Latania

Abstract: This paper describes the exciting characteristics of Latania sp. as a source of naturally immobilized polyphenol oxidase enzymes. Tissues from fruits of this palm tree present remarkably high enzymatic activity and this characteristic was explored for amperometric quantification of catechol and dopamine. These compounds were determined by the electrochemical reduction of their oxidation products on glassy carbon, after a biocatalytic conversion to quinone products. The quantification of these compounds was achieved in three different ways: by using an on-line tissue-based reactor associated with a flow injection analysis system; by incorporation of unripe tissue in carbon paste electrodes; and by exploring the use of dried tissue to construct reactors or modified carbon paste electrodes. This appears to be the first time that dry tissues have been utilized as an enzymatic source to construct enzymatic reactors, employed in the quantification of phenolic products. The last approach can address the unavailability of vegetable tissues (even out of the harvest season), and permits the dried material to be processed in a grinder, producing particles that can be selected accordingly to their size. Very high sensitivity, excellent reproducibility and long-term stability are some of the advantages obtained by using this tissue as a polyphenol oxidase source. Analogous measurements of phenol, based on the phenolase activity of Latania sp., are also reported.

Abstract: Latania scale, (Hemiberlesia lataniae (Signoret)), is now established in the North Island of New Zealand. The significance of this pest and methods of distinguishing latania scale from greedy scale (Hemiberlesia rapax (Comstock)) and oleander scale (Aspidiotus nerii Bouche) are discussed.

Abstract: Suitability of three armored scale insects (Homoptera: Diaspididae), their stages, the host plants and their parts, for the parasitic miteHemisarcoptes coccophagus Meyer was investigated. The studied scales were chaff scales,Parlatoria pergandii Comstock andP. cinerea Hadden, infesting grapefruit and orange orchards, latania scale,Hemiberlesia lataniae (Signoret), and oleander scale,Aspidiotus nerii Bouche occurring on acacia (Acacia cyanophylla) branches and leaves. Host suitability was evaluated by mite survival, mean intensity (active mites/attacked scales) and fecundity. It was highest on latania scale, lowest on oleander scale and intermediate on chaff scales. Results of laboratory experiments were consistent with these field findings: while developing on oleander scale, mites suffered 3× higher mortality, and their generation time was twice as long as on latania scale; the full egg clutch on the latter was high whereas on oleander scale it was negligible. Our data suggest that ovipositing females of latania and oleander scales, but not of chaff scales, are more suitable hosts than young scale females and the latter more suitable than immature stages. No direct effects of acacia plant parts on host suitability were detected. Citrus species affected chaff scale suitability for the mite through their effect on host diaspidid size. The ability ofH. coccophagus to control pestiferous diaspidids may depend on the specific host scale, its age structure and the specific host plant. The implications of these findings for the biological control of armored scale insects are discussed.