En el control de plagas agrícolas, los insecticidas representan la principal alternativa disponible. Para analizar la magnitud de su uso, se realizaron 539 entrevistas a agricultotes en los siguientes cultivos: Cucurbitaceae: melón, Cucumis melo L. y sandía, Citrullus lanatus (Thunb.), Fabaceae: frijol, Phaseolus vulgaris L., Solanaceae: papa, Solanum tuberosum L., pimiento, Capsicum annuum L. y tomate, Solanum lycopersicum L., ubicados en las provincias: Chimborazo, El Oro, Guayas, Loja y Santa Elena. Se recabó información sobre plagas importantes, tipo de manejo y si resultaba plaguicida químico, se consignaba: nombre genérico, ingrediente activo, toxicidad aguda, dosificación aplicada, frecuencia de aspersiones, períodos de carencia y mezclas de productos. El total de los entrevistados manifestó utilizar mezclas de insecticidas, generalmente elevando las dosificaciones recomendadas sin tomar en cuenta los periodos de carencia. Además, señalaron realizar 2,6; 1,1; 0,5; 2,0 y 2,8 aspersiones semanales promedios para cucurbitáceas (melón y sandía), frijol, papa, pimiento y tomate, respectivamente. Las plagas principales mencionadas fueron: áfidos (Hemiptera: Aphididae) en cucurbitáceas y pimiento, Liriomyza spp. en frijol (Diptera: Agromyzidae), Premnotrypes vorax (Hustache) (Coleoptera: Curculionidae) en papa y Prodiplosis longifila Gagné (Diptera: Cecidomyiidae) en tomate. Aproximadamente el 80% de los insecticidas utilizados pertenecen a las Clase I y II. Los resultados indicaron altas frecuencias de aspersiones, dosificaciones elevadas y alta toxicidad para vertebrados en los insecticidas usados. Dado el impacto de los insecticidas, es necesario estudiar los desequilibrios en los agroecosistemas, efectos en salud y ambiente, así como validar alternativas ecológicas y socioeconómicamente más racionales.

Begomoviruses are one of the major groups of plant viruses with an important economic impact on crop production in tropical and subtropical regions. The global spread of its polyphagous vector, the whitefly Bemisia tabaci, has contributed to the emergence and diversification of species within this genus. In this study, we found a putative novel begomovirus infecting tomato plants in Venezuela without a cognate DNA-B component. This begomovirus was genetically characterized and compared with related species. Furthermore, its infectivity was demonstrated by agroinoculation of infectious clones in tomato (Solanum lycopersicum) and Nicotiana benthamiana plants. The name Tomato twisted leaf virus (ToTLV) is proposed. ToTLV showed the typical genome organization of the DNA-A component of New World bipartite begomoviruses. However, the single DNA component of ToTLV was able to develop systemic infection in tomato and N. benthamiana plants, suggesting a monopartite nature of its genome. Interestingly, an additional open reading frame ORF was observed in ToTLV encompassing the intergenic region and the coat protein gene, which is not present in other closely related begomoviruses. A putative transcript from this region was amplified by strand-specific reverse transcription-PCR. Along with recent studies, our results showed that the diversity of monopartite begomoviruses from the New World is greater than previously thought.

Diaphorina citri Kuwayama (Hemiptera: Liviidae) is the main vector of the bacteria that causes Huanglongbing (HLB), the most destructive disease of Citrus. The presence of D. citri was reported in Ecuador in 2013 on branches of citrus, Citrus spp., and orange jessamine, Murraya paniculata (L.) Jack (Rutaceae), but HLB has not been detected so far in this country. This paper reports for the first time the presence of two important natural enemies of D. citri in Ecuador, i.e., its main parasitoid Tamarixia radiata (Waterston, 1922) (Hymenoptera: Eulophidae) and the adventitious ladybird beetle Cheilomenes sexmaculata (Fabricius, 1781) (Coleoptera: Coccinellidae) attacking psyllid nymphs on M. paniculata, in Guayaquil, Guayas province, Ecuador. A short diagnosis of the two natural enemies and their distribution in the New World is presented based on published literature.

Maize ( Zea mays L.), which is considered an important cereal everywhere, is widely cultivated in different agroecological conditions. Throughout their phenological stages, maize crops are attacked by pests and diseases, and in Ecuador these phytosanitary problems are usually counteracted with applications of pesticides. However, knowledge of beneficial entomofauna is fundamental to guide pest management programs. As part of this objective, the Coccinellidae species present in maize fields in localities (Santa Ana, Colon, and Danzarin) in Manabí province were identified. In each zone, maize plants were sampled from 2018–2019. A total of 2,654 specimens belonging to 14 taxa were collected in this study, of which Cheilomenes sexmaculata , Cycloneda sanguinea , Hippodamia convergens , Hyperaspis arida , and Psyllobora confluens were found in all the studied areas. Hyperaspis arida and Diomus apollonia are reported for the first time in Ecuador.

Numerous studies conducted on a variety of temporal and spatial scales around the world show that dipteran parasitoids can exert effective control over some insect pests. This paper provides an overview of major examples of successful classical and augmentative biological control initiatives, organized by major dipteran families which include parasitoid species (i.e., Tachinidae, Phoridae, Sarcophagidae, Cryptochetidae, Bombyliidae, Syrphidae) and according to different global regions. In addition, examples of unsuccessful attempts at biological control using dipteran parasitoids are discussed, along with potential reasons for these failures. A notable drawback found during our literature review is that many parasitoids and host species are not correctly identified, and information on laboratory and field studies is rather scarce. Reproductive strategies of dipteran parasitoids and host-parasitoid associations need to be better investigated. Expanding the knowledge of these parasitoids is crucial for improving biocontrol strategies, especially against pests for which dipterans are key natural enemies.

Corn (Zea mays L.) is an important cereal for food sovereignty, extensively planted due to its adaptation to various agroecological conditions. Climatic conditions and pests can affect its production. Concerning the latter, natural enemies could be considered in biological control programs. The objective of this study was to estimate the influence of the presence of insects, damage to plants and cobs, and their incidence on corn yield in two planting seasons. During the rainy (February to May) and dry seasons (Jun to October) of the year 2023, in Calceta, Lodana, and Quevedo, three important corn-growing areas on the Ecuadorian coast, corn plots of 1126 m² were planted. The diversity of phytophagous and natural enemies was estimated. Damage to young plants and cobs was observed, and corn yield was determined. Of the 9073 insects observed, 44.2% and 55.8% constituted phytophagous and natural enemies, respectively. A moderate diversity (Shannon-H Index = 2.474–2.629 and Margalef Index = 2.734–3.110) of insects associated with corn was determined. Yield (range: 6.9 to 15.3 t) was negatively correlated with rainfall and cob damage (p < 0.05). Although precipitation is necessary for planting in rainy season, frequent and intense rains could be affect corn yield.