Hand-Weeding Labor Shortages Result in Organic Crop Loss

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Agriculture is facing a severe shortage of workers. Many fruit crops are even going unharvested because of a lack of pickers. Organic growers require more labor for tasks such as weeding since herbicides cannot be used. A recent experience by an organic grower in Washington illustrates the risk of going without herbicides in these times of labor shortages…

“Jon Warling, a labor contractor in Othello, said demand for workers is high and that an organic corn grower near Connell is discing under his corn because he can’t find enough workers for weeding.”

Author: D. Wheat
Headline: Labor committee hears litany of woe.
Publication: CapitalPress.com. July 20, 2012.

Italian Farmers Produce 700 Million Tons of Pears Thanks to Fungicides

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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.

Organic Rice Growing Reduced Average Yield of Rice in Texas

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Eight percent of the rice acreage in Texas is managed organically. These organic acres have much lower yields than conventionally grown acres. As a result, the overall yield of rice in Texas has declined.

“Organic rice acreage accounted for ca. 8% of the state’s total rice production. Organic rice fields typically yield ca. 30-40% of conventional commercial yields, this brought down the statewide average rice yields. An organic rice crop that yields 40% of the yield of a conventionally [grown] crop is equal to a 60% yield decrease. Multiplying a 60% yield decrease by 8% of the acreage is equal to a 5% drop in the average yield per acre.”

Author: L.T. Wilson
Affiliation: Texas A&M University
Title: From the Editor… Changes in Texas Rice Production
Publication: Texas Rice. 2007. Winter:2.

At Mid-Century, German Crop Production Turned to Herbicides

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In the 1950s and 1960s, as Germany industrialized, millions of workers moved from rural to urban areas and to factory jobs. When people left the farms, weed control technology was desperately needed to replace the major task of hand weeding crop fields. The introduction of herbicides saved German agriculture.

“Weeds cause drastic yield losses in food production, on average 25% in developing countries and 5% in developed countries, despite the control measures practiced. … Weed control is one of the major labour-consuming operations in traditional crop production, amounting from <30 up to about 70% of the total labour input.”

“In Germany, industry needed an increasing number of employees around 1960 and rural people left their fields. When this occurred there was no longer the question about traditional weed control with high labour input, but growing the crop with chemical weed control or no crop at all.”

Author: W. Koch
Affiliation: University of Hohenheim, Stuttgart, Germany
Title: Impact of weeds on developing countries.
Publication: Proceedings of the First International Weed Control Congress. 1992. Melbourne, Australia.

Organic Vegetable Crops Require Thousands of Hours of Weeding by Hand

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The biggest constraint to the expansion of organic crop growing is the lack of chemical controls for weeds – herbicides. Hand weeding is often required to remove weeds from organic fields. A very large number of worker hours are required for weeding, as reported in a recent article from Germany…

“In organic crop production, manual control of weeds is still laborious in a number of row crops that have poor competitive ability. It is difficult to control weeds that grow within the crop rows (intra-row weeds) by physical weed control; typical figures for hand-weeding time are in the range of 100-400 hours/hectare in carrot, direct-sown leek and onion, and it has even been reported to exceed 1000 hours/hectare.” 

Authors: J Rasmussen¹, C B Henriksen¹, H W Griepentrog² and J Nielsen¹
Affiliations: ¹University of Copenhagen, Denmark; ²University of Hohenheim, Germany
Title: Punch planting, flame weeding and delayed sowing to reduce intra-row weeds in row crops.
Publication: Weed Research. 2011. 51:489-498.

Cancellation of Effective Insecticides Puts Carrots at Risk of Rejection by Food Companies

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The carrot weevil is native to northeastern North America. Each female can lay 300 eggs. After hatching and entering the carrot, the larvae tunnel through the carrot, filling the tunnels with excreta. The epidermal cells around the tunnels die and become dark brown. The presence of larvae, excreta and feeding damage are of major concern to carrot processors because of strict FDA quality control in processed foods. Processors are unwilling to accept carrots if they find one live larva in a sample or if the carrots have more than 1% damage. Since the 1940s, effective broad spectrum insecticides kept carrot weevil damage to a minimum; however, the most effective insecticides have been cancelled for use in the US.

“Adults [carrot weevils] overwinter in and near carrot fields where carrots were grown the previous year, emerging in late April to early May in New Jersey. The adults feed directly on the leaves and crowns of carrots, and females oviposit from the beginning of May until late June in carrot roots. Larvae tunnel extensively throughout the upper third of the roots, damaging 80% or more of the carrots in untreated processing carrot fields.”

“Consequently, pesticide applications are directed at adult weevils to prevent or reduce oviposition. … However, during the past several years, carrot weevil damage has been increasing in New Jersey carrot farms, and the damage has been as high as 90% loss on farms in Salem County. These losses are partly due to the cancellation of broad-spectrum insecticides, such as parathion, azinphos-methyl, and phosmet during the early 1990s.”

Authors: G.M. Ghidiu¹, E. Hitchner², M. Zimmerman¹ and E. Rossell¹
Affiliations: ¹Rutgers University; ²Virginia Tech
Title: Effect of two different nozzle arrangements on control of carrot weevil, Listronotus oregonensis (LeConte), in processing carrots.
Publication: Plant Health Progress. April 3, 2006.

Fungicides Essential to Carrot Production Worldwide

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Organisms that cause diseases on carrot foliage are present wherever carrots are grown. Research has demonstrated that using fungicides to control these foliar pathogens increases carrot yields by 4-8 tons/acre.

“Alternaria leaf blight (ALB) of carrot and cercospora leaf spot (CLS) contribute to significant and recurrent losses for the production of carrots worldwide. … Foliar pathogens defoliate carrots by infecting and blighting leaflets and petioles, which in turn limits photosynthesis and energy storage in roots. Several field studies have shown 20%-80% yield loss for unsprayed carrots compared with carrots subjected to a standard calendar fungicide program.”

“In addition to yield loss, deterioration of petiole and leaf health may reduce the commercial harvestability of roots since strong, healthy petioles are required to properly lift and remove carrots from the soil. When foliage is weakened by disease, additional crop losses ensue as unharvested roots are left behind in the field. … Repeated fungicide applications are expensive but necessary on susceptible carrot cultivars to maintain crop yield and value.” 

Authors: P.M. Rogers and W.R. Stevenson
Affiliation: Department of Plant Pathology, University of Wisconsin-Madison
Title: Integration of host resistance, disease monitoring, and reduced funigicide practices for the management of two foliar diseases of carrot.
Publication: Canadian Journal of Plant Pathology. 2006. 28:401-410.

US Drought Effects Would Be Worse Without Pesticides

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The current drought has received extensive media coverage. There will be no Dust Bowl this year thanks to the use of pesticides. Farmers have been using herbicides instead of tilling the soil for weed control. By not disturbing the soil, they have conserved soil moisture. Corn yields would be worse if it were not for herbicide technology, a point made in an editorial by David Bridges, President of Abraham Baldwin Agricultural College in Tifton, GA.

“The Midwest ‘flash drought’ is withering much of our 2012 corn crop. … Now is the perfect time to consider the benefits to farmers, consumers and the environment of something routinely demonized by activists – pesticides. Pesticides? Yes. Without them, things would be worse, on all ends of our current dilemma.”

“Between 1980 and 2011, corn yields here grew by 64 percent while soil loss dropped 67 percent, energy use dropped 43 percent and carbon emissions fell 36 percent. Of vital importance this year: Irrigation water use for corn dropped 53 percent in the same period.”

“Pesticides and other technologies conserve natural resources while providing a production buffer that limits the effects of natural disasters and the disruptions of unforeseen shortages.”

USA Today echoed these sentiments on August 20.

“The severe drought that has hit the Farm Belt does not immediately threaten to create another Dust Bowl or widespread crop failure, thanks to rapid innovations in the past 20 years in seed quality, planting practices and farming technology, farmers and plant scientists say. … In the past 20 years, farmers have transformed from plowing fields 8 to 11 inches deep to ‘no-till’ or ‘conservation-tillage’ practices designed to minimally disturb the ground. That exposes the soil to less wind erosion, preserves natural nutrients, and captures and retains what moisture does fall.”

Author: David Bridges
Affiliation: Agronomist and President of Abraham Baldwin Agricultural College, Tifton, GA
Headline: Drought Would Be Worse Without Pesticides
Publication: Des Moines Register, Wednesday, July 25, 2012.

Author: Chuck Raasch
Headline: Another Dust Bowl for Farm Belt Unlikely
Publication: USA Today, Monday, August 20, 2012

European Hop Production has Relied on Insecticides for 150 Years

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A key pest of hops in Europe is the hop aphid, which feeds directly on the hop plant, extracting cell sap and nutrients with its sucking mouth-part. Hop aphids excrete prolific amounts of honeydew. Sooty mold grows on the honeydew and can destroy a crop’s value, as mold renders hop cones unacceptable for brewing. How do European growers cope?

“Dried female flowers (cones) of hops are used for flavoring and as a preservative of beer and related beverages. They provide bitterness and aroma. … Feeding by large numbers of aphids can debilitate hop plants and may induce premature defoliation, sometimes followed by a total loss of yield. Because of the threat posed by [hop aphids], treating hops with pesticides was already being recommended in England by the end of the 17th century and has been used regularly since about 1865.”

Authors: A. Barber, C.A.M. Campbell, H. Crane, P. Darby and R. Lilley
Affiliation: Horticultural Research International, Kent, UK
Title: Cost-benefits of reduced aphicide usage on dwarf hops susceptible and partially resistant to damson-hop aphid.
Publication: Annals of Applied Biology. 2003. 143:35-44.

Residents Protest Organic Farm’s Mishandling of Pests

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In September 2011, the situation in Jacumba, California got so out of hand that residents planned to protest the neighboring organic farm. Why? Eye gnats. Since Bornt & Sons Organic Farm can’t use chemical insecticides to control gnats, humans and animals in the small town of Jacumba are continually plagued with them flying around their eyes. East County Magazine reported on the issue…

“The gnats serve as a vector for diseases including pink eye and summer mastitis, causing swelling and burning of the protective membrane lining the eyelids and discharge from the eyes. … Chelsea Russell, a teacher at Jacumba School, says for the past seven years, her students have suffered. …’I ask myself, do I teach in a third world country?'”

“Eye gnats are very common in warm, dry areas. They grow in light, well drained sandy soils that are freshly plowed and contain abundant organic matter. Conditions at Bornt’s farms are ideal and because the farm is organic, Bornt is limited to the types of pesticides he can use.”

As a follow up to this story, Bornt & Sons Organic Farm planned to cease operations as of June 2012. Because they have removed their non-chemical eye gnat controls in preparation to close, the eye gnat swarms have been growing in Jacumba this summer.

Title: Jacumba residents call for shut-down of organic farm over eye gnat infestation; plan protest march on Sept. 17.
Publication: East County Magazine. September 11, 2011.