Do Roadside Fruit Trees threaten commercial Orchards?
There is no evidence to show that wild fruit trees pose any sort of threat to commercial orchards.
On the contrary: as Jackie French says in her article in the Sydney Morning Herald: 'Has anyone ever picked roadside apples and found they were full of fruit fly or codlin moth? As dedicated feral apple sampler, I can duly swear I have never come across a bad wild apple.'
Neglected orchards may harbour pests and diseases that could affect commercial orchards. But the trees in neglected orchards are vastly different from wild, local roadside seedlings. Old orchards contain grafted trees whose rootstocks and scion have been brought in from elsewhere.
Roadside fruit trees are seedlings that have had to survive without human intervention. Without grafting, without fungicides, without pesticides and nematicides, they have inbuilt resistance to the pests and diseases that afflict our commercial orchard crops and their presence poses no threat to commercial orchards.
On the contrary: as Jackie French says in her article in the Sydney Morning Herald: 'Has anyone ever picked roadside apples and found they were full of fruit fly or codlin moth? As dedicated feral apple sampler, I can duly swear I have never come across a bad wild apple.'
Neglected orchards may harbour pests and diseases that could affect commercial orchards. But the trees in neglected orchards are vastly different from wild, local roadside seedlings. Old orchards contain grafted trees whose rootstocks and scion have been brought in from elsewhere.
Roadside fruit trees are seedlings that have had to survive without human intervention. Without grafting, without fungicides, without pesticides and nematicides, they have inbuilt resistance to the pests and diseases that afflict our commercial orchard crops and their presence poses no threat to commercial orchards.
Do commercial fruit growing practices threaten to our food supplies?
REPEATED ORCHARD SPRAYING LEADS TO PESTICIDE RESISTANCE
Source: Western Australian Government Department of Agriculture and Food
Pome and Summer Fruit Orchard Spray Guide 2012-13
What is pesticide resistance?
Most pest and disease populations have a very small number of individuals that are resistant to a given pesticide. Frequent use of the same pesticide kills susceptible individuals but leaves the resistant ones and therefore selects a strain of the pest or disease that contains an increasing number of resistant individuals. Once this resistant proportion reaches a critical level, the lack of control ultimately renders that pesticide useless. This is known as resistance.
What pesticides are prone to resistance?
All pesticides (herbicides, insecticides, miticides and fungicides) are prone to resistance but miticides and some of the fungicides are the most at risk. This is because mites and fungi are usually resident in orchards and have a short life cycle. These attributes favour the rapid selection of resistant individuals if pesticide use is heavy.
Resistance has occurred in almost every miticide since the 1950s. Fortunately new groups of miticides which possess different modes of activity have been released over the past decade. Details of the miticides registered for use in WA deciduous fruit tree orchards is updated regularly by the Department of Agriculture and Food. See Farmnote 512 ‘Miticides for WA deciduous fruit tree crops 2011-2012’ which also includes guidelines for spray threshholds and the best way to use miticides to avoid the development of resistance.
Many of the new generation fungicides were developed for a specific disease and have a very specific mode of action. This means that they often have only a single-site activity. Many of the older fungicides have multi-site activity and as a consequence the newer fungicides are more prone to the diseases developing resistance to them.
If the same fungicide is used repeatedly it will allow the resistant spores to multiply until almost all spores are resistant and unaffected by the fungicide. Often when a disease becomes resistant to a particular fungicide it is resistant to other fungicides in the same activity group. See information under Resistant Management Stategies for Fungicides, developed by CropLife Australia.
Source: Western Australian Government Department of Agriculture and Food
Pome and Summer Fruit Orchard Spray Guide 2012-13
What is pesticide resistance?
Most pest and disease populations have a very small number of individuals that are resistant to a given pesticide. Frequent use of the same pesticide kills susceptible individuals but leaves the resistant ones and therefore selects a strain of the pest or disease that contains an increasing number of resistant individuals. Once this resistant proportion reaches a critical level, the lack of control ultimately renders that pesticide useless. This is known as resistance.
What pesticides are prone to resistance?
All pesticides (herbicides, insecticides, miticides and fungicides) are prone to resistance but miticides and some of the fungicides are the most at risk. This is because mites and fungi are usually resident in orchards and have a short life cycle. These attributes favour the rapid selection of resistant individuals if pesticide use is heavy.
Resistance has occurred in almost every miticide since the 1950s. Fortunately new groups of miticides which possess different modes of activity have been released over the past decade. Details of the miticides registered for use in WA deciduous fruit tree orchards is updated regularly by the Department of Agriculture and Food. See Farmnote 512 ‘Miticides for WA deciduous fruit tree crops 2011-2012’ which also includes guidelines for spray threshholds and the best way to use miticides to avoid the development of resistance.
Many of the new generation fungicides were developed for a specific disease and have a very specific mode of action. This means that they often have only a single-site activity. Many of the older fungicides have multi-site activity and as a consequence the newer fungicides are more prone to the diseases developing resistance to them.
If the same fungicide is used repeatedly it will allow the resistant spores to multiply until almost all spores are resistant and unaffected by the fungicide. Often when a disease becomes resistant to a particular fungicide it is resistant to other fungicides in the same activity group. See information under Resistant Management Stategies for Fungicides, developed by CropLife Australia.
COMMERCIAL OVER-RELIANCE ON GRAFTING LEADS TO NEW PATHOGENS
"Grafting fruiting vegetables to manage soilborne pathogens, foliar pathogens, arthropods and weeds"
Frank J. Louws Cary L. Rivard Chieri Kubota
Department of Plant Pathology, North Carolina State University,
Raleigh, NC 27695-7616, USA;
Department of Horticulture, Forestry and Recreation Resources,
Kansas State University, Manhattan, KS 66506, USA;
School of Plant Sciences, The University of Arizona, Tucson, AZ 85721-0036, USA
Scientia Horticulturae 01/2010; DOI: 10.1016/j.scienta.2010.09.023
ABSTRACT
Grafting is an important integrated pest management strategy to manage soilborne pathogens and other pests of solanaceous and cucurbitaceous crops. Important diseases managed by grafting are caused by fungal pathogens such as Verticillium, Fusarium, Pyrenochaeta and Monosporascus; oomycete pathogens like Phytophthora; bacterial pathogens, particularly Ralstonia; root knot nematodes and several soil-borne virus pathogens.
Rootstocks can include intraspecific selections that utilize specific major resistance genes and interspecific and intergeneric selections that exploit non-host resistance mechanisms or multigenic resistance.
Rootstock selection has also been documented to impact foliar pests including pathogens, arthropods and viruses.
Over-reliance on specific rootstocks in production systems has led to the emergence of new pathogens or shifts in the host specificity of the pathogen population, emphasizing the need for multi-tactic approaches to manage soilborne pathogens.
One advantage and associated challenge of grafting is that rootstock selection for disease management is site specific depending on the presence, population structure and dynamics of the pathogen, as well as edaphic, environmental and anthropogenic factors.
The use of grafting as an Integrated pest management tool to manage biotic stress will be most successful when carried out with increasing knowledge about the biology, diversity, and population dynamics of the pathogen or other pests and when complemented with sustainable farming system practices.
This review highlights major uses of grafting to manage soilborne pathogens, provides some novel information on managing foliar or other soilborne pests (insects, mites, weeds) and offers discussion on future research and applications.
"Grafting fruiting vegetables to manage soilborne pathogens, foliar pathogens, arthropods and weeds"
Frank J. Louws Cary L. Rivard Chieri Kubota
Department of Plant Pathology, North Carolina State University,
Raleigh, NC 27695-7616, USA;
Department of Horticulture, Forestry and Recreation Resources,
Kansas State University, Manhattan, KS 66506, USA;
School of Plant Sciences, The University of Arizona, Tucson, AZ 85721-0036, USA
Scientia Horticulturae 01/2010; DOI: 10.1016/j.scienta.2010.09.023
ABSTRACT
Grafting is an important integrated pest management strategy to manage soilborne pathogens and other pests of solanaceous and cucurbitaceous crops. Important diseases managed by grafting are caused by fungal pathogens such as Verticillium, Fusarium, Pyrenochaeta and Monosporascus; oomycete pathogens like Phytophthora; bacterial pathogens, particularly Ralstonia; root knot nematodes and several soil-borne virus pathogens.
Rootstocks can include intraspecific selections that utilize specific major resistance genes and interspecific and intergeneric selections that exploit non-host resistance mechanisms or multigenic resistance.
Rootstock selection has also been documented to impact foliar pests including pathogens, arthropods and viruses.
Over-reliance on specific rootstocks in production systems has led to the emergence of new pathogens or shifts in the host specificity of the pathogen population, emphasizing the need for multi-tactic approaches to manage soilborne pathogens.
One advantage and associated challenge of grafting is that rootstock selection for disease management is site specific depending on the presence, population structure and dynamics of the pathogen, as well as edaphic, environmental and anthropogenic factors.
The use of grafting as an Integrated pest management tool to manage biotic stress will be most successful when carried out with increasing knowledge about the biology, diversity, and population dynamics of the pathogen or other pests and when complemented with sustainable farming system practices.
This review highlights major uses of grafting to manage soilborne pathogens, provides some novel information on managing foliar or other soilborne pests (insects, mites, weeds) and offers discussion on future research and applications.