Sustainable Management of Acromyrmex octospinosus (Reich): How Botanical Insecticides and Fungicides Should Promote an Ecofriendly Control Strategy.

Abstract

The leaf-cutting ant Acromyrmex octospinosus (Reich) causes serious damage to crops and protected areas due to its foraging activity. The main method of control of this species consists of the use of synthetic insecticides that can lead to environmental damage and negative side effects on human health. Consequently, alternative strategies, such as biopesticides, are needed. Insecticide evaluation by ingestion assays was performed using A. octospinosus in vitro bioassay and laboratory nests. Chemical analyses were also performed to know the contents of plant extracts. This study showed that Mammea americana L. is the most promising insecticidal plant extract in the control of A. octospinosus. Indeed, the lethal concentrations (LC 50 and LC 99 ) an the lethal dose (LD 99 ) of the M. americana extract (51.31 mg.mL -1 , 131.92 mg.mL -1 , and 17.36 mg/g of ant respectively) were the closest to those of Fipronil, 0.03 g/kg, the commercial insecticide used as positive control.

Bioactivity of Asclepias curassavica, Equisetum spp. and Rosmarinus officinalis Extracts Against Leaf-Cutting Ants

“…In addition, compounds such as terpenoids, caryophyllene epoxide, nerolidol and kolaenol isolated from Hymenaea courbaril, Melampodium divaricatum and Vismia bacciferae exhibited insecticidal activity when workers were supplied with an artificial diet containing these compounds (Howard et al, 1988). Feeding artificial diets, Boulogne et al (2018) observed insecticidal activity of the seed extract of Mammea americana against Ac. octospinosus workers whose lethal concentration was close to that of Fipronil (0.03g.kg -1 ).…”

“…The authors suggested that ricinoleic, oleic and linoleic acids are the toxic agents of Ricinus oil. Another compound is coumarin, identified in extracts of rue (Ruta graveolens), jimsonweed (Datura estramonium), Cordia verbenaceae, peppermint (Mentha pitanperita), goat weed (Ageratum conyzoides) and tropical apricot (M. americana), which is a potential insecticide for leaf-cutting ants (Araujo et al, 2008;Boulogne et al, 2018). Equisetum sp.…”

“…After 6 weeks of treatment, M. americana seed extract caused total decline of Ac. octospinosus colonies and the symbiotic fungus garden was completely infested with competitors (Boulogne et al, 2018). Pagnocca et al (1990) found that Sesamum indicum extract caused a decrease in the growth of Leucocoprinus gongylophorus, but the authors did not identify the compounds of this extract.…”

An organic bait based on Palicourea marcgravii (Rubiaceae) and Tephrosia candida (Fabaceae) does not control nests of Atta laevigata (Hymenoptera: Formicidae) in eucalyptus plantations

“…The lack of efficacy of this bait may be due to its constituents, which are possibly acting and killing the worker ants too quickly. Plant extracts cause mortality of individual ants in the laboratory, but have failed to control nests, due to the absence of the delayed action (Boulogne et al, 2018). The contamination of the workers is higher during the handling and preparation of the material to incorporate it into the fungus garden, which takes a few hours (Andrade et al, 2002).…”

“…and Atta spp. (White, 1998;Grosman et al, 2002;Boulogne et al, 2018), but it is an active ingredient with slow action toxicity in just few concentration ranges, when compared with others, such as sulfluramid (Nagamoto et al, 2004). Rapid action, as previously discussed, is not desirable to control leaf-cutting ants because it compromises workers foraging, and the dissemination of the insecticide baits inside the nest (Gandra et al, 2016).…”