Effects of the timing of applications on the incompatibility of three fungicides and one isolate of the entomopathogenic fungus Beauveria bassiana (Balsamo) Vuillemin (Deuteromycotina)

Abstract: The effect of timing of application on the incompatibility of three fungicides (metalaxyl, mancozeb, copper oxide) and isolate MK2001 of the entomopathogenic fungus Beauveria bassiana (Balsamo) Vuillemin was assessed in vitro . Isolate MK 2001 at 1 × 10⁷ conidia/ml concentration was highly pathogenous to adults of Lygus lineolaris (Hemiptera) (84% mortality at day 4 post-treatment). The fungicides at the manufacturer recommended rate (1X) were strongly fungistatic and inhibited the fungal isolate radial growth on Sabouraud dextrose agar (SDA). Mancozeb, metalaxyl and copper oxide exhibited insecticidal activity of 24, 40 and 48% respectively, on L. lineolaris adults. It is clear that application of the fungal isolate MK2001 2–4 days before applying fungicides metalaxyl, mancozeb or copper oxide synergized the insecticidal effect of the isolate. On the contrary, application of metalaxyl, mancozeb, copper oxide 2–4 days before applying isolate MK2001 antagonized the insecticidal effect. The simultaneous use of each fungicide (metalaxyl, mancozeb or copper oxide) and the isolate gave lesser insect mortality. This study revealed that although some fungicides are incompatible for use alongside fungal isolates, the proper evaluation of their time of use could be beneficial in biological control or IPM programmes. Furthermore, the application of B. bassiana isolate MK2001 followed by fungicide application could synergize insecticidal activity.     

Characteristics of Pustula tragopogonis (syn. Albugo tragopogonis) Newly Occurring on Cultivated Sunflower in Germany

In temperate climates, Pustula tragopogonis is rarely found on cultivated sunflower. In Europe, it was so far of little economic impact on other Asteraceae, except for some regions in the Mediterranean. In 2003, P. tragopogonis was found for the first time in sunflower fields in southern Germany. The pathogen has a widespread occurrence there, especially in the region around Stuttgart, BW. Fatty acid profiling, ultrastructural investigation and ITS sequencing revealed a high similarity to an 2002 isolate from southern Africa and an 2005 isolate from Australia, but revealed significant differences to P. tragopogonis s.l. on Cirsium arvense, a common weed, growing on or in the vicinity of sunflower fields in Germany. P. tragopogonis from this host can therefore be excluded from being the source of the reported infection.     

Further studies on the morphology of the Triviidae (Gastropoda: Prosobranchia) with emphasis on species from southern Africa

Aspects of the morphology of II species of Triviidae are described, including the living animal, shell, radula, mantle complex, central nervous system and reproductive system. Interspecific differences in radular morphology are important in distinguishing closely allied species. Trivia aperta, T. costata and T. verhoeft are protandric hermaphrodites while T. caluariola, T. neglccta, T. pellucidula, T. rubra, T. solandri and T. suavis are gonochoric. The elaboration of the receptaculum seminis varies between species. In T. aperta, T. calvariola, T. neglecta and T. who& the receptaculum is undivided while in T. costafa, T. pellucidula, T. solandri and T. suavis there are two or more lobes of the receptaculum.     

Canalicular system of enterocytes at rest and its changes during lipid absorption

A study was made of the structural changes in different organoids of enterocytes of the rat small intestine at "rest" and during lipid absorption using ultrathin sections, impregnation with Ur-Pb-Cu, and continuous impregnation with OsO4. With the latter technique a specific canalicular system was found in the enterocytes, which we failed to observe on ultrathin sections. During lipid absorption the canalicular system underwent fragmentation. The vesicules on the trans-surface of the Golgi apparatus were enlarged, and the number of flattened cisterns was significantly lower. The changes in cellular organoids and their interrelations observed in the present study support the earlier hypothesis of the resynthesis of triglycerides within the enterocytes, the formation of chylomicrons and their transfer into the intercellular space.     

The problem of sexual inversion in the minnow, Phoxinus phoxinus (L.)

The incidence of sexual inversion in Phoxinus phoxinus has been studied by examining histologically (a) the gonads of 406 adult specimens caught from the wild during a period of 16 months, (b) the gonads of 168 adults kept in captivity in groups with an experimentally altered sex-ratio, and (c) the differentiation of the gonads in the fry.
All the adults had either testes or ovaries and no case of intersexuality was observed. For both testis and ovary, we recognized two phases, depending on the seasonal cycle: an active spring-summer phase, corresponding with the period of reproduction, and a quiescent autumn-winter phase. The ovaries showed an asynchrony in oocyte development, which is typical of species that spawn many times during the breeding season.
In P. phoxinus the ovaries are easily recognizable just one month after hatching and testes are well differentiated in 2-month-old fingerlings. Differentiation is, therefore, precocious and follows a pattern typical of gonochoristic species in which hermaphroditism never occurs.