Treatment with hypovirulent binucleate Rhizoctonia (HBNR) isolates induced systemic resistance against anthracnose infected by Colletotrichum orbiculare in cucumber, as there were no direct interaction between HBNR and C. orbiculare . This is because of the different distances between HBNR and C. orbiculare , where the root was treated with HBNR isolate and C. orbiculare was challenged and inoculated in leaves or first true leaves were treated with HBNR isolate and C. orbiculare was challenged and inoculated in second true leaves. The use of barley grain inocula and culture filtrates of HBNR significantly reduced the lesion diameter compared to the control ( p = 0.05). The total lesion diameter reduction by applying barley grain inoculum of HBNR L2, W1, W7, and Rhv7 was 28%, 44%, 39%, and 40%, respectively. Similar results was also observed in treatment using culture filtrate, and the reduction of total lesion diameter by culture filtrate of HBNR L2, W1, W7, and Rhv7 was 45%, 46%, 42%, and 48%, respectively. When cucumber root was treated with culture filtrates of HBNR, the lignin was enhanced at the pathogen penetration, which is spread along the epidermis tissue of cucumber hypocotyls. Peroxidase activity in hypocotyls in the treated cucumber plant with culture filtrates of HBNR significantly increased before and after inoculation of pathogens as compared to the control. Significant enhancement was also observed in the fast-moving anodic peroxidase isozymes in the treated plants with culture filtrates of HBNR. The results showed the elicitor(s) contained in culture filtrates in HBNR. The lignin deposition as well as the peroxidase activity is an important step to prevent systemically immunised plants from pathogen infection.

No abstract

Four isolates of hypovirulent binucleate Rhizoctonia (HBNR), G1, L2, W1, and W7 were used for control of Fusarium wilt of tomato (FWT) caused by Fusarium oxysporum f. sp. lycopersici (FOL). HBNR isolates could significantly reduce disease severity (foliar symptoms and discoloration inside the stem) among five experiments under single and double applications. Reduction of disease severity by HBNR isolates, however, differed depending on HBNR isolates and treatments. Of four isolates, isolate HBNR W7 could significantly and consistently reduce (P ϭ 0.05) disease severity. Application of HBNR isolates significantly reduced (P ϭ 0.01) the number of colonyforming units of FOL in stems and roots of tomato. Among the HBNR isolates, G1, W1, and W7 could significantly increase (P ϭ 0.05) fresh weight of the plants (stems and leaves). These results indicate that isolates of HBNR have a greater potential as biocontrol agents against FWT. This is the first report of biocontrol of FWT by HBNR under greenhouse conditions.

Muslim, A., Horinouchi, H., and Hyakumachi, M. 2003. Control of Fusarium crown and root rot of tomato with hypovirulent binucleate Rhizoctonia in soil and rock wool systems. Plant Dis. 87:739-747.Hypovirulent binucleate Rhizoctonia (HBNR) isolates L2, W1, W7, and Rhv7 were studied as potential antagonists of Fusarium crown and root rot of tomato (FCRR) caused by Fusarium oxysporum f. sp. radicis-lycopersici, in either soil or hydroponic rock wool systems. Reduction of FCRR on tomato by HBNR isolates was different depending on the isolate, days after inoculation of pathogen, and experiments. In the greenhouse soil system, HBNR isolates significantly (P = 0.01) reduced vascular discoloration and discoloration of total roots systems by 90 to 100% and by 73 to 89%, respectively, in three experiments. Under field soil conditions, HBNR W1 provided significant (P = 0.05) reduction of vascular discoloration by 71%. In the rock wool system, all HBNR isolates except L2 in experiment 1 significantly reduced (P = 0.05) vascular discoloration by 18 to 100% in four experiments. Plants treated with all HBNR isolates had foliar symptoms reduced by 41 to 100% in four experiments under the rock wool system. Application of HBNR also resulted in increases of marketable and total yields of tomatoes as much as 70 and 73%, respectively, over the untreated plants. The number of colony forming units of F. oxysporum f. sp. radicis-lycopersici per gram fresh weight of roots and stems was significantly reduced (P = 0.05) in plants treated with HBNR in both soil and rock wool systems. HBNR was re-isolated at a high frequency from roots grown inside paper pots containing soil infested with HBNR, but rarely isolated from the roots grown in soil infested with only F. oxysporum f. sp. radicis-lycopersici outside the paper pots. HBNR was not re-isolated from the tomato stems. Stem extracts from HBNR-treated and pathogen-challenged plants in the rock wool system inhibited germination and production of budding cells of F. oxysporum f. sp. radicis-lycopersici. Additional keyword: Lycopersicon esculentumCorresponding author: M. Hyakumachi

The plant growth-promoting fungus (PGPF) Fusarium equiseti GF191 was tested for its ability to control Fusarium wilt of tomato (FWT) caused by Fusarium oxysporum f. sp. lycopersici (FOL) in both a hydroponic rock wool and soil system. F. equiseti effectively controlled FWT, with protective effects based on disease severity of 66.7-88.6% in four experiments. The numbers of colony-forming units of FOL per gram fresh weight of stems were significantly reduced (P \ 0.05) in plants treated with F. equiseti. Stem extracts from F. equiseti-treated and pathogenchallenged plants significantly inhibited the germination and germ-tube length of FOL microconidia and the production of FOL budding-cells. Tomatine content in tomato stems treated with F. equiseti was significantly increased compared with the non-treated control.

Background: Tapping panel dryness (TPD) is a stress-related disorder that afflicts rubber trees, contributing to yield losses in nearly every rubber-growing region. Method: We demonstrated the curative effects of biostimulants containing a fermented watery extract of shrimp waste-enriched compost (SWCE) on TPD in field trials. Undiluted SWCE was applied to lightly scraped bark in the first, third, and fourth trials, and applied directly without bark scraping in the second trial. Results: Bark treatment significantly (p < 0.05) reduced tapping cut dryness and increased latex yield, suggesting recovery from the disorder. When SWCE was applied to pre-scraped bark, 80% and 30% of trees with partial and complete TPD, respectively, recovered from tapping dryness within 2 months. The latex dry weight of treated trees with partial and complete TPD was 77.5% and 21.1% that of healthy trees, respectively. We observed slight recovery from TPD in trees treated without bark scraping and in trees with a history of ethephon stimulation. No curative effect of SWCE was demonstrated in treated trees without a tapping rest period. These findings suggest that compost extract could be a useful treatment for partial TPD.

In 2019, wilt and sudden death were observed on Artocarpus heterophyllus (jackfruit). Identification was performed by sequence analysis of the concatenated β-tubulin and ITS gene regions. Sequencing of the PCR product confirmed this pathogen was Ceratocystis fimbriata sensu stricto. This is the first report of C. fimbriata causing sudden death disease in A. heterophyllus in Indonesia and worldwide.

Wilt disease with unknown etiology causes mass mortality in commercial Acacia mangium nurseries in South Sumatra. This pathogen induces symptoms of chlorosis in the lower leaves and develops into the shoots; subsequently, the plants wither and die. This research identifies the pathogenic species causing this wilt disease and to assess its pathogenicity or virulence. Fifteen isolates of Fusarium oxysporum with varying colony sizes and color pigments were recovered from symptomatic A. mangium seedlings. The pathogenicity test showed that all isolates could infect plants with wilt severity reaching 80%, and the pathogen was verified as causing vascular disease. Koch’s postulate was verified by re-isolating the F. oxysporum isolates. The pathogen was confirmed by observing the morphological characters and elongation factor 1-α (tef1-α) gene sequences as F. oxysporum.