Articles
ENTOMOPATHOGENIC FUNGI FOR THRIPS MANAGEMENT: RECENT ADVANCES
Article number
431_49
Pages
521 – 534
Language
Abstract
Insect-killing fungi are increasingly being considered as viable alternatives to chemical insecticides.
In 1994, explorations were made to collect entomopathogenic fungi in vegetable fields infested with melon thrips (Thrips palmi) in Taiwan.
About 400 isolates were recovered, of which 136 were recognized entomopathogens.
Six genera and 10 species were represented. Metarhizium anisopliae var. anisopliae and Fusarium spp. were recovered most frequently and accounted for 32.4% and 31.4% of the isolates collected, respectively.
In a separate study for management of pear thrips (Taeniothrips inconsequens) in maple forests, the persistence and vertical movement of Beauveria bassiana were assessed when it was applied to soil as an emulsifiable concentrate (EC) or a nutrient-based granular (NBG) formulation.
Evaluations were based on the number of colony-forming units (CFU) recovered from different levels in the soil profile over time.
A significant elevation in CFUs was achieved after application.
Differences in persistence were observed between formulations.
Elevated CFU levels were obtained in the NBG plots 16 weeks after treatment at a depth of 0–2 cm; whereas, in the EC plots, a treatment effect was not detectable beyond 8 weeks.
Although vertical movement of B. bassiana through the soil was detected, the CFU levels below 2 cm may not be sufficient to reduce a pest population.
To maximize efficacy, it is critical to make applications when the pest is at or near the soil surface.
Because elevated fungal levels persisted for over 2 weeks after treatment, applications could be made prior to the appearance of the pest to increase the chance of contact.
In 1994, explorations were made to collect entomopathogenic fungi in vegetable fields infested with melon thrips (Thrips palmi) in Taiwan.
About 400 isolates were recovered, of which 136 were recognized entomopathogens.
Six genera and 10 species were represented. Metarhizium anisopliae var. anisopliae and Fusarium spp. were recovered most frequently and accounted for 32.4% and 31.4% of the isolates collected, respectively.
In a separate study for management of pear thrips (Taeniothrips inconsequens) in maple forests, the persistence and vertical movement of Beauveria bassiana were assessed when it was applied to soil as an emulsifiable concentrate (EC) or a nutrient-based granular (NBG) formulation.
Evaluations were based on the number of colony-forming units (CFU) recovered from different levels in the soil profile over time.
A significant elevation in CFUs was achieved after application.
Differences in persistence were observed between formulations.
Elevated CFU levels were obtained in the NBG plots 16 weeks after treatment at a depth of 0–2 cm; whereas, in the EC plots, a treatment effect was not detectable beyond 8 weeks.
Although vertical movement of B. bassiana through the soil was detected, the CFU levels below 2 cm may not be sufficient to reduce a pest population.
To maximize efficacy, it is critical to make applications when the pest is at or near the soil surface.
Because elevated fungal levels persisted for over 2 weeks after treatment, applications could be made prior to the appearance of the pest to increase the chance of contact.
Authors
B.L. Parker, M. Skinner, M. Brownbridge, A. Adamowicz, F.C. Su
Keywords
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