Native Entomopathogenic Fungi Isolated from Rhynchophorus palmarum (Linnaeus, 1758) in Northeast Brazil.

AMERICA; BRAZIL

Simple Summary: Microbial pest control offers promising opportunities to develop sustainable alternatives to synthetic chemical insecticides. In Brazil, the selection of native strains of entomopathogenic fungi suggests an option for South American palm weevil (Rhynchophorus palmarum, SAPW) management and potential tools for red palm weevil (R. ferrugineus, RPW) management. Both weevils in America are susceptible to the native isolates of Beauveria bassiana, CVAD01, CVAD02, CVAD06, and CPATC/032, which originate from palm orchard soils and infected SAPW adults in northwestern Brazil's Alagoas state. The SAPW mortality rates in our study were 90 and 100% on day 21, suggesting the efficacy of these strains that are well-adapted to the environment and to the pest. We suggest both the development of formulates for microbiological insecticides against R. palmarum and future tests on R. ferrugineus. Both palm weevils, the South American (Rhynchophorus palmarum) (SAPW) and the red palm weevil (R. ferrugineus, RPW), are present in South America, affecting commercial, ornamental, and native palms. These pests oviposit and thrive on selected Arecaceae. R. palmarum mainly infests coconut (Cocos nucifera), oil palms (Elaeis guineensis), and other ornamental and native palms in America, causing a significant social impact on growers. The weevils fulfill a significant ectosymbiotic macro- and microorganism role in the first period of larval development, worsening the damage which, during this period, is not yet apparent. Palm protection in the Brazilian context suggests the use of indigenous agents for microbiological biocontrol. This research identifies three Brazilian Beauveria bassiana isolates: CVAD01, CVAD02, and CVAD06. The results suggest that the strain's impact on R. palmarum can also be compared with that of the commercial strain Beauveria bassiana. Phylogenetic analysis allowed the delimitation of species of Beauveria (Hypocreales). Pathogenicity tests caused significant mortality in R. palmarum. The isolates CVAD01, CVAD02, and CVADO6 showed high pathogenicity between 7 and 21 days, with mortality rates between 90 and 100%, suggesting that they may be effective biological control agents of R. palmarum in the field when used, within available means, to mitigate the impact of R. palmarum and R. ferrugineus in South America. [ABSTRACT FROM AUTHOR]

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