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This praying mantis inflates a strange pheromone gland to lure mates

Such an organ may be crucial for reproduction in a vast, dense rainforest

a mantis hanging from a leaf
A female Stenophylla lobivertex mantis hangs from a leaf, extending her forked pheromone gland.CHRISTIAN J. SCHWARZ (CC-BY 4.0)

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By Jake Buehler

APRIL 26, 2021 AT 6:00 AM

Praying mantises — with their angular features, huge eyes and centaur posture — often seem a bit alien. But researchers have recently found one mantis species that takes this otherworldly quality to the next level: Females of this species have an inflatable pheromone gland that protrudes from the back of the abdomen like a green, Y-shaped balloon. 

This odd organ is unlike anything seen in mantises before, researchers report online April 21 in the Journal of Orthoptera Research.

In October 2017, herpetologist Frank Glaw was moving through the nighttime rainforest in Amazonian Peru at the Panguana research station, searching for amphibians and reptiles. His flashlight passed over a brown, leaf-mimicking mantis (Stenophylla lobivertex) in the tangle of vegetation, and he saw “maggotlike” structures protruding from its back. Those structures were quickly sucked back inside the insect after the light hit it, says Glaw, of the Bavarian State Collection of Zoology in Munich, Germany.

Glaw was reminded of “parasites that eat the animal from the inside,” having seen such fatally parasitized insects before. With the help of Christian Schwarz, an entomologist at Ruhr-University Bochum in Germany, and observations of some female specimens in captivity, the team figured out that the mantis was no parasite-riddled vessel. 

close-up of a y-shaped gland on a mantis
The inflatable pheromone gland of Stenophylla lobivertex (shown) may be highly efficient at spreading chemical signals throughout the rainforest.CHRISTIAN J. SCHWARZ (CC-BY 4.0)

When left undisturbed in total darkness, the female mantises extrude a pronged structure inflated with body fluids, roughly the hue and luster of polished jade. It appears to be a highly modified gland for producing pheromones — chemical signals that help female insects attract mates (SN: 5/13/15). 

Other mantises have simple, noninflatable glands that are located in the same section of abdomen as S. lobivertex’s bifurcated contraption.

This mantis species is rarely encountered by researchers and might be thinly spread throughout the rainforest, so locating receptive mates could be particularly challenging. The researchers think a large, protrusible pheromone gland with lots of surface area could be a workaround, more efficiently dispersing pheromones to be detected by the antennae of would-be suitors.

“It is a kind of chemical ‘dating app’ in the jungle,” says Glaw, noting that the observations “emphasize the importance of pheromones in [the mantises’] reproduction in a vivid manner.”

Females in some other mantis species are known to expose a pink, patchlike gland when doing their chemical call for mates, says Henrique Rodrigues, an entomologist at the Cleveland Museum of Natural History who was not involved with this research. 

“I can easily see something like that being the precursor of the protrusible gland,” says Rodrigues. He notes that since males have thin, hairlike antennae, “the other way to increase the odds of mate finding would be for females to increase the amount of pheromone released.”

Glaw thinks it’s likely that similar glands might exist in the other two species of Stenophylla, and possibly other mantises. “If this organ is really an important tool to improve the finding of mates,” he says, “it would be an advantage for many other mantis species as well and might be more widespread.”

Questions or comments on this article? E-mail us at feedback@sciencenews.org

CITATIONS

C.J. Schwarz and F. Glaw. The luring mantid: protrusible pheromone glands in Stenophylla lobivertex (Mantodea: Acanthopidae)Journal of Orthoptera Research. Vol. 30, April 21, 2021, p. 39. doi: 10.3897/jor.30.55274.

About Jake Buehler

Jake Buehler is a freelance science writer, covering natural history, wildlife conservation and Earth’s splendid biodiversity, from salamanders to sequoias. He has a master’s degree in zoology from the University of Hawaii at Manoa.

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How Moths Find Their Flame – Genetics of Mate Attraction Discovered

Biologists have discovered the gene controlling the mating preference of male European corn borer moths for the female sex pheromone
Tufts University

14-May-2021 5:00 AM EDT, by Tufts Universityfavorite_border

Newswise: How Moths Find Their Flame - Genetics of Mate Attraction Discovered

Callie Musto, Charles Linn

A male European corn borer moth (Ostrinia nubilalis) sexually courts a rubber septum doused with the sex pheromone of a female European corn borer moth

Newswise — The mysteries of sexual attraction just became a little less mysterious – at least for moths. A team of six American and European research groups including Tufts University has discovered which gene expressed in the brain of the male European corn borer moth controls his preference for the sex pheromone produced by females.  This complements a previous study on the gene expressed in the female pheromone gland that dictates the type of blend she emits to attract males. The study was reported today in Nature Communications.

The implications go beyond making a better dating app for bugs. Now scientists can begin to ask why mating signals and mating preferences change in the first place, which is a long-standing paradox since any change could reduce the ability of an organism to successfully mate. Knowledge of these two genes will provide a better understanding of how the pheromones of the 160,000 moth species have evolved.

Of course, one important role for mating preferences is to make sure you are not matching up with a completely different species. The signal sent by females must be preferred by males of the same species to ensure that like mates with like–a mechanism called assortative mating.  The European corn borer is interesting because there are two types, called E and Z, with assortative mating within each type.  Even though the two types can be mated to each other in captivity, E mostly mates with E, and Z with Z in the field.  For this reason, the European corn borer has been used as a model for how one species can split into two, ever since the two pheromone types were first discovered 50 years ago. 

 “That means we now know – at the molecular level – how chemical matchmaking aids in the formation of new species. Similar genetic changes to pheromone preference could help explain how tens of thousands of other moth species remain separate,” said Erik Dopman, professor of biology in the School of Arts and Sciences at Tufts and corresponding author of the study.

Different aspects of the research were conducted by the three co-first authors Fotini Koutroumpa of University of Amsterdam, Melanie Unbehend of the Max Planck Institute for Chemical Ecology, and Genevieve Kozak, a former post-doctoral scholar at Tufts University and now assistant professor at University of Massachusetts, Dartmouth.  “Our study’s success can be attributed to a team with a common vision and strong sense of humor that helped make the science worthwhile and fun,” said Dopman.

One of the surprise discoveries made by the team was that while females may vary their signals in the blend of pheromones they produce, preference in the male is driven by a protein that changes their brain’s neuronal circuitry underlying detection rather than affecting the receptors responsible for picking up the pheromones.

Preference for a particular cocktail of pheromones is determined by any of hundreds of variants found within the bab gene of the male. The relevant variants of bab are not in parts of the gene that code for a protein, but in parts that likely determine how much of the protein is produced, which in turn affects the neuronal circuits running from the antennae to the brain. The researchers were able to determine anatomical differences in the male, including the reach of olfactory sensory neurons into different parts of the moth brain, and link them to their attraction to E or Z females.

“This is the first moth species out of 160,000 in which female signalling and male preference genes have both been identified,” said Astrid Groot of the University of Amsterdam, who also helped identify the gene controlling the pheromone difference in E and Z females. “That provides us with complete information on the evolution of mate choice and a way to measure how closely these choices are linked to evolving traits and populations.”

The ability to predict mating could also help control reproduction in pest insects. The European corn borer is a significant pest for many agricultural crops in addition to corn. In the U.S., it costs nearly $2 billion each year to monitor and control. It is also the primary pest target for genetically modified “Bt corn” which expresses insecticidal proteins derived from the bacterium, Bacillus thuringiensis. While Bt corn remains an effective control of the corn borer moth in the U.S., corn borers in Nova Scotia are now evolving resistance to another variety of Bt corn.

“Our results can help to predict whether Bt resistance could spread from Nova Scotia to the Corn Belt of the U.S., or whether assortative mating could prevent or delay it”, said co-author David Heckel at the Max Planck Institute for Chemical Ecology, who also studies how insects evolve resistance to Bt.  “Bt corn has enabled a huge reduction in the use of chemical insecticides, and it should be a high priority to preserve its ecological benefits as long as possible.”REQUEST AN EXPERT

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CITATIONS

Nature Communications; 661322; CRIS-5030-22000-018-00D; 621-2014-4816; CRIS-3625-22000-017-00; 58-5030-7-066; 3543; 1257251

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HOME>FARM BUSINESS>FARM OPERATIONS>SUSTAINABILITY

Sustainable IPM efforts target insect pheromone use

TAGS: CROPSTodd Fitchettewfp-todd-fitchette-desert-broccoli-71.jpg

A biologically safe attractant using pheromones to entice honeybee visits to broccoli for seed is one of several new ag tech ideas promoting sustainable agriculture practices.A company is using a transgenic plant to create low-cost pheromones that could revolutionize pest control.

Todd Fitchette | Apr 21, 2021

Attracting bees to broccoli is just one of many ways a California ag tech company has its mind set on sustainable agriculture with global implications.

Scientists at the Riverside-based ISCA are using a transgenic plant to create low-cost pheromones that could revolutionize pest control and integrated pest management (IPM) efforts in agriculture and beyond.https://7456b58e549c0abcddebe4cfdc5b0937.safeframe.googlesyndication.com/safeframe/1-0-38/html/container.html

The example of bees and broccoli was demonstrated earlier this year near Yuma, Ariz. By placing a safe pheromone attractant on broccoli grown for seed production, colonies of managed honeybees were attracted to the plants, even during high wind events common during the winter months in the desert region of southwest Arizona.

The use of an attractant to entice honeybees to visit plants needing pollination is just one of several projects, according to ICSA Chief Executive Officer Agenor Mafra-Neto. Moreover, the bee attractant, which looks like a dollop of toothpaste applied to the top of the broccoli plants, could have implications other crops needing pollination by honeybee colonies. Studies in almonds suggest a 5-15% boost in fruit set. Those studies are ongoing.

Mating disruption – the art of fooling male insects into thinking female insects are in an area they are not by means of filling the air with the sex pheromone scent they emit – is yet another sustainable way to improve IPM efforts in agricultural systems. In this case ISCA scientists are using genetically modified strains of camelina plants to create the insect sex pheromones.

These efforts have shown themselves successful in protecting vineyards in Argentina against the European grapevine moth.

USDA funding

According to a company statement, the camelina plant efforts received U.S. Department of Agriculture funding to develop pheromones from natural resources over the use of standard chemical synthesis techniques. A $650,000 grant from the USDA’s National Institute of Food and Agriculture (NIFA) came after a $100,000 NIFA grant that kickstarted the project.

“Pheromone and other semiochemical controls are the future of crop protection, and ISCA’s breakthrough biological pheromone synthesis will propel agriculture into a more lucrative and sustainable enterprise,” Mafra-Neto said in a prepared statement.

Pheromone use is growing in popularity, particularly for mating disruption efforts that are proving themselves successful in agricultural systems. Almond growers are using pheromone attractants in mating disruption efforts against the Navel orangeworm. Unlike with pesticides, insects do not develop resistance against pheromone products.

Mafra-Neto points to the use of the camelina plant, a cousin of broccoli and canola, as a lower-cost method to create pheromones. Biosynthesis in plants eliminates the need to use petroleum-based chemicals as feedstock and bypasses most of the complex organic chemistry steps now required in pheromone production, he said.

Attract-and-kill

Moreover, ISCA studies are also looking at attract-and-kill products that entice targeted insects to a specific location that includes an insecticide capable of killing that insect. Rather than broadcast a chemical insecticide across large swaths of land or to rows of trees, the attract-and-kill method draws insects to a specific location through pheromones. The inclusion of pesticide materials capable of killing the pest when it feeds on or touches the formulation, allows this method to be targeted and safer for the environment.

The attract-and-kill method can greatly reduce the number of chemical pesticides applied on crops for insect control. It also protects non-targeted pests, including pollinators and beneficial insects, because the pheromones used to attract target pests are specific to those species.

Current attract-and-kill studies are ongoing in cotton, corn, and soybeans.

Another topic of study includes the idea of repellants, or semiochemicals that can cause insects to avoid specific plants. As studies in California avocados are ongoing on this front, Mafra-Neto believes forestry systems can use such technology to repel the bark beetle, which is responsible for widespread forest damage and explosive forest fires because of all the dead trees.

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HortiPro

Improved signaling and monitoring of thrips with Pherothrip 2.0

The problems with various species of thrips have occupied the minds of many cultivations in recent years. Reason for HortiPro to invest in signaling and monitoring techniques using pheromones in the near future and to further develop the techniques.

Growers try to start a new crop as cleanly as possible and with the aid of various, preferably green solutions, they have already come a long way. For example, thrips can be controlled with insect parasitic fungi and nematodes. Strategies with different beneficial insects are also being drawn up. It is important here that the possible solutions are deployed at the right time.

Timing
But when is the right time? Good signaling and monitoring is of crucial importance here, according to the HortiPro specialists. With the help of sticky traps, growers and advisers can keep an eye on whether thrips are already present and how a thrips population that may be present is developing in the crop.

To further optimise signaling and monitoring, HortiPro has launched the PheroThrip 2.0 on the market. PheroThrip 2.0 is a non-selective thrips pheromone in an evaporative spike. This evaporation spike can be placed in a hole in a yellow or blue sticky plate (see photo) and will increase the number of thrips caught on these sticky plates considerably. Various trials and demos, which have been carried out in collaboration with distributors and growers, have shown that the number of thrips caught on a sticky trap fitted with a PheroThrip 2.0 evaporation spike can be up to 40% higher.

Including Japanese flower thrips
These tests and demos also showed that the PheroThrip 2.0 pheromone attracts multiple thrips species. For example, Californian, pepper, tobacco, zebra, Echino, as well as Japanese flower thrips (Setosus thrips) were caught. The latter is usually particularly difficult to catch on sticky traps.

With the help of PheroThrip 2.0, Japanese flower thrips, among other things, can therefore be detected earlier. The necessary measures can then be taken against this in good time. In addition, both male and female thrips were caught on the sticky traps. This significantly reduces the reproduction speed.

Extensive experience has now been gained in, among other things: paprika, cucumber, chrysanthemum, gerbera, rose, hydrangea and strawberry.


Keep the cap closed
It is very important not to touch the evaporation spikes with bare hands. So place the spike in the catching plate with a plastic or latex glove or tweezers, the HortiPro specialists advise. The cap on the evaporation spike should remain closed.

The duration of action of the PheroThrip 2.0 is 6 to 8 weeks. They are available per 10 pieces in a resealable packaging and can be stored in the freezer (-18⁰C) for up to 2 years.

 For more information:
Hortipro 
www.hortipro.nl
info@hortipro.com

Publication date: Wed 31 Mar 2021

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By Charlotte Tucker -March 9, 2021Share on FacebookTweet on Twitter

Prof. Irina Borodina, founder of BioPhero

Today BioPhero, the insect pheromone company, today announced it has raised around €14.2 million in Series A funding led by DCVC Bio with participation from new investor FMC Ventures, as well as existing investors Syngenta Group Ventures and Novo Holdings. The startup, which has a mission to replace many chemical insecticides with sustainable biological insect pheromones, will use this funding to ramp up production of several products and to produce pheromones at the quantity, quality, and price required to allow farmers to control major pests in a variety of row crops.

Pheromones, being non-toxic, can be a powerful tool to achieve the objective of insect pest control, while avoiding the negative impacts on environment and biodiversity associated with overuse of synthetic chemicals. Pheromones are naturally produced by insects, but they can also be used very effectively to control the buildup of pest populations in farmers’ fields by disrupting their mating process. They are highly sustainable as they are insect-specific and non- toxic. Not only can they replace insecticide use but they can also reduce over-application by helping to prevent the buildup of resistance against both chemical insecticides and GM seeds.

Following its seed round in 2018, BioPhero developed – and scaled up – new and efficient production methods for insect pheromones using microbial fermentation. The production processes use renewable raw materials, produce less waste than the traditional chemical synthesis, and – crucially – are able to deliver insect pheromones at the cost, quality, and volume required for row crops such as wheat, maize, rice, and soybeans. BioPhero has successfully demonstrated that it can produce pheromones at tonne-scale, and the company is now ready to start production of its first product and to make it available to customers and development partners around the world.

Kristian Ebbensgaard, CEO of BioPhero, explained: “We aim to give farmers a new option: To protect their crops using biological insect pheromones rather than having to rely on insecticides. In row crops this has not been possible until now because of the high cost of pheromones. At BioPhero, we have shown we can break this cost barrier. We are delighted to continue to attract such high-quality investors and see this as a testament to the success we have had in developing and scaling biological pheromone production and delivering new options for growers”.

Unlike with insecticides, insects do not develop resistance to insect pheromones because they are produced by females to attract males for mating and do not present a single target that can easily be overcome by evolution. Insect pheromones are highly effective, have an exemplary safety record and do not harm pollinators or other non-target insects.

“We have been examining the use of insect pheromones in agriculture and new startups in this area for many years. Until now, no company has succeeded in manufacturing pheromones at a cost and scale suitable for worldwide use,” said John Hamer co-Managing Partner of DCVC Bio. “BioPhero’s patented breakthrough platform is the only one that is delivering the cost structure, manufacturing flexibility and quality that allow pheromones to be deployed on major row crops.”

BioPhero was founded in 2016 by Prof. Irina Borodina as a technology spin-out from the Technical University of Denmark. Borodina has assembled a dedicated world-class team with competencies within metabolic engineering, fermentation, chemistry, and process development, also participating as a consortium member in the EU-funded Projects OLEFINE and PHERA. 

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Management of Fall Armyworm: The IPM Innovation Lab Approach

https://ipmil.cired.vt.edu/wp-content/uploads/2020/12/IPM-IL-FAW-Management.pdf.

By:

Sara Hendery

Communications Coordinator

Feed the Future Innovation Lab for Integrated Pest Management

Hendery, Sara saraeh91@vt.edu

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Organised by
Promoted by

8th International Symposium

Plant Protection and Plant Health in Europe

Efficacy and risks of biorational products in IPM strategies – acceptable?

13-14 December 2017 – Braunschweig, Germany

  Dear colleague,

We inform you about the forthcoming international symposium

to be carried out at 13-14 December 2017 in  Braunschweig, Germany.

All details concerning the topic, the venue and the organizers please find at the symposium website (www.ppphe.phytomedizin.org)

Looking forward to meeting you soon,

On behalf of the symposium committee,

Best regards

Falko Feldmann

Institut für Pflanzenschutz in Gartenbau und Forst

Institute for Plant Protection in Horticulture and Forests

Messeweg 11-12

38104 Braunschweig

Fone: 0049 -(0)531 2994406

www. julius-kuehn.de.de

Falko.Feldmann@julius-kuehn.de

 

 

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Delta farm press

Boll weevil photo
Mississippi farmers, and others throughout most of the nation’s cotton-producing regions, have saved many millions of dollars by no longer having to battle the boll weevils that had destroyed cotton yields for decades

For nearly a decade, not a single boll weevil in Mississippi

Mississippi is now entering its tenth year free of the boll weevil that cost U.S. producers billions of dollars over the past century.

Hembree Brandon | Jul 11, 2017

As he had done for the past nine years, Farrell Boyd was beaming at the joint annual meeting of the Mississippi Boll Weevil Management Corporation and the Mississippi Farm Bureau Federation Cotton Policy Committee.

“It’s a pleasure for me to echo what I’ve said for the last nine years: Mississippi continues to be boll weevil-free,” said Boyd, who is program manager for the organization. “We’re going into our 10th year and not the first weevil has been caught — which is great! And we’ve gone from over 500 employees during the height of the eradication effort to just five today.”

Royal-Langley

Robert Royal, left, Midnight, Miss., producer/ginner, and James Langley, V&M Cotton Brokers, Yazoo City, Miss., were among those attending the joint annual meeting of the Mississippi Boll Weevil Management Corporation and the Mississippi Farm Bureau Federation Cotton Policy Committee.

Mississippi producers, and others throughout most of the nation’s cotton-producing regions, have saved many millions of dollars by nolonger having to battle the pest that had destroyed cotton yields for decades, he says.

Still, “We’re not letting our guard down — we’re continuing to operate the Mississippi program in a surveillance mode. We have pheromone traps within a mile of every cotton field in the state, and we monitor them throughout the season in case any weevils should slip in on farm equipment coming from the south Texas areas where the eradication effort is still under way.”
SOUTH TEXAS AND MEXICO AREAS REMAIN

Nearly all of the U.S. cotton belt is now weevil-free, Boyd notes. “The only place where weevils still exist is in the Rio Grande Valley bordering Mexico, along the Rio Grande River, and south of Uvalde in the Winter Garden area, which is a reinfestation area. The reinfestation there emphsizes why we have to be so careful — it’s not impossible weevils could reoccur here as a result of being transported in from an infested area. It’s very important that we continue our surveillance program.”

The cooperative program between Mexico, the Texas Boll Weevil Foundation, and APHIS, to provide training and equipment for Mexico has been “very effective” in enhancing the eradication effort in that region, he says. “Unfortunately, they continue to have intermittent problems with drug cartels. A recent report noted that Mexican eradication workers were out of the field several times due to gun battles in the area. That kind of environment makes their eradication effort even more challenging.”Deere picker

deere  picker

Nearly all of the U.S. cotton belt is now boll weevil-free. Only areas in southernmost Texas and across the Rio Grande River in Mexico remain to be eradicated.

But, Boyd says, there has been “significant progress” on both sides of the border. “Through June 12, in the Rio Grande Valley of Texas, they had an 81.4 percent decrease in weevil captures compared to a year ago. In the Mexican program across the river, through June 12 they’d captured 539 weevils, a 91 percent decrease over 2016.”

Both areas have significant increases in cotton acreages this year, he says, which could have an impact on weevil numbers, “but we’re still comfortable that they’re going to achieve eradication. The cooperative effort with Mexico has been a major achievement.”

BUFFER ZONE TO PREVENT REINFESTATION

Starting in 2014, he notes, the National Cotton Council Boll Weevil Action Committee established a buffer zone in the lower Rio Grande Valley to hopefully protect the rest of the cotton belt from weevil intrusion.

“An assessment was levied to fund the buffer zone, and in 2014 each state contributed 50 cents per acre, with 25 cents per acre in years since then. The buffer program will be reevaluated at the end of five years. So far, none of the money collected has been spent because the buffer zone is in the area where the Texas boll weevil eradication is going on, so it hasn’t cost any additional money to maintain the buffer. By the end of this year the fund will have accumulated between $11 million and $12 million, which is about enough to operate the program. So, they’re holding the money in escrow in the event some of it is needed for that.”

Everything is still “looking very promising” for eradication in the lower Rio Grande Valley, Boyd says, “and we’re looking forward to another weevil-free season in Mississippi. We appreciate everyone’s assistance in watching for harvest equipment or other equipment coming into our state from south Texas so we can be sure no weevils sneak in.

Coley Bailey, Jr., Grenada, Miss., producer, and president of the Mississippi Boll Weevil Management Corporation, echoed Boyd’s enthusiasm for the ongoing success of the program: “It’s great to be almost 10 years weevil-free. When I attended my first board meeting we were $60 million in debt; today we’re blessed to be in strong financial condition. But reinfestation could be costly — and we want to do all we can to prevent that from happening.”

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SE farm press

Boll Weevil USDA Agricultural Research Service

The weevil: an historical look at the ‘war’ that changed Southern cotton

The boll weevil and its hunger for cotton was powerful enough to forge an unprecedented partnership between farmers, legislators and scientists.

Dominic Reisig | May 18, 2017

The boll weevil is not much to look at – just a grayish, little beetle with an impressively long snout. But this particular beetle, and its hunger for cotton, was powerful enough to forge an unprecedented partnership between farmers, legislators and scientists. And that partnership showed how much can be accomplished when scientists and farmers work together.

What adult boll weevils lack in size they make up for with their larvae’s ability to feed on and destroy cotton. Boll weevils entered the U.S. from Mexico in the late 1800s, when they were first spotted in Texas. By the 1920s they had spread through all of the major cotton-producing areas in the country. The scope of the damage was breathtaking, as were the control efforts thrown at this insect: at one time, one-third of the insecticide used in the U.S. was used to combat boll weevils.

Editor’s Note: This was originally posted on the North Carolina State University website.

In 1903, the chief of the U.S. Department of Agriculture (USDA)

testified before Congress that the insect’s outbreaks were a “wave of evil,” and that afflicted areas in Mexico had abandoned cotton production altogether. Indeed, many scholars agree that the impact was so great on the rural South’s cotton-dependent economy that it was one of the causes of the “Great Migration,” when African Americans moved en masse to the northern U.S. during the early 1900s.Despite the arrival of the boll weevil, cotton production at first actually increased in the U.S., because the price of cotton increased as the boll weevil ran some cotton growers out of business. Cotton production moved in advance of the weevil, creating a boom in cotton plantings in areas that were weevil-free. But as the cotton spread, so did the boll weevil – costing cotton growers billions in revenue.

Declaring War on the Weevil

Then, in 1958, something novel happened. The National Cotton Council of America unanimously agreed, for the first time ever, on a piece of farm legislation. Among other things, that legislation called for cotton research to be expanded – and the boll weevil to be eliminated.

This was an unusual step for many reasons. First, efforts had been made to eradicate insects in livestock before, but no one had ever tried it with a crop pest; this was breaking new ground. Second, this was going to cost a lot of money, which would require the support of the federal government. Third, nobody had yet come up with a way to eradicate the insect. Finally, once eradication began, the eradication process would become a common pool resource. Because of this, cooperation would be vital, given that there would be a temptation for individuals, or whole regions, to get a free ride, relying on the contributions of their neighbors to the eradication effort. So mandatory farmer participation was a must. One by one, each of the challenges were addressed, requiring close collaboration at every step.

Insect eradication was not an entirely new concept. The promoter of eradication was a USDA Agricultural Research Service (USDA-ARS) scientist named Edward Knipling, who had come up with an idea called the sterile insect technique. This technique was pioneered in the 1950s to eliminate screwworm, a parasitic insect pest of cattle. The sterile insect technique relies on flooding the environment with lots of sterile males. Those males then mate with females, but don’t produce any offspring. Knipling now envisioned eradication of the boll weevil, recognizing that it had two chinks in its armor. First, it was an exotic species, which meant that it could be present without some of the parasites and predators that weakened populations in its native Mexico. Second, it was reliant on a single host plant, cotton, which was also not native to the U.S.

Unfortunately, the sterile insect technique bombed. One million sterile boll weevil males were released in a trial. But the sterile males couldn’t compete with their virile wild counterparts and the trial was unsuccessful.

If eradication was going to take place, scientists would have to develop a new method. To that end, the federal government, state governments, and various cotton foundations and associations appropriated millions of dollars to support the research needed to develop the necessary tools for eradication.

For example, Congress funded USDA-ARS laboratories in many states, including one on the campus of Mississippi State University that was critical to creating many of the tools needed for eradication. This support continued through the eradication effort, ensuring that the insect could be eliminated beginning in Virginia and northeastern North Carolina, and moving steadily southward.

But the researchers of eradication faced a significant challenge up front. They knew that, for eradication to be successful, there had to be a very effective method of controlling boll weevils – one with a success rate of close to 100 percent. And that would require a significant leap over the available control techniques.

During the 1950s, controlling boll weevil infestations required multiple applications of very harsh and toxic insecticides (e.g., aldrin, azinphosmethyl, benzene hexachloride, chlordane, dieldrin, toxaphene, malathion, methyl parathion, and parathion). But a separate scientific advance was just around the corner.

New Weapons

In the 1960s, researchers were just beginning to understand the importance of insect pheromones, the chemicals produced by insect species that change behavior of other individuals in the species. USDA-ARS scientists discovered the sex attractant pheromones of the boll weevil – the combination of chemicals that allowed male boll weevils to find female boll weevils. These researchers were able to perfect a synthetic attractant pheromone blend, creating a lure that could be used to trap the amorous boll weevils. This advance would prove to be the linchpin for successful eradication, as weevils could be attracted, trapped, and monitored.

Another major breakthrough was the discovery of a method of control that increased success from 85-90 percent control to 98-99 percent.

Insect development is dependent on temperature, and lower temperatures slow down weevil development and reproduction. Mississippi scientists discovered that, by making multiple insecticide applications at short intervals during the autumn, they could both reduce the last reproductive generation of the weevils and significantly limit the survival of potentially overwintering adults. This was termed the reproduction-diapause control method.

The combination of the pheromone traps and the reproduction-diapause control method meant that, given cooperation on an area-wide basis, the boll weevil might be eradicated. And the pheromone traps cold also be used to confirm whether eradication efforts were successful. This one-two punch was tested in a pilot program in Alabama, Mississippi and Louisiana during the early 1970s. The pilot program couldn’t prove that this approach would eradicate boll weevils, but it was successful enough at reducing population levels that government, industry and research officials opted to proceed with a large-scale approach. This next step involved rolling out two companion trials in the late 1970s: one trial took place in Mississippi using the best known control methods for boll weevil at the time, while another trial tested the reproduction-diapause control method in North Carolina and Virginia.

Cooperation was critical to the North Carolina/Virginia trial. The federal government came through with enough funding to support 50 percent of the trial, while the state of North Carolina agreed to pick up another 25 percent of the cost. And more than three-quarters of North Carolina cotton growers approved of the eradication, agreeing to fund the remaining 25 percent. Meanwhile, a new insecticide had become available, diflubenzuron, which proved to make the eradication even more successful.

After three years, the reproduction-diapause method proved so successful that only one weevil was trapped in the North Carolina/Virginia eradication area. Moreover, this weevil was thought to be left over in a contaminated trap that hadn’t been cleaned properly. Insecticide use plummeted after eradication, but expansion and continuation of the program was not easy. Problems with funding, grower support in new eradication areas, and outbreaks of other pests, resulting from intensive insecticide applications used in eradication efforts – which obliterated beneficial insects that normally kept pests in check – slowed the process However, by 2009, the boll weevil was declared eradicated from all U.S. cotton-producing states, with one exception: Texas, which is the biggest cotton producer in the country.

A Fragile Victory

Which brings us to 2017. Eradication efforts have been stalled at the Texas-Mexico border, largely due to the instability created by illegal drug trafficking. That instability has effectively made large cotton farms in Mexico inaccessible for treatment, creating a welcoming habitat for boll weevil populations to rebound. Another problem in Mexico is the presence of non-cotton plant species that can host boll weevil. Further efforts to limit cooperation across the border, including the proposed border wall, ensure that the boll weevil’s “wave of evil” remains a looming threat. As a result, there is an ongoing battle to keep boll weevils in check in the Lower Rio Grande Valley of Texas, funded by an ongoing annual assessment from cotton-producing states, which is aimed at preventing – and tracking – the spread of boll weevil populations.

But this story also highlights the fact that that the boll weevil has been largely conquered in the U.S., thanks to cooperation among growers, scientists and government officials – and due, in large part, to federal research funding. For example, in the southeastern U.S., a boll weevil has not been captured in a pheromone trap in 14 years. And those federal investments, made across the South, continue to pay dividends in the form of new projects, which are poised to tackle today’s native and invasive insects due to the investments made from boll weevil eradication.

For example, those early investments by state and federal governments created the USDA-ARS research system that is still present today across the southern U.S., including the facility at Mississippi State. This system continues to make a difference for U.S. farms. Research units in areas that still have boll weevil populations are using cutting-edge technologies, such as population genetics and aerial infrared imaging, to track movement of the species and identify potential patches of host plants for destruction. As boll weevils have been slowly eradicated, state by state, these researchers and facilities have shifted research priorities to other issues and pests affecting crop production. No one wants to fight another hundred-year war with a plant pest.

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Article taken from The Fruit Grower, written by Sue Jupe

Agrovista

30 January 2017

After three years of UK trials, BASF, working with Agrovista, has launched the first multi-pest pheromone disruption system, named RAK 3+4. Already commercially abailable in Europe, orchards are flooded with high rates of synthetic pheromones, and male moths become confused and give up trying to find a mate – mating is disrupted. With consumers being particularly wary of pesticide residues in fruit, this new approach to pest control in top-fruit offers real benefits for the control of challenging moth species.

Setting the scene, Simon Townsend of BASF said that, in line with other sectors of the industry, top fruit growers have lost valuable actives in the past 15 years following EC Regulation 1107/2009, changing the emphasis on plant protection products from a risk-based to a hazard-based system. Pest and disease challenges have been further compounded with growing biological resistance to some remaining actives.

Following approval through a mutual recognition label in Belgium, UK top fruit growers have a new IPM (integrated pest management) tool – RAK 3+4 – a mating disruption system for Codling Moth (Cydia pomonella) and Summer Fruit Tortrix (Adoxophyes orana). In addition, trials have produced observed efficacy against other Tortix species including Large Fruit Tree Tortix and Dark Fruit Tree Tortrix.

Adult Codling Moths emerge from cocoons in spring. Eggs laid on leaves and developing fruit hatch after a short time and the resulting larvae immediately bore into the fruit making control with insecticides difficult. As the moths directly damage the crop, the economic threshold is very low.

Importantly, in August or September there can be a partial second generation and, according to Agrovista’s Paul Bennett, this is particularly problematic as it necessitates insecticides being applied close to harvest. Whilst growers must adhere to strict harvest intervals, spraying at this stage has the potential for detectable residues to be found on the fruit, he warns.

Among the existing plant protection product options for Codling and Tortrix Moths are the ovicides Chlorantrantiliprole (Coragen) and Fenoxycarb (Insegar) and larvicides Spinosad (Tracer) and Methoxyfenozide (Runner).

How does it work?

As with all good IPM systems, the pest population should be monitored using an appropriate pest forecasting system or monitoring traps. “The new RAK 3+4 mating disruption system relies on the pheromones being in before the first target moths take flight in spring – around Arpil and before the end of the blossom,” explained Simon Townsend. “Designed to give season-long control, the pheromone cloud is released over nine months through to October.”

Simon went on to explain that in nature, female moths emit pheromones producing a concentration gradient which males travel down to locate a mate. “By releasing high rates of synthetic pheromones, male moths become confused and give up trying to locate a female. Mating is disrupted, no fertile eggs are laid and the population reduces,” he says.

With RAK 3+4, volatile female pheromone vapours are released from brown ampoules, each with two chambers – one containing Codling Moth pheromone the other Tortrix pheromone. By using multiple dispensers, a confusing cloud of pheromones is produced. BASF recommends that dispensers are used at a rate of 500 units/ha – at a uniform density of approximately one per 20 sq. metres. To prevent moths from adjacent areas encroaching into the treated orchard, and to maintain pheromone concentration at the edge of the treated area, additional product must be placed at the borders. BASF recommends doubling the dispenser rate at the edges of the treated area – such as orchard edges and along roads through orchards. “the dispensers should be hung in the top third of the tree, as the vapour is heavier than air, and at varying heights to achieve a ‘muddled’ vapour plune,” explained Simon Townsend. “The dispenser should be positioned so that it is clear of the body of the tree.”

To check efficacy during the season, pheromone monitoring traps (that attract male moths) should be installed in the treated orchards and checked weekly. If these traps no longer catch moths, this indicates that RAK 3+4 is working properly. However, it is always possible that mated females may enter the treated orchard from outside, and it is therefore important to check for fruit damage during the season. If the latest monitoring thresholds are exceeded, this is an indication that the moth population is too high, meaning that treatment with RAK pheromones alone may be insufficient. In this case, treatment with a conventional insecticide is necessary.

UK trials at Wisbech Contract Farming

Trials over several seasons at Wisbech Contract Farming in Norfolk have produced impressive results.

A modern progressive fruit farm, the highly uniform GPS-planted orchards employ modern post-and-wire hedgerow systems. Working closely with Paul Bennett of Agrovista, John Portass of Wisbech Contract Farming has trialled RAK 3+4 for the past three years on a total of 8ha.

The RAK 3+4 ampoules were distributed from a picking platform at the same time as workers carried out other operations, and took approximately 12 man-hours/ha. “In the first year of trials we selected an orchard with low moth pressure,” explained John. “The results gave us the confidence to extend the trial in the second year to a higher pest-pressure orchard. With no moths recovered in the traps we didn’t need to spray at all. We had extremely low level damage in fruit of just 1 or 2 per 1000 and as the season went on the moth population reduced.” In comparison, in untreated areas 60-70 codling-affected apples per 1000 fruit were recorded.

Summarising the results at the end of the third year of trials, Codling Moth numbers had been reduced by 95%, Summer Fruit Tortrix by over 89% and Fruit Tree Tortrix by over 99%. The economic thresholds were never exceeded and no caterpillar sprays were needed. Putting it in context, Paul Bennett said, “Using conventional pesticides the overwintering population tends to stay the same. Using 3+4 system the background population is reducing year-on-year.”

Impressed with the results, John Portass envisages rolling out the RAK 3+4 strategy to 60-70% of his 90ha in 2017. “We will be using it in high value varieties, such as the scab resistant Opal, but at this stage not the lower value Bramleys,” he says.

Commercial use in Europe

Mating disruption systems are already in commercial use in top fruit in Belgium, the Netherlands, Germany and France. It is estimated that 47% of top fruit in Belgium (7,000ha) currently uses mating disruption, with the RAK 3+4 system accounting for 20% and RAK 3 for a further 20%. While orchards receive a supplementary insecticide when required, or just around the outside rows, monitoring of 34 orchards in Wallonia showed 19 had used no additional insecticide.

According to Simon Townsend, pest pheromone disruption systems have been shown to work well in central Europe, withstanding extremes of temperature, and are already widespread in Germany in various crops, including vines. Trials in Belgium have shown that, compared to a reference orchard, RAK 3+4 delivers a major decrease in the number of males caught in traps and a significant decrease in infected fruit. The mating disruption system also showed a useful effect on many other species of Tortrix Moth including Fruit Tree Trotrix, Rose Trotrix an dMarbled Orchard Tortrix.

Simon Townsend is keen to point out that RAK 3+4 only controls specific moth species – Codling and Tortrix. It is therefore important that growers monitor for the occurence of these pests during the season, particularly at orchard borders. If thresholds are exceeded, BASF recommends that growers use a well-timed insecticide spray in addition to RAK 3+4. Under high pest pressure the level of control from RAK 3+4 can be reduced, making careful monitoring essential. “Growers should be mindful that using mating disruption does not rely on using any broad-spectrum insecticides, so new or past pest species may become a problem and will need to be controlled iwth appropriate IPM measures,” says Simon. “In some UK trials, there has been a resurgence of moth pests that have not previously been a problem (for example, Blastobasis sp). Other moth species not controlled that are potential pests in top-fruit include Spilonota sp and Epiphyas sp.

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