Evaluation of the efficacy and economics of irrigation management, plant resistance and Brassica(spot)(TM) models for management of white blister on Brassica crops

Options for the integrated management of white blister (caused by Albugo candida) of Brassica crops include the use of well timed overhead irrigation, resistant cultivars, programs of weekly fungicide sprays or strategic fungicide applications based on the disease risk prediction model, Brassica(spot)(TM). Initial systematic surveys of radish producers near Melbourne, Victoria, indicated that crops irrigated overhead in the morning (0800-1200 h) had a lower incidence of white blister than those irrigated overhead in the evening (2000-2400 h). A field trial was conducted from July to November 2008 on a broccoli crop located west of Melbourne to determine the efficacy and economics of different practices used for white blister control, modifying irrigation timing, growing a resistant cultivar and timing spray applications based on Brassica(spot)(TM). Growing the resistant cultivar, 'Tyson', instead of the susceptible cultivar, 'Ironman', reduced disease incidence on broccoli heads by 99 %. Overhead irrigation at 0400 h instead of 2000 h reduced disease incidence by 58 %. A weekly spray program or a spray regime based on either of two versions of the Brassica(spot)(TM) model provided similar disease control and reduced disease incidence by 72 to 83 %. However, use of the Brassica(spot)(TM) models greatly reduced the number of sprays required for control from 14 to one or two. An economic analysis showed that growing the more resistant cultivar increased farm profit per ha by 12 %, choosing morning irrigation by 3 % and using the disease risk predictive models compared with weekly sprays by 15 %. The disease risk predictive models were 4 % more profitable than the unsprayed control.

Impacts of level of utilisation by grazing on an Astrebla (Mitchell grass) grassland in north-western Queensland between 1984 and 2010. 1. Herbage mass and population dynamics of Astrebla spp

Managing large variations in herbage production, resulting from highly variable seasonal rainfall, provides a major challenge for the sustainable management of Astrebla (Mitchell grass) grasslands in Australia. A grazing study with sheep was conducted between 1984 and 2010 on an Astrebla grassland in northern Queensland to describe the effects of a range of levels of utilisation of the herbage at the end of the summer growing season (April–May in northern Australia) on the sustainability of these grasslands. In unreplicated paddocks, sheep numbers were adjusted annually to achieve 0, 10, 20, 30, 50 and 80% utilisation of the herbage mass at the end of the summer over the ensuing 12 months. Higher levels of utilisation reduced both total and Astrebla spp. herbage mass because of the effects of higher utilisation on Astrebla spp. and this effect was accentuated by drought. The tussock density of Astrebla spp. varied widely among years but with few treatment differences until 2005 when density was reduced at the 50% level of utilisation. A major change in density resulted from a large recruitment of Astrebla spp. in 1989 that influenced its density for the remainder of the study. Basal area of the tussocks fluctuated among years, with increases due to rainfall and decreases during droughts. Seasonal rainfall was more influential than level of utilisation in changes to the basal area of perennial grasses. Drought resulted in the death of Astrebla spp. tussocks and this effect was accentuated at higher levels of utilisation. A series of three grazing exclosures were used to examine the recovery of the density and basal area of Astrebla spp. after it had been reduced by 80% utilisation over the preceding 9 years. This recovery study indicated that, although grazing exclusion was useful in the recovery of Astrebla spp., above-average rainfall was the major factor driving increases in the basal area of perennial grasses. Spring values of the Southern Oscillation Index and associated rainfall probabilities were considered to have potential for understanding the dynamics of Astrebla spp. It was concluded that Astrebla grassland remained sustainable after 26 years when grazed at up to 30% utilisation, while, at 50% utilisation, they became unsustainable after 20 years. Results from this study emphasised the need to maintain the population of Astrebla spp. tussocks.

Seasonal Greeting token 1983

Obverse: Emblem of the Israel Government Coins and Medal Corporation. Reverse: Stylized design of the Western Wall and the Mount above.

Seasonal Greeting token 1986

Obverse: Emblem of the Israel Government Coins and Medal Corporation. Reverse: The monument to Jewish soldiers erected at the Jewish Martyrs Memorial Institute of Yad Vashem in Jerusalem.

Seasonal Greeting token 1993

Obverse: Emblem of the Israel Government Coins and Medal Corporation. Reverse: Stylized menorah, inscription.

Seasonal Greeting token 1978

Obverse: emblem of the Israel Government Coins and Medal Corporation. Reverse: Dove with spread wings.

Seasonal Greeting token 1998

Obverse: Emblem of the Israel Government Coins and Medal Corporation. Reverse: Stylized menorah with number fifty in the middle part.

Seasonal Greeting token 1994

Obverse: Emblem of the Israel Government Coins and Medal Corporation. Reverse: Three runners stylized, countryside in the background.

Seasonal Greeting token 2000

Obverse: Emblem of the Israel Government Coins and Medal Corporation. Reverse: Map from the15th century with Jerusalem as a center of the world.

Seasonal Greeting token 1999

Obverse: Emblem of the Israel Government Coins and Medal Corporation. Reverse: Menorah in the midddle of the zodiac symbols.

Seasonal Greetings Token 1979

Obverse: Emblem of the Israel Government Coins and Medal Corporation. Reverse: Building of the Israel Government Coins and Medal Corporation.

Seasonal Greeting token 1985

Obverse: Emblem of the Israel Government Coins and Medal Corporation. Reverse: Stylized view on Jerusalem.

Seasonal Greeting token 1987

Obverse: Emblem of the Israel Government Coins and Medal Corporation. Reverse: Dove of peace with olive branch in its beak.

Seasonal Greeting token 1989

Obverse: Emblem of the Israel Government Coins and Medal Corporation. Reverse: Stylized menorah with number forty.