Reivindicación 1: Una composición herbicida que comprende una cantidad sinérgicamente eficaz como herbicida de (a) (±)-2-exo-(2-metilbenciloxi)-1-metil-4-isopropil-7-oxabiciclo[2.2.1]heptano, cualquiera de sus enantiómeros individuales o cualquier mezcla no racémica de estos (herbicida A) y (b) pyroxasulfone (herbicida B). Reivindicación 4: La composición de acuerdo con cualquiera de las reivindicaciones 1 a 3, que también comprende al menos un herbicida C seleccionado del grupo que consiste en aclonifen (C.1), amicarbazone (C.2), amidosulfuron (C.3), aminopyralid (C.4), amitrole (C.5), asulam (C.6), atrazine (C.7), azimsulfuron (C.8), beflubutamid (C.9), benfluralin (C.10), bensulfuron (C.11), bensulide(C.12), bentazone (C.13), bicyclopyrone (C.14), bifenox (C.15), bispyribac (C.16), bromoxynil (C.17), carbetamide (C.18), carfentrazone (C.19), chloridazon (C.20), chlorpropham (C.21), chlorsulfuron (C.22), chlorthal (C.23), chlortoluron (C.24), clethodim (C.25), clodinafop (C.26), clomazone (C.27), clopyralid (C.28), cycloxydim (C.29), cyclopyrimorate (C.30), cyhalofop (C.31), 2,4-D (C.32), dazomet (C.33), 2,4-DB (C.34), desmedipham (C.35), dicamba (C.36), dichlorprop (C.37), dichlorprop-P (C.38), diclofop (C.39), diflufenican (C.40), diflufenzopyr (C.41), dimethachlor (C.42), dimethenamid (C.43), dimethenamid-P (C.44), diquat (C.45), dithiopyr (C.46), diuron (C.47), ethametsulfuron (C.48), ethofumesate (C.49), fenoxaprop (C.50), fenoxaprop-P (C.51), fenquinotrione (C.52), flazasulfuron (C.53), florasulam (C.54), fluazifop (C.55), fluazifop-P (C.56), flufenacet (C.57), flumioxazin (C.58), fluometuron (C.59), flupyrsulfuron (C.60), flurochloridone (C.61), fluroxypyr (C.62), fluftamone (C.63), foramsulfuron (C.64), glufosinato (C.65), glufosinato-P (C.66), glifosato (C.67), halauxifen (C.68), halosulfuron (C.69), haloxyfop-P (C.70), indaziflam (C.71), imazamox (C.72), imazaquin (C.73), imazosulfuron (C.74), iodosulfuron (C.75), iofensulfuron (C.76), ioxynil (C.77), isoproturon (C.78), isoxaben (C.79), isoxaflutole (C.80), lenacil (C.81), linuron (C.82), MCPA (C.83), MCPB (C.84), mecoprop (C.85), mecoprop-P (C.86), mesosulfuron (C.87), mesotrione (C.88), metam (C.89), metamitron (C.90), metazachlor (C.91), methiozoline (C.92), metobromuron (C.93), metolachlor (C.94), Smetolachlor (C.95), metosulam (C.96), metribuzin (C.97), metsulfuron (C.98), molinate (C.99), metil arseniato monosódico (MSMA) (C.100), napropamide (C.101), napropamide-M (C.102), nicosulfuron (C.103), orthosulfamuron (C.104), oryzalin (C.105), oxadiargyl (C.106), oxadiazon (C.107), oxasulfuron (C.108), oxyfluorfen (C.109), pendimethalin (C.110), penoxsulam (C.111), pethoxamid (C.112), phenmedipham (C.113), picloram (C.114), picolinafen (C.115), pinoxaden (C.116), pretilachlor (C.117), prodiamine (C.118), profoxydim (C.119), prometryne (C.120), propaquizafop (C.121), propoxycarbazone (C.122), propyzamide (C.123), prosulfocarb (C.124), prosulfuron (C.125), pyraflufen (C.126), pyridate (C.127), pyroxsulam (C.128), quinclorac (C.129), quinmerac (C.130), quinoclamine (C.131), quizalofop (C.132), quizalofop-P (C.133), rimsulfuron (C.134), saflufenacil (C.135), sethoxydim (C.136), siduron (C.137), simazine (C.138), sulcotrione (C.139), sulfentrazone (C.140), sulfosulfuron (C.141), tembotrione (C.142), tepraloxydim (C.143), terbuthylazine (C.144), thiencarbazone (C.145), thifensulfuron (C.146), tolpyralate (C.147), topramezone (C.148), tralkoxydim (C.149), tri-allate (C.150), triasulfuron (C.151), tribenuron (C.152), triclopyr (C.153), trifloxysulfuron (C.154), trifludimoxazin (C.155), trifluralin (C.156), triflusulfuron (C.157), tritosulfuron (C.158), ácido 4-amino-3-cloro-6-(4-cloro-2-fluoro-3-metoxifenil)-5-fluoropiridin-2-carboxílico (C.159), bencil 4-amino-3-cloro-6-(4-cloro-2-fluoro-3-metoxifenil)-5-fluoropiridin-2-carboxilato (CAS 1390661-72-9, C.160), acetochlor (C.161), benzobicyclon (C.162), cyclosulfamuron (C.163), flucarbazone (C.164), imazapic (C.165), imazapyr (C.166), imazethapyr (C.167), propanil (C.168), y sales, ésteres o amidas de estos aceptables en la agricultura. Reivindicación 8: Un método para controlar vegetación no deseada que comprende aplicar a la vegetación o a su locus o aplicar al suelo o al agua, para prevenir el surgimiento o crecimiento de la vegetación no deseada, la composición de acuerdo con cualquiera de las reivindicaciones 1 a 6.