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New research maps potential global spread of devastating papaya mealybug pest

   Delhi Bureau  1 Comment Biopesticides & BiocontrolsCABI  4 min read

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10 November 2020, UK: CABI scientists have mapped the potential global spread of the devastating papaya mealybug (Paracoccus marginatus), highlighting new areas in Africa, Asia and the Americas into which this pest could potentially invade.

Also Read: BASF commits to targets for boosting sustainable agriculture

The papaya mealybug, which is native to Mexico and Central America, can have severe impacts upon livelihoods and food security. In Ghana, for example, infestations led to a 65% yield loss which reduced export earnings and resulted in the loss of 1,700 jobs.

Using location data received through collaborations with Kerala Agricultural University, India; the National Rice Research Institute, India; the Bangladesh Agricultural UniversityUniversity of Queensland, Australia; the International Institute of Tropical Agriculture (IITA); Fujan Agriculture and Forestry University in China and CSIRO, researchers were able to model the potential distribution of this pest, taking into account environmental conditions, and the distribution of suitable host crops and irrigation patterns.

The researchers, led by CABI’s Dr Elizabeth Finch, believe the polyphagous insect pest, which affects over 200 plants including economically important crops such as papaya, cassava and avocado, could spread to areas such as the south of the Democratic Republic of Congo, northern Cameroon, Zambia, Madagascar and western Ethiopia which are environmentally suitable and have suitable crop hosts.

In the Americas, the research, published in the journal Pest Management Science, suggests papaya mealybug could extend into El Salvador, Honduras, Nicaragua, and Panama – although the scientists believe it could already be in these locations but its presence is yet to be confirmed.

Whilst papaya mealybug is already present in Florida, where it is under successful control as a result of the release of endoparasitoid wasp species – Acerophagus papayaeAnagyrus loeckiAnagyrus californicus – suitable conditions for this pest are also present in the southern tip of Texas.

Conditions are likely to be too cold in the rest of the USA for permanent papaya mealybug populations, however the research showed that seasonal populations could survive in California, along the Pacific coastline and in the central and eastern states of the USA during the warmer summer months.

Also Read: FMC Corporation Recognized at 2020 Crop Science Awards

In Asia, the areas with suitable conditions were more expansive than the areas with known populations of papaya mealybug, suggesting the potential for further expansion of papaya mealybug specifically in India, Southeast Asia and the southern regions of the Guangxi and Guangdong provinces of southern China.

However, in Australasia the risk is low as only a small amount of fragmented land along the north-eastern side of Queensland, from the very northern tip of Queensland to Bundaberg, is climatically suitable. This is due to heat stress from the high temperatures on the continent.

Similarly, in Europe – though due to cold rather than heat stress – widespread distribution of papaya mealybug is not expected, with only a very small area of land surrounding Seville in Spain and around Sicily in Italy having suitable conditions for resident populations.

Dr Finch said, “This pest has been so successful due to its quick development and prolific reproductive capacity. It has the potential to spread to new areas and rapidly reach high numbers unless suitable phytosanitary or control methods are implemented.

“Information about the papaya mealybug’s potential distribution is important as it can highlight key areas susceptible to invasion, giving an early warning to decision makers, allowing them to put into place phytosanitary measures to prevent or slow the invasion of the pest into their jurisdiction.”

Dr Finch added, “In areas where the papaya mealybug has become established and reached a high enough population density, the use of parasitoids – such as Acerophagus papayae and Anagyrus loecki – remains an effective potential control method.

“Further ecological niche modelling of these parasitoid species is recommended to anticipate their survival, fitness and ultimate biological control impact in areas into which papaya mealybug could potentially expand and become established.”

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Biopesticides and Biocontrols 

Could biocontrol solve the papaya mealybug problem for Ugandan farmers?

   Delhi Bureau  0 Comments CABI  4 min read

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14 September 2022, Uganda: Papaya mealybug, Paraccous margniatus, is native to Central America but has spread rapidly in invaded countries. It was detected in Uganda in 2021 where it has the potential to affect the production and quality of papaya and other host crops.

Typically, mealybugs are not pest problems in the countries they are native to because naturally occurring parasitoids and predators keep their numbers in check. The most serious outbreaks occur when mealybugs are introduced accidentally to new countries without natural enemies.

Papaya mealybug spread

The trade in live plant material, such as papaya fruits and seedlings, has accidentally accelerated the spread of papaya mealybug outside its native range. This pest threatens food and nutrition security and adversely affects the safe trade and competitiveness of the agricultural sector for many countries.

Without natural enemies to manage outbreaks, farmers often turn to pesticides. The lack of registered pesticides results in farmers using highly hazardous chemicals that are not only ineffective but can negatively impact native insect biodiversity such as pollinators and natural enemies of pests. A more ecologically sound approach to management is the use of biological control.

Rapid Rural Appraisal of papaya mealybug

As part of the PlantwisePlus programme, CABI in collaboration with the National Agricultural Research Organisation (NARO, Uganda), conducted a Rapid Rural Appraisal (RRA) of papaya mealybug in Uganda. The appraisal sought to gain an understanding of the presence, distribution, and impact of papaya mealybug in Uganda as well as farmers’ management practices. The evaluation also assessed farmers’ willingness to adopt and use biocontrol and their information requirements around biocontrol products.

Information from the appraisal will be used to design an integrated management strategy for papaya mealybug as well as help target community-level communications.

A major cash crop

The seventeen focus group discussions brought together papaya growers from four districts: North District (Lira), Central District (Kayunga, Luwero and Mukono). The districts captured a diversity of farming systems, agro-ecological zones, and agricultural potential. Papaya is a major cash crop for farmers in these districts, in addition to pineapple and traditional cash crops such as coffee. The average farmer cultivates the crop on 0.75-2.5 acres.

The participants confirmed papaya mealybug is already widespread in all four districts where it causes damage to several crops, not just papaya. Farmers started observing the pest between 2017 and 2019 with most saying it is a serious pest that can cause up to 100% crop loss. The official pest reporting to IPPC took place in 2021.

Papaya mealybug management

Farmers mainly attributed the papaya mealybug outbreaks to low productivity and poor-quality fruits. They observed that trees take longer to bear fruit and when they do, they only last one season compared to an average of 4 before. It was estimated that before the pest invaded, farmers obtained UGX 6-8 million/acre each season (£1,800), but currently only obtain UGX 1 million/acre each season (£230).

Regarding management options, commercial farmers reported using pesticides to deal with outbreaks. However, managing papaya mealybugs with pesticides is not always successful due to the pest’s waxy covering. In addition, misuse and/or improper use of these pesticides exacerbate pest problems by reducing beneficial organisms and natural enemies and negatively impacting biodiversity, human health and environmental safety. Further, some farmers don’t observe pre-harvest intervals, thus toxic substances are likely to enter the human food chain posing long-term health risks to consumers and the environment.

Sustainable options

Biological control represents a sustainable and effective management option, however, the farmers interviewed had mixed views on the method and the efficacy of the parasitoid in Uganda’s agroecologies. This highlights the importance of proper testing and community-level communications before the introduction of exotic natural enemies. Farmer and community engagement, and mass awareness are key in pest identification and management, especially with the promotion of unfamiliar pest management options. Extension in particular plays a vital role in the research and advancement of low-risk options.

However, one of the main takeaways from the appraisal was farmers’ papaya problems extend beyond papaya mealybug. Farmers reported other associated viral and bacterial diseases causing challenges, including bunchy top disease and leaf necrosis. As such, it is important that researchers assess the economic damage, effect and losses due to papaya mealybug and the associated pests and diseases before releasing biological control parasitoids.

Implementing a biocontrol programme

The PlantwisePlus programme is now looking at the activities required for the implementation of the biocontrol programme in Uganda. In particular, they are developing extension and farmer training manuals to cover papaya crop integrated pest management. These will include papaya mealybug as well as other pests affecting papaya production in the country. In addition, continuous community engagement and mass awareness campaigns will help farmers and their communities manage this highly destructive pest in a more sustainable way. 

PlantwisePlus is working to reduce the reliance on high-risk farm inputs that have adverse effects on human health and biodiversity. By implementing biological control programmes, PlantwisePlus is responding to the challenge and working to improve livelihoods through sustainable approaches to crop production.

Also Read: Tractor sale in India lowest in two months; 32 percent down in August 2022

(For Latest Agriculture News & Updates, follow Krishak Jagat on Google News)

Could biocontrol solve the papaya mealybug problem for Ugandan farmers?

Papaya mealybugParaccous margniatus, is native to Central America but has spread rapidly in invaded countries. It was detected in Uganda in 2021 where it has the potential to affect the production and quality of papaya and other host crops.

Papaya
Papaya fruit

Typically, mealybugs are not pest problems in the countries they are native to because naturally occurring parasitoids and predators keep their numbers in check. The most serious outbreaks occur when mealybugs are introduced accidentally to new countries without natural enemies.

Papaya mealybug spread

The trade in live plant material, such as papaya fruits and seedlings, has accidentally accelerated the spread of papaya mealybug outside its native range. This pest threatens food and nutrition security and adversely affects the safe trade and competitiveness of the agricultural sector for many countries.

Without natural enemies to manage outbreaks, farmers often turn to pesticides. The lack of registered pesticides results in farmers using highly hazardous chemicals that are not only ineffective but can negatively impact native insect biodiversity such as pollinators and natural enemies of pests. A more ecologically sound approach to management is the use of biological control.

Rapid Rural Appraisal of papaya mealybug

As part of the PlantwisePlus programme, CABI in collaboration with the National Agricultural Research Organisation (NARO, Uganda), conducted a Rapid Rural Appraisal (RRA) of papaya mealybug in Uganda. The appraisal sought to gain an understanding of the presence, distribution, and impact of papaya mealybug in Uganda as well as farmers’ management practices. The evaluation also assessed farmers’ willingness to adopt and use biocontrol and their information requirements around biocontrol products.

Information from the appraisal will be used to design an integrated management strategy for papaya mealybug as well as help target community-level communications.

Papaya mealybug on fruit
Papaya mealybug on a papaya fruit

A major cash crop

The seventeen focus group discussions brought together papaya growers from four districts: North District (Lira), Central District (Kayunga, Luwero and Mukono). The districts captured a diversity of farming systems, agro-ecological zones, and agricultural potential. Papaya is a major cash crop for farmers in these districts, in addition to pineapple and traditional cash crops such as coffee. The average farmer cultivates the crop on 0.75-2.5 acres.

The participants confirmed papaya mealybug is already widespread in all four districts where it causes damage to several crops, not just papaya. Farmers started observing the pest between 2017 and 2019 with most saying it is a serious pest that can cause up to 100% crop loss. The official pest reporting to IPPC took place in 2021.

Papaya mealybug management

Farmers mainly attributed the papaya mealybug outbreaks to low productivity and poor-quality fruits. They observed that trees take longer to bear fruit and when they do, they only last one season compared to an average of 4 before. It was estimated that before the pest invaded, farmers obtained UGX 6-8 million/acre each season (£1,800), but currently only obtain UGX 1 million/acre each season (£230).

Regarding management options, commercial farmers reported using pesticides to deal with outbreaks. However, managing papaya mealybugs with pesticides is not always successful due to the pest’s waxy covering. In addition, misuse and/or improper use of these pesticides exacerbate pest problems by reducing beneficial organisms and natural enemies and negatively impacting biodiversity, human health and environmental safety. Further, some farmers don’t observe pre-harvest intervals, thus toxic substances are likely to enter the human food chain posing long-term health risks to consumers and the environment.

Papaya on a farm infected with papaya mealybug
Papaya on a farm infected with papaya mealybug

Sustainable options

Biological control represents a sustainable and effective management option, however, the farmers interviewed had mixed views on the method and the efficacy of the parasitoid in Uganda’s agroecologies. This highlights the importance of proper testing and community-level communications before the introduction of exotic natural enemies. Farmer and community engagement, and mass awareness are key in pest identification and management, especially with the promotion of unfamiliar pest management options. Extension in particular plays a vital role in the research and advancement of low-risk options.

However, one of the main takeaways from the appraisal was farmers’ papaya problems extend beyond papaya mealybug. Farmers reported other associated viral and bacterial diseases causing challenges, including bunchy top disease and leaf necrosis. As such, it is important that researchers assess the economic damage, effect and losses due to papaya mealybug and the associated pests and diseases before releasing biological control parasitoids.

Implementing a biocontrol programme

The PlantwisePlus programme is now looking at the activities required for the implementation of the biocontrol programme in Uganda. In particular, they are developing extension and farmer training manuals to cover papaya crop integrated pest management. These will include papaya mealybug as well as other pests affecting papaya production in the country. In addition, continuous community engagement and mass awareness campaigns will help farmers and their communities manage this highly destructive pest in a more sustainable way. 

PlantwisePlus is working to reduce the reliance on high-risk farm inputs that have adverse effects on human health and biodiversity. By implementing biological control programmes, PlantwisePlus is responding to the challenge and working to improve livelihoods through sustainable approaches to crop production.

About PlantwisePlus

PlantwisePlus is supported by contributions from the UK Foreign, Commonwealth and Development Office, the Swiss Agency for Development and Cooperation, the Netherlands Ministry of Foreign Affairs and the European Commission (DG INTPA).

PapayaPapaya mealybugParaccous margniatusUgandaplant healthplant pestsplantwiseplus

Agriculture and International DevelopmentCrop healthInvasive species

Weedy rice has become herbicide resistant through rapid evolution

Aggressive, herbicide-resistant weed is a threat in nation’s largest rice production region

Date:September 8, 2022Source: Washington University in St. Louis

Summary: Weedy rice is a closely related cousin of crop rice. It aggressively competes with cultivated rice in the field, leading to loss of yield and reductions in harvest quality that compromise market value. Biologists used whole-genome sequences of 48 contemporary weedy rice plants to show how herbicide resistance evolved by gene flow from crop rice. Almost all other cases of herbicide resistance in agricultural weeds result from selection of tolerant genotypes in the weed species.Share:

FULL STORY


In a paper published Sept. 8 in the journal Communications Biology, scientists from Washington University in St. Louis and the University of Arkansas report that a crop pest called weedy rice has become widely herbicide resistant in regions where herbicide-resistant rice is planted. The study highlights challenges facing U.S. rice farmers when they battle a weedy enemy that is closely related to a desirable crop plant.

The genetic investigation was conducted with samples gathered in rice fields in Arkansas, where almost 50% of the nation’s rice is grown.

Weedy rice is a closely related cousin of crop rice. It aggressively competes with cultivated rice in the field, leading to loss of yield and reductions in harvest quality that compromise market value. Weedy rice infestations cause an estimated $45 million in economic losses in the United States each year and hundreds of millions of dollars worldwide.

Biologists used whole-genome sequences of 48 contemporary weedy rice plants to show how herbicide resistance evolved by gene flow from crop rice. Almost all other cases of herbicide resistance in agricultural weeds result from selection of tolerant genotypes in the weed species. Just 20 years after herbicide-resistant rice was first adopted in the southern United States, the majority of fields with a history of herbicide-resistant rice cultivation have weedy rice plants that are also herbicide resistant.

“Throughout its nearly 200-year history in the United States, weedy rice had a very low rate of outcrossing with cultivated rice,” said Marshall Wedger, a postdoctoral research associate in biology in Arts & Sciences at Washington University and first author of the study. “We found that U.S. weedy rice has persisted through herbicide pressure with the survival of those few plants that outcross, consequently acquiring the herbicide- resistance trait.”

“Technological changes in U.S. rice farming since the 2000s have led to a complete genetic revolution in the makeup of the weedy rice that infests U.S. fields,” said Kenneth Olsen, professor of biology at Washington University and senior author on the study.

“In the last 20 years, weedy rice has gone from being very genetically distinct from U.S. crop varieties to nowadays mostly being derived from crop-weed hybridization,” Olsen said. “The weeds are grabbing certain traits from the crop that are beneficial to them, including herbicide resistance.”

Weeds seize their moment

Weedy rice is a scourge of cultivated rice production around the world. But up until the early 2000s, weedy rice in U.S. fields rarely interbred with the kinds of rice that were commonly grown in this country.

Crop rice and weedy rice are the same species, so they are able to interbreed, or hybridize. Their rate of hybridization rate is usually low — generally less than 1% — because rice is self-pollinated.

But something happened that changed the centuries-old dynamic between these two closely related plants. Starting in the early 2000s, two new kinds of crop rice were adopted in U.S. fields. One was a new hybrid rice that offered substantially enhanced yield, compared with traditional inbred (self-pollinating) rice cultivars. The other was a new kind that had been tweaked to be tolerant to a certain kind of herbicide. These so-called Clearfield™ cultivars allowed farmers to plant rice and then apply chemicals to their fields to kill weedy rice and other agricultural weeds without harming the crop.

As early as 2004, just two years after the new rice was adopted locally, Arkansas farmers already were reporting some cases of herbicide resistance in weedy rice. Such resistant plants were likely outcrosses with herbicide-resistant rice.

“The situation is somewhat analogous to human health and the emergence of antibiotic-resistant bacterial pathogens. Widespread use of antibiotics ends up strongly selecting for the rapid evolution of the drug-resistant strains,” Olsen said. “With weedy rice, herbicide-resistant weeds were being detected just a couple of years after herbicide-resistant rice was first commercialized.”

How did it happen? For gene flow from a crop into a weedy relative to occur, the two have to be growing in close enough physical proximity for pollen transfer.

“The herbicide-resistant weedy rice plants are the products of outcrossing with herbicide-tolerant crop,” said Nilda Roma Burgos, professor of weed physiology at University of Arkansas and a co-author of the study. “Outcrossing occurs when weedy rice is not controlled 100% by the herbicide and the remaining weedy rice plants flower at the same time as the herbicide-tolerant rice crop.”

Rice and weedy rice certainly grow in the same fields. However, it was the hybrid rice’s pesky habit of producing volunteers — that is, successfully developing and dropping seeds that overwinter and then emerge as new plants in subsequent years — that opened a door for weedy rice.

The crop volunteers grew up exhibiting variable traits, including changes to flowering timing that made it much more likely that they would swap pollen with weedy rice.

“As a de-domesticated weedy relative, weedy rice has always been able to outcross with cultivated rice. Based on our results, this ability to interbreed is what led to most of the herbicide resistance that we see today,” Wedger said.

A uniquely challenging year for growers

The findings from this new study are being reported during a uniquely challenging year for Arkansas rice farmers. Problems with the global supply chain, as well as increases in the costs of key crop inputs such as fertilizer, have made growing rice more difficult and expensive.

At the same time, global climate change is having local effects on the timing of when rice can be planted. This year, farmers had to cram in planting that usually takes place over a period of four weeks into a much-shortened window. Also this year, nighttime temperatures in northeastern Arkansas were stubbornly high during the months of July and August, with possible negative effects on rice yields. Only time will tell what the 2022 harvest, beginning this month, will bring.

One thing is certain, though: The rapid adaptation of weedy rice to herbicide application serves as yet another example of the dangers of relying on single methods of control for agricultural pests, study authors said.

“How quickly a resistant weedy rice population builds up to a point where the herbicide is no longer useful depends on how the producer manages the herbicide-tolerant rice technology,” Roma Burgos said. “There are best management practices guidelines that help growers avoid resistance evolution for a long time, if implemented.”

“Just like in the case of antibiotic resistance, the rise of resistance to this particular herbicide will be met with a new technology that relies on a new herbicide,” Wedger said. “New herbicide-resistant cultivars are already in development, so I expect this process to repeat.”


Story Source:

Materials provided by Washington University in St. Louis. Original written by Talia Ogliore. Note: Content may be edited for style and length.


Journal Reference:

  1. Marshall J. Wedger, Nilda Roma-Burgos, Kenneth M. Olsen. Genomic revolution of US weedy rice in response to 21st century agricultural technologiesCommunications Biology, 2022; 5 (1) DOI: 10.1038/s42003-022-03803-0

Scientists sleuth out an elusive plant pathogen in Mexico

For years, scientists and online databases presumed the presence of clubroot—one of the main diseases on cruciferous crops (such as broccoli, cabbage, and kale)—in Mexico. However, no evidence to support this supposition existed until a team of researchers, led by Mauricio Luna and Legnara Padrón-Rodríguez of the University of Veracruz, donned their detective caps to pinpoint the clubroot pathogen.

Since Mexico is the world’s fifth largest broccoli producer and the main supplier to the eastern United States and Canada, determining the pathogen’s presence is important when preparing for potential outbreaks. Legnara Padrón developed the detection methodology during COVID-19, causing the authors to consider what could happen if a future pandemic affects plants. The methodology involved working alongside cruciferous crops growers in Mexico and collecting soil samples from three categories of fields: fields in production, fields without cruciferous crops for up to a year, and fields that had stopped growing cruciferous crops. They were able to extract the clubroot pathogen after growing an array of cruciferous crops plants in the soil collected. Typical clubroot symptoms appeared in the roots of infected plants, and the results were confirmed using molecular methods.

Now researchers can investigate if, as suspected, the clubroot pathogen has hindered the growth of cruciferous crops in certain Mexican fields. New fields affected by the disease have been added to the ClubrootTracker, an online tool developed by Dr. Pérez-López’s group to trace the clubroot pathogen. Additionally, their results will significantly improve the future management of clubroot, safeguarding the cruciferous crops economy in Mexico and the worldwide supply of these important vegetables.

Corresponding author Edel Pérez-López comments that their “results open the door to more exciting research, like studying the genome of P. brassicae Mexican isolates, geographic distribution, and its evolution compared to other North American isolates. The strategy we followed could help detect the clubroot pathogen in other geographic areas, or potentially, other soil-borne pathogens.”

Read the complete research at www.phys.org.

Legnara Padrón-Rodríguez et al, Plasmodiophora brassicae in Mexico: From Anecdote to Fact, Plant Disease (2022). DOI: 10.1094/PDIS-11-21-2607-RE 

Publication date: Wed 14 Sep 2022

Scouting pests and diseases

As a grower, you want to have an overview of what’s happening in your crop at all times. This is why many growers make sure that scouting takes place at regular times. Natutec Scout is a tool developed by Koppert to make sure every grower can utilize the benefits of having all your scout data in one central place.

To accommodate growers’ way of working, Natutec Scout offers four different ways to input your data:

  • Pen and paper scouting: write down your observations on paper like you’re used to, and enter your findings straight and simply. Record your findings directly into Natutec Scout using the manual input feature. Input is easier and quicker than using Excel with all the benefits and tools that Natutec Scout provides.
  • Enter your observations on the mobile Natutec Scout app – available for both Android and iOS – in which you make your observations, provide your location, and add notes and photos if you want to add additional findings to your scouting session. This data is then uploaded to the dashboard.
  • Automatic detection of whitefly using the Horiver Scanner: Using the power of Artificial Intelligence (AI) for automatic whitefly counts enables you to save a significant amount of time and labor when counting the whitefly on Horiver cards. Just take a picture of a Horiver card, and you are done.
  • Import historical scout data using the Excel import functionality. You can easily load multiple years of previous scout data (averages and specifics) into Natutec Scout. You immediately get the tools at your disposal to discover trends, hotspots, and other significant events in the IPM of your crop.

The scout data are transferable. Because of that, it’s nice to work with this knowledge between everyone in your company and for your external consultant(s).

For more information:
Koppert Biological Systems
koppert.com

Publication date: Wed 14 Sep 2022

Scouting pests and diseases

As a grower, you want to have an overview of what’s happening in your crop at all times. This is why many growers make sure that scouting takes place at regular times. Natutec Scout is a tool developed by Koppert to make sure every grower can utilize the benefits of having all your scout data in one central place.

To accommodate growers’ way of working, Natutec Scout offers four different ways to input your data:

  • Pen and paper scouting: write down your observations on paper like you’re used to, and enter your findings straight and simply. Record your findings directly into Natutec Scout using the manual input feature. Input is easier and quicker than using Excel with all the benefits and tools that Natutec Scout provides.
  • Enter your observations on the mobile Natutec Scout app – available for both Android and iOS – in which you make your observations, provide your location, and add notes and photos if you want to add additional findings to your scouting session. This data is then uploaded to the dashboard.
  • Automatic detection of whitefly using the Horiver Scanner: Using the power of Artificial Intelligence (AI) for automatic whitefly counts enables you to save a significant amount of time and labor when counting the whitefly on Horiver cards. Just take a picture of a Horiver card, and you are done.
  • Import historical scout data using the Excel import functionality. You can easily load multiple years of previous scout data (averages and specifics) into Natutec Scout. You immediately get the tools at your disposal to discover trends, hotspots, and other significant events in the IPM of your crop.

The scout data are transferable. Because of that, it’s nice to work with this knowledge between everyone in your company and for your external consultant(s).

For more information:
Koppert Biological Systems
koppert.com

Publication date: Wed 14 Sep 2022

ToBRFV project examines drain water samples, UV cell phone sanitizer, and powdered milk

“Each time we answer a ToBRFV question, three more pop up,” begins Evelien Aussems, a researcher at the ‘Proefstation voor de Groenteteel,’ a vegetable cultivation research facility in Belgium. This ToBRFV practical study – called PraKeTo – coordinator experienced this when the first year full of research concluded.

That was done in partnership with the Proefcentrum Hoogstraten, Scientia Terrae, and the East Flanders Provincial Research Center for Vegetable Production. “Growers keep asking for good hand disinfection methods and eagerly await the arrival of resistant varieties.” With the start of a new four-year research project, the research consortium will try to answer these and other pressing questions around ToBRFV.

Last week, ‘everyone that has anything to do with tomato cultivation’ gathered for an update about the ToBRFV study’s latest findings. The PraKeTo project focused on practical guidance and gathering knowledge about this virus. A group, including growers, was closely involved in the project. “As researchers, we followed up with several growers with infected plants,” says Evelien. At least 15 Belgian farms already have this virus present, while in the Netherlands, there are officially 41.

The PraKeTo discussion drew a full house

Drain water samples
One of the study’s focal points was monitoring via drain water. The idea is that virus detection should be possible before symptoms of infection become visible on the plants and fruit. “Taking drain water samples gives you a better, broader picture than sampling per plant. Then, you’d either have to take samples from all the plants, which is impractical, or you’d have to sample the ‘right’ plants. That’s not so easy to determine, especially at the onset of an outbreak.”

The grower group specifically requested the study, says Evelien. “If a grower hasn’t yet had an outbreak, we can successfully detect the virus in the drain water, and well in time. But what happens to the virus concentrations in the drain water of growers whose plants are already infected?” she had to wonder.

Nine growers already had this virus in their greenhouse, so researchers took bi-weekly drain water samples. They did so after the growers had cleared the greenhouse and, after a time, resumed planting according to all the relevant regulations. “We wanted to get an idea of how the virus concentration in the water evolves in a new crop, with or without a new outbreak. The virus did indeed return to some of the sites, while others were declared virus-free by the Federal Agency for the Safety of the Food Chain (FASFC) six months post-planting.”

This study showed that virus residue can remain in the drain water. “It is thus important not to draw conclusions based on a single water sample. You must monitor the virus concentrations trend over a longer period,” explains Evelien.


ToBRFV contamination leads to poorly colored tomatoes

Distinguishing active and inactive virus
The four-year research project has now begun. Researchers from Proefstation voor de Groenteteelt, Proefcentrum Hoogstraten, and  Scientia Terrae want to further investigate their findings. The researchers also want to further examine the virus residue to determine whether the virus is still active or not.

The B2B project, which stands for ‘Beheersing van ToBRFV op de Belgische tomatenbedrijven’ (‘Controlling ToBRFV on Belgian tomato farms’) allows researchers to do this further research. One of this ongoing study’s goals is to be able to distinguish inactive from active (infectious) viruses. “We learned that, after an outbreak, this virus is present all over. Much of this is probably residue that’s no longer infectious. Clarity about that can give growers a little more peace of mind.”

Researchers will also try to “get to know the virus better,” says Aussems. “We want to use monitoring on farms to do things like map symptom expression, determine the incubation period, and learn more about the spread of the virus. With a new virus, there’s always much to learn.”

Cell phone decontamination
Cell phones were a second major focus of the PraKeTo project. Everyone has one these days, including in the greenhouse. ToBRFV is known to be very tenacious and can survive on surfaces for a long time. So, the thinking is that it can be on phones, too, thus necessitating decontamination methods to be sought there.

“We’ve been researching UV decontamination. We got the idea for that from an experiment. In it, we touched a ToBRFV-infected plant with our hands, then sent a message on our cell phones. We then checked to see how much virus was on the phone. We were shocked to see the sky-high levels of virus concentration,” admits Evelien.

Thus, the search was on to find a way to disinfect cell phones. An American company, PhoneSoap, had developed a technique for this purpose. Evelien describes it as “a box in which you place your phone, where it is hit, on all sides, with UV light. After 15 minutes of exposure, the phone was virus-free.” Growers found this to be too long and thus asked that they try shorter exposures too. “However, five minutes of exposure and disinfection proved too short.”

It is up to each grower, but the best solution would be to keep your cell phone out of the greenhouse, the researcher points out. “Even if you disinfect your cell phone when going into the greenhouse, there’s still a risk, especially if you start using that phone intensively in the greenhouse. Growers, who struggle to ban phones in the greenhouse, can disinfect them. We do that at our test facility station. If you have sufficient time, UV light might be better for your phone’s lifespan than chemicals.”

Powdered milk
The researchers found that disinfecting your hands is a recurring topic among growers, as it was last week. After presenting the year’s first research results, the audience already had new questions. “We even looked at powdered milk as a hand disinfectant. It’s harmless to your skin and is widely used by growers,” says Evelien.

They tested, for example, skimmed powdered milk from the local supermarket. “We dipped our hands in a 5% milk powder solution. After a single dip, we tried to re-infect a plant, and the powdered milk seems to work well.” It is not as straightforward as that, though, and Evelien cautions against drawing hasty conclusions.

The milk powder (temporarily) encapsulates the virus but does not break it down. “After some time, especially at 15 immersions, the powdered milk was teeming with virus concentrations,” she explains. The researchers thus advise growers to replace the powdered milk very regularly. “Otherwise, it becomes a major source of contamination.”

Looking ahead
The new four-year project consists of five so-called work packages. Also, the new study explicitly seeks to connect with other research institutions doing ToBRFV investigations. For example, the European Virtigation project has close links with countries like Israel, where the virus emerged before reaching northwestern Europe.

“Above all, we don’t want to duplicate research,” Aussems points out. Not all five work packages will start simultaneously. The researchers, along with industry stakeholders, including growers, will review the study direction biannually. “It’s vital that what we’re investigating continues connecting to what growers want in practice.”

What is clear, however, is that the researchers have not yet solved the ToBRFV puzzle. The test facility itself became infected last year. “We’ve seen what a huge effect such an infection has. We’re fully committed to finding answers to the many questions.”

“Every day, we get asked, ‘Is this allowed?’, ‘Is that allowed?’ It is a ferocious virus that greatly affects plants and fruits. In the coming years, we want to gather new knowledge about the virus, results with new – resistant or not – varieties, prevention management, and an integrated, post-outbreak approach,” concludes Evelien.

For more information:
Evelien Aussems
Proefstation voor de Groenteteelt
Email: evelien.aussems@proefstation.be
Website: www.proefstation.be

Publication date: Wed 14 Sep 2022

Nigeria’s Cross River State Cocoa Farms Hit by Black Pod Disease

Sept. 2, 2022 at 1:28 p.m. ET

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By Obafemi Oredein

Special to Dow Jones Newswires





IBADAN, Nigeria–Cocoa farmers in Nigeria’s Cross River state are battling an outbreak of the black pod disease following regular and heavy rainfall the last two weeks, a cocoa industry official and traders said.

“Our farmers are up in arms with their agro-chemicals trying to curtail the black pod disease in their farms caused by incessant rains,” said Sayina Riman, a former president of the Cocoa Association of Nigeria.

Though the rains were beneficial to cocoa by providing moisture and nutrients, he said, “farmers would have to apply chemicals whose cost is always high.”

Cross River state is the largest cocoa producer in Nigeria’s southeast region and the second-largest grower in the country after Ondo in the southwest region, according to Cocoa Research Institute of Nigeria.

The midcrop has been “very poor in the state,” Mr. Riman said. But the 2022-23 main crop cocoa is now being threatened by the black pod at a time when farmers should be getting ready to harvest the crop.

Black pod disease thrives in wet and damp conditions on cocoa farms due to incessant rains without sunshine. It can destroy around 40% of Nigeria’s annual cocoa production if left untreated, officials at the Cocoa Research Institute of Nigeria said.





Write to Barcelona editors at barcelonaeditors@dowjones.com

Sky Islands: Isolated Mountaintops Teem With Unique Insect Communities

ENTOMOLOGY TODAY  LEAVE A COMMENT

For a study of the communities of parasitic wasps on mountains in the Interior Highlands of Arkansas, one of the sites chosen was Mount Magazine State Park in Arkansas, which rises 709 meters (2,326 feet) above sea level. With cooler, wetter climates than lowlands nearby, such each feature their own communities of parasitic wasps—and likely other insects—that differ from the insect fauna found on other mountains and in the surrounding valleys, according to a new study published in August in Environmental Entomology. (Photo courtesy of Allison Monroe)

By Ed Ricciuti

Ed Ricciuti

It’s not quite Sir Arthur Conan-Doyle’s Lost World of dinosaurs, but the insect life found by scientists atop so-called “sky islands” in Arkansas ranks as truly unique.

“Sky island” is a term popularized in the 1960s to describe isolated mountains with environments markedly different than that of surrounding lowlands. Conan-Doyle prefigured such environments in his story about an expedition that explored a plateau rising above jungle, where prehistoric dinosaurs, reptiles and “ape men” had survived the ages.

Although not as dramatic as dinosaurs, isolated endemic populations of animals of any size excite scientists. According to a study published in August in Environmental Entomology, such distinct assemblages of insects in the order Hymenoptera (sawflies, bees, wasps, and ants) live atop uplands in Oklahoma, Arkansas, Missouri, and Illinois called the Interior Highlands.

The study, by student researchers at Hendrix College in Conway, Arkansas, focused on parasitic wasps inhabiting three mountains, but the results can be extrapolated to other sky islands in the region and their insects in general, the researchers say.

“Given that each sky island in our study showed unique community characteristics of Hymenoptera, it is reasonable to predict that other insects follow the same pattern,” the authors write. Mountains studied were Petit Jean Mountain at 253 meters (830 feet) in elevation, Mount Magazine at 709 meters (2,326 feet) and Rich Mountain at 747 meters (2,451 feet).

overlook
field site

Parasitic Hymenoptera are a multitudinous group, with 50,000 or so identified species and perhaps millions in all. Typically, they parasitize other insects by laying their eggs in host eggs, larvae, or pupae. They are of immense ecological importance because they are fine-tuned to specific hosts, including many pest species, which they can regulate, like natural pest control managers. “We chose parasitic Hymenoptera as our focal group because they are considered bioindicators of broader diversity patterns, especially those of other insects,” the authors write.

The Interior Highlands, centered in Missouri and Arkansas and including the Ouachita Mountains and Ozark Plateau, were chosen as a study site because they have been above sea level for 320 million years, likely serving as a refuge for ecological communities avoiding the impact of the Pleistocene glaciers. The region is the only major mountainous area between the Appalachians and the Rockies, covering much more area than the Black Hills of South Dakota. Typical of the Interior Highlands, Mount Magazine is 10 degrees Fahrenheit cooler than normal temperatures in the landscape down below and wet, with an annual rainfall of 54 inches. Crowned with upland hardwood and upland pine-hardwood forests, these mountains rise from grasslands, with vegetation ranging from tallgrass prairie to lowland pine-hardwood and bottomland hardwood forests.

Much of the area where the research was conducted lies in state and federal lands. Sweating in the hot summer sun, the research team trekked along hiking trails from grasslands into woodlands. They set up traps, then collected insects from them.

“Though evidence is accumulating that the Interior Highlands host unique species relative to other areas of the North American continent, there is less known about how mountaintops within the region compare in terms of biodiversity,” the researchers write. “We used parasitic Hymenoptera to explore biodiversity patterns across high elevation areas in Arkansas to determine whether these patterns are similar to those exhibited by other sky island regions.”

malaise trap
research team

Each mountaintop had its distinct community of parasitoid species, indicating that the same applies to Hymenoptera in general and even to other groups of insects. On a given mountaintop, communities differed stratigraphically, with those on the ground distinct from those in the forest canopy.

The results of the study suggest the need for additional research. “Our study suggests that these highland areas are important regions of North American biodiversity and that they should be evaluated individually for conservation efforts in order to preserve their distinctive community structure,” the authors write.

Elaborating on the study, lead author Allison Monroe, says, “This study is important for a variety of reasons. Parasitic wasps are deeply important to our environment but are often overlooked if not deeply hated.”

Monroe, now a Ph.D. candidate at the Oregon State University College of Forestry, says, “Arkansas is an incredibly biodiverse state with high rates of agricultural production, yet little research exists on insect biodiversity trends and their applied impacts on diverse land management strategies within this system. We hope that this paper brings to light the extraordinary diversity housed in Arkansas, the importance of insect biodiversity more broadly, and the significance of parasites in our pursuits of nature conservation.”

Read More

Biodiversity of Parasitic Hymenoptera Across Sky Islands of Arkansas, United States

Environmental Entomology

Ed Ricciuti is a journalist, author, and naturalist who has been writing for more than a half century. His latest book is called Bears in the Backyard: Big Animals, Sprawling Suburbs, and the New Urban Jungle (Countryman Press, June 2014). His assignments have taken him around the world. He specializes in nature, science, conservation issues, and law enforcement. A former curator at the New York Zoological Society, and now at the Wildlife Conservation Society, he may be the only man ever bitten by a coatimundi on Manhattan’s 57th Street.

Flavonoids from sorghum plants kill fall armyworm pest on corn, may protect crop

by Jeff Mulhollem, Pennsylvania State University

corn plant
Credit: Pixabay/CC0 Public Domain

Flavonoids produced by sorghum leaves have shown promising results in combating fall armyworm larvae. When sprayed on the leaves of corn, sorghum flavonoids stunt the growth of fall armyworm and often kill the pest, Penn State researchers report in a new study.

The results of the research are important, according to Surinder Chopra, professor of maize genetics, because fall armyworm is an invasive insect pest that now damages corn crops around the world, significantly limiting yields. He suggests that flavonoids could be used as the basis for a nontoxic pest-management strategy to protect corn.

Plant flavonoids are natural compounds that often are seen as pigments in some flowers, vegetables and fruits. Flavonoids normally are considered nonessential byproducts of a plant’s primary metabolism, which produces sugars and other metabolites that work together to produce seed yield.

“When you survey the leaves and other parts of commercially grown corn, you do not see production of these flavonoids anymore,” he said. “These compounds were naturally present at one point until we started breeding against them. Actually, we did not breed against them so much as we just lost them trying to develop higher-yielding varieties.”

For two decades, Chopra’s research group in the College of Agricultural Sciences has studied mutant lines of corn that overproduce the flavonoids and has developed new lines that combine flavonoid overproduction with other desirable traits. And his lab has taken the gene that produces a precursor compound of flavonoids in sorghum and inserted this gene into corn to make more resilient plants that can discourage feeding by fall armyworms and possibly other pests.

Fall armyworm caterpillars are so destructive because they often feed on the younger corn leaves inside the whorl where they grow, Chopra explained. They stay inside the whorl gorging, and when the whorl opens, the young leaves already are destroyed.

In the study, the researchers demonstrated in a three-part experiment that sorghum and corn flavonoids affect survival of fall armyworm larvae. Their findings, recently published in the Journal of Pest Science, revealed that fall armyworm larvae reared in the lab on an artificial diet supplemented with sorghum flavonoids showed significant mortality and decreased larvae body weight.

To compare the levels of fall armyworm survival and feeding damage, the researchers developed breeding lines and grew four related lines of corn at Penn State’s Russell E. Larson Agricultural Research Center—two genetically modified lines to produce flavonoids, and two not producing flavonoids.

“The feeding assays showed significantly high mortality of larvae that were fed on flavonoid-producer lines compared to nonflavonoid lines or the wild types,” Chopra said. “And significantly less damage was done to corn plants producing flavonoids than to flavonoid-free corn.”

The researchers also extracted leaf flavonoids from certain sorghum lines and sprayed them on leaves of susceptible corn lines. The flavonoid extract effectively reduced the growth and increased the mortality of fall armyworm larvae, making the susceptible lines resistant to fall armyworm larval feeding.

Penn State entomologist Gary Felton, who has been collaborating on this research with Chopra, noted that when fall armyworms ingest flavonoids, their intestinal tract is degraded.

“The membrane that protects the caterpillar’s gut was severely damaged in larvae fed on leaves of flavonoid-producer corn lines, compared to wild types,” he said. “The effectiveness of the flavonoids as feeding deterrents demonstrates the eco-friendly potential for the management of fall armyworm larvae.”


Explore further

Insect-deterring sorghum compounds may be eco-friendly pesticide


More information: Debamalya Chatterjee et al, Sorghum and maize flavonoids are detrimental to growth and survival of fall armyworm Spodoptera frugiperda, Journal of Pest Science (2022). DOI: 10.1007/s10340-022-01535-y

Provided by Pennsylvania State University 

Boy’s discovery reveals highly complex plant-insect interaction

by Sara LaJeunesse, Pennsylvania State University

Boy’s discovery reveals highly complex plant-insect interaction
An ant holds an oak gall containing wasp larvae. Researchers discovered an elaborate relationship among ants, wasps and oak trees. Credit: Andrew Deans, Penn State

When eight-year-old Hugo Deans discovered a handful of BB-sized objects lying near an ant nest beneath a log in his backyard, he thought they were a type of seed. His father, Andrew Deans, professor of entomology at Penn State, however, knew immediately what they were—oak galls, or plant growths triggered by insects. What he didn’t realize right away was that the galls were part of an elaborate relationship among ants, wasps and oak trees, the discovery of which would turn a century of knowledge about plant-insect interactions on its head.

Looking back, Hugo, now 10, says that he “thought they were seeds, and I felt excited because I didn’t know ants collected seeds. I always thought ants would eat food scraps and stuff around the house. Then I got more excited when [my dad] told me they were galls, because [my dad] was so excited. I was surprised that ants would collect galls because why would they do that?”

According to Andrew Deans, who is also the director of Penn State’s Frost Entomological Museum, many plant-insect interactions are well documented. For example, most “cynipid” wasp species have long been known to induce oak trees to produce protective galls—or growths—around their larvae to ensure the safety of their developing offspring. Additionally, certain plants—including bloodroot (Sanguinaria canadensis), a wildflower native to North America—produce edible appendages, called elaiosomes, on their seeds to attract ants, which then disperse the seeds by carrying them back to their nests. This latter example is referred to as “myrmecochory”—or seed dispersal by ants.

“In myrmecochory, ants get a little bit of nutrition when they eat the elaiosomes, and the plants get their seeds dispersed to an enemy-free space,” Deans explains. “The phenomenon was first documented over 100 years ago and is commonly taught to biology students as an example of a plant-insect interaction.”

The team’s new research—initiated by Hugo’s discovery of galls lying near an ant nest—revealed a much more complex type of myrmecochory, one that combined the wasp-oak gall interaction with the edible appendage-ant interaction.

“First, we observed that, while these galls normally contain a fleshy pale-pink ‘cap,’ the galls near the ant nest did not have these caps, suggesting that maybe they were eaten by the ants,” says Deans. “Ultimately, this led us to discover that gall wasps are manipulating oaks to produce galls, and then taking another step and manipulating ants to retrieve the galls to their nests, where the wasp larvae may be protected from gall predators or receive other benefits. This multi-layered interaction is mind blowing; it’s almost hard to wrap your mind around it.”

The team’s findings published in the journal American Naturalist.

https://www.youtube.com/embed/5z4lz8lX-uA?color=whiteResearchers discovered that not only do gall wasps manipulate oaks to produce galls, but they also manipulate ants to retrieve the galls to their nests, where the wasp larvae may be protected from gall predators or receive other benefits. Credit: Michael Tribone

Investigating the interaction

To better understand the interaction, the researchers conducted a series of field and laboratory experiments. First, to determine if, like eliaosomes, the oak gall caps—which the researchers named kapéllos (Greek for “cap”)—were indeed edible and attractive to ants, the team directly observed oak galls in ant colonies in the wild in Western New York and central Pennsylvania. Additionally, they set up video cameras to capture additional animal/gall interactions. In both locations, they saw ants transporting galls to their nests. Within the nests, all the edible caps were removed, while the galls themselves remained intact.

In a second set of experiments to determine if kapéllos functioned similarly to elaiosomes, the researchers investigated ant preference for oak galls vs. bloodroot seeds. They set up seed/gall bait stations and observed that ants removed the same number of seeds and galls, suggesting no difference in ant preference.

Next, the scientists conducted a laboratory experiment to document whether ants collected galls because of their nutritious kapéllos. They set up three petri-dish treatments—containing entire galls, gall bodies with kapéllos removed or kapéllos with gall bodies removed—along with a control dish containing a different type of gall that did not have an edible appendage. They introduced ants to the petri dishes. They found that ant interest did not differ between the control galls and the kapéllo-free treatment galls, both of which lacked edible components. By contrast, ant interest was greater for galls with intact kapéllos and for kapéllos alone than for control galls.

“We showed that galls with caps were far more attractive to ants than galls without caps and that the caps by themselves were also attractive to the ants,” says John Tooker, professor of entomology. “This suggested that the caps must have evolved as a way to entice ants.”

Finally, the team asked, “What’s in kapéllos that make them so attractive to ants?” According to Tooker, the chemistry of elaiosomes is well studied and known to contain nutritious fatty acids. Therefore, the team compared the chemical compositions of kapéllos to elaiosomes and found that kapéllos, too, contained healthful fatty acids.

“The fatty acids that are abundant in gall caps and eliosomes seem to be mimicking dead insects,” says Tooker. “Ants are scavengers that are out trying to find and grab anything that’s suitable to bring back to their colony, so it’s not an accident that the gall caps and the elaiosomes both have fatty acids typical of dead insects.”

https://www.youtube.com/embed/isgN91SXm54?color=whiteCredit: Pennsylvania State University

Which came first?

The last, and according to the researchers, most intriguing, question the team pursued was, “Which came first in evolutionary time? The elaiosome interaction or the gall interaction?”

“Given that myrmecochory was described more than a century ago and has been well-researched and taught in schools, one might assume that the elaiosome interaction came first, but that assumption may be wrong for several reasons,” says Robert J. Warren II, professor of biology, SUNY Buffalo State.

One reason, he explained, is that myrmecochorous plants, like bloodroots, comprise only a very small percentage of all plant species and, therefore, may not contribute enough food resources to drive natural selection in ants. Oak galls, however, are widely abundant. In fact, says Warren, they were once so abundant that they were regularly used to fatten livestock.

“If these galls were so abundant and evolved this tactic of growing this cap thousands of years ago, that could have been a strong driver of natural selection in ants,” says Warren. “It could be that ants were long used to picking up galls with caps, and then when spring wildflowers began to produce seeds that happened to have an edible appendage, ants were already predisposed to picking up things with a fatty acid appendage.”

Deans noted that the team recently received a grant to conduct phylogenetic work to further investigate which of these interactions came first in evolutionary time.

“Understanding how these interactions evolved and how they work helps to untangle just a little bit more of the complexity of life on Earth,” he says.

On what it felt like to contribute to such an important discovery, Hugo says “I bet other kids have made similar discoveries but never knew how important they might be. I feel really happy and proud to know I was part of an important scientific discovery. It’s weird to think just some ants collecting what I thought were seeds was actually an important scientific breakthrough.”

When asked if he wants to be an entomologist like his dad when he grows up, given that he’s already made his first scientific discovery, Hugo says “not really. I want to be different … unique … when I grow up.”


Explore further

Crypt-keeper wasp found to parasitize multiple species of gall wasp


More information: Robert J. Warren et al, Oak Galls Exhibit Ant Dispersal Convergent with Myrmecochorous Seeds, The American Naturalist (2022). DOI: 10.1086/720283

Journal information: American Naturalist 

Provided by Pennsylvania State University 

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