Effects of inoculation time on damage potential of Aphelenchoides swarupi and Aphelenchus avenae to Rodman’s agaricus, Agaricus bitorquis

Resumo

An experiment was conducted to assess the damage potential of Aphelenchoides swarupi and Aphelenchus avenae against the white button mushroom, Agaricus bitorquis, inoculated with 1000 individuals per bag of either test nematode. Half of the bags were inoculated at spawning time and half at casing time. Percentages of mycelial growth were recorded at casing time and pinhead formation stage. Treatmentwise sporophore production on a day to day basis was recorded for the entire cropping period so that weekly yield and flush gap period could be ascertained along with the total yield. The damage potential of A. swarupi and A. avenae was high when inoculated at spawning time as the nematodes restricted the mycelial growth significantly. Similar amounts of mycelial growth of 66% and 74.9% were recorded at casing time in the bags inoculated at spawning with A. swarupi and A. avenae, respectively, significantly less than the 98.5% mycelial growth in the control. However, the observations at pinhead stage revealed declines in mycelial growth, which was reduced to 39.8% and 49.1% in bags inoculated with A. swarupi and A. avenae, respectively. Mycelial growth in the bags inoculated at casing reached 52.9% at pinhead formation stage in bags inoculated with A. swarupi, compared to 59.1% in bags inoculated with A. avenae. Yield losses to the tune of 72% and 53%, respectively, were estimated in the bags inoculated with A. swarupi and A. avenae at spawning time. Percentage yield reduction was comparatively low when the nematodes were inoculated at casing and were 48.5 and 38.1% in the bags inoculated with A. swarupi and A. avenae, respectively. Thus, A. swarupi was more damaging than A. avenae and the cropping stage at which nematodes were inoculated affected the extent of damage caused to mushroom growth and production. Also, nematodes disrupted the mushroom flush pattern and reduced the cropping period.