Desarrollo postembrionario de Cactodera galinsogae (Tylenchida: Heteroderinae) en cebada (Hordeum vulgare L.) Y el papel de malezas como hospedantes

During 2005, two field assays were carried out in Singuilucan, Hidalgo, Mexico, with the purpose of establishing the development time of Cactodera galinsogae life cycle phases in barley roots of the locality type. The first assay consisted in broadcast planting seeds of barley cv. Esmeralda over a 25 m² experimental plot at a sowing density of 200 kg ha^-1. Every seven days from sowing date to the conclusion of the barley cycle, a soil and a plant sample was collected. In parallel with this assay, a secon experiment was conducted to evaluate the effect of C. galinsogae on two barley varieties. All the weed species grown during the barley crop cycle were collected every seven days. In the first assay, the second stage juveniles (J₂) were found in the soil, from the sowing date and during all the samplings carried out. Likewise, the juveniles J₂ were observed in the root from die seventh day and until the last sampling. Juveniles (J ₃) and (J₄) appeared within the roots at 21 and 28 days, respectively. The white females adhered to the roots and males in soil were found at 42 days. At 56 days, females with eggs and the first cysts adhered to the root were detected. In the second assay, 20 weed species grown in the barley fields of the zone were identified, belonging to 13 botanical families. The nematode reproduced best on Galinsogae parviflora and Bidens odorata, followed by Bidens ballsii and Bidens serrulata, members of Asteraceae. C. galinsogae also reproduced on barley and wild oats, members of Poaceae.