Disease control by sulphur induced resistance

As early as the 19th century, Justus von Liebig (1803 – 1873) identified the lack of vitality of soils and non-existent vigour of plants as relevant causes of increased infections of crops by fungal diseases. Organic farming requires alternative strategies for combating pests and diseases. Soil-applied sulphate fertilisation proved to significantly reduce infection rate and severity of crops by fungal diseases. The potential efficacy of socalled Sulphur Induced Resistance (SIR) expressed as a reduction of the disease index ranged from 5–50% and 17–35% in greenhouse and field experiments, respectively. Metabolic pathways involved in SIR imply, for instance, the synthesis of phytoalexins, glutathione, glucosinolates and the release of sulphur-containing volatiles

Role of the Basal Ganglia in Balance Control

In this review paper, we summarize the important contributions of the basal ganglia to the regulation of postural control. After a brief overview of basal ganglia circuitries, the emphasis is on clinical observations in patients with focal lesions in parts of the basal ganglia, as the impairments seen here can serve to highlight the normal functions of the basal ganglia nuclei in postural control. Two particularly relevant functions are discussed in detail: first, the contribution of the basal ganglia to flexibility and to gaining control of balancecorrecting responses, including the ability to lend priority to the elements of a postural task; and second, processing afferent information by the basal ganglia, which is increasingly recognized as being highly relevant for postural control

Diel Flight Pattern and Flight Performance of Cactoblastis cactorum (Lepidoptera: Pyralidae) Measured on a Flight Mill: Influence of Age, Gender, Mating Status, and Body Size

Cactoblastis cactorum (Berg) (Lepidoptera: Pyralidae) is an invasive herbivore that poses a serious risk to Opuntia cacti in North America. Knowledge of the flight behavior of the cactus moth is crucial for a better understanding of natural dispersal, and for both monitoring and control. We used computer-linked flight mills to investigate diel flight activity and flight performance in relation to gender, age, mating status, and body size. Maximal flight activity for both mated and unmated moths occurred during twilight, whereas flight activity was low during photophase. The total distance flown and the number of initiated flights within a diel cycle were higher in both unmated and mated females than in males, but the longest single flight was similar in both genders. These findings suggest that pheromone trap captures of males likely indicate the simultaneous presence of females and that mated females might even be in areas where males are not detected yet. Flight performance heterogeneity was large, with a small portion of the population (both males and females) performing long unbroken flights, whereas the majority made short flights. Females had higher pupal and adult body size and shorter longevity than males. A few individuals, particularly young mated females, flying long distances may be important for active spread of a population and the colonization of new habitats. Implications of this study in the control of the cactus moth by using the sterile insect technique are discusse

Identification of Factors Influencing Flight Performance of Field-Collected and Laboratory-Reared, Overwintered, and Nonoverwintered Cactus Moths Fed with Field-Collected Host Plants

Environmental conditions during egg and larval development may influence the dispersal ability of insect pests, thus requiring seasonal adjustment of control strategies. We studied the longest single flight, total distance flown, and the number of flights initiated by wild Cactoblastis cactorum (Berg) (Lepidoptera: Pyralidae) to determine whether the flight performance of overwintered cactus moths with a prolonged feeding phase during development differs from nonoverwintered cactus moths. Pupae of field-collected and laboratory-reared moths were transported together from the United States to Switzerland, and flight mills were used to characterize the flight capacity of 24- to 48-h-old adults during their most active period of the diel cycle. The lack of seasonal variation in flight performance of those moths that developed under controlled environment but were fed with field-collected Opuntia cacti showed that seasonal changes in host plant quality did not affect flight. This consistent flight performance in the mass-reared laboratory population throughout the year is beneficial for sterile insect technique programs, which aim to limit the dispersal of this pest. For field-collected C. cactorum, the larger overwintered females performed similarly to nonoverwintered females, indicating that longer feeding time at lower temperature increases body size but does not influence female flight capacity. Young mated females had a similar flight capacity to unmated ones, suggesting that gravid females may play an important role in invading new habitats. For males, overwintering increased the proportion of long-distance flyers, suggesting that they are well-adapted to locate the more sparsely dispersed females in the sprin