HATCH AND REPRODUCTION OF GLOBODERA-TABACUM-TABACUM IN RESPONSE TO TOBACCO, TOMATO, OR BLACK NIGHTSHADE

The effects of broadleaf tobacco, tomato, and black nightshade on juve nile hatch and reproduction of Globodera tabacum, tabacum were determi ned in laboratory and greenhouse experiments. Root exudates from night shade stimulated greater egg hatch than those from either 'Rutgers' to mato or '86-4' tobacco. Hatch was greater at higher proportions of roo t exudates for all three plane species. Root exudates from plants grea ter than 3 weeks old stimulated more hatch than younger plants. No reg ression relationships existed between plant age and nematode hatch. In other experiments, hatch from eggs in cysts was higher for tomato and nightshade after 10 weeks in greenhouse pots compared to tobacco and bare soil. Numbers of second-stage juveniles in eggs in cysts produced from a previous generation on the same host were highest on nightshad e and less on tomato and tobacco. Cysts of variable age recovered from field soil had increased hatch in both root exudates or water compare d to recently produced cysts from plants in growth chambers. Globodera t. tabacum may be subject to both host and environmentally mediated d iapause.