RESUMO
Root rot caused by soil borne pathogenic fungi is the most sever disease attacks lupine plants. Isolation trials from diseased plants in some areas of Dakahlia Province (Egypt) was carried out. Rhizoctonia solani and Fusarium solani proved to be the most dominant isolates. Meanwhile, Fusarium oxysporum and Sclerotium rolfsii were less frequent. Efficacies of some plant resistance elicitors viz.: chitosan (CHI), Salicylic Acid (SA) and hydroquinone (HQ) in comparing to the fungicide Rhizolex T-50 as seed treatments showed significant reduction in the fungal growth in vitro. Chitosan at 8 g L(-1) and fungicide completely inhibited the growth of all isolated fungi, while SA at 1.4 g L(-1) and HQ at 1.2 g L(-1) inhibited the growth of Fusarium solani and F. oxysporum, respectively. The greenhouse experiments showed that S. rolfesii (No. 6) and R. solani (No. 2) followed by F. solani (No. 5) and F. oxysporum (No. 9) were the most aggressive root rot fungi. Soaking susceptible lupine seeds (Giza 1) in each one of the three selected elicitors showed a significant reduction in seedlings mortality. CHI at 8 g L(-1) was superior in increasing the percentage of healthy plants to record 72.5, 80.9, 62.7and 64.3%, when seeds were grown in soil infested with of F. solani, F. oxysporum, R. solani and S. rolfesii, respectively. These results were confirmed under field conditions in two different locations i.e., Tag El-Ezz and El-Serow Research Stations. CHI 8 g L(-1) proved to be the best elicitor after fungicide, in reducing lupine root rot disease. It showed 41 and 60% reduction in the plants mortality comparing to 56.37 and 69.13% in case of Rhizolex-T in Tag El-Ezz and El-Serow locations, respectively. The treatments were accompanied with a significant increase in lupine growth parameters, yield components and physiological aspects. Application of CHI at 8 g L(-1) or HQ at 1.2 g L(-1) was the most potent in this respect as compared to check treatment.
