AgPest Alert – 2 April 2019

Check pasture for grass grub or porina damage

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

In grass grub or porina prone areas check pastures for damage. Grass grub damage is indicated initially by loss of clover and subsequently by patches of pasture turning yellow and later becoming soft underfoot. Porina damage initially appears as small (approx 5 cm dia.) areas of bare ground. Both pests should be controlled as early as possible to maximise returns and protect long term pasture production and quality. Although heavy rolling or high stocking rates may provide some level of grass grub control, conventional insecticide (diazinon) may be the only recourse. It is now generally too late to obtain good control of porina using diflubenzuron, although caterpillars from late February/March flights in the North Island are still susceptible. In most cases, porina control now needs to be by conventional insecticide.


Black beetle larvae damage may be showing

Region: Northland, Auckland, Bay of Plenty, Waikato

In the northern North Island, damage from black beetle larvae may be showing. Unfortunately little can be done to prevent this. Adults are deterred by some endophyte- infected grasses which will reduce egg laying and larval numbers. See DairyNZ Pasture Renewal Guide 

Social tagging: > > > > >

Comments are closed.