Red spider mites, Tetranychus merganser Boudreaux (Acari: Tetranychidae), is an agricultural pest that causes economic losses in papaya and nopal crops in Mexico. The aim of this research was to assess antibiosis and antixenosis as resistance mechanisms in seven host plants (Thevetia ahouai, Carica papaya, Phaseolus vulgaris, Moringa oleifera, Pittosporum tobira, Helietta parvifolia, Capsicum annuum var. glabriusculum) to red spider mites. Antixenosis was evaluated by non-preference for oviposition and feeding, antibiosis by infinitesimal rate of increase, finite rate of increase and doubling time, and the percentage of spider mites mortality. Oviposition and damage by feeding of T. merganser were significantly greater on C. papaya than on the other host plants. The growth rate of the spider mite was significantly lower in P. tobira and T. ahouai than in the other host plants. The percentage of hatched eggs of T. merganser was significantly higher in P. vulgaris than in the other plant species. Based on the demographic parameters, survival, food intake, and oviposition, these results indicated that compared with C. papaya, P. tobira and T. ahouai were more resistant. These results may be due to the fact that they were plants species of different families. The resistant plants can be studied as alternatives in the management of T. merganser.

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ResumenLa mosca mexicana de la fruta Anastrepha ludens (Loew), es una de las plagas de mayor impacto en la citricultura en Tamaulipas. Ataca hospederos de importancia comercial como la naranja, toronja y mandarinas restringiendo su movilidad comercial a mercados nacionales o internacionales. En este estudio a partir de la fluctuación poblacional durante los años 2008 a 2011 de A. ludens en el área de Santa Engracia se determinaron tres periodos con base a la presencia del insecto y su relación con la temperatura promedio: eneroabril, mayo-agosto y septiembre-diciembre. La estadística descriptiva destacó la variabilidad entre las observaciones, sugiriendo una heterogeneidad en las densidades del insecto. El MTD (mosca/trampa x día) promedio semanal se relacionó con diferentes variables climáticas mediante un análisis de regresión lineal y múltiple, observándose correlaciones débiles en general debido a la variación del MTD promedio. La temperatura mínima fue la variable más consistente y con mayor ajuste. La temperatura mínima y máxima en la regresión múltiple representaron las variables explicatorias para cada año, mientras que la precipitación no presentó una asociación clara con el MTD promedio quizás por actividades de riego dentro de las áreas comerciales o por una influencia desfasada. Se observó una asociación AbstractThe Mexican fruit fly Anastrepha ludens (Loew) is a pest of great impact on citrus in Tamaulipas.

Large citrus areas in Tamaulipas are affected by Anastrepha ludens (Loew) populations. Here we report the findings of a spatio-temporal analysis of A. ludens on an extended citrus area from 2008-2011 aimed at analyzing the probabilities of A. ludens infestation and developing an infestation risk classification for citrus production. A Geographic Information System combined with the indicator kriging geostatistics technique was used to assess A. ludens adult densities in the spring and fall. During the spring, our models predicted higher probabilities of infestation in the western region, close to the Sierra Madre Oriental, than in the east. Although a patchy distribution of probabilities was observed in the fall, there was a trend toward higher probabilities of infestation in the west than east. The final raster models summarized the probability maps using a three-tiered infestation risk classification (low-, medium-, and high risk). These models confirmed the greater infestation risk in the west in both seasons. These risk classification data support arguments for the use of the sterile insect technique and biological control in this extended citrus area and will have practical implications for the area-wide integrated pest management carried out by the National Program Against Fruit Flies in Tamaulipas, Mexico.

The Mexican fruit fly, Anastrepha ludens Loew (Diptera: Tephritidae), is one of the most important pests of citrus in Mexico. We report the results of an analysis of A. ludens populations that inhabit the semi-arid highlands of the Sierra Madre Oriental in northeastern Mexico. This study aimed to provide information on population fluctuation of A. ludens and how it relates to climate variables, as well as insights into habitat and native parasitoids. Population peaked in the period July-November when ripe fruits of the wild host, Casimiroa pubescens Ramírez, were available. No adults were captured the rest of the year, suggesting that high populations depend on the availability of wild host fruit. No significant relationships between population fluctuation and climatic variables were observed, except for minimum temperature. Fruit samples of citron (Citrus medica L.), pomegranate (Punica granatum L.), and C. pubescens were collected to determine degree of infestation. Infestation levels (pupae/g) ranged between 0.0006 for citron, 0.0047 for pomegranate, and 0.0240 for C. pubescens. A native parasitoid of Tephritidae, Doryctobracon crawfordii (Viereck) (Braconidae), was identified. Parasitism percentage was calculated at 12.5% on C. pubescens fruits. No parasitoids were observed on citron or pomegranate fruit samples. These results contribute to knowledge on behavior of A. ludens native to temperate environments where no commercial hosts are available. Further research on host expansion of this pest in light of scenarios of global climate change is suggested.