The influence of lime sulphur on the quality and sulphur content of organic 'Royal Gala' and 'Braeburn' apples : a thesis presented in partial fulfilment of the requirements for the degree of Master of Philosophy in Agribusiness at Massey University

Black spot or apple scab is a major disease in apple (Malus domestica) production. Its control is especially difficult in organic production systems that rely on copper- and sulphur-based fungicides which are not very effective and demand a high number of applications throughout the season. The most commonly used fungicide in organic apple production is lime sulphur, which is known to be phytotoxic, especially towards the cultivar 'Braeburn'. The influence of different application rates of lime sulphur (1% anti 2%) was evaluated when applied 11 times throughout the growing season from October to February. As varieties differ in their susceptibility to lime sulphur, the two cultivars 'Royal Gala' and 'Braeburn' were compared in this study. Black spot incidence and severity, russet development and postharvest quality parameters were evaluated. At harvest, residues of sulphur on and in the apple were determined as total sulphur, total water-soluble non-protein thiol compounds and cysteine content. Both cultivars behaved similarly to the application of lime sulphur, but 'Braeburn' was affected to a greater extent. Lime sulphur decreased background colour, blush, firmness, soluble solids content and dry matter content in both cultivars; fruit size in 'Braeburn' and titratable acidity in 'Royal Gala'. The changes observed can possibly be attributed at least in part to the decrease in the photosynthetic rate, which was especially drastic in 'Braeburn'. Lime sulphur caused increased russet on 'Royal Gala', but not on 'Braeburn'. Significant sulphur residues were found in the skin and flesh of both cultivars and part of the lime sulphur applied was metabolized into water-soluble non-protein thiols and cysteine. These results are of significant interest to the organic industry as the use of lime sulphur may compromise the residue-free status of organic apples and could have an influence on consumer acceptance and flavour

Results from scab trials with Armicarb in the years 2006 and 2007

In organically cultivated orchards of the LVWO Weinsberg in the years 2006 and 2007 trials were carried out about new products and their efficacy against apple scab. In the year 2006 (variety ‘Gala’) Armicarb and BioPluss sprayed preventively during primary ascospore season could not convince, also not in combination with lime sulphur as stopapplication. Armicarb showed at ‘Gala’ a tendency to increase russetting of the fruits. In the year 2007 (Variety ‘Elstar’) different combinations of wetting sulphur with yuccasaponin and stop-applications (lime sulphur, Armicarb) were tested with focus on the time immediately after blossom. The effect of Armicarb as stop-application was weaker than of lime sulphur at an infection-period with extreme high ascospore potential. The differences between the tested combinations were low. Wetting sulphur+yucca-saponin showed interesting tendencies in the year 2007, but should not be combined with lime sulphur as stop-application because of significantly increased reticular russetting of the apples

Modelling the sulphur chemistry evolution in Orion KL

We study the sulphur chemistry evolution in the Orion KL along the gas and grain phases of the cloud. We investigate the processes that dominate the sulphur chemistry and to determine how physical and chemical parameters, such as the final star mass and the initial elemental abundances, influence the evolution of the hot core and of the surrounding outflows and shocked gas (the plateau). We independently modelled the chemistry evolution of both components using the time-dependent gas-grain model UCL_CHEM and considering two different phase calculations. Phase I starts with the collapsing cloud and the depletion of atoms and molecules onto grain surfaces. Phase II starts when a central protostar is formed and the evaporation from grains takes place. We show how the gas density, the gas depletion efficiency, the initial sulphur abundance, the shocked gas temperature and the different chemical paths on the grains leading to different reservoirs of sulphur on the mantles affect sulphur-bearing molecules at different evolutionary stages. We also compare the predicted column densities with those inferred from observations of the species SO, SO2, CS, OCS, H2S and H2CS. The models that reproduce the observations of the largest number of sulphur-bearing species are those with an initial sulphur abundance of 0.1 times the sulphur solar abundance and a density of at least n_H=5x10^6 cm^-3 in the shocked gas region. We conclude that most of the sulphur atoms were ionised during Phase I, consistent with an inhomogeneous and clumpy region where the UV interstellar radiation penetrates leading to sulphur ionisation. We also conclude that the main sulphur reservoir on the ice mantles was H2S. In addition, we deduce that a chemical transition currently takes place in the shocked gas, where SO and SO2 gas-phase formation reactions change from being dominated by O2 to being dominated by OH.Comment: 14 pages, 28 figures, 6 table

The side effects of lime sulphur on predaceous arthropods, i.e. Typhlodromus pyri, and other leaf occupying arthropods

Conclusions and further studies The significant reduction of T. pyri and of larvae of predaceous gall midges, the complete loss of mite-diversity and the possible enhancement of P. ulmi and other harmful mites (i.e. C. vitis) are clear disadvantages of lime sulphur. Densities of T. pyri between 0.5 and 1 mite per leaf as mentioned to be necessary for controlling harmful mites (BOURQUIN 1989, FORTMANN 1993, HARZER 1993, KARG 1992, KOHLER ET AL. 1991), were never reached in lime sulphur treatment, while the untreated control always showed densities above this value. On the other hand low densities of predaceous mites are quite normal in intensively sulphur treated, biological orchards and are often replaced by other mite predators, like predatory bugs (Miriadae, Anthocoridae) or the coccinellid beetle Stethorus punctillum (HÄSELI & BOSSHARD 1994). Therefore further studies should include these arthropods, because lime sulphur may also have adverse effects on them (BORIANI 1994, BROWN 1978). Furthermore the lowest application strategy in terms of frequency and concentrations for scab control should be examined to minimise the quantity of applied lime sulphur (ZIMMER 2000). In addition the effects of different application methods, for example by sprayer or overhead irrigation on beneficial arthropod as well as on scab should be studied (KELDERER ET AL. 2000). The side effects of lime sulphur should not be considered separated from other used fungicides, moreover the whole spraying program should be included, because wettable sulphur (MILAIRE ET AL. 1974) and clay powder (HÄSELI & BOSSHARD 1994) also harm arthropods. For agronomic interests but also from the points of view of the registration of lime sulphur and the public image of organic apple growing, the question is: whether lots of preventive applications with copper, sulphur and clay powder have more adverse effects on beneficial arthropods than fewer curative applications of lime sulphur by using an infestion prediction model. Only by further studies under realistic farming conditions it is estimable, whether the use of lime sulphur in organic orchards can be accepted. In the common enthusiasm about this new curative fungicide, we should not forget the important role of beneficial arthropods. In this context the registration without any indication in the EU should be critically discussed

Insights into the regulation of DMSP synthesis in the diatom Thalassiosira pseudonana through APR activity, proteomics and gene expression analyses on cells acclimating to changes in salinity, light and nitrogen

Despite the importance of dimethylsulphoniopropionate (DMSP) in the global sulphur cycle and climate regulation, the biological pathways underpinning its synthesis in marine phytoplankton remain poorly understood. The intracellular concentration of DMSP increases with increased salinity, increased light intensity and nitrogen starvation in the diatom Thalassiosira pseudonana. We used these conditions to investigate DMSP synthesis at the cellular level via analysis of enzyme activity, gene expression and proteome comparison. The activity of the key sulphur assimilatory enzyme, adenosine 5′- phosphosulphate reductase was not coordinated with increasing intracellular DMSP concentration. Under all three treatments coordination in the expression of sulphur assimilation genes was limited to increases in sulphite reductase transcripts. Similarly, proteomic 2D gel analysis only revealed an increase in phosphoenolpyruvate carboxylase following increases in DMSP concentration. Our findings suggest that increased sulphur assimilation might not be required for increased DMSP synthesis, instead the availability of carbon and nitrogen substrates may be important in the regulation of this pathway. This contrasts with the regulation of sulphur metabolism in higher plants, which generally involves upregulation of several sulphur assimilatory enzymes. In T. pseudonana changes relating to sulphur metabolism were specific to the individual treatments and, given that little coordination was seen in transcript and protein responses across the three growth conditions, different patterns of regulation might be responsible for the increase in DMSP concentration seen under each treatment

The rate of oxidation of hydrogen sulphide by oxygen to elemental sulphur over NaX and NaY zeolites and the adsorption of sulphur

The rate of oxidation of H2S by O2 over synthetic sodium faujasite zeolites to produce elemental sulphur has been studied at partial sulphur l

REPCO contribution to the development of products for apple scab control

Natural compounds were sprayed according the RimPro scab warning system from start of bud break until the mid of June. Scab incidence was measured on the leaves and the fruit. Phytotoxicitiy and russet-ing was assessed. The natural compounds were sprayed together with sulphur and were compared with the standard biological fungicides copper hy-droxide and sulphur alone. Compound E73 + sulphur was the most effective on fruit. Armicarb and Resis-tim both sprayed with sulphur were comparable in efficacy with Funguran-OH. In our study laminarin (GL 32) did not shown any effect on the control of scab on apple

Heathland creation on improved grassland using sulphur: is there a conflict between optimal application rates for plant and animal communities?

We examined the effectiveness of using elemental sulphur (a soil acidifier) as a method for creating heathland on improved pasture. We determined i) optimal rate of sulphur application to control mesotrophic grasses ii) if invertebrates avoid areas of sulphur application. Results indicated that optimal sulphur application attracted invertebrates

Archaeological Sites Along Cuthand Creek and the Sulphur River in the Mid–Sulphur River Basin, Red River County, Texas

The Cuthand Creek and Little Mustang Creek drainage basins in the mid–Sulphur River basin are in the Post Oak Savannah of East Texas. Prehistoric archaeological sites are abundant in both basins and along the Sulphur River, dating from as early as Paleoindian times to the Late Caddo periods. Nevertheless, this area remains poorly known and there have been few professional archaeological investigations conducted here. In this article, we present information on a range of prehistoric sites and associated artifact assemblages known along Cuthand Creek and the Sulphur River in the mid–Sulphur River Basin, in Red River County, Texas. The artifacts that are discussed herein are in the collections of the junior author