All Issues

A test collection of macadamia nut varieties–10 from Hawaii and five from Australia, the native home of the nut– is under study for evaluation as a commercial crop for California.

The problematical nature of the exocortis disease of trifoliage orange – whether it is of a virus nature transmitted to the trifoliate stock by an infected scion which in itself may show no symptoms, whether it is transmitted by an insect vector or whether it is genetic and an inherent character of the root-stock–is under further study in an experimental planting at Riverside.

Annual applications of two to three pounds of actual nitrogen per tree are commonly made in California orange orchards.

Little is known regarding the effect of 2,4-D–and especially of a range of 2,4-D concentration–on the growth of the tops or of the rootstock of citrus trees, although considerable information is available as to the effect of 2,4-D when applied to citrus fruit and its effect on the retention by the tree of oil-soaked citrus leaves.

The frosted scale–Lecanium pruinosum Coquillett–occurs in most of the walnut orchards in northern California.

Among the many insects attacking sunflowers in California the most serious is the sunflower moth, Homoeosoma electellum (Hulst).

A potato flavor evaluation test was one phase of a coordinated investigation of the effects insecticides–absorbed by the soil–might have on plants, crops, and soils.

Coyote brush–Baccharis pilularis–a perennial evergreen shrub growing from two to eight feet in height, is the principal problem-brush on San Mateo County rangeland.