| The top 10 most serious weeds of the world based
on total number of countries infested (Holm
et al. 1977). |
| Species |
Countries |
| Nutgrass (Cyperus rotundus) |
52 |
| Barnyard grass (Echinochloa crus-galli) |
32 |
| Bermuda grass (Cynodon dactylon) |
28 |
| Summer grass (Digitaria sanguinalis) |
23 |
| Barnyard grass (Echinochloa colona) |
22 |
| Johnson grass (Sorghum halapense) |
22 |
| Crowsfoot grass (Eleusine indica) |
20 |
| Dirty dora (Cyperus difformis) |
19 |
| Blady grass (Imperata cylindrica) |
18 |
| Pigweed (Portulaca oleracea) |
17 |
