Invertebrate predation on the soil-living stages of Australian so'ldier fly may be a significant factor in the regulation of thi's pest of North Island grasslands. La:bora'tory and field experiments on larvae of Conoderus exsul and Agrypnus variabilis (ElateI'idae), 'adults and larvae of Thyreocephalus orthodoxus (Staphylinidae), and aduIts '()If Rhytisternus miser (Carabidae) suggest that a'll may influence the densities of soldier fly through predation on larvae and/or eggs. The functional responses of C. exsul, A. variabilis, and T. orthodoxus to soldier fly larval density are discussed. Selective removal of predators from pasture with insecticide sh'Owed that predation may aocount for up to 75% loss 'of the early 'instars of soldier fly.

Soldier fly, Inopus rubriceps (Macquart), larvae suck nutrients from the roots of ryegrass, 'reducing root growth, tiller and foliage production, and probably plant survival. Accurate placement of insecticide with the seed killed larvae, and en'hanced establishment of the seedlings. The use of minimum cultivation, paraquat, and fertilizer sown with the seed, all made larvae move on to the rows of new seedlings thereby improving the efficiency of the insecticide and establishment of the seedlings. This was associated with increased root weights and pasture production. These techniques warrant consideration as alternatives to full surface cultivation and should readily fit into farm undersowing programmes.

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