Bacterial blight (BB) caused by Xanthomonas oryzae pv. oryzae (Xoo) is a serious threat to rice production in the world. Identification of Xoo races pattern, distribution and deployment of race-specific resistant genes is a sustainable strategy to develop bacterial blight resistant varieties. In this study, a total of 118 isolates of Xoo were collected from 8 rice-growing regions of Bangladesh to identify the existing pathotypes of Xoo. All tested isolates were virulent on the susceptible rice varieties viz. IR24, Purbachi and BR11. The tested isolates were evaluated on 13 near-isogenic lines of rice and each line consisted of a single bacterial blight resistant gene viz Xa1, Xa2,
Prickly acacia (Vachellia nilotica subsp. indica), one of the most harmful weeds of the Australian rangelands, has been occasionally observed displaying natural dieback symptoms since 1970's.More recently in 2010, a prominent widespread dieback event was observed among the plants growing around Richmond and Julia Creek in north-western Queensland. Affected plants were found with disease symptoms such as; ashy internal staining, defoliation, blackening of shoot tips through to widespread plant mortality. It was hypothesized that a pathogenic fungus/i could be implicated with this phenomenon and a potential for biological control of this invasive species might ensue.Fungi isolated from dieback-affected and healthy stands of prickly acacia were putatively identified by partial sequencing of the Internal Transcribed Spacer (ITS) region of genomic DNA.Botryosphaeriaceae was the best represented family of fungi associated with dieback. Among the Botryosphaeriaceae fungi, Cophinforma was found to be the most prevalent genus with 60% of the total isolates identified as Cophinforma spp. following BLAST searches. Cophinforma was also isolated from the healthy plants growing in the trial site at Richmond. Natural dieback on prickly acacia was previously observed in the surrounding areas. Phylogenetic analysis of the ITS sequences revealed the potential existence of new species of Cophinforma in Australia. Apart from Cophinforma sp., a range of other Botryosphaeriaceae and non-Botryosphaeriaceae fungi were isolated from both dieback-affected and healthy prickly acacia plants growing at different locations.Based on a seedling pathogenicity screening, a sub-set of 40 potentially pathogenic isolates across the range of species were selected to challenge the juvenile plants following a stem inoculation technique under glasshouse conditions. In the glasshouse trials, the test-isolates of Cophinforma sp.(isolated from both dieback-affected and healthy prickly acacia) and an isolate of Lasiodiplodia pseudotheobromae strain NT039 (isolated from dieback-affected Parkinsonia aculeata) consistently caused significant stem lesions, gummosis and leaf mortality. Cophinforma sp., Fusarium acuminatum, Neofusicoccum parvum and Tiarosporella graminis isolated from healthy prickly acacia also caused similar symptoms in glasshouse inoculation trials. The remaining species tested in the glasshouse trials were mostly non-pathogenic to the juvenile plants.In another study, given the observation that several fungi are often isolated from a single piece of dieback-affected stem, it was investigated whether typical dieback symptoms in prickly acacia could be replicated with combinations of different fungi. Therefore, the effect of inoculating with iii two isolates of Cophinforma sp. and one isolate of L. pseudotheobromae singly and in combination under glasshouse and field conditions was tested. In the glasshouse trial, significant stem lesions were observed with each of the test-isolates and their combinations. However, there was no signifi...
Habitat management is an ecologically based approach to suppress pest densities, utilising properties of non-crop vegetation to improve the impact of natural enemies or to directly affect pest behaviour. Research in this approach has escalated dramatically this century, extending to uptake in some crops, but adoption in Australia has been lower than overseas. Here, we address the need of the Australian vegetable sector to reduce reliance on insecticides by assessing the scope for habitat management in brassica (Brassicaceae), lettuce (Lactuca sativa) (Asteraceae), capsicum (Capsicum annuum) (Solanaceae), carrot (Daucus carota) (Apiaceae), French bean (Phaseolus vulgaris) (Fabaceae) and sweetcorn (Zea mays) (Poaceae) crops. Each crop is of major economic importance, and together, they represent contrasting botanical families and production systems that are associated with different arthropod complexes. We review studies of habitat management that are based on provision of shelter, nectar, alternative prey or pollen for natural enemies (top-down effects) or changing pest behaviour (bottom-up effects) through intercropping or trap crops. The likely utility of these approaches under Australian conditions is assessed, and recommendations are made to promote adoption and for adaptive research. Nectar-and pollen-providing plants, such as alyssum (Lobularia maritima) (Brassicaceae), offer strong potential to promote natural enemies in multiple crops whilst trap crops, especially yellow rocket (Barbarea vulgaris) (Brassicaceae), have more targeted utility against diamondback moth, Plutella xylostella (Lepidoptera: Plutellidae), the most serious pest of brassicas. Opportunities for intercrops and banker plant species are also identified. Our recommendations serve as a platform for researchers and for farmer-led studies to help realise the full potential of habitat management approaches in Australian vegetable production systems.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.