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Andrew Warren

Genetic ‘road map’ reveals the lost birthplace of a 150-year-old butterfly

Some scientific battles are epic: Think Nikola Tesla and Thomas Edison’s war of currents. Others fly under the radar, like a heated dispute over the origins of Mead’s skipper (above), a 150-year-old butterfly gathering dust on a Harvard University museum shelf. Now, using DNA from the dead insect, scientists have discovered its birthplace: a small mountain town in Colorado. The discovery settles old scores—and it could also help museum curators worldwide trace the origins of their own “lost” species.

When U.S. naturalist Theodore Mead found a tiny skipper butterfly (Hesperia colorado) in 1871, he didn’t label its location—typical for birds, insects, and other animals collected before GPS coordinates were added to most specimen tags in the early 2000s. That failure came back to haunt lepidopterists, one of whom discovered a nearly identical butterfly in the early 1980s. He classified it as a new subspecies. Other butterfly scientists were not so sanguine.

To solve the mystery of Mead’s butterfly, researchers from Texas and Florida started with its DNA. They gently removed the skipper’s abdomen from its pinned, fragile body, and extracted one-quarter of its nuclear DNA—and all of its mitochondrial genome—using a chemical solution to break down the genetic material.

They then sequenced the DNA, along with the DNA of 85 other H. colorado skippers. Next, the researchers compared each sequence to a reference genome of the species, creating a genetic “road map” that shows just how closely each specimen is related. From there, it was easy for the scientists to pinpoint the geographic origin of Mead’s skipper: Twin Lakes, Colorado, they report this month on bioRxiv.

Scientists have been using ancient DNA to trace early human remains to the places they lived for 2 decades, but this may be the first time DNA sequencing has been used to pinpoint the geographic origin of a museum specimen older than 100 years. Experts say it may not be the last. If the method can be replicated, it could soon uncover the origins of many old species that lack collection details.

 

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Ne farmer

A UAV applying herbicides to a research field at Texas A&M University Photo courtesy Texas A&M Weed Science
A UAV applying herbicides to a research field at Texas A&M University. The system is equipped with a four-nozzle boom and has a capacity of over five quarts.

How can UAVs be used in weed management?

Sep 11, 2019

Weed Science Society of America scientists say unmanned aerial vehicles may soon revolutionize weed management.

UAVs, often referred to as drones, can travel where it is hard to navigate by ground – from flying over dense forests to hovering over lakes, streams and other bodies of water. And when equipped with the right tools, researchers say they can be quite effective at both finding and treating problem weeds.

Just consider the following findings from John Nowatzki, a scientist at North Dakota State University:

Weed Identification and Mapping

UAVs equipped with cameras and other sensor technologies have successfully measured weed density and have been used to identify and map multiple weed species with greater than 90% accuracy. They also have been used to detect differences in canopy temperatures between glyphosate-susceptible and glyphosate-resistant weed species – data used to identify resistant weeds with an accuracy level of more than 95%.

One downside: Analyzing data collected by UAVs takes time, and that can mean a costly delay in weed management decisions. Researchers say artificial intelligence tools can eliminate the lag as computers learn to identify and map weeds on the go. More work must be done, though, to develop the massive databases of weed images needed for machine learning.

Aerial Application of Herbicides

Researchers are testing a semi-autonomous UAV spray system guided by global positioning system coordinates fed into the UAV’s flight planner. They’ve found that UAVs can hover over targeted treatment areas with an accuracy of one to two feet – improving the precision and safety of herbicide applications.  Before such systems become widely used in agriculture, though, researchers say it is important to learn more about spray drift patterns, the impact of droplet size, and the environmental and health impacts of UAV-based herbicide applications.  Such information will be critical to the U.S. Environmental Protection Agency as it works to establish policies that will address acceptable UAV use patterns, herbicide labeling, and regulatory, safety and enforcement issues.

But those investigating UAVs as a tool for weed control are upbeat about the potential. With the appropriate computer processing capacity and battery power, UAVs may one day become fully autonomous – able to identify weeds and make site-specific herbicide applications in real-time, all as part of a sustainable, site-specific weed management system.

“It’s easy to imagine early response programs to spot-treat potentially resistant weeds that escaped a previous treatment,” says Muthu Bagavathiannan, Ph.D., of Texas A&M University. “Doing so could greatly improve weed control and minimize weed seedbank replenishment, while reducing the amount of herbicides used.”

UAVs for Aquatic Weed Management

Aquatic weed management is an area where UAVs can really shine. Weed mapping is crucial to assessing the risk of plant invaders that threaten vital water resources. But it can be a tough task to accomplish by boat or shoreline observations.

According to Rob Richardson, Ph.D., of North Carolina State University, UAVs equipped with high-resolution cameras can quickly travel over bodies of water to detect new weed infestations, estimate the biomass of submersed or floating weed beds, and monitor weeds before and after treatment.

“UAVs give us a timely, low-cost way to reach areas of a waterway that would otherwise be inaccessible by boat due to shallow water, lack of launch facilities, or the presence of stumps, rocks or other hazards,” Richardson said. “They can be an important tool for rapid response and for making better-informed weed management decisions.

UAVs can also be used to apply treatments to specific areas over broad swaths of weedy invaders, Richardson says. Research is underway to explore important aquatic treatment variables – from the most appropriate applicator nozzles to best practices for managing spray drift.

Regulatory Controls

UAVs used in agriculture must be registered with the Federal Aviation Administration (FAA). The FAA also offers a certification process for operators. Details can be found on the FAA’s website, specifically at Parts 107 and 137 of its small, unmanned aircraft regulations.

Source: Weed Science Society of America, which is solely responsible for the information provided and is wholly owned by the source. Informa Business Media and all its subsidiaries are not responsible for any of the content contained in this information asset.

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western farm press

Rice breeder at field day Tim Hearden
Shyamal Talukder, a plant breeder at the Rice Experiment Station in Biggs, Calif., stands in a test plot for the new medium-grain variety, M-210, which was released in 2018.

Rice breeding, research aimed at boosting yields

Scientists at California facility developing new varieties.

Tim Hearden | Sep 10, 2019

The latest in rice research is focusing on maximizing yields, partly by building disease resistance, as growers seek to get the most out of every acre they plant.

Scientists at the Rice Experiment Station in Biggs, Calif., last year released foundation seed for a new variety – called M-210 – with a gene that promotes resistance to rice blast disease.

The gene was developed with marker-assisted selection provided by the DNA lab at the industry-funded station, which works with researchers from the USDA and University of California Cooperative Extension.

Other new varieties recently developed at the station include Calaroma-201, a long grain with jasmine cooking quality, and S-202, a short grain with a smooth hull and high yield potential, the researchers told growers at a recent field day.

“If Hollywood has its walk of fame, welcome to the walk of star rice,” plant breeder Teresa De Leon told about 350 growers at the Aug. 28 gathering at the station.

DROUGHT AND RAIN

The quest for higher yields comes as rice planting in recent years has been complicated by two weather extremes – drought and abundant rainfall. During California’s historic drought from 2012-16, water uncertainties – including later-than-normal deliveries to leave water in the Sacramento River for fish – prompted many growers to plant only portions of their land.

In 2015, growers in the Golden State ended up planting about 423,000 overall acres of rice, down from 585,000 acres in 2011, according to the National Agricultural Statistics Service. California’s planted acreage of all varieties rebounded to 506,000 last year, including 455,000 acres of medium grain, which is dominant in the state.

This year, NASS estimated that 485,000 overall acres would be planted in the state, but that was before late spring rains delayed or prevented planting in many areas. At the research station, some test plots weren’t planted until June 15, said Bruce Lindquist, a plant sciences specialist from UC-Davis.

“That’s the latest we’ve ever planted rice,” he said.

Scientists have been working for years to develop varieties with resistance to diseases like blast fungus, which is known to cause lesions on leaves, stems, peduncles, panicles, seeds and even roots, according to the University of Arkansas Division of Agriculture Research and Extension.

IMPROVING YIELDS

Scientists have a systematic way of naming rice varieties, with a letter for long, medium and short, followed by numbers for maturity and order of release, De Leon said. The researchers grow all three types at the Biggs facility, even though medium grain represents more than 90 percent of the rice planted in California.

“M-206 is still the reigning queen in California, although M-209 and M-210 are coming on now,” De Leon said.

M-206 is an early-maturing medium grain released for seed production in 2003, explains the California Rice Commission. It has been broadly adapted to California’s rice-growing regions, but newer varieties could provide growers with as much as 20 percent more yield, said Luis Espino, a UCCE rice systems advisor based in Oroville.

In 2005 and 2006, M-207 and M-208 were released with a gene for blast resistance, but the latter succumbed to a new race of blast, the station’s scientists explain. The setback prompted the breeders to try adding several blast-resistance genes to M-206, finally releasing M-210 in 2018.

M-209, released in 2015, has in recent years been the station’s highest yielding medium-grain variety, averaging 10,040 pounds per acre compared to M-206 and M-205 yields of 9,290 and 9,240 pounds per acre, respectively, the researchers note. M-209 is adapted to warmer areas and may not perform as well where it’s cooler, such as in the San Joaquin Valley, the scientists say.

The M-210 variety has registered an average yield of 9,090 pounds per acre at the station.

BUILDING ON SUCCESS

The breeding program was one of several topics covered at the annual field day, which is sponsored by the UC and the California Cooperative Rice Research Foundation. Rotating groups of growers also heard talks on managing nitrogen fertilizer and evaluation of new weed control methods.

Station scientists say they want to build on the success of their DNA marker laboratory by expanding its capability to include genetics and genomics research, which will be the foundation of a genetics lab that is under construction.

Research efforts will also continue seeking to improve and develop specialty varieties such as waxy rice, aromatic rice and others while also working on grain quality, yield and disease resistance, according to the center’s website.

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Anthropocene-delta-logo4

 

A new AI-powered app scans banana crops for early signs of disease

The banana is the world’s most popular fruit: we consume 100 billion of them a year. And yet, their future is threatened by a spate of diseases that are ravaging crops worldwide. Now, researchers have developed a tool to tackle these silent killers: an artificially-intelligent smartphone app that can scan banana plants for early signs of infection, and alert farmers before it takes hold on their crops.

In field studies in India, China, the Democratic Republic of Congo, Benin, Colombia and Uganda, the researchers found that the new tool – which uses the phone’s camera to screen crops – is at least 90% accurate in identifying the six most serious diseases and pests that plague banana plants. Those include two globally-destructive infections known as Black Sigatoka and Fusarium Wilt which together have decimated vast tracts of banana plantations worldwide.

This invention – produced by researchers from global institutions including Biodiversity International and the International Centre for Tropical Agriculture – is driven by the harsh reality that the bananas we know and love risk being wiped out globally, by the growing threat of disease. This especially affects the Cavendish, the banana variety that we consume most widely worldwide, and the type that most people in the west typically buy in grocery stores.

Our love for this particular variety has driven the establishment of massive monoculture plantations in banana-growing countries, which has caused the fruit’s downfall: without genetic variety on these farms, they’re left exposed to the ravages of disease, which can rapidly decimate vast tracts of cropland in one go.

Already, crops in Asia and Africa have been affected by one of the most voracious of these threats, Fusarium Wilt. Recently, the disease even reached Latin America, which is home to Ecuador, the world’s largest exporter of Cavendish bananas.

The smartphone app is based on a computer model that uses algorithmic deep learning to make its predictions. To produce this, the researchers gathered 18,000 photos of banana plants from farms around the world, many exhibiting various signs of poor health. Then they used the gallery to train several computer models to identify the hallmarks of particular pests or disease in these images.

The major benefit of the app is its flexibility, according to the researchers. It can identify signs of disease on any part of the plant, and can accurately identify disease even in low-quality photos, or in images where there’s lots of background noise – such as leaf litter coating the ground. In some cases, the detection rate for disease was as high as 100%.

Apart from protecting the world’s favourite fruit, the app is aimed particularly at protecting the livelihoods of smallholders. These farmers typically rely on small plots of land to support themselves and their families – places where an outbreak of disease could destroy an entire livelihood. The app is explicitly designed to avert that disaster, by equipping farmers with a DIY, hand-held tool to regularly check crops and rapidly identify disease-risk.

The app could also provide support for at-risk farmers: if a detection is shared through a live network, it could be used to alert agricultural extension workers – people who work between research institutions and farmers – who could come to the farmers’ aid to nip the disease in the bud.

This is exactly what the researchers have in mind for the next stage of development. Now they’re hoping to use the app to develop an interconnected, global system, fuelled by farmers who share information about their crops. This would enable experts to pinpoint where disease outbreaks begin, and figure out how to contain them before they spread out of control.

The researchers decided to call the app ‘Tumaini’, which means ‘hope’ in Swahili. They think that’s what the tool offers to the planet’s most vulnerable banana farmers. “This is not just an app, but a tool that contributes to an early warning system that supports farmers directly,” they say.

Source: Selvaraj, et. al. “AI-powered banana diseases and pest detection.” Plant Methods. 2019.
Image: MaxPixel

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SE farm press

DFP-RonSmith-Mueller.jpg Ron Smith
Clemson University Extension nematologist John Mueller talks about the damage nematodes cause in cotton.

Invisible cotton pest steals 1 million bales

Nematodes steal 1 million bales of cotton annually

Ron Smith | Aug 28, 2019

Nematodes are stealing as much as 10 percent of U.S. cotton production annually and many producers are not aware that they are being robbed.

“Yield losses of 10 percent within a field are common and often go unnoticed,” says Clemson University Extension nematologist John Mueller.

“Yield losses in some fields,” he said at a recent PhytoGen field day in Lee County, S.C., “can exceed 50 percent.”

Across the Cotton Belt, nematodes may be taking close to 1 million bales annually. Root-knot and reniform species are the most common and extend from North Carolina to Texas with annual Beltwide losses averaging 5 percent.

Widespread problem

“Cotton production in every state is affected by one or more nematode species,” Mueller says. “In addition to reniform and root-knot, South Carolina and some counties in North Carolina and Georgia also lose cotton to the Columbia Lance nematode. Other damaging species include the sting and stunt nematodes.

Mueller says nematodes may occur and limit yield on most soil textures. If plants are under stress from other factors — moisture or heat — nematode losses may increase and could be worse in coarse, sandy soils.

“Nematodes occur in scattered patches. These areas develop more slowly than the rest of the field, which makes maintenance, including herbicide application, and especially defoliation and boll opening, difficult. Often, yield is in the field but lost due to late maturity.

“Irrigating more will not eliminate damage,” he adds. “The damage from nematodes often blocks the vascular system, so, no matter how much soil moisture you have, the plant is still not taking up all it needs.”

Yield loss may come from stunted and abbreviated root systems from nematode feeding; reduced efficiency of water and nutrient uptake from impeded vascular systems; and potential increased levels of fungal root diseases and Fusarium wilt, in addition to seedling diseases.

Four steps

Mueller recommends four important steps farmers should take to manage nematodes.

1. The first thing you need to do is sample all your fields, find out what you have. Submit those samples to the nematode lab; identify the species — root-knot or reniform (the main two across the Belt).

2. Follow a good crop rotation. Work with your county agent or your local consultant. Pick a rotation that will minimize the nematode buildup.

3. Use available resistant varieties if rotation is not adequate. Currently, several varieties with root-knot resistance are available and reniform resistant options are about two years away.

“That will be a great addition to fight the nematode damage in a conservative manner, no pesticides into the soil,”

4. The last resort is where you spend the most money. A nematicide is probably going to cost $30 to $50, $60 an acre.

Sample timing critical

Timing of sampling is important, Mueller says. “We need to sample between harvest and Thanksgiving in most places. Take samples in the fall and send them to your state lab or local commercial lab. Look over the numbers and design a two- or three-year plan to control nematodes in the crops that you want to plant.”

Mueller says samples should be pulled from the crop row, about 3 inches from the stalk, not the middles where producers typically collect soil fertility samples.

He recommends storing samples out of sunlight, preferably in a cool spot but not frozen.

“Send samples to a nematode laboratory as quickly as possible. They do not need to be shipped in a cooler with ice if sent in a package with numerous samples and the outside temperature is not extreme.”

Producers should “sample every field for nematodes to develop an effective nematode management scheme.”

In South Carolina, cost for nematode samples vary from $5 to $20 per sample and may be as high as $50.

“Although that seems high, it is easy to justify a $20 per sample fee,” Mueller says. “Normally, a sample represents more than 20 acres. At 20 acres per sample, that’s just $1 an acre.”

Species and population density depend on several factors, including crop, variety, weather and planting date, he says.

Crop mixes are important but Mueller cautions that eliminating nematodes by rotation may be difficult. Cotton and soybeans are hosts for root-knot, reniform, lance and sting nematodes. Corn is host to root-knot, lance and sting but not reniform. Peanut is host only for the sting nematode.

Variety selection

Variety selection is also important and underscores the importance of sampling to identify species. “Host plant resistance is specific to one species,” Mueller says.

Varieties first released with root-knot resistance were associated with a “yield drag,” Mueller says. “The latest Southern Root-Knot (SRK) resistant varieties (PhytoGen 480, for one) have overcome the yield drag and reduce nematode reproduction and carryover significantly.”

Nematicides, on the other hand, work across nematode species.

Mueller also cautions producers about moving nematodes from an infected field into a clean one. Nematodes may hitchhike on soil carried in mud on vehicle tires. Implements such as discs and planters or other pieces of equipment inserted into the soil are potential nematode movers.

Wind may bring in nematodes. Also, birds and mammals and any movement of water that carries soil may transport nematodes. “Flooding will not kill off a nematode population,” Mueller explains.

Need to know

The critical first step in managing nematodes, Mueller says, is knowing what’s in the field — population density and species. Next is realizing how damaging the pests can be.

The life cycle of a nematode from egg to egg is less than 28 days and one female can produce more than 200 eggs with multiple generations per year. The female dies after producing eggs and once a female infects a root, she cannot move to another location.

Knowing the population dynamics of nematodes and the amount of loss a cotton farmer can incur should encourage producers to manage the pests.

Control costs may seem high, he says, but are also justifiable. The $20 per sample, for instance, adds just $1 per acre to production costs.

Nematicide treatments range from $5 to $60 an acre. “In two-bale cotton, a 10 percent yield loss will cost at least $60 per acre,” Mueller says. “You can spend $1 per acre to help make decisions that could cost you $5 to $60 in nematicide cost or lost yield.”

Unless producers sample, they don’t know if nematodes are costing them lost pounds and if so, which species is doing the damage. A modest investment at least provides information to make informed decisions.

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Delta f perss

DFP-Brad-Robb-MRhine-SStewart.jpg Brad Robb
At the Union City AgKnowledge Field Day, Matt Rhine, left, technology development representative, Bayer CropScience, and Dr. Scott Stewart, Extension entomologist, University of Tennessee, highlighted some of the latest insecticide trait technologies some growers may be adopting when they are commercially released.

New insect control trait technologies showcased

Review Extension data before making crop varietal decisions.

Brad Robb | Aug 29, 2019

Although some of the new insect control trait technologies coming through the developmental pipeline from Bayer CropScience for 2020 may not have a direct application to your row crop operation, there are some that do. According to Dr. Scott Stewart, Extension entomologist, University of Tennessee, growers should review information on what is becoming commercially available and cross-reference that information against available Extension data to help make a more informed decision.

Stewart and Matt Rhine, technology development representative, Bayer CropScience, broke down the new cotton, corn, and soybean trait offerings at the Union City AgKnowledge Field Day and over 300 farmers were in attendance to listen. “This Trecepta variety is bringing three different Bt traits to the market,” says Stewart. “The VIP trait found in Trecepta brings greatly improved control of corn earworms.”

Depending on the registration and export approvals, there may be a cotton lygus trait variety coming for 2021. “When this new technology was first being developed, Monsanto called it a ‘lygus’ trait, which is actually the genus name for tarnished plant bug,” says Stewart. “It wasn’t long before testing showed that it provided much-needed control of thrips, and thrips are the top insect pest of seedling cotton.”

In a cotton insecticide trial that Stewart did this year, he used every available insecticide option to affect control, but crop injury was still substantial. “I believe this is where this lygus trait technology will shine, because much less thrips injury was observed in test plots having this new technology,” says Stewart.

Work conducted by Stewart’s previous graduate student confirmed that Bt lygus trait provides some control of tarnished plant bugs. “They don’t lay as many eggs, and it also has a negative effect on their growth,” says Stewart. “It’s not a stand-alone control for plant bugs like it appears to be on thrips, but it definitely reduces the numbers. You won’t have to make as many insecticide applications if you use the new lygus trait, and that’s where you’ll potentially save some money.”

Stewart has seen significant yield losses if threshold numbers of plant bugs are reached and insecticide applications are not made — and this includes cotton having this new lygus trait. “In reality, you’d still have to make some sprays anyway because this technology doesn’t control stink bugs — especially if you’re not spraying as much for tarnished plant bugs,” says Stewart. “Stink bugs will slip in on you. This isn’t a walk-away technology.”

Stewart expressed concern about the VIP technology being placed in corn varieties, like the Trecepta technology. “Other entomologists around the Mid-South and I are worried about selecting resistance in corn that will impact corn earworm (a.k.a. bollworm) control in cotton,” says Stewart. “We are dependent on VIP trait also present in Bollgard III, TwinLink Plus, and Wide Strike III to get us over the hump until the next trait is released because we’re seeing bollworm resistance to the Bt traits present in Bollgard II, TwinLink, and the original Wide Strike technology, and quite frankly, we’re seeing little economic benefit, at least in our geography, of having that VIP trait in corn. The increased protection against corn earworm in corn having the CIP trait is really not translating into yield.”

Resistance, remaining vigilant on soybeans

Some corn farmers in Texas have observed corn earworm infestations where the VIP technology is being used in corn. “We’ve not seen much of this in the Mid-South, but that shows the potential for resistance is out there and is real,” says Stewart.

The Mid-South corn, cotton, and soybeans crops are progressing, and according to Stewart, progressing well. “I always like to remind farmers to be vigilant in soybean scouting the remainder of the growing season as we near corn and cotton harvest,” says Stewart. “From this point forward, you’ll have 90 percent of your insect problems in soybeans. Stink bugs will start spiking when you hit R5/R6, which is also where your late-season caterpillars increase.”

Soybean pest pressure has been relatively low this year, but Stewart reminds everyone that when corn is drying down and cotton is finishing up, all of those pests will be looking for something green on which to feed. “Their most readily available choice is late-season soybeans,” concludes Stewart.

 

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western farm press

Tomatoes Tim Hearden
Brown rugose fruit virus is a threat to tomato production.

‘Ebola of plant viruses’ concerns tomato industry

Brown rugose fruit virus found in Arizona, California.

Lee Allen | Aug 28, 2019

Virologists have brewed up a new alphabet soup — ToBRFV or tomato brown rugose fruit virus — and much to the consternation of greenhouse tomato growers in the U.S., it’s headed their way, already sending out advance scouts in Arizona and California.

First discovered in Jordan in 2015, it moved on to Israel, Turkey, and Saudi Arabia, was spotted in Germany (2016) and Italy (2018) with likely occurrences reported  (but not confirmed) in Chile, Ethopia, Sudan, Thailand, Peru, China, and the Netherlands.  Now it’s being reported as widespread in Mexican greenhouses, just a hop and a skip across the border into neighboring states.

“We’ve had two incidents of it in California,” says Bob Gilbertson, who specializes in plant virology and seed pathology at University of California, Davis.  “It was identified in a Santa Barbara County production greenhouse in September last year, confirmed by Kai-Shu Ling of the U.S. Department of Agriculture and by our plant pathologists.  In that instance, all ToBRFV-infested and symptomatic plant material was voluntarily destroyed.

“Then, sometime in early August, we received suspect fruits from a market in Sacramento that had obtained them from Baja, Mexico,” he said.  According to a report by Gilbertson and Zach Bagley of the California Tomato Research Institute, “They didn’t have necrotic lesions on the fruit — there were white blotches — but when we tested them, ToBRFV showed up.”

The acronym for tomato brown rugose fruit virus represents a new species of a well-known group of plant viruses, tobamoviruses.  It’s highly virulent and seems to override existing genetic controls and researchers are noting: “Because of the rapid spread of this virus, it represents a major concern for worldwide tomato production because no tomato varieties are known to be resistant to it as it breaks or is not recognized by Tm-2 2 or any other resistance gene currently used to protect tomatoes genetically against tobamoviruses.”

GREENHOUSES AFFECTED

Available information to date suggests ToBRFV is primarily a threat to protected culture (greenhouse or screenhouse) production although outbreaks in open fields have been reported in Mexico.

Because they grow more than 90 percent of the nation’s processed tomatoes but don’t grow for the fresh market, the California Tomato Growers Association is keeping a watchful eye on the situation, but suggests the greater concern belongs to the Western Growers Association.

Asked for comment, WGA’s Communications Manager Stephanie Metzinger replied by e-mail: “While we are aware of the situation, we do not have a statement to provide.”

One of WGA’s larger growers, Houweling’s in Camarillo, CA — with 125 acres under glass and additional production facilities in Utah and Canada — was willing to comment.

In a statement to Western Farm Press, they reported, “We’ve been diligent since the rumors and early news of ToBRFV, reassessing all our phytosanitary and operating protocols.  We’ve eliminated packing products from other sites and opened satellite packing operations to manage partner grower products.  Empty trucks get disinfected and cleaned, and in cooperation with our partners, we have eliminated the use of RPC shippers which we identified as a significant risk.”

‘EBOLA OF PLANT VIRUSES’

“We’re calling this one The Ebola of Plant Viruses,” says Gilbertson, first cautioning, “you’ve got to be vigilant about it because it spreads so rapidly,” and then cajoling, “but growers shouldn’t be paranoid and panicking because we have a number of ways to manage it.”

Because Arizona is a major hub of tomatoes imported into the U.S., it could be a bellweather for California growers and Gilbertson suggests everybody needs to be on heightened awareness.

Already recognizing that the best defense is a good offense, Wholesum Farms (Wholesum Harvest) with tomato greenhouses in Arizona as well as Sonora and Sinaloa, Mexico, is on alert with their beefsteak, cherry, Roma, and tomatoes-on-the-vine production.

“ToBRFV is a very serious threat to our production and we’re taking all necessary steps to insure we remain virus-free,” says Theojary Crisantes, Chief Operations Officer of the company with 60 acres of greenhouses, 220 acres of protected fields, and 325 acres of open field production who partner with other family-owned and -operated organic growers from Central Mexico through California.

“There has been no detected presence of the virus in any of our operations in Mexico or the USA and we’re taking extreme measures in sanitation going in and out of our greenhouses to make sure things stay that way.”

SYMPTOM SPOTTED

Not so lucky is the nearby NatureSweet operation that maintains 500 hectares in Mexico and 120 hectares in Arizona, with an annual production of 18 million plants, all under glass.

“We found rugose in one of our greenhouses in March of this year,” says General Manager Alexandro Briones Sanchez. “We spotted it from the first symptom and took immediate action, removing that row and five rows on either side and burning the plants and the coconut coir before performing a complete sanitizing.

“Some companies, when they find the first symptom, they’ll take a plant sample and send it to analysis which could take 48-72 hours.  Because the virus is spread mechanically, by that time you may have touched all of your greenhouses if you’re not segregated and share labor.  From our experience, if you make your decisions immediately when you find a plant with viral symptoms and remove it, it will be controllable at that point and pay off in the long run.”

Pathologist Gilbertson emphasizes the speed of the spread factor.  “There is no insect vector here.  It’s solely transmitted by contact, human touch or machines or tools.  It’s extremely stable and can survive in dry tissue for years.”

Diagnostic seed testing is one of the keys to slowing down the spread of the virus, he says, advocating, “Management before, during, and after the growing season.”  After the seed is tested, implement the safety factor, Plan B, which is to treat that seed with a 10% triple sodium phosphate solution “which will virtually eradicate any virus in the seed.”

GET THEM OUT EARLY

That’s what you can do before planting.  During the growing season, constantly walk the rows looking for any kind of mosaic, a mottling on the leaves that will sometimes elongate.  “Get those plants out early and don’t let them touch other plants to minimize the amount of inoculum.  Workers need to be wearing clean protective clothing and dip their gloves and tools in TSP.”

After the growing season — “Remove all the plants and spray down the inside of the house…all the benches, strings, ropes, tools, everything.  This kind of sanitation is practiced in protected culture for bacterial canker, but the possibility of ToBRFV requires even more vigilance and intense sanitation.”

Gilbertson offers the following: “Although growers may have to spend more on sanitation protocol, this virus is hardly going to threaten tomato production in the U.S., protected or open-field.  And although we have to up our game a bit, it shouldn’t cause a panic because we have a number of ways to manage it.”

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