Diaphorina citri Kuwayama (Hemiptera: Liviidae) is a vector of Liberibacter asiaticus Jagoueix et al. and Liberibacter americanus Teixeira et al., causal agents of the critical yellow dragon disease or Huanglongbing (HLB), which affects citrus production worldwide. Recently, green synthetic nanoparticles have emerged as a potential alternative to control of agricultural insect pests. The insecticide effect of silver nanoparticles (AgNPs) on 2nd instar nymphs of D. citri under laboratory and greenhouse conditions was evaluated. Mortality was recorded 24, 48, and 72 h after application on D. citri nymphs under both laboratory and greenhouse conditions. The laboratory results showed that AgNPs caused 97.84 and 100% mortality at 32 and 64 ppm, respectively, 72 h after treatment. In the greenhouse, AgNPs caused 78.69 and 80.14% mortality using 64 and 128 ppm 72 h after application. This research is the first to evaluate the green synthesis AgNPs on D. citri and are a promising strategy to control the pest.

En México, Anastrepha ludens (Loew, 1873) (Díptera: Tephritidae), es una de las plagas más importantes en el cultivo de cítricos. Actualmente, en el estado de Tamaulipas A. ludens genera daños económicos en el cultivo de naranja temprana (Citrus sinensis var. navelina, 1765), naranja valencia (Citrus sinensis L. Osbeck, 1765) y en el cultivo de toronja roja (Citrus paradisi var. red blush, 1830). Debido a esto es necesario conocer cómo las etapas fenológicas de los cultivos participan en la ocurrencia del insecto. Por lo que, el presente estudio tuvo como objetivo analizar el grado de asociación de la fenología del cultivo de naranja temprana, naranja valencia y toronja roja, con la abundancia de adultos de A. ludens. El estudio se realizó de enero a diciembre de 2022, en 120 sitios distribuidos en los municipios de Güémez, Llera de Canales, Padilla y Victoria, Tamaulipas, México. En estos sitios se registró el número de adultos por semana en cada una de las etapas fenológicas de las tres variedades de cítricos. La asociación entre el número de adultos de A. ludens y las etapas fenológicas de las tres variedades de cítricos, se determinó mediante el análisis de correspondencia múltiple (ACM). Los resultados obtenidos indican que la mayor cantidad de insectos ocurrió en árboles con flores y frutos en etapa de madurez de cosecha. Mientras que, la menor cantidad de insectos se presentó en árboles con frutos en la etapa de desarrollo y madurez fisiológica. Estos resultados servirán para redefinir el manejo integrado de A. ludens en Tamaulipas.

In Tamaulipas, citrus production faces a phytosanitary risk due to the presence of Anastrepha ludens (Loew,1873), Anastrepha obliqua (Macquart, 1835), Anastrepha serpentina (Wiedemann, 1830), and Anastrepha striata (Schiner, 1868), since the females of these species oviposit inside the fruit, and the larval instars feed on them. However, the population fluctuation of these four species in the citrus-growing region of Tamaulipas remains unknown. The objective of this study was to determine the population fluctuation of A. ludens, A. obliquas, A. serpentina, and A. striata in Early orange (Citrus sinensis var. Navelina), Valencia orange (Citrus sinensis L. Osbeck) and Red grapefruit (Citrus paradisi Macfad var. Red Blush) cultivars in the municipalities of Güémez, Llera de Canales, Padilla and Victoria, Tamaulipas. To accomplish this, Multilure traps baited with hydrolyzed protein were deployed for 52 weeks, and the number of captured adults was recorded to calculate the FTD (Flies/Trap/Day) index. The data were then analyzed using analysis of variance and the Kruskal-Wallis test to assess differences among crops. The results showed that the average capture rates of A. ludens, A. serpentina and A. striata were similar in three citrus varieties, while the abundance of A. obliquas was significantly different in Valencia orange crop. Additionally, A. obliquas, A. serpentina and A. striata were recorded from January to August, whereas A. ludens was present from January to December, with peak abundance in March, May and October.

Background: Currently, there is little information on the abundance of Diaphorina citri Kuwayama (Hemiptera: Liviidae) eggs and nymphs in the size of vegetative shoots. Such information is relevant for the control of D. citri in early stages of development. Objective: To associate the abundance of eggs and N1 nymphs of D. citri with the size of the vegetative shoots of the Valencia orange (Citrus sinensis (L.) Osbeck) crop. Methodology: The study was carried out in the Valencia orange crop in the municipality of Güémez, Tamaulipas. In the field, five categories of shoots were selected under a randomized experimental design. Thirty shoots of each size were confined in a teal tulle bag and 30 shoots of each size were cut to one side of the confined shoot. The number of eggs and N1 nymphs was recorded at 3, 5 and 7 days in each shoot size. The result obtained was subjected to a multivariate analysis of multiple correspondence. Results: In the confined outbreaks, 9 to 27 eggs were recorded in the V2 and V3 outbreaks at three days, and from 71 to 213 eggs in the V4 outbreak at five days. At seven days the number of eggs was like that recorded on day five. In the control shoots, at three and five days, 1 to 3 eggs were recorded in the V5 shoot. At seven days, the number of eggs recorded in shoots V2, V3, V4 and V5 was like that recorded at three and five days. In the confined shoots, at three days no N1 nymphs were recorded in the V5 and V1 shoots. On day five, nine N1 nymphs were recorded in the V2 shoot. While, on day seven the number of N1 nymphs was like that recorded on days three and five. In the control shoots, at three, five and seven days, 1 to 71 N1 nymphs were recorded in the V3 shoot. Implications: The results of this study are useful input for the development of management strategies targeting D. citri eggs and nymphs to suppress the presence of adults. Conclusion: According to the results, the trials allowed the identification of those categories of vegetative shoots preferential for N1 nymphs and oviposition of adults. This preference may be related to the quality and quantity of photo assimilates present in the different developmental stages of vegetative shoots, which are essential for insect development.

En campo, la presencia y abundancia de Diaphorina citri es influenciada por múltiples componentes bióticos y abióticos. En el presente trabajo se determinó la participación de la temperatura y precipitación pluvial en la abundancia poblacional de D. citri. El trabajo fue desarrollado durante el periodo 2015-2018 en el Área Regional de Control (ARCO) número 3 localizada en los municipios de Ciudad Victoria y Güémez, Tamaulipas, México. En el ARCO, el trampeo de D. citri se realizó con trampas pegajosas amarillas y se registró la temperatura y precipitación por mes. Los datos previamente ordenados fueron sometidos a un análisis de correspondencia múltiple. Se encontró que temperaturas entre 22 a 28°C y precipitaciones menores a 22 mm fueron las óptimas para mantener altas poblaciones de D. citri en la zona de estudio.

Citrus production faces significant phytosanitary challenges caused by Anastrepha ludens (Loew, 1873) and the bacterium Candidatus Liberibacter asiaticus (Jagoueix, Bové, and Garnier, 1994), transmitted by Diaphorina citri (Kuwayama, 1908), which causes Huanglongbing (HLB) disease. HLB-infected fruits are poorly colored (reverse ripening, yellow/green), deformed, small, and have reduced acidity and total soluble solids. These fruit characteristics may influence the abundance of A. ludens, since fruits are used as feeding, oviposition, and refuge sites. This study associated the abundance of A. ludens in commercial citrus orchards (with different numbers of HLB-infected trees) in the municipalities of González, Güémez, Hidalgo, Llera de Canales, Padilla, and Victoria, Tamaulipas, Mexico. The association between A. ludens abundance and the number of trees with HLB was analyzed using Multiple Correspondence Analysis (MCA). MCA revealed a higher frequency of A. ludens adults in Güémez, Padilla, and Victoria, where HLB incidence was highest (highest number of trees). In contrast, the lowest abundance of A. ludens adults was recorded in González, where HLB was virtually absent (lowest number of trees). It is recommended that the municipalities of Güémez, Padilla, and Victoria be prioritized in integrated management plans for A. ludens and HLB to mitigate the impact on citrus production.