Crop background intensification impact on predatory nematode-capturing fungus Arthrobotrys oligospora prevalence in wheat roots

The aim of the study is to assess the influence of the variety, crop rotation, nitrogen fertilization and pesticides on the prevalence of the predatory nematophage fungus Arthrobotrys oligospora on the roots of nine Siberian varieties of spring wheat Triticum aestivum L. (Altajskaya 70, Altajskaya 75, Krasnoyarskaya 12, Novosibirskaya 15, Novosibirskaya 16, Novosibirskaya 29 , Novosibirskaya 31, Novosibirskaya 41, Svirel) in the Kansk-Krasnoyarsk forest-steppe. The prevalence of A. oligospora statistically significantly (p < 0.01) depended on the cultivar, crop rotation pattern (p < 0.001), fertilization (p < 0.001), and pesticide use (p < 0.001). The minimum prevalence (on average 43.8–45.8%) was found in the varieties Krasnoyarskaya 12, Novosibirskaya 15 and Novosibirskaya 16. The maximum prevalence (on average 61.5–66.7 %) was found in the varieties Svirel, Novosibirskaya 29 and Novosibirskaya 31. Fallow as a precursor increased the prevalence of A. oligospora by 1.2–1.5 times as compared to wheat as a precursor for all varieties, except for the Svirel variety. The effect of fertilization and pesticides on the prevalence of A. oligospora depended on the crop rotation pattern. The maximum prevalence of the fungus (on average for varieties 81.5%) was observed in the variants “wheat as a precursor + fertilizer + pesticides” and “fellow as a precursor + fertilizer”. The minimum prevalence (27.8 and 24.1 % on average for varieties) was observed in the variants "wheat as a predecessor" and "wheat as a predecessor + fertilizer". The results of the study demonstrate the possibility of enriching the soil microbial community with the fungus A. oligospora, which can serve as a biological agent for the control of nematodes parasitizing plants.