Microbial Control of Leptopharsa heveae Drake & Poor (Hemiptera: Tingidae) in Brazilian Rubber Tree Plantations: a Brief Historical Account and Identification of Entomopathogenic Fungi by Means of Multigene Phylogeny

Abstract

Over the last decades, a few fungal species have been mentioned in the literature associated with the rubber tree lace bug, Leptopharsa heveae Drake & Poor (Hemiptera: Tingidae). The rubber plantation area treated with these biocontrol agents has been steady since the 1990s, estimated in 10,000-15,000 ha per year. A few large-scale rubber operations, one biocontrol company, and three government-owned laboratories were, and currently one still is, involved in their commercialization. One species, currently referred to as Sporothrix insectorum, has been historically deployed in biocontrol applications in Brazilian rubber farms. However, L. heveae-infecting isolates have only been identified through morphological examinations; therefore, proper molecular assessments are needed for accurate identifications. Hence, DNA of six L. heveae-infecting isolates (five of which have been deployed in field applications) were extracted and sequenced. Multigene phylogeny found that both Simplicillium lanosoniveum and Cordyceps (formerly Isaria) sp. have been sprayed on rubber plantations to manage L. heveae populations, although the former is the only one currently applied. Simplicillium lanosoniveum and Cordyceps sp. have no relation whatsoever to true Sporothrix species associated with human and animal diseases. Therefore, our molecular data may encourage biocontrol companies to register mycoinsecticides targeting L. heveae. We also added unpublished historical accounts after contacting key contributors to the launching of this not so well-known biocontrol program in the 1980s.