4 July 2022

Grass grub (yellow patches) and porina (bare ground) damage showing.

Region: Bay of Plenty, Waikato, Gisborne, Hawkes Bay, Taranaki, Manawatu Wanganui, Wellington, Nelson Tasman, Marlborough, Canterbury, West Coast,
Otago, Southland

Grass grub and porina damage will now be evident in most areas. Grass grub damage is indicated initially by loss of clover and subsequently by patches of pasture turning yellow. At this time of year these patches become soft under foot and are prone to pugging. Porina damage will show as bare areas of pasture often with only weed plant species present. At this time of year conventional insecticide is the only control option likely to give control of either pest. By now production losses have already occurred but treatment may save the affected pastures.


Porina damage in southern North Island from late moth flights may be apparent.

Region: Hawkes Bay, Taranaki, Manawatu Wanganui, Wellington

Porina damage especially in Hawkes Bay, Taranaki, Wairarapa and Manawatu from caterpillars arising from late February/March flights may only now be becoming apparent. Careful consideration needs to be given to control options as spring growth may occur before damage becomes such that plants are lost from pastures.


Tasmanian grass grub damage may be showing.

Region: Gisborne, Hawkes Bay

In areas where Tasmanian grass grub can be a problem damage may be seen. Check pastures particularly around stock camps and assess numbers to determine if insecticidal control is warranted. Bear in mind feeding is slowing and with spring growth approaching control may only be warranted if it is required to preserve pasture plants.


Apply broadleaved weed herbicide to established pastures if needed once clover growth has slowed.

Region: All of NZ

Check established pastures for seedling broadleaved weeds such as nodding or winged thistle, ragwort or other troublesome weed and apply herbicide as necessary to the young weeds once clover growth has slowed.

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