Summer weeds

Page last updated: Tuesday, 4 September 2018 - 11:29am

Melons

Paddy melon (Cucumis myriocarpus) and Afghan melon (Citrullus lanatus) are both prostrate annual melons germinating in spring and summer. Their growth is favored by good moisture relations and bare or fallowed paddocks. Melons can stabilise areas prone to wind erosion and provide stock feed when food is scarce (although opinions vary greatly). Horse, sheep and cattle losses have been associated with eating the melon but the smell of the plants generally makes them unpalatable.

Prickly Paddy Melon seedling
Afghan Melon seedling

The simplest distinguishing feature is the size of the fruit and the seeds. Paddy melon fruit are bristly and 2-3cm in diameter with small pale seeds. Afghan melon has large smooth-skinned fruit up to 15cm in diameter and large brown seeds.

Afghan melon seeds (left), Paddy melon seeds (middle) and colocynth seeds (rare in WA) (right) 

Control

  • Grazing is an effective control method after applying low rates of a hormone herbicide to make the melons more palatable.
  • Another example for melons control in summer might be a mixture of triclopyr, 2,4-D and metsulfuron in the early morning when plants are not stressed. Graze heavily five days after spraying. Increase rates if grazing not possible.
  • Prevention of seed set by mechanical removal is feasible on small areas.

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