Common ragweed

The broadleaf weeds responded to tillage in the same general manner when rye root residue was present, however, it does appear that the growth of all the weeds was inhibited by the presence of rye root residue. This can be seen in Table II by comparing results from the tilled treatment with and without rye root residue. In the case of common ragweed, biomass was reduced 34% (178.3 g no rye, till versus 118.3 remove mulch till), but the density increased by 69% (140 plants/2.2 m versus 280 plants/2.2 m ) when rye root... 

Treatment Grass 5 Redrootc,d Pigweed Q Common Lambsquarters c Common Ragweed... 

The same compound (or structurally very similar varieties) may occm in several related species, which explains why allergy is usually not specific to a single plant. This is called cross-reactivity, and since chamomile belongs to the same family (Asteraceae) as notorious allergenic common ragweed, cross-reactivity carmot be excluded. 

Uses Preemergence or preplant herbicide used in many vegetable and field crops to control armnal broad-leaved weeds and grasses. Also for postemergent control of common ragweed, redroot pigweed, smartweed and velvet-leaf. 

Ambrosia artemisiifolia Common ragweed Asteraceae Plant Encyclopedia (2012) and... 

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