Australia’s Most Delicious Bush Nut Protected with Fungicides


Husk Spot on Macadamia Nuts

Australia is the home of the macadamia nut. Australia accounts for about one-third of world production. Husk spot caused by Pseudocercospora macadamiae is a serious disease affecting macadamia in Australia. Husk spot has not been reported from any other macadamia producing nation. The spores adhere to the husk, germinate and penetrate the host through openings (stomata). A major part of the economic impact is caused by premature fruit abscission from the tree when the kernels are still immature and of low oil content, making them unsuitable for processing and consumption.

“Husk spot, caused by Pseudocercospora macadamiae is a major fungal disease of macadamia in Australia, costing over $10 million in lost productivity if the disease is not adequately controlled. P. macadamiae infects macadamia husks on which it continually produces inoculum, the infection causes premature abscission of diseased fruit, thus, resulting in extensive yield losses and reduced kernel quality. Application of fungicide is currently the only effective method of controlling husk spot.”

Author: Akinsanmi. O. A., et al.
Affiliation: Tree Pathology Centre, The University of Queensland.
Title: An integrated approach to husk spot management in macadamia.
Source: Plant Health Management: An Integrated Approach. APPS 2009. Pg. 22.

Australian Wheat Yields Have Doubled Thanks to Herbicides

Australian Wheat Yield 1930-2010 (Trendlines)

Australian Wheat Yield 1930-2010 (Trendlines)

Australian wheat-growing areas are dry. Historically, tillage was used to remove weeds, but tillage further dried out the soil. Herbicides have made it possible for Australian wheat farmers to stop tilling entirely. As a result, soil moisture retention has increased and wheat yields have doubled.

“An analysis of the yield trends of wheat production in Australia showed that yields have increased by an average of 12-13 kg ha-1 year-1 over the past six decades, despite rainfall not changing and irrigated wheat contributing only a very small proportion to total production. A more recent analysis of wheat yield trends in Australia and the various states of Australia has shown that since the early 1980s there has been a more rapid increase in yield of over 30 kg ha-1 year-1. In Western Australia, where wheat is not irrigated and rainfall has probably declined over the last 25 years, the increases… arise solely from increases in rainfall-use efficiency.

However, the major impact of agronomic management on rainfall-use efficiency has not arisen from increasing total water use by the crop in evapotranspiration, but from increasing water use by the crop itself in transpiration at the expense of water loss by weeds or from the soil by soil evaporation, deep drainage, surface runoff, or lateral throughflow.

The use of minimum tillage or conservation tillage, whereby residues from the previous crop are left on the surface, weeds are controlled by herbicides rather than tillage, and the seed is sown with minimum disturbance of the soil surface by the use of narrow tines, has led to reduced losses of water by soil evaporation and increased yields. Further, minimum tillage systems allow earlier planting as delays resulting from using tillage to remove weeds are reduced.”

Author: Turner, N. C.
Affiliation: CSIRO Plant Industry.
Title: Agronomic options for improving rainfall-use efficiency of crops in dryland farming systems.
Source: Journal of Experimental Botany. 2004. 407[55]:2413-2425.

Apple Rots Reappear Because of Fungicide Cancellations


Core rot

Core rot


Many storage rots of apples are actually initiated in the orchard. There are often no pre-harvest symptoms. Core rot is a wet rot that spreads into the flesh of the apple. Core rot can be controlled with spring fungicide sprays in the orchard. However, core rot has reappeared in some Australian apples in storage due to cancellation of some key fungicides.

“In the last couple of months I have attended to a couple incidences of core rot in apples that have arrived in their destination market. This is not a pretty sight and costs the packer/marketers both in financial and brand terms, not to mention degradation of Australia’s reputation as a supplier of quality fruit.

This situation has probably arisen due to low levels of core rots being encountered in the last 15 or so years. This has meant that this problem has slipped from our memories and we have forgotten that in the 1980s core rot could be present in up to 20 per cent of our fruit. This level of infection cannot be tolerated in today’s marketing environment. Its re-appearance is probably due to the de-registration of both Benlate and Rovral for spraying onto the apple flowers, a treatment in common use in the 1990s and 2000s for the control of core rots.”

Author: Brown, G.
Affiliation: Technical Editor.
Title: Getting to the core of the problem: Core rots.
Source: Australian Fruitgrower. September 2012. Pgs. 12-15.

Greenhouse Gas Emissions Lower With Herbicide Use

Cultivating Weeds in Australia

Cultivating Weeds in Australia

Agricultural greenhouse gas emissions can be curbed by decreasing fuel use by field equipment. The largest contribution to reducing emissions associated with farming is made by the reduction of tillage operations which are made primarily to control weeds. By substituting herbicides for tillage, dramatic reductions in fuel use and emissions occur because one herbicide application substitutes for multiple tillage trips. Tillage equipment is also heavier than herbicide sprayers and needs more energy to pull steel implements through the soil. A row crop cultivator requires four times more diesel fuel per acre than an herbicide sprayer. A recent study in Australia calculated the effects on greenhouse gas emissions…..

“In a wheat fallow system in semi-arid subtropical Queensland, Australia, practicing zero tillage reduced fossil fuel emissions from machinery operation by 2.2 million g CO2/ha over 33 years or 67 kg CO2/ha/year (four to five tillage operations with a chisel plough to 10 cm during fallow each year were replaced by one herbicide spray).”

Authors: Ortiz-Monasterio, I., et al.
Affiliation: CIMMYT, Mexico
Title: Greenhouse Gas Mitigation in the Main Cereal Systems: Rice, Wheat and Maize
Source: Climate Change and Crop Production. CAB International 2010.

Australian Grains Council Extols Importance of Pesticides

Australia’s Grains Research & Development Corporation (GRDC) is one of the world’s leading grains research organizations, responsible for overseeing R&D that deliver improvements in production, sustainability and profitability across the Australian grains industry. Recently, draft legislation concerning regulation of agricultural and veterinary (Agvet) chemicals in Australia was circulated for comment. The Grains Council weighed in with their view on how important these chemicals are…

“The Australian grains industry is heavily dependent on the efficient use of pesticides in maintaining productivity and profitability.”

“Access to a wide range of effective, safe Agvet chemicals is crucial to maintaining the productivity, sustainability and international competitiveness of many farming systems. Australia’s biosecurity depends on access to a diversity of pesticides and a responsive regulatory system.”

Author: J. Harvey
Affiliation: Grains Research & Development Corporation
Source: Comments in relation to GRDC research delivery under the draft Agricultural and Veterinary Chemicals Legislation Amendment (Agvet) Bill. February 28, 2012