Author : Phoutthasone Sibounnavong

Summary : The research findings on tomato wilt collected from infested fields in Bangkok, Phetchaboun, Tak, Nakhonratchasima, Burirum, Nongkhai, Sakonnakhon, and khonkaen provinces resulted to isolate and identify the casual agent as Fusarium oxyporum f. sp. lycopersici race 2 according to confirmation work on morphological and molecular phylogency by sequencing the internal transcribed spacer (ITS) region ITS1, 5.8S and ITS2 and a small portion of 18S rDNA and a small portion of the 28S rDNA and AFLP marker. The pathogenicity test abd ALFP analysis revealed that 11 isolates were categorized as non-pathogenic or avirulent group and 14 isolates were categorized as pathogenic group which divided into 3 subgroups of low virulent (L.), moderate virulent (M) and high virulent (H). As a result, the isolates of KSoC02, NKRC09, SSoC03 and SSoC04 were shown to be non-pathogenic isolates. Isolates KK2 isolated from Northeast part of Thailand was tested its pathogenicity to cause wilt symptom on tomato Sida var which susceptible to standard tested isolate F. oxysporum f. sp. lycopersici race 2. This work provided new information on formae specials of F. oxysporium f. sp. lycopersici which could classify as race 2 that can cause wilt to different varieties of tomato e.g. Cheery and Sida varieties rather one variety. The antagonistic fungi of Chaetomium brasilense CB01, Chaetomium cupreum CC03, Chaetomium elatum ChE0, Chaetomium lucknowense CLT01, Emericella nidulans EN01, and Emericella rugulosa ER01 were proved to antagonize F. oxysporum f. sp. lycopersici NKSC02. The antagonism test demonstrated the antagonistic activity of Ch. brasilense CB01, Ch. cupreum CC03, Ch. elatum ChE01, Ch. lucknowense CLT01, E. nidulans EN01 and E. rugulosa ER01 to inhibitthe conidial production of F. oxysporum f. sp. lycopersici NKSC02. Bioactivities test of crude extracts and pure compounds from tested antagonistic fungi were proved as a control mechanism. To elucidate the control mechanism involved in the inhibitation of F. oxysporum f. sp. lycopersici, crude extracts of Ch. brasilense CB01, Ch. cupreum CC03, Ch. elatum ChE01, Ch. lucknowense CLT01,, E. nidulans EN01 and E. rugulosa ER01 were confirmed for antifungal activity against of F. oxysporum f. sp. lycopersici NKSC02. the other control mechanism involved in releasing antibiotic subtances to inhibit F. oxysporum f. sp. lycopersici. All tested crude extracts of Ch. brasilense CB01, Ch. cupreum CC03, Ch. elatum ChE01, Ch. lucknowense CLT01, E. nidulans EN01 and E. rugulosa ER01 were significantly inhibited conidia production of F. oxysporum f. sp. lycopersici. It is clearly demonstrated that a pure compound produced by E. rugulosa ER01, Chaetoglobosin C, a pure compound produced by Ch. elatum ChE01 and Ch. luckowense CLT01, inhibited conidia production of F. oxysporum f. sp. lycopersici NKSC02 with the ED50 value of 5.94 ug/ml. Moreover, tajixxanthone, a pure compound produced by E. rugulosa ER01, inihibited conidia production of F. oxysporum f. sp. lycopersici NKSC02 with an ED50 value of 167 ug/ml/ Chaetoglobosin C and tajixanthone are expressed as a antibiotic substances to destroy the pathogen cell implies antibiosis. Inocula of F. oxysporum f. sp lycopersici (1 x 10 spores/ml) were mixed with chaetoglobosin-C and tajixanthone and inoculated to tomato seedling caused no symptoms at day 21 while the treatment with pathogen alnoe showed significantly highest disease severity index. with this, no wilt incidences were appeared at all tested concentration of 10, 50 and 100 ug/ml of either Chaetoglobosin C or tajixanthone. it is stated that chaetoglobosin-C and tajixanthone affcted directly to the pathogen inocula implies antibiosis which the occurences of ruptured cells and abnormal conidia of pathogen. The research findings inicated that treated tomato seedling var Sida with crude EtOAc of E. rugolosa at 1000 ug/ml gave sigificant lower DSI from treated with crude EtoAc of E. rugulosa at 500 ug/ml when compared to the inoculated with F. oxysporum f. sp. lycopersici NKSC02. Disease immunity of fusarium witl in Sida variety appeared the highest immunity when treated with crude EtOAc at 1000 ug/ml and follwed by treated with crude EtOAc at 500 ug/ml. Microbial extracts expressed to induced immunity in term of microbial elicitors. Ch. elatum ChE01, E. nidulans EN01 and to E. rugulosa ER01 were formulated as oil and powder bioformulations gave a good result to control wilt of tomato var Sida caused by F. oxysporum f. sp. lycopersici NKSC02 race 2. the treated tomatoes showed the lowest wilt incidence in oil and powder bioformulations from Ch. elatum ChE01, E. nidulans EN01 and to E. rugulosa ER01 which significantly diferred from Prochoraz and inoculated control. The application of oil bioformulation from E. rugulosa could reduce wilt incidence and followed by application of powder bioformulation and Prochoraz which also reduced wilt incidence. Based on the resul, oil bioformulation from Ch. elatum ChE01, E. nidulans EN01 and E rugulosa ER01 gave significantly better plant parameters in terms of plants height, plant weight, root weight, number of fruits and fruit weight than powder bioformulation and Prochoraz when compared to the inoculated control with F. oxysporum f. sp. lycopersici. It is suggested that this new report of bioformulation of Ch. elatum ChE01, E. nidulans EN01 and E. rugulosa ER01 could be applied to control tomato with caused F. oxysporum f. sp. lycopersici in the fields.