Susceptibility of Atta sexdens rubropilosa (Forel) (Hymenoptera: Formicidae) to Metarhizium anisopliae (Metsch.) Sorokin in laboratory conditions

Abstract

This study aimed to evaluate the pathogenicity of the entomopathogenic fungus Metarhizium anisopliae on leaf-cutting ants Atta sexdens rubropilosa, under laboratory conditions. It was inoculated suspensions containing different concentrations of conidia on specimens of soldiers and workers, kept under controlled conditions. The mortality was verified daily until 15 days after inoculation. The experimental delineation was entirely random. Sporulation data were submitted to variance analysis and the average of the treatments were compared to each other by the Scott-Knott test. Probit analysis was performed to obtain the values of LT50 (in days). All isolates were pathogenic to A. sexdens rubropilosa, being more virulent for workers than for soldiers. Isolates IBCB 348, IBCB 410 and IBCB 425 were the most efficient in the mortality of the ants. Isolates IBCB 425 and UFGD 03 caused high percentages of confirmed mortality. The results showed that the tested isolates have the potential for using them as control agents of A. sexdens rubropilosa.

Leaf-cutting ant species (Hymenoptera: Formicidae, Myrmicinae) in three agrosystems and the attractiveness of a natural bait to Atta laevigata’s biocontrol

“…The research occurred in both: 1. laboratory: bait preparation and evaluation of bait quality; 2. field: evaluation of bait acceptance and carrying of different concentration of fungi conidia incorporated in the baits. So, this research can be qualified as qualitative and quantitative (see Alves 1988;Loureiro et al 2022aLoureiro et al , 2022b.…”

“…The prospecting for non-polluting methods aimed at managing populations of leaf-cutter ant species, which have pest status in agrosilvipastoral systems is of paramount importance. Techniques that use physical barriers to protect trees and shrubs, have shown to be more promising (Jiménez et al, 2022), as well as the population suppression methods with biological weapons, especially entomopathogenic fungi (Loureiro et al, 2022a(Loureiro et al, , 2022b. The coexistence with leaf-cutting ant species should be sought, in order to enable the production of food free of pesticides; without major damage to rural producers, avoiding the local extinction of Attini species, because that last mission, is a task that is not only ecologically undesirable, but also, probably, impossible.…”

“…The isolate IBCB 21 also caused high percentages of confirmed mortality, being recommended for use in the biological control of leaf-cutting ants (Loureiro et al, 2022a). Loureiro et al (2022b) tested five isolates of the entomopathogenic fungus M. anisopliae against leaf-cutting ant adults. All isolates were pathogenic for A. sexdens, being also more virulent for workers than for soldiers.…”