Day 1 :
University of Wyoming, USA
Keynote: Understanding plant diversity and physiology for resilient production systems and environmental benefits
Time : 09:30-10:15
University of Illinois, USA
Time : 10:15 - 11:00
Bacterial spot of cucurbits, caused by Xanthomonas cucurbitae, is an emerging disease in the United States (US) and other cucurbit growing areas of the world. The pathogen can infect all cucurbit crops, but its major hosts are pumpkins and winter squash. Leaves and fruits of cucurbits are infected by X. cucurbitae at all growth stages. Infected fruits are usually colonized by opportunistic fungi and bacteria and rot. Our surveys in the North Central Region if the US during 2012-2013 showed that 159 of 180 and 71 of 79 of pumpkin and squash fields, respectively, had fruits infected with X. cucurbitae. The average incidence of fruits with bacterial spot in all pumpkin and squash fields surveyed was 25 and 19%, respectively. We identify the pathogen based on the colony morphology on yeast dextrose agar (YDC), polymerase chain reaction (PCR) test using RST2/RST3 primers, and pathogenicity test on susceptible pumpkin ‘Howden’. X. cucurbitae survived in infected leaves and fruits in the field for more than 24 months. Also, X. cucurbitae survived longer than 18 months in the seeds at 4 and 22°C and remained viable. No cultivar of cucurbits resistant to X. cucurbitae is available. We eradicated the pathogen in the naturally-infected and artificially infested seeds by hot-water treatment at 55°C for 15 min and HCl treatment at 0.5% concentration for 40 min. Also, in our field trials, copper oxychloride + copper hydroxide (Badge X2 DF), copper sulfate (Cuprofix Ultra 40 DF), oxytetracycline (Mycoshield 40 WSP), copper sulfate pentahydrate (Phyton-016B), copper hydroxide (Kocide-3000 46.1 DF) plus acibenzolar-s-methyl (ActiGard 50 WG), Kocide-3000 46.1 DF plus famoxadone + cymoxanil (Tanos 50D WG), an extract from Reynoutria sachalinensis (Regalia), and B. subtilis (Serenade ASO) were effective in reducing incidence and severity of bacterial spot on both leaves and fruits compared to controls.
University of Agricultural Sciences, India
Keynote: Molecular characterization, epidemiology and integrated management of Papaya Ringspot Virus (PRSV) in papaya (Carica papaya L.)
Time : 11:20-12:05
N Nagaraju graduated in University of Agricultural Sciences Bengaluru and expertise in Plant Virology. He worked as an Extension Pathologist during 1998-2010 and expertise in diagnosis, identification of plant disease and recommending suitable management practices. He is serving in UAS, Bengaluru since 20 years and worked on different plant viruses viz., Papaya ring spot virus (PRSV), Pepper veinal mottle virus (PVMV), Cucumber Mosaic Virus (CMV), Tomato leaf curl virus (ToLCV), Tomato spotted wilt virus (ToSPO) and other Gemini viruses. He developed integrated management practices for the important viruses for sustainable agriculture and were included in University Package of Practice. He is presently working on use of bio-molecules for inducing defense in crop plant against plant viruses.
Papaya cultivation is worldwide ravaged by Papaya ringspot virus (PRSV) disease. Surveys conducted in Southern Karnataka during 2012-2014 revealed the maximum PRSV incidence in Bangalore Rural (77.53%) followed by Bangalore Urban (68.89%), Kolar (65.00%) and Chikkaballapura (52.78%) districts. Monitoring of the population of different aphid species during August-2013 to July-2014 using yellow sticky traps revealed the occurrence of eight aphid species. Of which, three species viz., Aphis gossypii (66.04%), A. craccivora (26.80%) and Myzus persicae (2.12%) were regularly trapped throughout the year. Transmission studies proved that, M. persicae (53.33%) was more efficient vector in transmitting PRSV followed by A. gossypii (46.66%) and A. craccivora (26.66%). The aphid population was peak when rainfall was below 8.00 mm with temperature range of 17-350C, relative humidity of 30-90% and with wind speed of 3-5km/hr. Based on the symptoms on differential var. Red lady, the PRSV isolates viz., BRD-1, BRH-1, BUH-1 were considered as severe, while MMD-1 and MML-1 as mild isolates. Partial characterization of isolate BUH-1 by CP gene showed highest homology of 98% with South Indian and 87-92% with Asian isolates. Among the defence inducing molecules Salicylic [email protected] 0.002%, Silicic [email protected] 0.2% and Boric [email protected] 0.2% found effective in reducing the disease under field and glasshouse condition. In PRSVdisease management studies, growing papaya as intercrop with African Tall maize (1:1) and Grand Naine banana