Host status of weeds for Pratylenchus coffeae

Abstract

Background: Populations of yam dry rot nematodes Scutellonema bradys, Pratylenchus coffeae and P. brachyurus can be sustained on weed hosts. Objective: Evaluate the reaction of 10 weeds frequently found in Alagoas to P. coffeae under greenhouse conditions. Methods: Two experiments were carried out in a completely randomized design, with 11 treatments, constituted of 10 weed species and the control (Dioscorea cayenensis) with eight replications. Plants were inoculated with 2,000 nematode specimens, nematode populations were evaluated in roots and soil 60 days after inoculation and the reproduction factor (RF) defined as RF = final population/initial population was calculated. Results: Euphorbia hyssopifolia showed RF=0 and was considered as non-host, whereas Chenopodium album, Amaranthus sp., Panicum maximum, Eleusine indica, Senna occidentalis, Emilia coccinea and Richardia brasiliensis, showed RF<1, being rated as poor hosts. Ricinus communis and Macroptilium lathyroides showed RF>1 only in the second trial and were classified as good hosts. Conclusion: Ricinus communis and M. lathyroides are potential sources of nematode inoculum for dry rot disease development.