Disease Management Sprays Have Doubled and Quadrupled in Florida Citrus Groves since 2004 Due to New Exotic Pests

Citrus Canker

Citrus Canker

Before 2004, Florida citrus growers were concerned with only a few diseases. Thanks to hurricanes and tropical storms, new exotic disease organisms have been spread around the state. As a result, Florida citrus growers have had to dramatically increase sprays to manage disease: sprays for processed juice fruit have quadrupled and sprays for fresh grapefruit have doubled.

“The Florida example begins before 2004 when citrus tristeza and blight-decline were the major disease problems. Average annual sprays were two for processed juice fruit and six sprays for fresh market grapefruit. After the 2004-05 hurricanes and the ending of the citrus canker eradication program in 2006, the number of sprays to manage canker and other diseases increased to three or four sprays for processed juice fruit and 10 sprays for fresh grapefruit. With the 2005 discovery of huanglongbing (HLB) in Florida and citrus black spot in 2010, costs continued to increase. Now the annual spray program includes eight or nine sprays for processed juice fruit and 14 for fresh market grapefruit.”

Author: Muraro, R. P.
Affiliation: University of Florida, IFAS, Citrus Research and Education Center.
Title: Evolution of citrus disease management programs and their economic implications: the case of Florida’s citrus industry.
Source: Proceedings of the Florida State Horticultural Society. 2012. 125:126-129.

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Organic Apple and Pear Growers Fear Fire Blight

Fire Blight: Apple

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.

California Avocado Production Would be 82 million Pounds Lower with Conversion to Organic Practices

New Orchard Weeds

New Orchard Weeds

California farmers produce 550 million pounds of avocados annually. 8% of the avocado acres are managed with organic production practices. A recent economic analysis by the University of California shows why so few avocado acres are organic. Even though organic avocados receive a price premium, lower yields (15% lower) means lower profits than avocados grown with chemical inputs. The 15% lower yields would mean a loss of 82 million pounds of avocados if all the California avocado growers switched to organic practices. Weeds are the biggest problem for organic avocado growers.

“Profitability estimate of organic avocados in these counties is lower than avocados produced conventionally. Though organic avocados are considered to receive $0.20 more per pound than conventional avocados, organic avocado production shows lower yield than the conventional production.

Based on our discussions with growers and the UCCE farm advisor, organic yield is considered lower than the conventional production. In this study, organic avocado yield is estimated at 15% lower than the conventional yield.”

Author: Etaferahu Takele, et al.
Affiliation: Area Farm Advisor, Agricultural Economics/Farm Management, University of California Cooperative Extension (UCCE) Southern California
Title: Avocado sample establishment and production costs and profitability analysis san diego and riverside counties, 2011 organic production practices
Source: University of California Cooperative Extension. 2013.

Walnut Blight Sneaks Back Into California

Walnut Blight

Walnut Blight

California produces 99% of the walnuts grown in the U.S. and 38% of those grown worldwide. Walnut blight is the most destructive disease of walnuts and is caused by a bacterium that infects only walnuts. When the nut is infected, the infected area turns black as the bacteria invade the surrounding tissues. Drops of black slimy exudates containing myriads of bacteria and decomposed cellular materials may ooze out of the lesions. Control studies were initiated in 1930 and were carried out by the federal government for 16 years. The research demonstrated that the only practical method of controlling walnut blight was by spraying or dusting with protectant bactericides. Control practices for walnut blight have not changed substantially for decades. They are still based upon use of copper-containing materials.

“Walnut blight, depending on the variety, the weather and the pathogen populations, can cause significant crop loss. Such was the case in 2012, when some Chandler walnuts in the late leafing varieties saw 15 percent damage.

Rick Buchner, University of California Cooperative Extension farm advisor for Tehama County, said he thinks growers may have become lulled into a false sense of complacency because they haven’t had a lot of problems with blight in recent years. Consequently, they weren’t vigilant in their management practices as they’ve been in the past, he added.

A lesser treatment program was used that worked well in the past several years when there was low blight pressure, Buchner said, but that has resulted in the inoculum building.

Reverting to old management practices will bring the blight under control, Buchner said. “We’ve actually done that. It’s taken us two years to beat it back down,” Buchner said, recommending that growers plan for two very aggressive treatment years to take it back down.

“Copper spray is not cheap, but it’s a lot cheaper than 10 percent loss of walnuts,” Buchner said.

“Those bacteria are hanging out there now. They’re all set. They’re sitting in those trees just waiting to take off in the spring, so it is very important to stay vigilant,” Buchner said.”

Author: Kathy Coatney
Affiliation: Reporter
Title: Walnut Blight Slowly Sneaks Back Into North State Orchards
Source: Ag Alert. January 16, 2013. Pgs. 9-10.

Hand-Weeding Labor Shortages Result in Organic Crop Loss

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.

Organic Rice Growing Reduced Average Yield of Rice in Texas

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.

Organic Vegetable Crops Require Thousands of Hours of Weeding by Hand

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.

Birds Prefer Conventionally Grown Wheat Due to Higher Protein Levels

There is considerable debate about the merits of consuming organic foods. Some studies have found that certain animal species prefer to eat organically-grown crops. However, these results have been challenged by a recent study…

“One key reason why consumers buy organic food is because they consider it to be better for human and animal health. Reviews comparing organic and conventional food have stated that organic food is preferred by bird and mammals in choice tests. This study shows the opposite result – that captive birds in the laboratory and wild garden birds both consumed more conventional than organic wheat when given free choice. There was a lag in preference formation during which time birds learnt to distinguish between the two food types, which is likely to explain why the present results differ from those of previous studies.”

“A further experiment confirmed that, of 16 potential causal factors, detection by birds of consistently higher levels of protein in conventional seeds (a common difference between many organic and conventional foodstuffs) is the likely mechanism behind this pattern. The results of this study suggest that the current dogma that organic food is preferred to conventional food may not always be true, which is of considerable importance for consumer perceptions of organically grown food.”

Authors: A.J. McKenzie and M.J. Whittingham
Affiliation: School of Biology, Newcastle University, Newcastle upon Tyne, UK
Title: Birds select conventional over organic wheat when given free choice.
Publication: Journal of the Science of Food and Agriculture. (2010) 90:1861-1869.

To Find People to Hand Weed Organic Farms, Send Them to Jail

Without herbicides to control weeds, organic farms have to find people to pull weeds by hand. Workers are hard to find because hand weeding is drudgery. One solution is to tap into the prison population in the US…

“In a lush field southeast of Iowa, convicts serving time for theft, drug dealing and other crimes are hoeing weeds in what is planned as the state prison system’s first organic farm.”

“In the future, as many as 1,000 acres of prison farms throughout Iowa may be converted to organic crops, said Deputy Iowa Corrections Director Roger Baysden. … ‘This is perfect for prisons,’ Baysden said. ‘What I have got is labor, and I can save money on the chemical side by putting inmates to work with hoes. That is what the public really wants to see anyway.'”

Author: William Petroski
Affiliation: The Des Moines Register staff writer
Headline: Prison farm going organic; Inmates tend crops without chemicals
Publication: The Des Moines Register, Monday, 19 July 2004.