We report on studies aimed to evaluate the effects of five nematophagous fungi on population dynamics of northern root knot nematode, Meloidogyne hapla and sugar beet cyst nematode, Heterodera schachtii in laboratory and greenhouse trials. During our biocontrol studies, mainly five fungal species Arthrobotrys oligospora, Dactylella oviparasitica, Clonostachys rosea, Stropharia rugosoannulata, and Lecanicillium muscarium were isolated from eggmasses of nematodes during root and soil samples collected in Czech Republic and tested against Meloidogyne hapla in carrots while Heterodera schachtii in sugar beet, both in-vitro and in-vivo fashions. All fungi exhibited varied type of infection on nematodes but L. muscarium proved to be the most potential bioagent in controlling nematode population enormously. Lecanicillium muscarium not only halted nematode reproduction factor (Pf/Pi) but also escalated plant growth. Plant root systems treated with L. muscarium were observed colonized by fungi while seen under microscope which depicted that fungi provided a protecting shield or body guard against plant parasitic nematodes. Moreover, L. muscarium was further compared with commercially available nematicides and a fertilizer to justify its highly potential for diminishing nematode population. L. muscarium along with nematicides and fertilizer had dramatic effects in reduction of both nematodes (M. hapla, H. schachtii) population in soil but improvement of plant growth was only noticed in case of L. muscarium. The chemical nematicide, Dazomet had some negative effects which appeared in the form of chlorotic spots on leaves which further suggested that there were some the phytotoxic effects.

The interaction of herbicides and Northern root-knot nematodes (Meloidogyne hapla Chitwood) on onions and beans was studied in the greenhouse. Seeds of onions (Allium cepa L.) were planted in soil treated with defferent levels of dimethyl 2,3,5,6-tetrachloroterephthalate (DCPA). Seeds of beans (Phaseolus vulgaris L.) were planted in soil treated with different levels of DCPA or α, α, α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine (trifluralin). Seedlings were inoculated with root-knot nematode larvae after 2 week's growth. DCPA reduced root and shoot growth on onions but did not significantly affect bean growth. Trifluralin significantly reduced root and shoot growth of beans. Growth reduction was directly related to the concentration of DCPA or trifluralin. Anatomical studies on onion roots indicated that the epidermal cells were seriously affected by DCPA treatment. They were greatly misshapen, overlapped, and in various stages of apparent dissolution or collapse. Symptoms were more severe under higher concentrations. Macroscopic examination of roots treated with DCPA or trifluralin showed soil particles strongly adhered to root tissue. DCPA-treated and non-treated nematode larvae were equally pathogenic on onions. Both DCPA and trifluralin significantly reduced the number of nematode galls formed on beans and onions grown in treated soil.