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Archive for the ‘Biological control’ Category

    

“Air pollution threatens natural pest control”

When fields of oilseed rape are exposed to diesel exhaust and/or ozone – both found in emissions from diesel-burning vehicles and industry – the number of parasitic insects available to control aphids drops significantly, according to research published today.

The team, led by scientists from the University of Reading, used special equipment to deliver controlled amounts of diesel exhaust and ozone to oilseed rape plants. They also added aphids to the plants and measured the reproductive success of parasitic wasps that habitually lay their eggs inside a freshly stung aphid.

Dr. James Ryalls, University of Reading said: “Even at the levels we used, which were lower than safe maximums set by environmental regulators, the overall numbers of parasitic insects still fell. This is a worrying result as many sustainable farming practices rely on natural pest control to keep aphids and other unwelcome creatures away from valuable crops.


Parasitic wasp and aphid – Peter Swatton, Rothamsted Research 

“Diesel and ozone appear to make it more difficult for the wasps to find aphids to prey upon and so the wasp population would drop over time.”

While the majority of parasitic wasp species decreased in polluted environments, one species of parasitic wasp appeared to do better when both diesel and ozone were present. However, the researchers found that this combination of pollutants also correlated with changes in the plants which might explain the finding.

With both pollutants present, oilseed rape plants produced more of the compounds that give brassica family crops, including mustards and cabbages, their distinctive bitter, hot, and peppery flavor notes. These usually repel insects but in the case of Diaretiella rapae wasps, there was greater abundance and reproductive success associated with diesel exhaust and ozone together.

Dr Ryalls said: “Diaretiella rapae particularly likes to prey on cabbage aphids, which love to eat brassica crops.

“We know that some of the flavor and smell compounds in oilseed rape are converted into substances that do attract D.rapae. So, we could speculate that the stronger smell attracts the wasps and they are more successful in finding and preying upon aphids, that way. It could be that D.rapae is a good choice for pest control in diesel and ozone polluted areas.

“This really goes to show that the only way to predict and mitigate the impacts of air pollutants is to study whole systems.”

As transport shifts away from diesel and towards electric motors, air pollution will change. Knowing how pest-regulation service providers, such as parasitic wasps, respond to these progressive changes, will be essential to planning mitigation strategies to ensure sustainable food security now, and in the future. This research shows that we also must consider the impact of pollution on the plants, wasps, and prey insects, and the interactions between all three.

For more information:
University of Reading
www.reading.ac.uk 

Publication date: Thu 10 Nov 2022

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NOVEMBER 1, 2022

Bats protect young trees from insect damage, with three times fewer bugs

by University of Illinois at Urbana-Champaign

bat
Credit: CC0 Public Domain

Bats help keep forests growing. Without bats to hold their populations in check, insects that munch on tree seedlings go wild, doing three to nine times more damage than when bats are on the scene. That’s according to a new study from the University of Illinois. The article, “Bats reduce insect density and defoliation in temperate forests: an exclusion experiment,” is published inEcology.

“A lot of folks associate bats with caves. But as it turns out, the habitat you could really associate with almost every bat species in North America is forest. And this is true globally. Forests are just really important to bats,” says Joy O’Keefe, study co-author and assistant professor and wildlife extension specialist in the Department of Natural Resources and Environmental Sciences at Illinois. “We wanted to ask the question: Are bats important to forests? And in this study, we’ve demonstrated they are.”

Other researchers have demonstrated bats’ insect-control services in crop fields and tropical forest systems, but no one has shown their benefits in temperate forests until now.

“It’s especially important for us to learn how bats affect forests, given that bats are declining due to diseases like white-nose syndrome or collisions with wind turbines. This type of work can reveal the long-term consequences of bat declines,” says Elizabeth Beilke, postdoctoral researcher and lead author on the study.

The research team built giant mesh-enclosed structures in an Indiana forest to exclude the eight bat species that frequent the area, including two federally threatened or endangered species. The mesh openings were large enough to allow insects free movement in and out, but not flying bats. Every morning and evening for three summers, Beilke opened and closed the mesh sides and tops of the structures to ensure birds had daytime access to the plots. That way, she could be sure she was isolating the impacts of bats.

Beilke then measured the number of insects on oak and hickory seedlings in the forest understory, as well as the amount of defoliation per seedling. Because she erected an equal number of box frames without mesh, Beilke was able to compare insect density and defoliation with and without bats.

Overall, the researchers found three times as many insects and five times more defoliation on the seedlings when bats were excluded than in control plots that allowed bats in each night. When analyzed separately, oaks experienced nine times more defoliation and hickories three times more without bats.

“We know from other research that oaks and hickories are ecologically important, with acorns and hickory nuts providing food sources for wildlife and the trees acting as hosts to native insects. Bats use both oaks and hickories as roosts, and now we see they may be using them as sources of prey insects, as well. Our data suggest bats and oaks have a mutually beneficial relationship,” Beilke says.

While insect pressure was intense in plots without bat predation, the seedlings didn’t succumb to their injuries. But the researchers say long-term bat declines could prove fatal for the baby trees.

“We were observing sublethal levels of defoliation, but we know defoliation makes seedlings more vulnerable to death from other factors such as drought or fungal diseases. It would be hard to track the fate of these trees over 90 years, but I think a natural next step is to examine the impact of persistent low levels of defoliation on these seedlings,” Beilke says. “To what extent does repeated defoliation reduce their competitive ability and contribute to oak declines?”

The researchers point out that birds, many of which share the same insect diets as bats, are also declining. While they specifically sought to isolate bats’ impact on forest trees, the researchers are confident insect density and defoliation rates would have been higher if they had excluded both birds and bats in their study. In fact, similar exclusion studies focusing on birds failed to account for bats in their study designs, leaving mesh enclosures up all night.

“When we were initially working on the proposal for this research, we looked at 37 different bird exclusion studies, across agriculture and forest systems. We found nearly all of them had made this mistake. Most of them had not opened or removed their treatment plots to bats,” Beilke says.

In other words, before Beilke’s study, birds were getting at least partial credit for work bats were doing in the shadows.

Clearly, both types of winged predators are important for forest health in temperate systems. And, according to O’Keefe, that makes these studies even more critical to inform forest management.

“I think it’s important to stress the value of this type of experimental work with bats, to really try to dig into what their ecosystem services are in a deliberate manner. While we can probably extrapolate out and say bats are important in other types of forest, I wouldn’t discount the value of doing the same kind of work in other systems, especially if there are questions about certain insect or tree species and how bats affect them. So rather than extrapolating out across the board, let’s do the work to try to figure out how bats are benefiting plants,” she says. “And before they’re gone, hopefully.”

More information: Elizabeth A. Beilke et al, Bats reduce insect density and defoliation in temperate forests: An exclusion experiment, Ecology (2022). DOI: 10.1002/ecy.3903

Journal information: Ecology 

Provided by University of Illinois at Urbana-Champaign 


Explore further

Bats’ midnight snacks reveal clues for managing endangered species

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Why a Little Bit of This Tree Pest is a Good Thing in Urban Landscapes

<img aria-describedby="caption-attachment-18801" data-attachment-id="18801" data-permalink="https://entomologytoday.org/2022/10/26/why-tree-pest-good-urban-landscapes-scale-insects-natural-enemies/scale-insects-trees/" data-orig-file="https://i0.wp.com/entomologytoday.org/wp-content/uploads/2022/10/scale-insects-trees.png?fit=1315%2C775&ssl=1" data-orig-size="1315,775" data-comments-opened="1" data-image-meta="{"aperture":"0","credit":"","camera":"","caption":"","created_timestamp":"0","copyright":"","focal_length":"0","iso":"0","shutter_speed":"0","title":"","orientation":"0"}" data-image-title="scale insects on trees" data-image-description="<p>Tiny, dome-shaped scale insects can damage or kill trees in heavy infestations, but their presence in moderate numbers actually supports a variety of other beneficial insects that protect trees and surrounding vegetation from other pests, a new study shows. Shown here are (left) a branch on an urban willow oak tree (<em>Quercus phellos</em>) that is covered in oak lecanium scales (<em>Parthenolecanium quercifex</em>) and (right) an urban red maple (<em>Acer rubrum</em>) branch covered with gloomy scales (<em>Melanaspis tenebricosa</em>). (Left photo by Clyde Sorenson, Ph.D.; right photo by Caleb Wilson, Ph.D.</p> " data-image-caption="<p>Tiny, dome-shaped scale insects can damage or kill trees in heavy infestations, but their presence in moderate numbers actually supports a variety of other beneficial insects that protect trees and surrounding vegetation from other pests, a new study shows. Shown here are (left) a branch on an urban willow oak tree (<em>Quercus phellos</em>) that is covered in oak lecanium scales (<em>Parthenolecanium quercifex</em>) and (right) an urban red maple (<em>Acer rubrum</em>) branch covered with gloomy scales (<em>Melanaspis tenebricosa</em>). (Left photo by Clyde Sorenson, Ph.D.; right photo by Caleb Wilson, Ph.D.

Tiny, dome-shaped scale insects can damage or kill trees in heavy infestations, but their presence in moderate numbers actually supports a variety of other beneficial insects that protect trees and surrounding vegetation from other pests, a new study shows. Shown here are (left) a branch on an urban willow oak tree (Quercus phellos) that is covered in oak lecanium scales (Parthenolecanium quercifex) and (right) an urban red maple (Acer rubrum) branch covered with gloomy scales (Melanaspis tenebricosa). (Left photo by Clyde Sorenson, Ph.D.; right photo by Caleb Wilson, Ph.D.

By Caleb Wilson, Ph.D.

Urban trees often host higher densities of scale insects than trees in rural areas. Scales are tiny dome-shaped insects that feed on sap that they extract from plants with their hidden straw-like mouth parts. Because scales are minute and nondescript, they often go unnoticed as they feed on plants. However, when scales are abundant on trees they can cause leaf dieback in tree branches and, in extreme cases, tree death.The good news, however, is that scales are usually only a problem on trees in highly urbanized locations with little surrounding vegetation—such as a tree in a paved parking lot. In moderately urbanized locations such as yards or parks with surrounding vegetation such as turfgrass, shrubs, and neighboring trees, scales typically do not become dense enough to worsen tree health.So, why should we care about these largely unnoticeable insects in our yards if they aren’t killing our trees? The answer is that scales may help conserve insect predators and parasitoids (collectively referred to as natural enemies), which could help prevent pest problems elsewhere in our yards.

Scales are eaten by a multitude of arthropods such as lady beetles, lacewing larvae, and spiders. Additionally, many parasitoid wasp species use scales as hosts in which to lay their eggs and feed their larvae. Many scale species also excrete honeydew as they feed, which is eaten as a supplemental food source by natural enemies and other non-predatory insects as well. Thus, scales may help support natural enemies by directly serving as prey or hosts for parasitoids, and scales could support natural enemies indirectly by providing honeydew for other arthropods that insect predators might consume.If scales support natural enemy communities in trees, they might also support natural enemy communities in nearby plants. Natural enemies attracted to the high scale densities found in urban trees may also forage for food in plants below these trees. Therefore, a shrub planted below a tree with many scales might be visited regularly by natural enemies which, could prevent pest issues from arising within the shrub. To investigate these dynamics, my advisor Steven Frank, Ph.D., at North Carolina State University and I conducted a study that was published last week in Environmental Entomology.First, to determine the ability of scale insects to support natural enemy communities, we collected arthropods from the canopies of scale-infested willow oaks (Quercus phellos) and uninfested sawtooth (Q. acutissima) and overcup (Q. lyrata) oaks in Raleigh, North Carolina, in 2019 and 2020. Willow oaks are commonly planted urban trees in the southeast that can host high densities of oak lecanium scale (Parthenolecanium quercifex), European fruit lecanium scale (P. corni), and many other species. Sawtooth and overcup oaks are also commonly planted urban species that host few scales in their canopies.We found that scale-infested oaks hosted more natural enemies than uninfested oaks in both years. Specifically, scale-infested oaks had more spiders, parasitoids, and lady beetles than uninfested oaks.To see if shrubs growing below scale-infested trees had more natural enemies than shrubs underneath uninfested trees, we then collected arthropods from shrubs below both tree types in 2020 and 2021. We collected arthropods from landscape yaupon holly (Ilex vomitoria) and Chinese holly (I. cornuta) shrubs. We also ran an accumulation experiment in which we resampled holly shrubs at three- and six-day intervals to see if natural enemies became more abundant on shrubs under scale-infested trees compared to uninfested trees over short time scales.

We found that in both 2020 and 2021 natural enemies were more abundant in shrubs below scale-infested trees compared to uninfested trees. Namely, spiders, predatory hemipterans (e.g. assassin bugs), and ants were more abundant in shrubs below scale-infested trees. In our accumulation experiment, natural enemies became more abundant in shrubs below scale-infested trees compared to uninfested trees in six to nine days.

<img aria-describedby="caption-attachment-18808" data-attachment-id="18808" data-permalink="https://entomologytoday.org/2022/10/26/why-tree-pest-good-urban-landscapes-scale-insects-natural-enemies/natural-enemies/" data-orig-file="https://i0.wp.com/entomologytoday.org/wp-content/uploads/2022/10/natural-enemies.png?fit=1847%2C1709&ssl=1" data-orig-size="1847,1709" data-comments-opened="1" data-image-meta="{"aperture":"0","credit":"","camera":"","caption":"","created_timestamp":"0","copyright":"","focal_length":"0","iso":"0","shutter_speed":"0","title":"","orientation":"0"}" data-image-title="natural enemies" data-image-description="<p>Representatives of the natural enemy groups found in greater abundance in shrubs below scale-infested trees compared to uninfested trees. Left: A jumping spider (family Salticidae). Middle: An assassin bug, <em>Sinea</em> sp. (Reduviidae). Right: A winter ant, <em>Prenolepis impairs</em> (Formicidae). (Photos by Matt Bertone, Ph.D.)</p> <p>Caption: A willow oak grows in a landscaping bed with holly shrubs and roses below it. (Photo by Caleb Wilson, Ph.D.)</p> " data-image-caption="<p>Representatives of the natural enemy groups found in greater abundance in shrubs below scale-infested trees compared to uninfested trees. Left: A jumping spider (family Salticidae). Middle: An assassin bug, <em>Sinea</em> sp. (Reduviidae). Right: A winter ant, <em>Prenolepis impairs</em> (Formicidae). (Photos by Matt Bertone, Ph.D.)</p> <p>Caption: A willow oak grows in a landscaping bed with holly shrubs and roses below it. (Photo by Caleb Wilson, Ph.D.)

Representatives of the natural enemy groups found in greater abundance in shrubs below scale-infested trees compared to uninfested trees. Left: A jumping spider (family Salticidae). Middle: An assassin bug, Sinea sp. (Reduviidae). Right: A winter ant, Prenolepis impairs (Formicidae). (Photos by Matt Bertone, Ph.D.)

So, what should we take away from these results? First, it is important to recognize that scales, even though they can be pests of urban trees, help support natural enemy communities both within trees and in nearby plants. This means that tolerating scales on trees helps ensure that natural enemy communities are available to consume other insect pests on nearby plants.Second, our results indicate that the natural enemy communities in trees and shrubs are linked. Treating a tree with pesticides could kill off natural enemies that would otherwise help manage nearby pests. In other words, treating a tree with pesticides could alleviate pest problems within the tree but could result in pest outbreaks in shrubs beneath the tree as natural enemies are killed off. When treating trees with pesticides, it may be better to treat them in the winter, when natural enemies are not active. If a tree needs to be treated during the summer, it may be better to use a pesticide such as horticultural oil that can kill scales but is less likely to kill natural enemies than a broad-spectrum pesticide might.Above all, our results suggest that urban landscapes should be viewed as ecosystems in which natural enemy communities in trees and shrubs are linked and that management decisions in either location has the potential to affect arthropod communities in the other.

Caleb Wilson, Ph.D., is a postdoctoral research associate in the Department of Entomology at Michigan State University and a recent doctoral graduate from North Carolina State University. Email: wils1852@msu.edu.

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Pest Management Science

Licorice strips enhance predator-mediated biological control in China’s cotton crop

Research Article

Zhengxuan Xue,Tianxiang Peng,Bing Liu,Yangtian Liu,Zhijian Zhang,Kris A.G. Wyckhuys,Peiling Wang,Yanhui Lu

First published: 19 October 2022

https://doi.org/10.1002/ps.7243

This article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process, which may lead to differences between this version and the Version of Record. Please cite this article as doi: 10.1002/ps.7243.

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Abstract

BACKGROUND

Habitat management such as field- or farm-level diversification can conserve arthropod natural enemies, enhance biological pest control and lower (or suspend) insecticide use in agricultural crops. These approaches however have been underexploited to manage the aphid Aphis gossypii in cotton cropping systems of Xinjiang, China. In this study, we investigated whether the presence of licorice (Glycyrrhiza uralensis) at the field edge benefits generalist predator abundance and aphid biological control in local cotton crops.

RESULTS

Field trials during 2020 and 2021 showed that licorice strips enhanced the in-field abundance of generalist predators (primarily ladybeetles) 2.2–4.3 fold during early season i.e., initial growth before A. gossypii peak infestation pressure. During peak outbreak conditions in July, treatment fields with licorice strips experienced a respective 17.5–61.2% lowered aphid density and 12.3–14.6 fold higher predator to aphid ratio (PAR) than control fields. In late season (aphid decline phase) of either year, cotton fields with licorice strips also attained a respective 4.7–9.9 fold higher PAR. Exclusion cage assays quantitatively assessed predator-mediated A. gossypii biological control and the relative contribution of licorice strips. The biocontrol services index (BSI) was 2.8 times (2020) and 1.4 times (2021) higher at 5 m distances from the licorice strip as compared to control fields.

CONCLUSION

Licorice strips in the immediate vicinity of cotton fields benefit generalist arthropod predators and improve aphid biological control throughout the cotton cropping season. These findings help to integrate habitat management within integrated pest management (IPM) frameworks in the biggest cotton production region of China.

This article is protected by copyright. All rights reserved.

Accepted Articles

Accepted, unedited articles published online and citable. The final edited and typeset version of record will appear in the future.

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Mites enlisted to battle weeds

  • By Katie Klingsporn WyoFile.com
  • Oct 6, 2022
  •  0
Hoary cress
Researchers are exploring using mites to combat the spread of whitetop, or hoary cress, an invasive plant that has colonized much of the West.U.S. DEPARTMENT OF AGRICULTURE

The noxious invasive weed whitetop, which has colonized vast tracts of the West, has long confounded landowners and resource managers. Also known as hoary cress, the plant proliferates quickly, has no natural North American predators and is reportedly toxic to cattle in large quantities.

An unlikely warrior has emerged in the whitetop battle: a microscopic mite from Europe that researchers believe can stunt the weed’s growth. This summer, land managers released the mite in Wyoming for the first time.

“We’re really excited about having the mites,” said Dr. Tim Collier, a University of Wyoming associate professor who specializes in biological control of rangeland weeds. “Whitetop is a huge problem in Wyoming.”

Technicians spread mite-infested “galls” — plant deformities caused by feeding mites — on a 3.5-acre piece of state-owned property in Fremont County in May. The hope is that the mites in the galls will spread to live plants and create new galls, which impede growth.

Dr. Jeffrey Littlefield, a research scientist at Montana State University in Bozeman, is a major player in the whitetop mite effort, a collaboration many years in the making that spans the globe.

The plant-stunting gall mite in question, Aceria drabae, hails from northern Greece.

“It’s been known for a number of years and was thought to be a potential bio control agent for whitetop,” Littlefield said.

A biological-control laboratory began transporting the tiny creature to a containment facility at MSU in the mid-’90s, Littlefield said. Over the years of transfer, testing and monitoring, researchers found positive results. The mites produce different galls that prevent the plants from going to seed, Littlefield said. Galls also spread to secondary stems and forced their host plants to divert energy that would otherwise be used to proliferate.

“They can really stunt the plant,” he said.

Littlefield and his team had to secure U.S. Department of Agriculture regulatory approval. The process for approving biological control agents — natural enemies such as parasites, predators or pathogens — is painstaking and comprehensive.

“And that took probably another good six years or so,” Littlefield said.

But that approval gave Littlefield and his collaborators the green light to release the mites on wild whitetop plants, which they first did in Montana in 2019.

The first year they put mites in one Montana site, Littlefield said, they counted 10 gall-infected stems.

“This past year we’ve had well over 6,000 stems,” he said. “We’re finding not only the number of infested stems has increased, but the gall intensity has increased.”

The hope is to slowly grow the program in order to facilitate releases in more of the West and see a slowing or reversal in the weed’s colonizing patterns.

When the mites became available for release, the Wyoming Weed and Pest Control Council wanted in on it. Whitetop has, after all, affected every county in the state, Larry Smith, president of the Wyoming Weed and Pest Council, said in a release.

There are plenty of introduced plants that don’t cause ecological disorder, said Fremont County Weed and Pest District Supervisor Aaron Foster, who chairs the Wyoming Biological Control Steering Committee.

“But some have the advantage of being competitive and can cause havoc,” he said. “And whitetop is one of those.”

Whitetop “has the ability to use that root system to crowd out the surrounding vegetation,” Foster said. “And it grows and it forms these dense monoculture patches. And they just get bigger and bigger and kind of expand, and start pushing out the desirable grasses, the other forbs that are in there that we like, and pretty quick, the dominant plant is whitetop.”

That’s not good for biodiversity, wildlife or agriculture, he said.

The site near Dubois was selected for a few reasons, Foster said. Fremont County has been a longtime and significant contributor to biological control, research and development in Wyoming, he said, and county weed and pest officials already had sites identified and prepared there.

Now that the mites have been released, the next step is to wait, monitor their effect and evaluate whether to distribute them more widely, Foster said.

The project will take years and isn’t expected to eradicate whitetop in Wyoming. But the hope is that it can slow the spread and save money by preventing other, more expensive measures.

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Number I                                                                                                                     January, 2023

NEW INTERACTIVE PATHWAY KEYS FOR IDENTIFYING INSECT PESTS OF RICE AND THEIR NATURAL ENEMIES

The correct identification of insect pests and their natural enemies is critical for developing sound and sustainable pest management strategies. As agriculture intensified and insect pests became more problematic, identification of major insect pests and their natural enemies became increasingly relevant when designing appropriate pest management strategies, especially for rice. 

Appointed as the first entomologist at the International Rice Research Institute (IRRI) based in the Philippines, Dr. Mano D. Pathak, established a comprehensive rice insect pest and natural enemy collection in the early 1960s. The aim was to support national rice research programs identify specimens in their own rice arthropod collections. Subsequently, to support this objective, a dichotomous key to over 862 species was published in the chapter Taxonomy of Rice Insect Pests and their Arthropod Parasites and Predators, authored by insect and spider taxonomist, Alberto T. Barrion, with James A. Litsinger, in the book, Biology and Management of Rice Insects,edited by E. A. Heinrichs and published by IRRI in 1994.

In the 1990s, a similar collection program was begun to establish a rice insect and natural enemy collection at WARDA (West African Rice Development Association), now AfricaRice. Specimens of major insect pests and natural enemies found in West African rice were identified by Dr Barrion, who then created an illustrated, dichotomous identification key which was published in the book, Rice Feeding Insects and Selected Natural Enemies in West Africa, authored by E. A. Heinrichs and Alberto Barrion (2002).

Since the printed versions of both books have been out-of-print for several years, a recent upgrade of the Lucid software program https://www.lucidcentral.org provided the possibility of creating interactive, digital versions of both keys. Initially developed for creating matrix identification keys, the Lucid builder now enables paper-based dichotomous keys to be converted and “published” as online, interactive pathway keys. Courtesy of IAPPS, the IRRI and West African keys are now freely available online. You can access them here. Please note that we will soon add 450 photos of rice insect pests and their natural enemies to the Taxonomy of Rice Insect Pests and their Arthropod Parasites and Predators key. For further information, please email support@plantprotection.org

Prof. Geoff Norton

IAPPS President

E-mail: geoffn86@gmail.com

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Mites enlisted to battle weeds

  • By Katie Klingsporn WyoFile.com
  • Oct 6, 2022
  •  0
Hoary cress
Researchers are exploring using mites to combat the spread of whitetop, or hoary cress, an invasive plant that has colonized much of the West.U.S. DEPARTMENT OF AGRICULTURE

The noxious invasive weed whitetop, which has colonized vast tracts of the West, has long confounded landowners and resource managers. Also known as hoary cress, the plant proliferates quickly, has no natural North American predators and is reportedly toxic to cattle in large quantities.

An unlikely warrior has emerged in the whitetop battle: a microscopic mite from Europe that researchers believe can stunt the weed’s growth. This summer, land managers released the mite in Wyoming for the first time.

“We’re really excited about having the mites,” said Dr. Tim Collier, a University of Wyoming associate professor who specializes in biological control of rangeland weeds. “Whitetop is a huge problem in Wyoming.”

Technicians spread mite-infested “galls” — plant deformities caused by feeding mites — on a 3.5-acre piece of state-owned property in Fremont County in May. The hope is that the mites in the galls will spread to live plants and create new galls, which impede growth.

Dr. Jeffrey Littlefield, a research scientist at Montana State University in Bozeman, is a major player in the whitetop mite effort, a collaboration many years in the making that spans the globe.

The plant-stunting gall mite in question, Aceria drabae, hails from northern Greece.

“It’s been known for a number of years and was thought to be a potential bio control agent for whitetop,” Littlefield said.

A biological-control laboratory began transporting the tiny creature to a containment facility at MSU in the mid-’90s, Littlefield said. Over the years of transfer, testing and monitoring, researchers found positive results. The mites produce different galls that prevent the plants from going to seed, Littlefield said. Galls also spread to secondary stems and forced their host plants to divert energy that would otherwise be used to proliferate.

“They can really stunt the plant,” he said.

Littlefield and his team had to secure U.S. Department of Agriculture regulatory approval. The process for approving biological control agents — natural enemies such as parasites, predators or pathogens — is painstaking and comprehensive.

“And that took probably another good six years or so,” Littlefield said.

But that approval gave Littlefield and his collaborators the green light to release the mites on wild whitetop plants, which they first did in Montana in 2019.

The first year they put mites in one Montana site, Littlefield said, they counted 10 gall-infected stems.

“This past year we’ve had well over 6,000 stems,” he said. “We’re finding not only the number of infested stems has increased, but the gall intensity has increased.”

The hope is to slowly grow the program in order to facilitate releases in more of the West and see a slowing or reversal in the weed’s colonizing patterns.

When the mites became available for release, the Wyoming Weed and Pest Control Council wanted in on it. Whitetop has, after all, affected every county in the state, Larry Smith, president of the Wyoming Weed and Pest Council, said in a release.

There are plenty of introduced plants that don’t cause ecological disorder, said Fremont County Weed and Pest District Supervisor Aaron Foster, who chairs the Wyoming Biological Control Steering Committee.

“But some have the advantage of being competitive and can cause havoc,” he said. “And whitetop is one of those.”

Whitetop “has the ability to use that root system to crowd out the surrounding vegetation,” Foster said. “And it grows and it forms these dense monoculture patches. And they just get bigger and bigger and kind of expand, and start pushing out the desirable grasses, the other forbs that are in there that we like, and pretty quick, the dominant plant is whitetop.”

That’s not good for biodiversity, wildlife or agriculture, he said.

The site near Dubois was selected for a few reasons, Foster said. Fremont County has been a longtime and significant contributor to biological control, research and development in Wyoming, he said, and county weed and pest officials already had sites identified and prepared there.

Now that the mites have been released, the next step is to wait, monitor their effect and evaluate whether to distribute them more widely, Foster said.

The project will take years and isn’t expected to eradicate whitetop in Wyoming. But the hope is that it can slow the spread and save money by preventing other, more expensive measures.

Read Full Post »

Scientific Reports volume 12, Article number: 15706 (2022) 

Abstract

Beauveria bassiana and Metarhizium anisopliae are two of the most important and widely used entomopathogenic fungi (EPFs) to control insect pests. Recent studies have revealed their function in promoting plant growth after artificial inoculation. To better assess fungal colonization and growth-promoting effects of B. bassiana and M. anisopliae on crops, maize Zea mays seedlings were treated separately with 13 B. bassiana and 73 M. anisopliae as rhizosphere fungi in a hydroponic cultural system. Plant growth indexes, including plant height, root length, fresh weight, etc., were traced recorded for 35 days to prove the growth promoting efficiency of the EPFs inoculation. Fungal recovery rate (FRR) verified that both B. bassiana and M. anisopliae could endophytically colonize in maize tissues. The recovery rates of B. bassiana in stems and leaves were 100% on the 7th day, but dropped to 11.1% in the stems and 22.2% in the leaves on the 28th day. Meanwhile, B. bassiana was not detected in the roots until the 28th day, reaching a recovery rate of 33.3%. M. anisopliae strains were isolated from the plant roots, stems and leaves throughout the tracing period with high recovery rates. The systematical colonization of B. bassiana and M. anisopliae in different tissues were further corroborated by PCR amplification of fungus-specified DNA band, which showed a higher detection sensitivity of 100% positive reaction. Fungal density comparing to the initial value in the hydroponic solution, dropped to be well below 1% on the 21st day. Thus, the two selected entomopathogenic fungal strains successfully established endophytic colonization rather than rhizospheric colonization in maize, and significantly promoted its growth in a hydroponic cultural system. Entomopathogenic fungi have great application potential in eco-agricultural fields including biopesticides and biofertilizers.

Read on: https://www.nature.com/articles/s41598-022-19899-7


Wednesday, 21 September 2022 00:51:45

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UAF VC Urges Scientists To Discover New Biological Control For Parthenium

 Sumaira FH  Published September 09, 2022 | 07:48 PM

UAF VC urges scientists to discover new biological control for Parthenium

University of Agriculture Faisalabad (UAF) Vice Chancellor Prof Dr Iqrar Ahmad Khan has urged agricultural scientists to discover new biological control for Parthenium as it is spreading at an alarming rate across the country

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FAISALABAD, (UrduPoint / Pakistan Point News – 9th Sep, 2022 ) :University of Agriculture Faisalabad (UAF) Vice Chancellor Prof Dr Iqrar Ahmad Khan has urged agricultural scientists to discover new biological control for Parthenium as it is spreading at an alarming rate across the country.

He was addressing an international seminar on “Biological Control of Parthenium hysterophorus in Pakistan using stem boring weevil (Listronotus setosipennis)”, organised by the university in collaboration with the CABI Regional Bioscience Centre Pakistan.

He said that Parthenium was spreading rapidly both in rural and urban landscapes in the country after crossing continents. It was highly-invasive due to its prolific seed production, flower production within four weeks of germination, tolerance to varying climatic conditions, and the production of allelochemicals that affect the growth of nearby plants.

He said that agri scientists were duty bound accelerate their efforts for control Parthenium in addition to creating awareness among the farming community about destructive effects of this weed so that it could be controlled at maximum extent.

Dr. Philip Weyl, Weed Biocontrol Specialist from CABI Switzerland during his address said that Listronotus was a natural enemy of Parthenium, from the weed’s native range of Central America. Listronotus was a nocturnal weevil that layed its eggs primarily in the flowers of Parthenium where newly hatched larvae tunnel into the stem and continue to feed, eventually exiting at the base of the stem to pupate in the soil. Several larvae feeding in the stem can kill Parthenium rosettes and mature plants.

Pro-Vice Chancellor UAF Prof Dr Anas Sarwar Qureshi also addressed the seminar and called for innovative approaches to address the issues of the agricultural sector.

He said that excessive usage of chemicals on crops was creating health and environmental hazards. He said that adoption of latest scientific trends was need of the hour to cope with agricultural challenges at national level because this sector was directly linked to poverty alleviation.

Chairman Entomology UAF Prof Dr Sohail Ahmad highlighted the importance of research needed around the biocontrol of parthenium and other invasive weeds.

He said that the country faced the catastrophe due to heavy floods in which we had lost vast range of agriculture. The university had also mapped out a comprehensive plan to rehabilitate this sector in flood hit areas, he added.

Abdul Rehman from CABI said that keeping in view the destructive impacts of Parthenium weed, CABI initiated a biological control programme in Pakistan in 2017. For this purpose, CABI’s established a new quarantine laboratory at its Rawalpindi centre in Pakistan to enhance its capabilities to manage Parthenium weed.

The new quarantine facility allowed scientists to investigate a range of biological control options including the stem boring weevil Listronotus setosipennis.

Dr. Ijaz Ashraf from UAF shared updates on an awareness campaign for control of Parthenium hysterophorus in Pakistan and said that university students were on front foot to sensitize stakeholders and communities on negative impacts of Parthenium.

He vowed that such awareness-raising interventions around invasive species management and other agricultural challenges would be continued in close collaboration with CABI.

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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)

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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

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