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.

Domesticated tomato (Solanum lycopersicum L.) crops have presented an increased susceptibility to pests under field and greenhouse conditions. Among these pests is tomato/potato psyllid, Bactericera cockerelli Sulc (Hemiptera: Triozidae), a major pest in solanaceous crops. In this study, we evaluated volatile organic compound (VOC) emissions from the headspace in three healthy varieties of tomato plants (Floradade, Micro-Tom and wild) under greenhouse conditions using solid-phase microextraction and gas chromatography–mass spectrometry (SPME/GC-MS). Later, independent bioassays were performed to evaluate VOC emissions with three varieties infested with nymphs of B. cockerelli. The results in healthy plants showed markedly different VOC profiles in each variety (14 compounds for wild, 17 for Floradade and 4 for Micro-Tom). Plants infested with nymphs showed changes in VOC emissions distinctly in Floradade and wild varieties. We suggest that these qualitative differences in VOC profiles by the degree of domestication could explain the preferences of B. cockerelli.

The potato/tomato psyllid Bactericera cockerelli is the Candidatus Liberibacter solanacearum bacterium vector that causes diseases in Solanaceae crops. Pest control is based on synthetic chemical insecticides, plant extracts, and natural enemies such as parasitoids. Tamarixia triozae feeds on nymphs of B. cockerelli, reaching up to 95% parasitism. This work aimed to evaluate the parasitic performance of T. triozae on tomato leaves with B. cockerelli N3 nymphs, using two domesticated (Floradade and Micro-Tom) and one Wild tomato variety. Several assays were completed to identify the parasitoid attraction toward un-infested plants (healthy) and infested plants (damaged) of three varieties. Parasitism preference and “Y” tube olfactometer tests were performed, respectively. The parasitism of Tamarixia triozae showed a preference toward plants of the Floradade variety by 44% compared with the other two varieties (p = 0.0003). T. triozae was more attracted to damaged plants of the Wild variety (p = 0.0523). Healthy plants of Floradade and Micro-Tom varieties attracted a higher proportion of parasitoids, except in the Wild variety, where T. triozae was more attracted to damaged plants. Taken together, the results of this study show that the domestication degree in tomato plants positively influenced the interactions between tomato plants and the parasitoid, T. triozae.

The agave pulquero (Agave salmiana Otto) has ecological, economic, and social value in several regions of México, especially Hidalgo State. The current importance of the plant requires developing more agricultural practices for effect production of the crop. From September to October 2019 at the municipality of Alfajayucan, Hidalgo, México, unusual damage was detected on A. salmiana plants and suckers with symptoms of severe defoliation by lepidopteran larvae, later identified as Spodoptera ornitogalli (Guenée). The species damaged 23% of plants with severity as much as 100% on the agave pulquero crop. This is the first report of A. salmiana foliage damaged by S. ornithogalli, which should be considered a potential pest of the agave crop.

The objective of the research was to evaluate the effect of relative humidity (RH) and moisture content (MC) on the incidence of pathogenic fungi on the seeds of Agave lechuguilla, Lippia graveolens, and Nolina cespitifera. Seeds were stored 90 days at 60, 75, 80, and 85% RH, and results were processed with a correlation analysis in the R software using the Spearman test. Higher fungi incidence (FI) in seeds was found from 10 to 20% RH; however, correlation between RH and MC of seeds was positive with r = 0.311 and $p=2.2\times {10}^{-16}$ . In general, RH is related to MC, but not to fungi incidence, which is related mainly to MC of seeds. Correlation between RH and FI for each seed species was not significant, r = 0.026, −0.040, and 0.071 and $p=0.687$ , 0.540, and 0.272 for A. lechuguilla, N. cespitifera, and L. graveolens, respectively. There was a positive correlation between the MC of seeds with fungi incidence; a negative correlation between the RH and the FI; and a positive correlation between the RH and the MC of seeds. In this type of seeds (orthodox), the MC is probably the most important factor in determining its longevity. The seeds under study can be stored in a 60% to 75% RH. Five fungi genera were found, predominating Aspergillus with five identified species.

Introducción: Bactericera cockerelli es un insecto que daña cultivos de solanáceas, principalmente papa (Solanum tuberosum L) y tomate (Solanum lycopersicum L). El manejo de B. cockerelli ha sido el control químico; sin embargo, se han tratado de implementar otras estrategias de control con insecticidas menos tóxicos para el medio ambiente, la salud humana e insectos no blanco. Esta implementación consiste en incluir organismos de control biológico como depredadores, parasitoides, insecticidas de origen natural y botánicos, hongos entomopatógenos e insecticidas químicos con menor impacto en fauna benéfica. Con el fin de profundizar en estas interacciones, el presente trabajo determinó la concentración letal media (CL50) de insecticidas sobre las poblaciones de B. cockerelli y su parasitoide Tamarixia triozae. Con estos datos se calculó el porcentaje de selectividad (PS) de los diferentes insecticidas con el parasitoide T. triozae.Método: Se realizaron bioensayos mediante el método de inmersión tratando de simular las aplicaciones de cobertura completa que se realizan en campo; se evaluaron seis insecticidas; Profenofos y Cipermetrina de origen organosintético; Azadiractina y AEC (Aceites esenciales de cítricos con canela y jabón de aceites vegetales) de origen botánicos; una cepa de Beauveria bassiana y otra de Metarhizium anisopliae. Con los datos obtenidos se determinó la selectividad utilizando la Proporción de Selectividad (PS), dividiendo la CL50 del producto sobre el enemigo natural entre la CL50 del producto sobre el insecto plaga, donde valores iguales o mayores a uno nos indica selectividad.Resultados: Los productos insecticidas evaluados mostraron mortalidad en B. cockerelli y su parasitoide T. triozae. La menor proporción de selectividad fue para Cipermetrina (PS = 0.01) y solo M. anisopliae mostró selectividad con T. triozae al obtener un valor de PS = 3.58. Los demás insecticidas mostraron valores de PS menores a uno por lo que se consideraron no selectivos para el parasitoide.Conclusión: Con base en los índices de selectividad, la letalidad hacia T. triozae fue mayor que a B. cockerelli. La mayor toxicidad fue en los insecticidas de origen organosintéticos, botánico y biológico en ese orden. La excepción fue la cepa de la especie Metarhizium anisopliae, que mostró selectividad (PS=3.58) hacia el parasitoide.