In areas where grass grub or porina are a concern inspect pastures now for early damage. Grass grub damage is indicated initially by loss of clover and subsequently by patches of pasture turning yellow and later becoming soft under foot. 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, high stocking rates and application of nitrogen can lessen damage, conventional insecticide (diazinon) may be the only recourse. It is now generally too late to obtain good control of porina using diflubenzuron, although in much of the North Island caterpillars from February/March flights are still susceptible. In most cases porina control now needs to be by conventional insecticide.

Social tagging: Pest Alert