Protocolo de experimentação para avaliar a atratividade de novas formulações de iscas granuladas utilizadas no controle das formigas cortadeiras Acromyrmex spp. e Atta spp. (Hymenoptera: Formicidae: Myrmicinae: Attini) no campo

Phillips F.T., Etheridge P., Scott G.C.

AbstractTen non-organochlorine insecticides which had shown promise in laboratory tests as formicides, because of their delayed toxic action, were field-tested in Brazil in experimental leaf-cutting ant baits and were compared with a mirex bait. Seven of these gave good control (similar to mirex) against Atta sexdens (L.) colonies. Several showed some success, at the concentrations used, against the larger Atta cephalotes (L.) colonies, but were not as good as mirex.By microencapsulating some quick-acting and very potent insecticides it was shown that useful formicides could be produced, presumably because encapsulation delayed the toxic action.Substituting vermiculite plus orange juice in place of dried citrus pulp as an attractive bait matrix gave successful results.

Littledyke M., Cherrett J.M.

AbstractIn laboratory colonies of Atta cephalotes (L.) and Acromyrmex octospinosus (Reich) pick-up responses to paper discs impregnated with arrestant and inhibitory solutions and feeding responses to measured amounts of these solutions were progressively increased by increasing the concentration of arrestants and decreasing the concentration of inhibitor; the inhibitor had a much greater effect on feeding than on pick-up. Both species picked up paper discs impregnated with arrestants and Acromyrmex readily incorporated these into the fungus garden, while Atta did this less readily. Foraging of arrestive paper discs presented regularly for several days was maintained by Acromyrmex but declined in Atta. Both species were less selective during periods of high foraging activity and during a shortage of suitable substrate. Incoming foragers did not seem to influence the preferences of the outgoing ants, but different colonies showed different preferences. Initially little preference was shown for new materials but on subsequent encounters widely fluctuating preferences emerged, which stabilised within two weeks. Over longer time periods further changes in preferences occurred. The ants' pick-up, cutting or feeding response to a particular material is determined by its chemical and physical nature, the amount of chemical information which the ants obtain, and the threshold of their response. This threshold is modified by such factors as the genetic composition of the colony, the previous quantitative and qualitative availability of the substrate, and the general level of foraging activity. Practical implications of these findings for toxic bait production are discussed.

Lewis T., Phillips F.T.

AbstractA technique is described for the preparation of large quantities (up to 1100 kg) of plain and waterproofed leaf-cutting ant bait from dried citrus meal, soyabean oil and aldrin. Small amounts (500 g) were weathered in sun and shade during wet and dry periods in Trinidad and the acceptability of the bait to ants {Acromyrmex octospinosus (Reich) and Atta cephalotes (L.)) and the persistence of toxicants in it were assessed in laboratory tests. Methyltrichlorosilane was the most effective of three waterproofing agents tested. In the wet season, waterproofed bait remained acceptable to ants for at least 30 days whereas plain bait deteriorated in less than four days; in the dry season waterproofed bait was only marginally more attractive. In the wet season, Acromyrmex strongly preferred weathered waterproofed bait to fresh leaves, whereas Atta slightly preferred leaves to bait. In the dry season, Acromyrmex showed little preference between bait and leaves, whereas Atta strongly preferred bait. Over the period that the bait remained attractive to the ants it retained between one-third and two-thirds of the original aldrin in the form of aldrin and dieldrin.

Fowler H.G., Pagani M.I., Da Silva O.A., Forti L.C., Da Silva V.P., De Vasconcelos H.L.

Leaf-cutting ants of the generaAcromyrmex andAtta are considered the principal polyphagous pests of the Neotropics Although some members of these genera are of economic importance, have a broad geographic distribution, and are extremely good colonizers, others are endemic and closely interact with native ecosystems. Control is generally practiced against any colony, irrespective of its taxonomic status. Indiscriminate control coupled with habitat destruction threatens endemic species with extinction, and, through habitat simplification, favors other pest species. As nests ofAtta are large, having several square meters of nest surface, the endemic taxa can be easily used as environmental indicators for natural ecosystems Likewise, the pest species can be used to detect environmental disturbance As these ants are keystone species and easily identified by nonspecialists, efforts should be made to integrate these into viable conservation programs

Rockwood L.L.

Three colonies each of two species of leaf—cutting ants (Atta colombica Guer. and Atta cephalotes L.) were studied for 1 yr in the Guanacaste Province of Costa Rica to determine the following: (1) Do colonies of Atta cut leaves from a limited number of species (i.e., are they selective)? (2) What determines which plant species are attacked? (3) Do leaf—cutters optimize foraging in terms of energy expended by attacking palatable plants closest to the nest or do they distribute their efforts more or less evenly throughout their foraging territory? Several line of evidence support the hypothesis that A. cephalotes and A. colombica are selective in terms of plant material attacked. The ants sampled a large majority of the plant species present, but concentrated their foraging on a restricted subset of species. The mature leaves of only 31.4% and 22.0% of the species present were readily acceptable to A. colombica and A. cephalotes, respectively. The new leaves of another 12—16 plant species were acceptable. Different colonies of the same Atta species consistently attacked the same plant species if they were available, cut leaves from the same species at similar rates, and even attacked the same species of plants at the same time of year. The amount of material cut from host plant species was not correlated with host plant abundance in four of the six colonies studied, and was even slightly negatively correlated in two of these four. An analysis of plant distance from the nest versus amount harvested shows that palatable plant species close to the nest have a greater probability of being visited by the ants, but do not necessarily suffer more defoliation than other such plants within 50—60 m of the nest. Amount harvested decreases greatly for plants farther than 60—80 m from the nest. Thus colonies of Atta do not normally concentrate their efforts on plants closest to the nest, but foraging cannot be described as evenly distributed either. The factor responsible for selectivity in colonies of Atta is probably the internal chemistry of the material selected. An Atta colony must provide the fungus garden when a proper balance of nutrients and moisture without overlapping it with secondary compounds from the plants selected. The ants' attempt to solve this problem may explain some of the complexities of leaf—cutter foraging behavior.

Zanetti R., Sanches J.J., Wenzel A.V., Haddi K., Ferreira H., Santos L.V.

Leaf-cutting ants are the most important pests in several cropping systems in the Neotropics. Granulated baits containing active ingredients, considered hazardous by the Stockholm Convention, are the usual method to control these ants. Isocycloseram is a new insecticide molecule with high safety margin for mammals, but without registration for the ants in general. Thus, this study investigated the effectiveness of granulated baits with isocycloseram in leaf-cutting ants control under laboratory and field conditions. Initially, the mortality of Atta sexdens workers, fed with dehydrated citrus pulp paste containing different concentrations of isocycloseram was evaluated in the laboratory for 21 days, for toxicological classification. Subsequently, the loading, devolution, and incorporation of baits with different concentrations of isocycloseram and the mortality of A. sexdens colonies were evaluated in the laboratory. After that, the percentages of loading and devolution of baits, foraging activity, and colony mortality treated with 0.05, 0.1, 0.2, and 0.3% of isocycloseram were evaluated for the species A. sexdens, A. laevigata, and Acromyrmex lundii in field conditions. All concentrations of isocycloseram killed more than 15% of ants in 24 h and more than 90% in 21 days in the laboratory, being classified as a fast-acting and highly effective active ingredient. Baits with 0.001 to 0.03% of isocycloseram were highly loaded and exhibited low rate of devolution. The mortality of A. sexdens colony was higher at concentrations between 0.075 and 0.3%, in the laboratory. Baits containing isocycloseram at concentrations of 0.2 and 0.3% were highly loaded, presented low devolution rates, and were highly efficient in controlling A. sexdens, A. laevigata, and A. lundii in the field, at dosages of 6, 10, and 12 g/m² of nest. This is the first report of the use of isocycloseram against leaf-cutting ants, contributing to the development of efficient and toxicologically safer ant baits.

Sabattini J.A., Zanuncio J.C., Lemes P.G.

Leaf-cutting ants are pests in agriculture, forests and pasture and, usually, controlled with toxic baits. The management and control of leaf-cutting ants is complex as a consequence of its sociability and behavior. We tested three toxic baits with abamectin, fipronil and sulfluramid to control colonies of Acromyrmex lundi Mayr, 1865 (Hymenoptera: Formicidae), in two seasons: 'Spring 2020' and 'Summer 2020/21', in Argentina.The percentage of effective bait carried in the spring was similar between treatments with 80%, 80% and 90% for those with abamectin, fipronil and sulfluramid. The ant flow of A. lundi decreased after toxic bait applications compared to the control through time in all treatments. This activity was higher in the spring than in the summer. The baits reduced the foraging activity of A. lundi from 5 to 96 days after application (DAA). Abamectin and fipronil baits controlled 50% and 67% of the nests in the spring, and 20% and 43% at 96 DAA in the summer. Sulfluramid was the best treatment, killing 90% of A. lundi nests.The baits decrease the foraging activity of A. lundi until 96 DAA, with total or partial death of its colonies varying between treatments. The ant symptoms with the sulfluramid bait appeared faster than with fipronil and may be a result of the low level of carry-over or differences in the chemical quality of the active ingredients. © 2022 Society of Chemical Industry.

Lemes P.G., de Matos M.F., Araújo C.A., Serrão J.E., Zanuncio J.C.

Catalani G.C., Sousa K.K., Camargo R.S., Caldato N., Matos C.A., Forti L.C.

Zanuncio J.C., Lemes P.G., Antunes L.R., Maia J.L., Mendes J.E., Tanganelli K.M., Salvador J.F., Serrão J.E.

The recommendations accompanying pesticide derogations from the FSC are not efficient for the management of leaf-cutting ants and termites in certified forest plantations in Brazil compared with chemical control using insecticides. FSC recommendations ignore the biological and ecological features of pests and forest plantations in Brazil when they set global rules for forest certification.

Moreira D.D., Dáttilo W., Morais V., Erthal M., Silva C.P., Samuels R.I.

Tatagiba-Araujo G., Viana-Bailez A.M., Bailez O.

The effect of larval cuticle extract (larval pheromone) and venom gland extract (trail pheromone) on transport of formulated baits by Atta sexdens rubropilosa (Forel) was studied in the field and under laboratory conditions. In the laboratory, we observed the transport to the nest of baits impregnated with 10 μL of venom gland extract (0.01 gland/bait) or 10 μL of larval cuticle extract (0.05 larva/bait). The most transported impregnated bait was then tested in the field placing rubber septa impregnated with 100 mL of extract or with 100 mL of solvent with the baits at 0.2, 1.0, 5.0, and 10.0 m away from the trail and from the nest entrance. Baits impregnated with venom gland extract were transported more often than baits formulated with larval cuticle extract. In field tests, the venom gland extract reduced the time required for ants to detect baits and increased the transport of baits displayed at 0.2 m from the foraging trail or nest entrance. The increase in the transport of impregnated baits and the lower time to be transported might help to reduce the loss of bait in the field and decrease the risk of active ingredient contacts with non-target species.

Teixeira M.L., Santos M.N.

A atratividade da polpa do fruto de jatobá para saúva-limão foi avaliada tendo como parâmetro comparativo a polpa cítrica desidratada, utilizada como veículo por diversas marcas comerciais. O experimento foi conduzido em quatro formigueiros de saúva-limão em canteiros gramados com espécies arbóreas. As iscas de jatobá e de polpa cítrica desidratada, ambas sem princípio ativo, foram confeccionadas em grânulos com formato e diâmetro semelhantes aos das iscas granuladas comerciais. As iscas de jatobá foram mais atrativas para as operárias de saúva-limão, que fizeram o primeiro contato aos 17s, em contraste com os 29s gastos para o primeiro contato com as iscas de polpa cítrica. As iscas de jatobá também começaram a ser carregadas mais cedo, aos 26s, sendo que as iscas de polpa cítrica foram carregadas 48s mais tarde. A grande aceitação do jatobá foi reforçada pelo menor tempo para o encerramento dos testes, 5min 39s, contrastando com os 11min 17s necessários para o encerramento do teste com a polpa cítrica. A polpa do fruto do jatobá foi mais atrativa para saúva-limão do que a polpa cítrica desidratada.