Assessment and monitoring of damage from insects in Australian eucalypt forests and commercial plantations

Abstract   This paper presents a review of recent developments in the assessment and monitoring of health in Australian eucalypt forests and plantations of pine and eucalypt species, with an emphasis on damage caused by herbivorous insects. The diverse range of interests and priorities amongst Australian stakeholders of native forests and plantations influences the scale, resolution and accuracy of results sought, and this in turn influences how the assessment data are collected, analysed and reported. The authors discuss sampling systems that include extensive ground-based surveys, permanent plots and airborne technologies being developed in Australia. In all cases, there is an appreciation that the assessment protocols should be objective, repeatable and cost effective. Significant progress has been made in the application of digital, remotely sensed imagery to detect and classify damaged forest canopies. The success of this approach depends, in part, on a sound understanding of the progression of symptoms at the leaf, tree crown and stand scale, especially those symptoms that influence spectral reflectance behaviour.     

Control of in vivo protein synthesis and peroxidase formation by DNA-containing extracts of normal and crown gall tissues

Nucleic acids extracted from normal bean hypocotyl tissue (NE) and crown gall tumors (TE) affect amino acid incorporation into protein and the development of peroxidase activity when vacuum infiltrated into normal receptor tissues. TE enhances and NE inhibits both processes; NE from successively older tissues produces progressively greater inhibitions per unit of infiltrated nucleic acid. The active material has an absorption maximum at 257 nm with an A_260:280 ratio of more than 2·0. On acrylamide gel electrophoresis it shows a small DNA peak, four typical r-RNA peaks and a small low molecular weight RNA peak. Activity in such extracts is completely destroyed by hydrolysis with 0·3 N KOH or DNAase; RNAase is only slightly effective and pronase ineffective. It is deduced that the effective material contains DNA that may be complexed with RNA or other materials in the extract. Pretreatment of donor tissues with actinomycin d or 5-fluorouracil diminishes or annuls the activity of the extract. Pretreatment of receptor tissue with actinomycin d inhibits the action of TE but not of NE; pretreatment with cycloheximide prevents the action of both NE and TE.