Ms Haworth said she had seen several dead frog and insect species along paths at Lake Gwelup after watching City of Stirling offices spraying the broad-spectrum herbicide.
"The round-up can also get into the water and kills the tadpoles; at one stage you used to be able to hear the frogs at the lake, now you battle to ever hear one," she said.
"They're killing an enormous amount of insects; those that are killed are eaten by birds, which will suffer."
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READ NOWCity of Stirling parks and reserves manager Ian Hunter said the City had used the chemical for close to 40 years.
Mr Hunter said the City had addressed the issue of pesticide usage in 2013, establishing an integrated approach to weed and pest control.
"In 2014, the use of steam control of weeds was commenced at selected road reservations sites as an alternative to herbicide use," he said.
"In the 12 months to the end of 2014, more than 21 tonnes of hand-pulled and mechanically-slashed weeds were disposed."
Ms Haworth said the City should consider banning the chemical completely.
"If we had to get rid of a weed, why not use community work instead of poison," she said.
"Get them down there to pull it out; we've become a civilisation of quick fixes. We should be looking after our planet, we've done enough damage how it is and the less poison we can pump into it, the better."
Several Perth councils confirmed the use of glyphosate, including the Town of Bassendean and the cities of Vincent and Nedlands.