In Mexico, agaves (Asparagaceae) have great economic importance due to several uses, which the species have (Gentry, 1982; Granados, 1993; Valenzuela, 2011). According to SIAP (2017) there are 105,690 ha cultivated with different agave species. In Morelos state, commercial agaves are growing recently in extension by number of farmers, but this crop is having some important pest as the agave weevil Scyphophorus acupunctatus Gyllenhal, 1838 (Coleoptera: Dryophthoridae). Integrated Pest Management of this weevil in Jalisco is based on adult monitoring with semiochemical-baited traps (Figueroa-Castro et al., 2013; Figueroa, 2014), but this tool has never been tested under Morelos conditions. In order to calculate the infestation level of S. acupunctatus on agave crops, we conducted a monitoring study with semiochemical-baited traps in Tlaquiltenango, Morelos.
The present research was performed (May - June 2017) in five agave plantations located at the municipality of Tlaquiltenango, Morelos: 1) Plantation “La Era 1”, Agave angustifolia Haw., surface 2 ha, 3 years-old (18.552721, -99.099418, 894 m asl); 2) Plantation “La Era 2”, A. angustifolia, surface 2 ha, 3 years-old (18.551373, -99.097901, 885 m asl); 3) Plantation “El Poste”, A. angustifolia, surface 2 ha, 4 years-old (18.563930, -99.093300, 890 m asl); 4) Plantation “Mezquitera Verde”, A. angustifolia, surface 2 ha, 2 year-old (18.564151, -99.084299, 898 m asl); and, 5) Plantation “Mezquitera azul”, A. tequilana F. A. C. Weber, surface 2 ha, 2 year-old (18.563775, -99.084698, 897 masl). In each plantation four traps were placed at ground level, with 50 m between traps.
Traps were handmade (design TOCCI, Figueroa-Castro et al., 2016). Each trap was baited with a dispenser of synthetic aggregation pheromone Tequilur® (Ferocomps, México) plus 400 g of ripped banana fruit, as recommended by Figueroa-Castro et al. (2017) sprinkled with the insecticide clorpirifos ethyl (Losrban 480 EM, Dow Agrosciences, Mexico). Traps were checked and give service biweekly. Trapped weevils were kept in ethyl alcohol at 70% and were taken at “Laboratorio de Producción Agricola del Campo Experimental de la Facultad de Ciencias Agropecuarias de la Universidad Autónoma del Estado de Morelos” for recording males/females using a stereoscopic microscope according to the criteria of Ramírez-Choza (1993). Data were organized and graphed in Excel© Office by Microsoft 2016.
Agave weevil was collected (May - June 2017) in all agave plantations sampled (Table 1), confirming the potential of pheromone-baited traps as a tool for detecting and monitoring the weevil density in agave plantations (Figueroa-Castro et al., 2013). Agave weevil were detected in high numbers at the “El Poste” plantation (the oldest plantation studied). The lowest number of captured weevils were recorded on “Mezquitera Azul” and “Mezquitera verde” both two years old plantations (the youngest plantations). It was observed that the age plants may have a strong influence on agave weevil response, for example Waring and Smith (1986) observed that the agave weevil prefer blooming wild agave plants compare to no blooming wild agave plants.
The mean number of weevils captured in these agave plantations is lowest than captures of this pest on the tuberose crop (Polianthes tuberosa L.) in Morelos (López-Martínez et al., 2011) and in blue agave in Jalisco (Figueroa-Castro et al., 2013) using the same trap design, but it is higher than captures in mezcal agave in Guerrero (Figueroa-Castro et al., 2017). The presence of this pest in all the sampled agave plantations may be due to that in Morelos State there are several wild agave plants that are attacked by this pest. In Morelos the tuberose plant crop P. tuberosa is also an important host of this weevil (Camino-Lavin et al., 2002; López-Martínez et al., 2011).
By the other hand, sexual proportion of weevil showed an irregular pattern between agave plantations (Table 1), where more females were collected in two plantations (La Era 1 and La Era 2), more males in two (Mezquitera verde and Mezquitera azul), and in “El Poste” this proportion was 1:1. In contrast, Figueroa-Castro et al. (2013) found more females than males in traps with this synthetic pheromone in blue agave tequilero plantations.
Based in our results we can confirm that agave weevil has an important phytosanitary risk to agave plantations in Morelos, and future studies should be conducted to try and implement control strategy for developing an integrated pest management program against the agave weevil. This infestation levels are lower compare to those detected in Jalisco state (Figueroa-Castro et al., 2013), but are higher than those infestations levels found in Guerrero state (Figueroa-Castro et al., 2017).
Plantation | agave kind | weevils/trap/biweekly | Sexual rate(%) | |
---|---|---|---|---|
Females | Males | |||
La Era 1 | Espadín oaxaqueño | 22.75 | 52.14 | 47.86 |
La Era 2 | Espadín oaxaqueño | 28.83 | 67.08 | 32.92 |
El Poste | Espadín oaxaqueño | 34.92 | 50.67 | 49.33 |
Mezquitera Azul | Tequilero | 21.58 | 45.14 | 54.86 |
Mezquitera Verde | Espadín oaxaqueño | 18.42 | 34.96 | 65.04 |