The influence of temperature, nutrition, light and the growth time of the mycelium on capture and infection of Meloidogyne hapla by Arthrobotrys oligospora

An isolate of Arlhrobolrys oligospora (CBS 289.82) caprured the second-stage juveniles 02) of a population of Meloidogyne hapla by attadunent to its hyphae. The effects of temperarure, substrate, light and ageing of fungal mycelium on the ability to caprure nematodes was srudied in the laboratory. Firm binding of the J2 of M. hapla to hyphae of A. oligospora (CBS 289.82) occurred within 1 h irrespective of temperarure (between 5 to 30 oC) and irrespective of differences in nematode mobiliry. Subsequent development of ring strucrures (comparable to adhesive nerworks) around the nematode, however, was significantly slower at the lower temperarures (5 to 10°C) than at the higher temperarures (15 to 30 oC). The colonization of the nematode by trophic hyphae was clearly affected by temperarure. At temperarures below 15 oC development of trop hic hyphae was significantly reduced in comparison to higher temperarures. Furthermore, the nutritional conditions tested did not correlate to the efficacy in nematode-hypha attachment, however the subsequent development of adhesive networks was delayed on water agar. The present results provide evidence that the trapping abiliry in the isolate tested continues over the whole test period of more than 70 days. Light dit not influence the abiliry of the fungus to caprure nematodes. Our results suggest that the formation of an adhesive hypha is less temperarure and nutrient dependent than the development of the morphologically more complex adhesive nerworks. This observation suggests that the range of conditions under which this isolate of A. oligospora caprures nematodes is wider than in isolates where adhesive networks are the oruy caprure devices, which makes this isolate interesting for evaluation as a possible control agent.