EVALUATING THE EFFICACY OF THIOPHANATE METHYL IN THE CONTROL OF CORKY ROOT IN TOMATO

摘要

Corky-root, caused by Pyrenochaeta lycopersici (Schneider and Gerlach), is an important soil-borne disease of tomato and other Solanaceous crops worldwide. Its symptoms consist in necrotic brown lesions on roots that soon become corky with swollen, cracked and furrowed bark surfaces. The disease is considered a serious problem for fresh market and processing tomato cultivations both in open field and protected culture. Early detection is problematic since symptoms are hardly noticeable until the roots are exposed, except for a decrease in fruit yield and shoot growth.Three studies were performed in 2015 with the purpose of evaluating the efficacy of thiophanate methyl (ENOVIT METIL FL g 41,7 (500 g/l) - Sipcam], a systemic fungicide with protective and curative action absorbed by the leaves and roots, in the controlof corky root caused by P. lycopersici in tomato. The first of these experiments was realized in open field, the other two in the laboratory, in a thermo-conditioned greenhouse: one of them was performed in an artificially inoculated soil, using as inoculum a P. lycopersici strain available at the Bioagritest mycotheca and coded BIOPYRLYP83 (concentrated 2 x 10s U.F.C./m3), the other in a soil naturally contaminated by the target fungus. All the three experiments consisted in 2 treatments (Tr.) plus acheck (untreated control) [Tr. 1, ENOVIT METIL FL 1,7 l/ha; Tr. 2, ENOVIT METIL FL 3,4 l/ha; Tr. 3, check (untreated plants)] and 3 drench applications, respectively 0, 15 and 45 days post-transplant.Parameters evaluated were: phytotoxicity, index of disease (corky root), index of chlorophyll (measured by SPAD), biomass of aerial part of the plant.Results obtained from the three experiments clearly show the efficacy of ENOVIT METIL 8 FL in containing the symptoms of corky root caused by P. lycopersici on tomato, both in open field and in controlled conditions. No statistically significant difference was detected between the two doses of application (1.7 and 3.4 l/ha), except in the laboratory experiment with naturally contaminated soil, where the highest dose shows a slight greater efficacy. No phytotoxicity phenomenon due to the ENOVIT METIL wasobserved. The present study concludes that the soil-borne fungus Pyrenochaeta lycopersici can effectively be managed by application of ENOVIT METIL FL.