Organic growers face the same potentially severe pest problems as non-organic farmers. By contrast, the organic farmers have a very limited range of approved products with which to control these problems. In many countries, very few fruit farmers even dare trying to grow with the less effective organic pest control methods.
“The demand for organic pears in North-western Europe is high compared to the limited production. In spite of the good market perspective there are very few pear growers in the Netherlands who dare convert to organic production. The most prominent reason for this is their fear of scab (Venturia pirina). And indeed it is the experience of those who are growing organically that it is very hard to control this important disease. This is even more so since Copper based products were banned as fungicides in the Netherlands.”
Author: Jansonius, P. J.
Affiliation: Louis Bolk Institute, Hoofdstraat, NL
Title: Conference pears; work on system changes to enable better scab control in organic orchards in the Netherlands.
Source: Ecofruit Proceedings. 2008.
Fire Blight: Apple
In April 2013, the National Organic Standards Board voted to not extend the approved use of antibiotics in organic orchards for fire blight control past October 21, 2014.Fire blight is the most devastating bacterial disease affecting apples and pears in the U.S. Fireblight is caused by the bacterial organism Erwina amylovora which grows readily and utilizes sugars and acids as food sources. An infected tree may die within a few months of infection. Fire blight was so named because the plants look as though they have been burned. Tissue infected with fire blight will exude droplets of sticky ooze that contain fresh inoculum. Infected fruit may exude copious amounts of bacterial ooze. Antibiotics have long been key disease control materials for fire blight control and both organic and non-organic growers have been permitted their use. However, after October 21, 2014, only the non-organic growers will be able to use them.
“A bad fire blight year after 2014 could devastate some Northwest organic apple and pear growers, who have relied on oxytetracycline to control the disease, a researcher said.
When the National Organic Standards Board voted April 11 not to extend the sunset for use of the antibiotic, orchardists faced the prospect of losing a useful tool without having a suitable replacement.
David Granatstein, sustainable agriculture specialist with Washington State University, said, “I suspect we’ll see some exit organics or selectively exit some blocks.”
A study he performed in 2011 found that only a quarter of surveyed Washington growers expected they could survive a fire blight outbreak without tetracycline.”
Author: Brown, S.
Affiliation: Capital Press
Title: Organic growers fear fire blight
Source: Capital Press. 4-26-2013, Pg. 7.
The codling moth is the most destructive insect pest of pears and apples worldwide. Females deposit eggs on or near fruit and the hatched larvae bore into the fruit and tunnel to the core. As they near development, they eat out an exit hole which they plug with frass. Fruit attacked by codling moth cannot be used for fresh shipment or for commercial canning.
“The codling moth has been the key pest in South African pome fruit orchards since the species was first reported in the country in 1885. The infestation potential of codling moth in South Africa is one of the highest in the world, and moths may be active over as much as 8 months of the year. Codling moth causes extensive damage to apples and pears, with stone fruit being only occasionally attacked. The use of insecticides remains the primary means of controlling codling moth in South African pome fruit orchards, with up to 11 different insecticides being used for control.”
Authors: A.E. Timm1, H. Geertsema1 and L. Warnich2
1Department of Entomology and Center for Agriculture Biodiversity, University of Stellenbosch, South Africa; 2Department of Genetics, University of Stellenbosch, South Africa
Title: Gene flow among Cydia pomonella (Lepidoptera: Tortricidae) geographic and host populations in South Africa.
Publication: Journal of Economic Entomology. 2006. 99(2):341-348.
Italian farmers annually produce 700 million tons of pears, which require protection with fungicides from a disease known as brown spot. The fungus overwinters in leaf litter on the orchard floor and spores are released in the spring under wet conditions. Spots appear on the fruit and internal rots occur as the result of fungal invasion. Severe outbreaks can result in defoliation of the pear tree and fruit dropping off the tree.
“Stemphylium vesicarium is the causal agent of brown spot, the main fungal disease of pear in Italy since the late 1970s. … Many pear orchards in Po valley, the main pear growing area in Italy, are affected by this fungal disease that may cause heavy loss of production, up to 100%. … Besides some cultural practices, scheduled preventative applications of dithiocarbamates, dicarboximides, strobilurins and tebuconazole (DMI) from petal fall to fruit ripening are the only way to control the disease.”
Authors: G. Alberoni, M. Collina, D. Pancaldi and A. Brunelli
Affiliation: University of Bologna
Title: Resistance to dicarboximide fungicides in Stemphylium vesicarium of Italian pear orchards.
Publication: European Journal of Plant Pathology. 2005. 113:211-219.