The Impact of Phytophthora cinnamomi on Six Rare Native Tree and Shrub Species in the Brisbane Ranges, Victoria

The impact of Phytophthora cinnamomi was measured on six native tree and shrub species occurring in the Brisbane Ranges, Victoria, that are considered significant, rare or vulnerable and likely to become endangered. Seedlings of Eucalyptus yarraensis (rare) and cuttings of Grevillea chrysophaea (significant), Olearia pannosa, Pultenaea graveolens (both vulnerable) and Prostanthera decussata and Rhagodia parabolica (both rare) were grown in disease-free soil and inoculated with P. cinnamomi. After 60 days, all plants of G. chrysophaea and P. graveolens were dead and, hence, were regarded as highly susceptible. Inoculated plants of P. decussata developed severe symptoms and 13% died, while O. pannosa showed decreased vigour with 11% dying. Both species were classified as susceptible. Some plants of R. parabolica developed symptoms and were slightly susceptible, butE. yarraensis was resistant. A foliage spray of the phosphonate, Foli-R-Fos (dipotassium phosphonate) on healthy susceptible species, followed by stem inoculation with the pathogen, reduced both stem infection and mortalities, but did not eliminate the pathogen. The concentration of 3% was slightly phytotoxic to G. chrysophaea and P. decussata. The distribution of the six species and of disease due to P. cinnamomi was mapped. Stands of G. chrysophaea, O. pannosa and P. graveolens are diseased and at risk. One of the few known stands of P. decussata was invaded recently. When measured on replicate quadrats located in areas of recent disease, old disease and areas free from disease, P. cinnamomi was shown to produce significant reductions in plant density, plant growth, flowering and regeneration, particularly in areas recently invaded by the pathogen, but less on old infested areas. One-third of the population of O. pannosa is dying due to P. cinnamomi and its seed production is inhibited. There is a strong decline in populations of G. chrysophaea, and P. graveolens, which may place these species at risk.

Controlling Sprout Clumps of Bigleaf Maple with Herbicides and Manual Cutting

Bigleaf maple (Acer macrophyllum) clumps were controlled using the herbicides glyphosate, imazapyr, metsulfuron methyl, triclopyr amine, triclopyr ester, and 2,4-DP + 2,4-D; by basal spray, thinline, foliage spray, and on cut surfaces; during early foliar, late foliar, and dormant periods on five sites across western Oregon and Washington. Three timings of manual cutting alone also were compared. Imazapyr foliage sprays, triclopyr ester thinline, dormant 3% triclopyr ester basal spray, late-foliar 2, 4-DP + 2,4-D basal spray, and manual cutting with triclopyr amine cut-surface application provided the best control among the treatments tested over the 3 yr of study. Imazapyr foliage sprays provided the best long-term control by killing most treated clumps. Triclopyr ester thinline treatments provided the most consistent and effective results among the basal applications. Stump applications of triclopyr amine were more effective than manual cutting alone or manual cutting with glyphosate cut-surface application. West. J. Appl. For. 9(4):118-124.

Effect of nine growth retardants applied to loblolly and slash pine

In an effort to dwarf seed orchard trees without reducing fruitfulness, nine growth-retardant chemicals were applied at several concentrations each as either aqueous foliar sprays or oil-based bark bands. All treatments which significantly retarded growth also caused injury or death. Mefluidide, as a 0.7% foliage spray, reduced growth and caused only minimal injury. Effects of the chemicals on seed production could not be observed, as no control or treated trees flowered. Slash pine was more sensitive to the chemicals than loblolly pine.

Propanil and Adjuvants for Barnyardgrass Control in Rice

A nonphytotoxic paraffinic oil at 2.5, 5, and 10% (v/v) or a blended alkylaryl sulfonate surfactant at 0.5, 1, and 2% (v/v) did not enhance the activity of propanil (3′,4′-dichloropropionanilide) at 1.7, 3.4, and 6.7 kg/ha applied as a foliage spray in aqueous systems on barnyardgrass [Echinochloa crus-galli(L.) Beauv.] or rice (Oryza sativaL. ‘Starbonnet’). Time and rate of applying propanil affected control of barnyardgrass. Barnyardgrass control and rice yield were best with treatments of 3.4 or 6.7 kg/ha of propanil to four-leaf grass plants. Propanil at 6.7 kg/ha controlled tillering and jointing barnyardgrass well enough to increase grain yields over those of untreated rice.

Some aspects of insecticidal and biological control of the woolly apple aphid, Eriosoma lanigerum (Hsm.) in Rhodesia

In insecticide trials in 1962–63 in Rhodesia against woolly apple aphid, Eriosoma lanigerum (Hsm.), no appreciable control was achieved by applying ½ fluid oz. of a 40 per cent, emulsifiable concentrate of dimethoate per tree at 2- to 3-week intervals for 16 weeks in any of the following ways: painted directly on the lower trunk; absorbed in a cotton-wool band applied to the trunk, after being diluted 1:3 in water; applied to a furrow around the stem after being diluted in four gallons of water; injected into the soil with a nematicide injector after being diluted 1:4 in water.A foliage spray of DDT (0·195% active ingredient) had a gradual controlling effect on the aphid and caused no upsurge such as might have occurred had the parasitic activities of Aphelinus mali (Hald.) been suppressed.Activity of the ant Pheidole megacephala (F.) was immediately halted on trees sprayed with DDT and was suppressed on trees the trunks of which were painted with dimethoate and on those banded with a dimethoate-soaked barrier.Over a fourteen-month period, the numbers of living aphid colonies fluctuated before decreasing at the same time as the activity of A. mali intensified.