Revista Colombiana de Entomología

Prodiplosis longifila (Diptera: Cecidomyiidae), evolution as a pest and a method to assess its populations on tomato

2019-08-30T14:32:01-05:00

Since the mid 1980´s, Prodiplosis longifila has become the most important entomological problem for tomato crops in Ecuador. The lack of bioecological knowledge for guiding its rational management has resulted in excessive insecticide usage. Since both the insect and the plant are of neotropical origin, the insect’s recent evolution as a phytosanitary problem raises challenging questions. Population studies including biotic regulatory factors are necessary to answer these questions. One methodological approach consists of estimating the percentage of affected plants, complemented with the number of insects in periodic samples of infested foliage along the crop cycle. The usual method of carrying field samples to the laboratory wrapped in paper towels inside plastic bags was inefficient since many larvae became trapped in the moisture inside the bags or spun their cocoons on the paper towel, making their recovery for rearing to obtain adults and parasitoids time consuming. Thus, taking advantage of the insects’ habit of pupating in the soil, a sample container with sieved soil in the bottom was designed so larvae that completed development could drop to spin their cocoons, which were then easily recovered by sieving. The time economy (5x < time), the number of cocoons obtained from the samples and the adults reared from them (5.0-7.7x>), as well as the higher correlation coefficients (1.2-1.9x>) for cocoons vs. adults and parasitoids reared from containers with soil compared to plastic bags, show the comparative efficacy of this new sampling method.

Distribution of Haplaxius crudus (Van Duzee, 1907) (Hemiptera: Cixiidae), in the oil palm areas of Colombia

2021-09-18T23:48:13-05:00

Lethal wilt of oil palm (ML, for it name in Spanish) is an economically important disease of the oil palm Elaeis guineensis Jacq., 1897 (Arecales: Arecaceae) in Colombia, where it has reached epidemic levels in the Eastern Palm Zone, with 902,529 cases recorded between 1997 and 2018. The insect vector of ML is probably the cixiid planthopper Haplaxius crudus. The objective of this study was to obtain information on the presence and distribution of H. crudus in the oil palm areas of Colombia. Sampling was carried out by passing an insect net to the oil palm foliage, to collect the adults, and checking grasses, and sedge hosts to collect the nymphs. The results indicate that H. crudus is present in 163 oil palm plantations, located in 42 palm municipalities distributed in the North, Central, and Eastern oil palm zones of Colombia. We concluded that the presence of this insect is broader than what had been initially recorded. This work provides essential information to the oil palm industry since it allows to be alert about the possible spread of lethal wilt of oil palm once a diseased palm is detected in areas free of this disease.

Bt protein toxicity in Spodoptera frugiperda (Smith) (Lepidoptera: Noctuidae) fed on maize stigmas in Paraguay

2021-12-12T15:45:18-05:00

The “The fall armyworm” Spodoptera frugiperda (Smith) is considered a key pest in the maize crop. Genetically modified maize, event or Bt maize (Bacillus thuringiensis) contain genes that express toxic proteins for this pest, different for each event. The objective of this research was to evaluate the toxicity between Bt events, determining the mortality and the biological parameters of importance. The S. frugiperda population previously collected from the field was reared under laboratory conditions fed with stigmas of MIR162TM (Vip3A19), VT3ProTM (Cry1A105, Cry2Ab2, Cry3Bb), PowerCoreTM (Cry1A105, Cry1F, Cry2Ab2), and treatment with non-Bt BR106 maize. The event with the VIP3Aa19 protein (MIR162TM) had high toxicity in the expression of the plant stigmas against S. frugiperda. The VT3ProTM (Cry1A105, Cry2Ab2, Cry3Bb) and PowerCoreTM (Cry1A105, Cry1F, Cry-2Ab2) events showed low toxicity in the expression of plant stigmas. The VT3ProTM event (Cry1A105, Cry2Ab2, Cry3Bb) can affect the fecundity of the surviving insect population.

Repellence and oviposition inhibition of Diaphorina citri (Hemiptera: Liviidae) with minerals oils in controlled conditions

2021-10-11T15:56:09-05:00

Diaphorina citri is one of the most important pests in citrus orchards and is associated with the transmission of Huanglongbing (HLB), a disease caused by the bacterium Candidatus Liberibacter asiaticus on citrus. Currently, the use of chemical insecticides is the most common control strategy for controlling D. citri; however, other alternatives such as the use
of mineral oils have been considered. Based on this, we studied the repellence and oviposition inhibition activity by the commercial mineral oils Akaroil®, Anasef - T®, Saf-T - Side® and Stylet Oil® on D. citri. The repellency was determined by exposing adults to previously treated orange leaves with different concentrations of mineral oils and the inhibition of oviposition by the residual application method. All tested oils caused significant ≥ 90 % repellent activity to 35 mg/mL, however, this decreased to concentrations below 10 mg/mL. The greatest repellent activity was achieved by the Saf-T-Side oil (RC50 = 0.14 mg/mL), followed by Anasef-T, Akaroil and Stylet Oil, with CR50 of 1.33, 1.92, 3.32 mg/mL, respectively. Doses as low as 1 mg/mL were enough to inhibit oviposition in up to 90 % in all tested oils. We conclude that the activity of mineral oils should be validated under field conditions to determine if they represent a useful tool within D. citri integrated management.

Susceptibility of sixteen strawberry (Fragaria × ananassa) cultivars to Drosophila suzukii (Matsumura, 1931) (Diptera: Drosophilidae) in Southwestern Spain

2021-10-25T18:37:23-05:00

The susceptibility of the newest and most used strawberry cultivars to the Spotted Wing Drosophila (SWD) in southwestern Spain was evaluated. Sixteen strawberry cultivars
were selected (‘Calderón’, ‘Calinda’, ‘Charlene’, ‘Flaminia’, ‘Flavia’, ‘Fortuna’, ‘Marisol’,
‘Marquis’, ‘Melissa’, ‘Palmeritas’, ‘Petaluma’, ‘Plared0955’, ‘Primoris’, ‘Rábida’, ‘Rociera’
and ‘Sabrina’) and no-choice tests were carried out under laboratory conditions. In addition, fruit weight, fruit firmness, °Brix, pH, protein content and total phenolic content were recorded in order to assess what influence these variables had on SWD infestation. The sixteen strawberry cultivars tested in this study were susceptible to SWD, although significant differences have been found among them. The mean number of emerged adults in ‘Calderon’ and ‘Plared0955’ were significantly higher than in the other tested cultivars. Significant differences in developmental time were also detected among these cultivars and both sexes but these were unrelated to the level of infestation. No correlation between fruit quality and chemical traits and infestation parameters was found. Our results detected significant differences in the susceptibility of strawberry cultivars in southwestern Spain to SWD; these may help to design IPM programs and to make recommendations for strawberry production, one of the most important crops in southern Europe.

Edaphic arthropods in different land use forms at Sierra Nevada, Tepetlaoxtoc, Estado de México, Mexico

2022-03-07T21:49:52-05:00

The objective of this study was to describe the diversity and abundance of edaphic microarthropods in relation to the physical and chemical characteristics of soils under different use and management and to characterize their structure in an area of stone mining or quarrying. For this purpose, edaphic microarthopods assemblages were studied in five zones with different land use: Conserved Pine-Oak forest (B), Degraded Pine-Oak forest (Z), Agricultural (V), Erosion (E), Mine (M), in Sierra Nevada (Tepetlaoxtoc, Mexico), in order to know their relationship with both physical and chemical parameters, and also their potential as bioindicators, using the values of the QBS-ar index, in stony mining areas. A positive and significant relationship was found with the abundance and moisture and organic matter percentages. Groups described as bioindicators, hyperparasitoids and predators were identified in sites with more conservation than those with greater degradation. The QBS-ar index values were higher in the area B. Three zones, B, M and E, were identified, according by their suitability for ecological rehabilitation action. The potential of soil microarthropods to be integrated into management programs and conservation and rehabilitation strategies in areas of stone mining was recognized.

Evaluation of Novaluron 0.2 G against Aedes (Stegomyia) aegypti (Diptera: Culicidae) in an urban area in Antioquia, Colombia

2021-11-08T19:38:22-05:00

Dengue, zika and chikungunya are globally important arboviruses. In the absence of a vaccine, health entities focus mainly on vector control using insecticides, Growth Regulatory Insecticides (IRC), including Novaluron, have proven to be effective in vector control. The objective was to determine the optimal application dose of Novaluron 0.2G on the emergence of Aedes aegypti in an urban area endemic for dengue, Carepa, in the department of Antioquia, Colombia. Twenty-one dwellings were randomly selected, where three 250-L tanks were located, two corresponded to treatments and one to control, evaluating three concentrations (treatments), ramdomly selected for each dwelling. The study was carried out for 18 weeks: seven weeks of pre-treatment, one week of product application and ten weeks of post-treatment. For this, the pupae of A. aegypti were collected, allowing the emergence of adult mosquito under controlled conditions, in order to estimate the weekly inhibition of the emergence. The results indicated that a reduction in the emergence of A. aegypti of close to 100% was achievedwith the highest concentration evaluated (0.584 mg/L). For the other concentrations (0.292 and 0.146 mg/L), the percent inhibition of emergence for week two was 79% and 45%, respectively.

A new species of Aleuropleurocelus Drews and Sampson (Hemiptera: Aleyrodidae) on grass from Mexico

2021-12-27T12:40:20-05:00

A new species of whitefly, Aleuropleurocelus popocatepetl Carapia-Ruiz y San-
chez-Flores sp. nov., is described from the State of Morelos, Mexico. It was collected on the leaves of the grass Dichanthelium dichotomum (L.) Gould (Poaceae) in Ocuituco, Morelos.
Microphotographs of the morphological structures of the puparia are included. Differences
with close species are discussed.

A new species of small myrmicine ant in the genus Eurhopalothrix Brown & Kempf, 1961 (Hymenoptera: Formicidae) from Colombia

2022-01-17T22:19:38-05:00

A new species of Eurhopalothrix Brown & Kempf, E. amati Fiorentino, Tocora and Fernández, n. sp. is described based on workers collected in northwestern Colombia. A taxonomic key and distributional map for the new species in the country are provided. This new species differs from other Eurhopalothrix ants by the configuration of specialized setation, a decrease in its propodeal spines, its irregular metanotum profile, and the triangular shape of the head capsule.

First report of Cephalonomia gallicola (Ashmead) (Hymenoptera, Bethylidae) in Mexico: A case of stings in humans

2021-11-15T08:39:52-05:00

Among the medically important Hymenoptera, the family Bethylidae stands out, among these the wasp Cephalonomia gallicola (Ashmead) (Hymenoptera: Bethylidae) that causes dermatitis in humans. This work reports for the first time in Mexico the presence of C. gallicola and a case of stings in humans. This report was raised in October 2019 where the affected people collected 20 specimens of C. gallicola and four individuals of its host (Lasioderma serricorne) within their home. The wasps caused approximately 10 stings per individual in three members of the affected family. This is the first reported record in Mexico of C. gallicola causing health problems in humans. Case records are sparse, possibly because the diagnosis must be based on the history and physical findings of the sting, which can be difficult unless a detailed explanation of the home environment is obtained. More research is required in the country of possible accidental human encounters with these insects, and how it affects the health of the population.