Anais da Sociedade Entomológica do Brasil (1999) 28, 101-110

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C. Luz, I.G. Silva, B.P. Magalhaes, C.M.T. Cordeiro and M.S. Tigano (1999)
Control of Triatoma infestans (Klug) (Reduviidae: Triatominae) with Beauveria bassiana (Bals.) Vuill.: preliminary assays on formulation and application in the field
Anais da Sociedade Entomológica do Brasil 28 (1), 101-110
Abstract: Beauveria bassiana (Bals.) Vuill., isolate CG 306, was assayed against Triatoma infestans (Klug) using indirect application by contact with a treated filter-paper. The fungus was deposited on filter paper by vacuum-filtration of a conidial suspension. Estimates of 50% survival time of insects were between 15 and 21 days at 3 x 106 and 107 conidia/cm2 of treated support, respectively, without significant difference between concentrations. A concentration of 2.4 x 106 conidia/cm2 of CG 306 was necessary to kill 50% of T. infestans third instar nymphs 25 days after inoculation at 25°C and 50% relative humidity, when insects were continuously exposed to conidia. The LC50 was significantly higher (2.0x 107 conidia/cm2) when insects were exposed for 1 h to the treated filter paper, than with continuous exposure. A mineral oil based emulsifier (2%) had no effect on germination of conidia in vitro. Fewer formulated conidia were necessary to kill 50% of insects after constant exposure to the treated surface, compared with unformulated conidia. After a 1 h exposure, unformulated conidia were more effective than formulated. After spraying B. bassiana (107 conidia/cm2) and releasing third instar nymphs of T. infestans in small wooden test houses, the rate of insect recovery after 25 days was significantly lower in the fungus treated houses compared to the control house. Mortality due to fungal infection of recovered insects transferred to the laboratory was between 38.1 and 93.8%, compared with no mortality in the control group. The rate of mortality of insects exposed to treated filter paper in gauze covered cups in the houses was between 35 and 78.8% after 25 days. Persistence of conidia on filter paper exposed inside the houses was > 98% during the field tests. There was no development of CG 306 on cadavers originating from laboratory infection and exposed to field conditions in the houses.
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Database assignments for author(s): Christian Luz

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
formulation/storage of bioagents
application technology

Pest and/or beneficial records:

Beneficial Pest/Disease/Weed Crop/Product Country Quarant.

Triatoma infestans
Beauveria bassiana (entomopathogen) Triatoma infestans