbs. Postemergence Before peas bloom; air temperature must be less than 85° F. Propachlor 3.9 to 4.9 lbs. Pre-emergence (Ramrod) Diallate or 1J lbs. Preplant For wild oat control work into soil by cross Triallate discing (Avadex) Barban i lb. Postemergence For wild oat control. Apply when wild oats (Carbyne) have 2 to 3 leaves Trifluralin i to i lb. Preplant Work into soil thoroughly (Treflan) PEPPERS Diphenamid 3 to 5 lbs. Pre-emergence Use low rate on light soil (Dymid or or 1 month Enide) after trans- planting Paraquat 1 lb. Prior to planting On emerged weeds or crop emergence Trifluralin 1 to I lb. Before Work into soil thoroughly (Treflan) transplanting SQUASH Chloramben 4 lbs. Pre-emergence (Amiben) Bensulide 6 lbs. Preplant Incorporate shallowly (Prefar) TOMATOES Diphenamid 4 to 6 lbs. Immediately Use low rate on light soil ■(Dymid or after seeding Enide) or trans- planting Paraquat 1 lb. Prior to planting On emerged weeds or crop emergence Bensulide 4 to 5 lbs. Preplant (Prefar) Isopropalin 1.1 to 1.9 lbs. Preplant For transplanted crop only (Paralan) NOTE: 1. The chemical rates suggested are for complete coverage applications. For hand applications reduce the quantity of material used proportion- ate to the area actually sprayed. 2. For spray applications use 20 or more gallons of water per acre or as specified on the label. 3. Pre-emergence applications of herbicides are more satisfactory if applied to moist soil and followed immediately by a light irrigation or rain. The first line of defense against weeds is the use of cides. Heavier soils usually require higher rates of appli- good cultural practices. In fields with known weed infes- cation of pre-emergence herbicides to obtain weed con- tations, where possible, select crops that respond to trol than do lighter, sandy soils. weed-control programs for the weed species present. Remember: All agricultural chemicals are dangerous Adequate seedbed preparation improves the effective- if not handled properly. Store in locked compartments ness of chemical weed-control programs. away from children and destroy empty containers. Fol- Use close row spacings, where it is not possible to low manufacturer's safety recommendations on label. cultivate between the rows, only if it is certain that an adequate chemical weed-control program is available. Prepared by GARVIN CRABTREE, associate professor Weeds are killed most easily when conditions favor of horticulture, and N. MANSOUR, Extension vegetable germination of weed seeds and rapid plant growth. Sat- production specialist, Oregon State University. isfactory results can be expected if herbicides are ap- plied as directed and under normal conditions. Unusual Extension Service, Oregon State University, Corvallis, Henry A. Wads- temperatures or rainfall soon after application of herbi- worth, director. This publication was produced and distributed in further- ance of the Acts of Congress of May 8 and June 30, 1914. Extension work cides may cause unsatisfactory results. is a cooperative program of Oregon State University, the U. S. Depart- Soil characteristics, such as clay content and organic ment of Agriculture, and Oregon counties. Extension invites participation in its programs and offers them equally to all people, without discrimina- matter level, strongly influence, the effect of some herbi- tion.