Adult polyphagous coleopterans overwintering in cereal boundaries: winter mortality and susceptibility to the entomopathogenic fungus Beauveria bassiana

Autumn-collected Bembidion lampros and Agonum dorsale were kept outdoors under semi field conditions to determine winter mortality. On three occasions (autumn, mid-winter and late winter) sub-samples of the population were incubated in the laboratory at room temperature and mortality was recorded. Generally the mortality was low in autumn and mid-winter, not exceeding 5%. A more pronounced post-winter mortality of up to 30% was observed at the end of hibernation. Only a negligible number were infected by the entomopathogenic fungi Beauveria bassiana and Paecilomyces farinosus. Infection experiments with B. bassiana isolates from Sitona lineatus, Tachyporus hypnorum and three species of ground beetles showed a similarly low susceptibility of B. lampros and A. dorsale to B. bassiana and, although Tachyporus spp. showed a distinct mycophagy and a significantly higher mortality, this could not be related to mycosis.     

Antifungal and antitumor activity of heterocyclic thiosemicarbazones and their metal complexes: current status

More than 75 substituted thiosemicarbazones and a number of metal complexes of each have been assayed for their antifungal activity. Their activity is significantly affected by the substituted groups attached at both¹ N and⁴ N of the thiosemicarbazone moiety. Greatest activity occurs for 2-substituted pyridine thiosemicarbazones with differences observed for 2-formylpyridine, 2-acetylpyridine and 2-benzoylpyridine derivatives and their metal complexes. Further, there are activity differences for⁴ N-alkyl-,⁴ N-aryl-,⁴ N-dialkyl- and 3-azacyclothiosemicarbazones and their metal complexes as well as changes in the substituent size among each of these subgroups. Cu(II) complexes are often more active than the uncomplexed thiosemicarbazones, with the latter showing similar activity to Ni(II) complexes in many instances. The reduction potential of the thiosemicarbazone ligand in a Cu(II) complex, the strength of the ligand field and various spectral properties can be correlated to the inhibitory activity.     

Ovicidal and Larvicidal Activity of Conidia and Blastospores of Paecilomyces fumosoroseus (Deuteromycotina: Hyphomycetes) Against Bemisia argentifolii (Homoptera: Aleyrodidae) with a Description of a Bioassay System Allowing Prolonged Survival of Control Insects

Fungi are the only effective entomopathogens of members of the Aleyrodidae and other homopterans because of the piercing and sucking feeding strategy of these insects. The laboratory assessment of the entomopathogenic activity of fungi often requires a prolonged period of observation. Leaf quality can be the limiting factor in bioassays of fungi against whiteflies that require longer observation periods or those that require conditions that are as close to natural ones as possible. A bioassay system is described that utilizes rooted cabbage leaves infested with the highly polyphagous whitefly, Bemisia argentifolii . Using this method, discriminating dosages of aerial conidia and blastospores of two isolates of Paecilomyces fumosoroseus (Pfr) were bioassayed against eggs and nymphs of B. argentifolii . Low, but significant, mortality (10-20%) of eggs was observed 14 days after exposure to 3.8 104 blastospores/cm2 for the Pfr 97 and European Biological Control Laboratory (EBCL) Pfr 42 isolates. Additionally, the majority of crawlers that had hatched from treated eggs died on the surface of the leaves. Exposure of early second-instar nymphs of B. argentifolii to 3.8 103 conidia or blastospores/cm2 of Pfr 97 resulted in mortalities of 27 and 77% respectively. Identical dosages of conidia and blastospores of the Pfr 42 isolate resulted in mortalities of 59 and 68% respectively. The bioassay method described enables the comparative evaluation of entomopathogenic fungi against whiteflies under diverse biotic and abiotic conditions.