A novel method for standardized application of fungal spore coatings for mosquito exposure bioassays

<p>Abstract</p> <p>Background</p> <p>Interest in the use of fungal entomopathogens against malaria vectors is growing. Fungal spores infect insects via the cuticle and can be applied directly on the insect to evaluate infectivity. For flying insects such as mosquitoes, however, application of fungal suspensions on resting surfaces is more realistic and representative of field settings. For this type of exposure, it is essential to apply specific amounts of fungal spores homogeneously over a surface for testing the effects of fungal dose and exposure time. Contemporary methods such as spraying or brushing spore suspensions onto substrates do not produce the uniformity and consistency that standardized laboratory assays require. Two novel fungus application methods using equipment developed in the paint industry are presented and compared.</p> <p>Methods</p> <p>Wired, stainless steel K-bars were tested and optimized for coating fungal spore suspensions onto paper substrates. Different solvents and substrates were evaluated. Two types of coating techniques were compared, i.e. manual and automated coating. A standardized bioassay set-up was designed for testing coated spores against malaria mosquitoes.</p> <p>Results</p> <p>K-bar coating provided consistent applications of spore layers onto paper substrates. Viscous Ondina oil formulations were not suitable and significantly reduced spore infectivity. Evaporative Shellsol T solvent dried quickly and resulted in high spore infectivity to mosquitoes. Smooth proofing papers were the most effective substrate and showed higher infectivity than cardboard substrates. Manually and mechanically applied spore coatings showed similar and reproducible effects on mosquito survival. The standardized mosquito exposure bioassay was effective and consistent in measuring effects of fungal dose and exposure time.</p> <p>Conclusions</p> <p>K-bar coating is a simple and consistent method for applying fungal spore suspensions onto paper substrates and can produce coating layers with accurate effective spore concentrations. The mosquito bioassay was suitable for evaluating fungal infectivity and virulence, allowing optimizations of spore dose and exposure time. Use of this standardized application method will help achieve reliable results that are exchangeable between different laboratories.</p

The effect of Harpin(Ea) as plant activator in control of bacterial and fungal diseases of tomato

8th International Symposium on the Processing Tomato -- JUN 08-12, 2002 -- ISTANBUL, TURKEYWOS: 000188788000039The objective of this study was to integrate a systemic acquired resistance (SAR) inducing plant activator and available chemical control measures, consequently to determine if comparable efficacy with less chemical applications were possible. Variations in the activity of specific peroxidase enzymes that likely present the enhancement of host resistance were analyzed from the leaves of tomato seedlings after individual and combined applications. The efficacy tests of the compounds against several major diseases of tomato were conducted with replicated pot experiments under controlled conditions in the greenhouse. Possible correlations between higher efficacy of the compound in question and increased specific enzyme activity were evaluated with SPSS 8.0 for Windows. The highest efficacy for the control of both the late blight (Phytophthora infestans) and bacterial speck (Pseudomonas syringae pv. tomato) and the highest specific enzyme activities were obtained from Harpin(Ea)+ Experimental Aventis, and Harpin(Ea)+ Cupracol, respectively. Specific enzyme activities were increased about 148.5% and 126.0%, respectively. The results have revealed that comparable efficacies with combined applications of Messenger (Harpin(Ea)) as plant activator with fungicide or bactericide could possibly be efficacious and applicable in practice.Int Soc Hort Sc