Dinomyrmex gigas (Latreille, 1802): a potential icon for Taman Negara Johor Endau Rompin

Dinomyrmex gigas (Latreille, 1802) is one of the largest ants in the world and the largest in Southeast Asia. It is also more commonly known as the giant forest ant. This large charismatic ant can be found in the forests of Southeast Asia, however it is not often sighted by the public due to its predominant nocturnal nature. Despite being considerably well studied compared to its smaller counterparts, most people know little about the giant forest ant beyond its large size. Most studies on this species focus on the populations found in Malaysia and Brunei characterizing many aspects of the natural history and biology of this species including its foraging behaviour, diet, territoriality, reproduction and colony structure. While much is known about the biology of this species, fragmented forest habitats may have an impact on the viability and behaviour of this majestic giant ant of the forest. This study involved insects’ viability observation and sampling of ant specimens. The results of observations showed that D. gigas is viable in Endau Rompin Johor National Park (TNJER). Then, various ecological aspects of D. gigas was investigated through field studies and secondary information. Due to its size and uniqueness this species has a potential to be developed into a nature tourism product for Malaysia. The present study elaborated to further discover its daily activity, nesting and defence behaviour which could be useful in developing it into a nature tourism product. As the species is also limited in distribution to undisturbed forest, the issue of its survival is discussed with relation to conservation of the tropical rainforest

Quiver Presentations for Descent Algebras of Exceptional Type

The descent algebra of a finite Coxeter group $W$ is a basic algebra, and as such it has a presentation as quiver with relations. In recent work, we have developed a combinatorial framework which allows us to systematically compute such a quiver presentation for a Coxeter group of a given type. In this article, we use that framework to determine quiver presentations for the descent algebras of the Coxeter groups of exceptional or non-crystallographic type, i.e., of type $E_6$, $E_7$, $E_8$, $F_4$, $H_3$, $H_4$ or $I_2(m)$.Comment: 25 pages, 10 figure

Results from an experiment about pruning of the apple variety ‘GoldRush’

The scab resistant apple variety ‘GoldRush’ can be grown in regions, where vineyards are common. At the LVWO Weinsberg ‘GoldRush’ is ripening about October 20th. In organic fruit growing this variety must be thinned strongly, because it tends to alternate bearing. The intention of the small experiment in the organi-cally grown orchard Katzental was to reduce by special pruning measurements the time for thinning by hand and to improve the fruit quality. During the years 2001 to 2005 clear effects could be seen on the size of the apples. The time for hand thinning varied from year tot year depending from the setting of blossom clusters, but there was no success in reducing thinning time by pruning alone. There was a positive influence on the quantity of picked apples per hour. The trees grew more balanced, the number and the length of the one-year-old twigs/branch were higher in 2005. There was a middling effect of the severe pruning on the alter-nate bearing. Well-considered pruning is an important component within organic cultivation to produce ap-ple of high quality

Testing of strawberry-varieties (with/without biodegradable mulch film) for organic cultivation

Different strawberry varieties, available from organic propagation at that time were, planted in August 2004 and proofed about their suitability for organic cultivation, each variety was tested with and without biodegradable mulch film. Within the early ripening strawberry varieties ‘Clery’ had a middle yield and was susceptible for infections with leaf spot, losses of plants by Verticillium were seldom. This variety should be planted early to reach enough vigor in autumn. ‘Clery’ has an interesting potential in the phase of higher prices at the beginning strawberry season. ‘Darselect’ ripened shortly before ‘Elsanta’, the yield was lower, but the fruit-size bigger, so the picking could be done more quickly. ‘Elsanta’ showed in this trial under organic conditions not too bad results, but on this area no strawberries had been cultivated for many years before, so the potential of soil-borne diseases was only low to middle. In the group of middle ripening varieties ‘Korona’ suffered under the hot weather in June 2006 and reacted with heavy wilting symptoms, first of all caused by Verticillium, and with more leathery and small fruits. ‘Florence’ and ‘Peco’ had often sunburst (by intensive sunbeams). ‘St. Pierre’ had a vigor plant, middle yield and less sunburst, but should be picked well ripened. The late variety ‘Yamaska’ was robust, but tasted only middle good. The biodegradable mulch film increased in the first year the yield of the early ripening varieties, in the second year with a hot summer this effect disappeared. Partly snails used the mulch film as refuge, damages of the film also were caused by birds. The natural decomposition was sufficient, when the film was tilled into the soil after the second harvest

New Results from scab-experiments (treatments on fallen leaves and summer-applications)

In the leaf-decompositon-trials to reduce the ascospore potential of Venturia inaequalis (2003/2004 and 2004/2005) different agents were tested with regard to direct effects on scab and to increasing the attractivity of the leaves for earthworms. TSB (lab medium with soya extracts) had a heavy direct effect on ascospore potential, but in this formulation it cannot be used in organic fruit-growing. Humofix and Bactofil B didn´t re-duce the potential as strongly as in the trial 2002/2003. A yeast extract and a combination of bean extract with powdered milk increased the attractivity for earthworms. In the trial 2004/2005 the reduction of the asco-spore potential was at best to 60 % of the control (powdered milk+Humofix), respecting the loss by earth-worms yeast extract+malt showed positive effects. In the experiment about applications against scab in summer 2004 the fluid formulation Sommerschwefel was comparable with wetting sulphur, during the stor-age season Frutogard and Agromil+BioPluss retarded best the development of late scab lesions on the ap-ples. Why Agromil+BioPluss caused an increasing of superficial scald in April 2005, cannot be explained at the moment

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