Effects of superphosphate on the incidence and severity of fused needle disorder in a Pinus radiata plantation at Narbethong.  J. M. James.  December 1983.  7 pp. (unpubl.)

SUMMARY

A survey of the incidence and severity of fused needle disorder in Pinus radiata D. Don (radiata pine) was undertaken at an experimental site in the Narbethong Plantation, central Victoria, where the phosphorus nutrition of P. radiata is being studied. The survey took place between 1978 and 1981 in a stand planted in 1973 and fertilised with superphosphate at establishment (180 g tree^-1), then four years later at rates of 0, 700, 1050 and 1400 kg ha^-1. Trees were rated on a scale of 0 (unaffected) to 5 (severely affected).

Most of the trees fertilised at establishment and four years later were largely unaffected by the disorder, an average of 11% were mildly affected and 2% were severely affected. In contrast, an average 18% of trees fertilised only at the time of planting were mildly affected by fused needle disorder and 5% was severely affected. These results indicate that the incidence and severity of the disorder were reduced by the broadcast application of superphosphate four years after planting. It was concluded that for the area studied in the Narbethong plantation the disorder is of minor importance, especially where phosphorus deficiency in the trees has been prevented by application of superphosphate.