Phylogeography of the scarab beetle Antitrogus parvulus Britton (Coleoptera : Scarabaeidae) in south-eastern Queensland, Australia

This study surveys the population genetic structure of Childers canegrub, Antitrogus parvulus, to elucidate its population dynamics and gene flow. Antitrogus parvulus is a pest of sugarcane in the Bundaberg region and this knowledge can be used to optimise integrated pest management practices. Here, base-pair differences in the cytochrome oxidase II gene (COII) were used to characterise haplotypic diversity, infer levels of gene flow, and phylogenetic relationships of alleles and their phylogeographical structure. There were 28 unique haplotypes among the 70 sequenced individuals from the seven locations. All three variance components (among regions, among populations, within populations) are highly significant, with highest genetic diversity among regions and lowest among populations within regions. A positive correlation between migration rates and geographical distance and significant phylogeographical structure between four main geographical regions. The main implication of these findings for pest management is that if a grower can eliminate an existing infestation within a field, then reinvasion will be slow and further outbreaks within that field are unlikely to occur. The low dispersal ability of females also means that any resistance to insecticides that develops is likely to remain localised, but will rapidly become dominant within the affected population.

Evaluation of different models to describe egg and pupal development of Xyleborus fornicatus Eichh. (Coleoptera: Scolytidae), the shot-hole borer of tea in Sri Lanka

Abstract Development data of eggs and pupae of Xyleborus fornicatus Eichh. (Coleoptera: Scolytidae), the shot-hole borer of tea in Sri Lanka, at constant temperatures were used to evaluate a linear and seven nonlinear models for insect development. Model evaluation was based on fit to data (residual sum of squares and coefficient of determination or coefficient of nonlinear regression), number of measurable parameters, the biological value of the fitted coefficients and accuracy in the estimation of thresholds. Of the nonlinear models, the Lactin model fitted experimental data well and along with the linear model, can be used to describe the temperature-dependent development of this species.

Ecological genetics of Melaleuca quinquenervia (Myrtaceae): Population variation in Florida and its influence on performance of the biological control agent Oxyops vitiosa (Coleoptera: Curculionidae)

Melaleuca quinquenervia (Cav.) Blake (Myrtaceae) was imported into Florida from Australia over a century ago as a landscape plant. A favorable climate and periodic wildfires helped M. quinquenervia thrive; it now occupies about 200,000 hectares in southern Florida. A biological control (i.e., biocontrol) program against M. quinquenervia has been initiated, but not all biocontrol releases are successful. Some scientists have argued that poor biocontrol agent success may relate to genetic differences among populations of invasive weeds. I tested this premise by determining (1) the number and origins of M. quinquenervia introductions into Florida, (2) whether multiple introduction events resulted in the partitioning of Florida's M. quinquenervia populations into discrete biotypes, and (3) whether Oxyops vitiosa, an Australia snout beetle imported to control this weed, might discriminate among putative M. quinquenervia biotypes. Careful scrutiny of early horticultural catalogs and USDA plant introduction records suggested at least six distinct introduction events. Allozyme analyses indicated that the pattern of these introductions, and the subsequent redistribution of progeny, has resulted in geographic structuring of the populations in southern Florida. For example, trees on Florida's Gulf Coast had a greater effective number of alleles and exhibited greater heterozygosity than trees on the Atlantic Coast. Essential oil yields from M. quinquenervia leaves followed a similar trend; Gulf Coast trees yielded nearly twice as much oil as Atlantic Coast trees when both were grown in a common garden. These differences were partially explained by the predominance of a chemical phenotype (chemotype) very rich in the sesquiterpene (E)-nerolidol in M. quinquenervia trees from the Gulf Coast, but rich in a mixture of the monoterpene 1,8-cineole and the sesquiterpene viridiflorol in trees from the Atlantic Coast. Performance of O. vitiosa differed dramatically in laboratory studies depending on the chemotype of the foliage they were fed. Larval survivorship was four-fold greater on the (E)-nerolidol chemotype. Growth was also greater, with adult O. vitiosa gaining nearly 50% more biomass on the (E)-nerolidol plants than on the second chemotype. The results of this study thus confirmed the premise that plant genotype can affect the population dynamics of insects released as weed biocontrols. ^

O efeito da adubação foliar na variedade de batata (Solanum tuberosum) de indústria “LADY ROSETTA”

A batata está sujeita a stresses bióticos (doenças, pragas, infestantes) e abióticos (condições climáticas, secura, excesso de água, ou fitotoxicidade provocada por herbicidas, entre outros). Os adubos foliares contendo nutrientes (macro e micronutrientes) poderão contribuir para uma melhor nutrição da planta, para além de exercer uma ação benéfica ao nível do potencial hídrico da folha e sua proteção contra os diversos inimigos bióticos. Instalou-se um ensaio em Marinhais na variedade de batata de indústria Lady Rosetta, para avaliar o efeito da adubação foliar de uma gama de adubos foliares “Humigel”, contendo, entre outros nutrientes, o enxofre e o potássio, numa situação de fitotoxidade causada pela aplicação de um herbicida. O ensaio foi instalado com um dispositivo experimental de parcelas totalmente aleatórias, com 4 repetições. Os tratamentos foram a aplicação de “Humigel” e sem aplicação (testemunha). A produção comercial nas parcelas com “Humigel” foi significativamente mais elevada (48 192 kg/ha) do que nas parcelas testemunha (43 458 kg/ha). Não se registaram diferenças significativas ao nível do número de tubérculos (comercial e total) por planta, nem ao nível dos parâmetros de qualidade (peso específico e teste de fritura).

Older bag lady

General note: Title and date provided by Bettye Lane.

Bag Lady

General note: Title and date provided by Bettye Lane.

Bag lady asleep on bench

General note: Title and date provided by Bettye Lane.

Bag Lady

General note: Title and date provided by Bettye Lane.