Revista Colombiana de Entomología

Occurrence of Ancistrosoma klugii Curtis (Coleoptera: Scarabaeidae: Melolonthinae), and its importance as a possible phytosanitary risk in Peru

Agustina Valverde-Rodríguez — 2024-03-12

The objective of the present study is to report the feeding and copulation habits and provide a diagnosis of the adult stage of Ancistrosoma klugii and its importance as a possible phytosanitary risk based on specimens collected in the department of Huánuco, Peru, where the insect is a polyphagous pest at certain times of the year. The habits of the insect were monitored through observations of the populations in the field. Groups of A. klugii were observed made up of 6 to 8 individuals close to each other, found in the floral parts, foliage and branches of citrus trees, avocado trees, mangoes, grapevines and alfalfa fields, feeding and copulating simultaneously, especially in the morning hours, from 8:00 am to 10:00 am. In alfalfa crops, up to an average of 42 adult individuals per square meter could be counted. Differences were found in the size of male and female individuals with 27.2 mm in length and 24.4 mm, respectively, as well as differences in the abdominal sternites with a modification in a reduction of the sternites to a spine and a heavily sclerotized stooped aedeagus in the male; and the female with an abdomen without the spine, with the anterior margin of the pygidium sinuous.

Strategus aloeus (Coleoptera: Scarabaeidae) damage in two agave species and its management based on entomopathogenic fungi in oil suspensions

Teodulfo Aquino-Bolaños — 2024-01-11

Due to its agroecological characteristics, more than 24 species of agave have been developed and cultivated in the state of Oaxaca, Mexico, which have been fully exploited for the production of mezcal, an activity of economic importance. This crop is affected by the incidence of Strategus aloeus (Coleoptera: Scarabaeidae), an insect that causes damage and losses of economic importance to agave plants less than 3 years of age, for its control systemic insecticides are used; however, due to the habits of the insect, biological control is an alternative for its management. In this study, losses and damage caused by adults of S. aloeus on Agave potatorum Zucc. and A. angustifolia Haw. were determined from field observations. In the laboratory, two entomopathogenic fungi, Beauveria bassiana and Metarhizium robertsii (formerly known as M. anisopliae), were evaluated at a concentration of 1X107 conidia/insect in vegetable oil emulsions (Persea americana, Ricinus communis, and Prunus dulcis) at two concentrations of 20 % and 40 %. The damage found for A. potatorum with a sample size of 85 plants evaluated was 79.90 %. For A. angustifolia, with the same number of plants, 65.86 % damage was found. The losses found in 85 plants of A. angustifolia with damage grades 4 and 5 were 1 794.9 and 2 227.5 g/plant and for A. potatorum with damage grades 4 and 5 were 1 631.9 and 2 119.7 g/plant. In the laboratory, 48 hours were needed for 10 0% effectiveness on S. aloeus adults with the treatments B. bassiana + P. americana 40 % and B. bassiana + P. dulcis 40 %.

The Development and survival of Triatoma barberi and Triatoma longipennis (Hemiptera: Reduviidae) is affected by Trypanosoma cruzi colonization

Marco Antonio Becerril-Flores — 2024-03-13

Triatomines are insect vectors of the flagellate protozoan Trypanosoma cruzi, the causative agent of Chagas disease. This occurs when the triatomine defecates on the skin of the vertebrate host when it bites its host for feeding. This lesion causes the penetration of T. cruzi, whose infective phase is the tripomastigote, and the non-infective replicative phase epimastigote. Although the effects of T. cruzi on the development and survival of different species of triatomine bugs are known, it has not been fully described how the parasite affects many of the species that inhabit Mexico. Therefore, the present study aimed to investigate the effect of the presence of T. cruzi on triatomine development and survival. For this, five triatomines of each instar of each species, Triatoma barberi and Triatoma longipennis, were inoculated, from their second instar to their adult stage, female or male. Each triatomine was infected with 3-5 x105 parasites and they were incubated for 100 days and the kinetic of parasites in the feces and T. cruzi phases were recorded. The results showed that T. barberi and T. longipennis development was affected in all stages because of T. cruzi infection. It was greater for T. longipennis, both in its mortality, as well as time to molt in each phase.