ISHS Acta Horticulturae 808: II International Symposium on Tomato Diseases
EFFECT OF BLACK LEAF MOLD (PSEUDOCERCOSPORA FULIGENA) EPIDEMICS ON HOST GROWTH PARAMETERS OF TOMATO (SOLANUM LYCOPERSICUM) GROWN UNDER PROTECTED CULTIVATION IN THAILAND |
| Authors: | Z. Mersha, B. Hau |
| Keywords: | black leaf mold, epidemics, P. fuligena, S. lycopersicum 'FMTT260', host growth, healthy leaf area index |
| DOI: | 10.17660/ActaHortic.2009.808.3 |
| Abstract:
Effect of black leaf mold (P. fuligena) on host dynamics of a fresh market tropical tomato (S. lycopersicum ‘FMTT260’) was studied in four plantings (A to D). Black leaf mold (BLM) epidemics were the highest during plantings B and C (August and September 2005, respectively) followed by that of D (November 2005). Epidemic of the planting A in July 2005 was the lowest. The highest peaks (plantings B and C) and that of lower epidemic from planting D corroborated with the seasonal classification of central Thailand as hot-wet and cool-dry seasons, respectively. On the other hand, it was most likely that the level of inoculum played a role for the low epidemics of the planting in June 2005. In all cases, disease incidence and severity fitted well to logistic functions with R2 > 0.98. At times of peak epidemics, a clear effect of reduced host growth in terms of healthy leaf area (HLA) was discernible from a comparison of treatments with (F) and without (NF) fungicide spray. A mean severity of 0.3 (proportion) from the NF treatments of the two peak epidemics resulted in an average of 68% loss of HLA. Furthermore, a respective loss of 11% and 50% was encountered when healthy leaf area index (HLAI) from healthy plants (HLAIHP) was compared with that of fungicide sprayed (HLAIF) and non-sprayed (HLAINF) once. Overall, 2 applications of mancozeb at 4 and 6 weeks after transplanting significantly reduced the disease (60-90%). BLM, however, did not significantly affect other host parameters such as plant height and total leaf number. | |
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