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Spotted lanternfly, an invasive threat to fruit crops and many trees, reveals a potential weakness
Scientists have discovered that the spotted lanternfly, an invasive threat to fruit crops and many trees, may have an Achilles heel – an attraction to vibration.
A native of China, the insect was discovered in Pennsylvania in 2014 and has since spread to 13 other states. Though beautiful as an adult, the insect is a voracious eater that feeds on woody and ornamental trees as well as a wide variety of crops and plants.
According to Richard Mankin, an entomologist with the Agricultural Research Service’s Center for Medical, Agricultural, and Veterinary Entomology in Gainesville, FL, spotted lanternfly has the potential to be an agroeconomic nightmare. Left unchecked, he said, Pennsylvania alone could lose hundreds of millions of dollars and thousands of jobs.
Fortunately, Mankin and two research colleagues (Barukh Rohde, postdoctoral researcher at the University of New Hampshire, and Miriam Cooperband, entomologist with USDA’s Animal and Plant Health Inspection Service) found a way to potentially corral and control the pests. Their research was published in the Journal of Economic Entomology.
“[Spotted lanternfly] can be controlled with pesticide, but spraying grapevines is problematic, so there is a need for other control methods,” Mankin said. “There were rumors that lanternflies are attracted to vibrations of buzzing electrical power lines, so we did a laboratory study of nymph and adult responses to 60-cycle (60Hz) vibrations. The rumor proved to be correct! Both nymphs and adults walked towards the source of [the] vibrations.”
Using vibration to entice the lanternflies to gather is a major step toward improving control methods, including traps. Mankin said that further research will focus on finding ways to disrupt spotted lanternfly mating behavior.
Vibrations may not disrupt all spotted lanternfly mating in vineyards, but there have been some positive results in studies with other similar pests. Mankin said that scientists have recently achieved mating disruption of grapevine pests (leafhoppers and glassy-winged sharpshooters) in Italy and California, respectively, by sending vibrations along grapevine wires. Grapes are commonly grown with their vines hanging from suspended wires.
Mankin has experience with disrupting the mating behavior of invasive pests. He and Rohde previously co-authored papers that explained how vibrations could mimic the “mating calls” of Asian citrus psyllid (ACP) to trap them and disrupt their mating behavior.
Successful development of an integrated pest management program could result in growers using fewer insecticide applications – saving time, energy, and money. It could also help reduce the risk of pesticide exposure to pollinators and other inadvertent impacts on the environment. – by Scott Elliott, ARS Office of Communications
‘Dinosaur’ pesticide law clings to life as SA dithers on poisons reform
Some critics suggest that South Africa remains locked in a chemical culture time warp, where pesticides continue to be cast in a ‘heroic’ role, discouraging less toxic products and non- chemical weed and insect control alternatives. (Photo: schmidtlaw.com / Wikipedia)
There are more than 3,000 registered pesticides sprayed across South Africa, several of which are banned or severely restricted in Europe and other countries because of human and environmental safety risks. Despite the government’s promises to reform outdated pesticide policies, public health experts say there has been little movement.
It has been 77 years since the first law to regulate chemical pesticide safety was passed in this country. This was back in the days of King George VI, Jan Smuts and the Union of South Africa.
Since then, South Africa has become the largest consumer of pesticides in Africa, accounting for roughly a third of all farm chemicals used on the continent.
Here is one example: The current Act still specifies a fine of “£500” for government officials who unlawfully disclose any confidential business affairs of the agricultural industry.
Juxtaposed against this £500 fine (roughly R12,000 at today’s exchange rate), the current version of the Act only permits a maximum penalty of R1,000 for violations of the country’s main pesticide control law.
The Adjustment of Fines Act of 1991 does provide for a retrospective stiffening of fines using a ratio determined by periodic government notices, so the R1,000 fine may now be closer to R80,000.
Nevertheless, the £500 fine crafted to protect industry secrecy and the derisory scale of maximum fines for pesticide law violations, remain on South Africa’s statute book – stark evidence of an outdated legal legacy and powerful influence of vested industry interests in an era where modern agricultural systems seemingly remain addicted to chemical poisons to sustain the growth of food or cash crops.
As evidence continues to pile up about the serious harm to humanity and the environment from the increasing volumes of pesticides sprayed across the world, the government has failed to implement a series of reforms recommended by its own policy document – the “new” Pesticide Management Policy published 14 years ago.
There has also been a two-decade delay in passing domestic laws to enforce the Rotterdam Convention, an international treaty ratified by South Africa in 2002 to limit the global movement of banned or severely restricted pesticides.
It was only in May 2021 that Forestry, Fisheries and the Environment Minister Barbara Creecy gazetted new Rotterdam domestic regulations, which introduced new penalties of up to R5-million for pesticide manufacturers and distributors who either import or export hazardous chemical and pesticide formulations in contravention of the international treaty obligations.
But in November 2021, Creecy changed her mind and suspended the implementation of the new regulations for 12 months. Following a further series of delays, she has since repealed the original regulations and published a new version that is only due to take effect in mid-June 2024 (barring further delays).
Creecy’s department has rejected claims of any improper influence from the agrochemicals industry in delaying the new Rotterdam domestic regulations and attributed some of the delays to “substantive” objections that included the apparent omission of CAS chemical registry numbers from the published regulations.
Croplife SA, an industry body whose members include agrochemical companies such as BASF, Bayer, Corteva, UPL and Syngenta, says it is also “not of the opinion that Minister Creecy is intentionally delaying the implementation, but rather ensuring that the regulations are free of errors, which is of paramount importance”.
Nevertheless, documents on its website suggest that it is pushing back against international pressure to phase out at least 29 chemical substances linked to greater risks of cancer, genetic damage and other harms to people, animals and the environment.
At a series of workshops last May for farmers, government officials and journalists, senior Croplife leaders said there was a need to “bring the African narrative more firmly into relevant policy discussions” around the European Green Deal – a recent initiative to protect human health and restore damaged ecosystems. This includes plans to reduce use of the most hazardous pesticide types by 50% by 2030.
According to European Health and Food Safety commissioner Stella Kyriakides: “It is time to change course on how we use pesticides in the EU … We need to reduce the use of chemical pesticides to protect our soil, air and food, and ultimately the health of our citizens. For the first time, we will ban the use of pesticides in public gardens and playgrounds, ensuring that we are all far less exposed in our daily lives.”
According to a European Commission “Farm to Fork” policy document, EU scientific advisers have concluded that the current food system in Europe is no longer sustainable.
“This does not mean that pesticides are not needed. There are cases where satisfactory pest control can only be achieved in commercial food production through the use of chemical pesticides. However, chemical pesticides should be used only as a last resort.”
The commission also cites a World Health Organisation report which estimates that there are about 1 million cases of unintentional pesticide poisonings every year, leading to approximately 20,000 deaths. A more recent review estimated about 385 million cases of unintentional acute pesticide poisonings occur annually worldwide, including around 11,000 fatalities.
Chemically active pesticides were found in up to 30% of European rivers and lakes, and regulators are worried about the increasing impact on the pollination of food crops at a time when up to 10% of bee and butterfly species in Europe are on the verge of extinction, and 33% are in decline.
Croplife SA has made it clear that it will push back against so-called EU “mirror clauses” that would prohibit South African farmers from using certain pesticides if they export products to Europe – even if these pesticides are legally registered in South Africa.
Global pesticide distributors have frequently been accused of double standards, by peddling in African and other developing countries agrochemical products that have been either banned or severely restricted in Europe because of human safety and environmental concerns.
Croplife SA, however, responds that enforcing European policies on local farmers is a “threat to the government’s right to make decisions for its people based on the local conditions and requirements”.
“Products cannot just be ‘dumped’ in South Africa as some activists claim; they must go through a rigorous registration process that considers the local production conditions and environmental impact.”
Croplife insists that the current regulatory framework in South Africa remains “robust” and “very strong” even though the original Act dates back to 1947.
But that is not how several other interest groups view the 1947 pesticides control law.
Prof Leslie London, a senior University of Cape Town (UCT) public health research expert on pesticide hazards, chemical neurotoxicity and farm worker safety, says: “I think what Croplife really mean is that South Africa has a regulatory environment very favourable to industry. It would be laughable to consider it ‘strong’ unless you mean strongly biased to industry.”
He argues that at a time when many developed countries are adopting policies that promote pesticide reduction, South African policy remains largely out of step with international concerns
The primary 1947 law to control pesticides is regulated by the national Agriculture department, via the Registrar for Pesticides. But because this department is also mandated to promote agricultural expansion, Prof London believes this creates a clear conflict of interest concerning independent pesticide regulation.
He also suggests that the national department has done little to promote the Integrated Pest Management philosophy, which encourages farmers to reduce their reliance on chemical pesticides.
In a journal critique published in 2000, Prof London and fellow UCT public health researcher Prof Hanna-Andrea Rother argued that pesticide regulation fines were “grossly inconsistent with the gravity of offences” while inspectorates were hugely understaffed.
Nearly a quarter of a century later, those derisory fines remain unchanged, and Prof London says that though there has been some “tinkering”, the current pesticide regulation model remains more or less unchanged.
He suggests that South Africa is still locked in a “pesticide culture” that sees intensive chemical control of farm pests as the norm, rather than as a last resort.
“This consent is manufactured by many forces, economic and ideological, and can be seen in the nature of pesticide advertising, and discourses surrounding the heroic role pesticides can play in economic development in the new South Africa,” according to the two researchers..
They noted that 100 to 200 cases of pesticide poisoning were reported every year to the Department of Health (mostly farmworkers or rural residents), while other surveys suggested that the true rates were anything between five and 20 times higher.
To resolve conflicts of interest and the fragmentation of regulation, the two researchers call for a new independent regulatory body to act as guardian of the public interest, separated from the economic motive to promote agricultural production.
Similar proposals for reform have also been made by Advocate Susannah Cowen SC on behalf of the Real Thing natural health products company.
In a legal opinion submitted to the SA Law Reform Commission in 2021, Cowen draws attention to the apparent double standards of South Africa importing hazardous chemicals from countries where these same chemicals are banned.
Cowen (now a judge of the labour court) said: “No amount of tinkering or amendment can render the 1947 Act fit for purpose in a democratic South Africa. It is wholly outdated.”
At the time of the submission, she said there was also no requirement for periodic safety reviews of currently registered pesticides or re-evaluations of old chemicals.
“The State made important reform commitments in the Pesticide Management Policy for South Africa in 2010. However, these commitments have not been realised and very little has been done since 2010 when these commitments were made.” DM
The Department of Agriculture Land Reform and Rural Development responds:
“The (1947) Act may only be amended once its relevance, applicability, suitability and responsiveness is under question, and so far the Act is still potently applicable
“Over the years, the department has phased out or banned many pesticides of concern under the same Act. We will continue to review the pesticides on concern, and where applicable we will phase out or ban them.
“There have been several regulations under the Act which the Minister has made in order to respond to some substantive recommendations which were part of the 2010 Pesticide Management Policy. The regulations relating to agricultural remedy, as published in Government Notice No. R. 3812 of August 2023, are aimed at addressing the recommendations of the 2010 Pesticide Management Policy.
“The latest regulations were published on 25 August 2023, which, among others, are aimed as phasing active ingredients and their pesticides formulations that potentially may cause cancer, genetic mutation and damages to fertility of a human being (including negatively affecting the unborn child); implementation of the Globally Harmonised System of classification and labelling of chemicals; restrictions of sale and use of certain hazardous pesticides, disclosure by agrochemical companies of amounts the of pesticides sold and other measures.
The Department of Forestry, Fisheries and the Environment (DFFE)responds:
A spokesperson said the department “categorically rejects [suggestions] that it has taken 20 years to implement the Rotterdam Convention. DFFE has been facilitating the exchange of information for more than 17 years (as far back as 2006).”
Commenting on the reasons for a recent series of notices to suspend, repeal or amend the convention’s domestic regulations, the department said it was compelled by law to undertake public participation when developing regulations.
“There were submissions on substantive matters that were submitted after the finalisation of the (Rotterdam) PIC Regulations that influenced the department to reconsider and opt for the suspension of the PIC Regulations. The department rejects claims or any perceptions of improper influence and maintains that the Batho Pele principles of consultation, courtesy and responsiveness remained at the centre of the department’s decision to suspend the regulations while the specific amendments were being attended to.”
Croplife South Africa responds:
Croplife confirmed that it made submissions to Creecy’s department to correct certain errors in the registration status of chemicals listed in the Rotterdam regulations.
Responding to criticism about the “double standards” of selling pesticides in Africa when they were banned in Europe or other developed nations, Croplife said: “It is quite normal for some countries to have plant protection solutions authorised for local use when they are not registered in other countries. Local climatic conditions, pest occurrence, crops and regulatory procedures differ from country to country. Therefore, products can be registered in one country and not in another.”
The industry group acknowledged that current laws only provide for a R1,000 fine for contraventions of the 1947 Act, but noted the government could impose much more severe sanctions – such as a banning or cancelling sales of certain chemical products.
There had also been “several” amendments since 1947, while specific product registrations were reviewed every three years.
New regulations published in August 2023 also contained a clause that a pesticide registration holder was obliged to inform the registrar of any new data pertaining to environmental or human toxicology
“Act No 36 and its supporting regulations provide a robust regulatory framework for plant protection solutions in South Africa. As with any government department, the Act No 36 of 1947 regulatory team could be more efficient if central Treasury provided greater funding. In this way, the approval and registration process could bring newer technologies to South African farmers more quickly.
“Government still has the overall right to approve or not approve a product. But our opinion remains that the system for product registrations can be more efficient, bringing newer technologies to farmers quicker, by better utilising the fees already paid to government for product registrations”.
Note the 100 Euro discount for active IAPPS members on registration fees for the International Plant Protection Congress., 1-5 July 2024, Athens, Greece. For more information on the IPPC and to become an IAPPS member ($30 for students, $35 for developing countries and $50 for industrial countries) go to the IAPPS website http://www.plantprotection.org and click on the Join IAPPS icon. If you have a problem joining please contact me at eheinrichs2@unl.edu
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Chemotherapy, thermotherapy and cryotherapy: New Zealand scientists unveil innovative methods to eradicate PVS, PVA, and PVM viruses
on
A research study conducted by scientists in New Zealand has developed a reliable and efficient method for eradicating Potato Virus S (PVS), Potato Virus A (PVA), and Potato Virus M (PVM) from infected in vitro-grown potato shoots. These viruses are known to significantly impact the yield and quality of potatoes, and current eradication methods have proven to be challenging.
The research study was published in the journalFrontiers in Plant Science here, titled “Eradication of Potato Virus S, Potato Virus A, and Potato Virus M From Infected in vitro-Grown Potato Shoots Using in vitro Therapies“.
Chemotherapy and cryotherapy
The researchers focused on in vitro-based techniques, which have been used in the past to eradicate viruses in potato plants. They found that combining two or more of these techniques can lead to more effective virus eradication than using a single technique.
The study identified specific procedures that resulted in high frequencies of virus-free potato plants. These procedures included the use of combined chemotherapy and cryotherapy, as well as the use of chemotherapy in combination with thermotherapy followed by cryotherapy. The researchers found that these methods were more efficient at producing virus-free potato plants than current reported methods.
In the research paper, the research team wrote: “We found that the combination of chemotherapy and cryotherapy (C + Cryo), or chemotherapy treatment prior to combining chemotherapy treatment with thermotherapy followed by cryotherapy {[C + (C + T)] + Cryo} resulted in high efficiency of PVS, PVA, and PVM eradication; 70–100% across the three potato cultivars tested.”
The development of efficient virus eradication methods is crucial for ensuring the production and supply of high-healthy planting material for the potato industry.
The researchers concluded: “Our study identified procedures that resulted in high frequencies of eradication of PVS, PVA, and PVM viruses from infected potato cultivars.
“The consistency of the results across three cultivars with single or mixed infections suggests that these procedures have great potential to assist the production and supply of virus-free planting materials for the potato industry.
“Furthermore, it might also be a valuable tool to support the global exchange of germplasm underpinning breeding activities.”
Addressing plant biosecurity of New Zealand
In New Zealand, more than 200 plant viruses and many of their invertebrate vectors have invaded the country in the last two centuries. These invaders are associated with introduced agricultural activities, and the number of plant viruses recorded in New Zealand has been steadily increasing.
Potato crops in New Zealand have also been affected by virus infections, leading to yield depression. PVS, which is a mechanically transmitted virus, has been found to be at a high incidence in these crops, and international research has shown that it can cause significant yield losses.
The development of this new virus eradication method can help address these challenges and contribute to the ongoing plant biosecurity of New Zealand. The researchers’ findings have the potential to benefit the potato industry not only in New Zealand but also in other countries where these viruses are a significant concern.
Note:This news story is a summarized interpretation of the research paper from Frontiers in Plant Science:https://www.frontiersin.org/articles/10.3389/fpls.2022.878733/full. The researchers involved in the study are from the New Zealand Institute for Plant and Food Research Limited, Food Industry Science Centre, Palmerston North, New Zealand and the Plant Health and Environment Laboratory, Ministry for Primary Industries, Auckland, New Zealand.
Source:Front. Plant Sci., 19 May 2022,Sec. Plant Biotechnology, Volume 13 – 2022 |https://doi.org/10.3389/fpls.2022.878733Research team:Jean Carlos Bettoni, Liya Mathew, Ranjith Pathirana, Claudia Wiedow, Donald A. Hunter, Andrew McLachlan, Subuhi Khan, Joe Tang, and Jayanthi NadarajanContact and additional information:Jean Carlos Bettonijcbettoni@gmail.comPhoto:In vitro potato plants. Courtesy Jean Carlos Bettoni
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A new species of the genus Potyvirus infecting potatoes was discovered by scientists working at Science and Advice for Scottish Agriculture (SASA) in Edinburgh. In a recent scientific paper they are proposing the name “Potato yellow blotch virus” (PYBV) to identify the virus in future. It was discovered in a potato breeding line. Plants…
A common potato virus and a fungus-like pathogen can team up to cause even more damage in potatoes. Washington State University scientists found that potato virus S, or PVS, breaks down late blight resistance in potatoes. The discovery will mean that potato breeders will have to take the virus under…
Western juniper is a native shrub that grows to tree size, thriving in the Great Basin, which spans most of Nevada, much of Oregon and Utah, and portions of California, Idaho, Wyoming, and Mexico.
In recent decades, hardy junipers have been dominating vast areas, crowding out other plant species. Large populations of juniper can negatively impact sage grouse habitat and diminish sustainability of grazing land.
The goal of many rangeland managers has been to restore ecologic balance. Juniper removal on the Modoc National Forest in California, for instance, is part of an effort to improve sage grouse habitat, but there are many other ecological benefits resulting from removing the encroaching juniper stands.
These trees pull more water from the ground than the surrounding vegetation does, leaving less moisture for the other plants. With loss of understory vegetation in juniper woodlands, there is soil loss and erosion during intense rain storms. They outcompete most other plants; with their efficient root system they consume a lot of water that would have helped the survival of other plants.
Effect on watersheds has been noticed; with increased demand for water by juniper, combined with several years of drought in Northeast California, many springs and streams have dried up.
Removal projects
Kyle Sullivan, District Manager, Soil and Water Conservation District, Grant County, Ore., says there were government projects in earlier years to help ranchers remove juniper; there was funding for mechanical removal—sawing the trees, piling and burning them. “Logging crews brought equipment to take out the trees, with hand-labor follow-up for the smaller trees,” Sullivan said.
Loggers piled the trees, and after they dried out the landowners burned the piles during winter when there was no risk of fire danger.
“Our Soil and Water Conservation District received grants to try to control juniper with herbicide. A dozen years ago we did an experiment, cutting incisions into the trunk with a chain saw, then squirted herbicide into the trunk with a spray bottle. But juniper is so bushy that it is difficult to get to the base of the tree,” he said.
The crew tried different herbicides and different concentrations. It was effective for killing the trees, but the time and labor involved didn’t pencil out, economically. The Forest Service preferred that method, however, because it left the dead trees standing and didn’t tear up the ground or disrupt surrounding vegetation.
A landowner might choose this method, to kill some of the larger trees and keep them from reproducing, but dead trees on the range might be fuel for wildfires.
“If standing trees are limbed high enough, a grass fire might quickly burn through underneath, but many junipers have low branches under the duff which could raise the fire higher off the ground and into the tree itself,” said Sullivan.
Junipers proliferate
“We left a few trees on the landscape to provide shade for livestock and wildlife, but they had to be trees with no berries (seeds). Juniper trees have genders, and some can have both male and female characteristics. If a tree isn’t producing berries it doesn’t spread seeds,” he explained.
“We also learned the importance of maintenance after trees are cut/piled/burned, because the seed source is still there.” The seeds are viable for years, to produce new seedlings. The problem will re-emerge if you don’t keep after it.
“After you cut them down you may get a new flush of young trees in 7 to 10 years, but you can do periodic controlled burning or remove the young ones, or use herbicide and eventually get rid of most of them.”
Junipers are tough and hardy, with high survival rate. If they take over a range or watershed, they can be detrimental. “Research is still ongoing in central Oregon, looking at the effects of hydrology, and how a canopy of juniper can keep snow from coming to the ground. This watershed study is providing new information; we realize what an aggressive root system they have. If there is a high population of junipers, they have a negative effect on the watershed,” he said.
Herbicide pellets can be used for juniper control. Wilburn Ranches in Oregon started using chemical control of juniper invasions on their range pastures a few years ago, with good results. They took photos of trees afterward, showing how it killed them.
Label directions suggest putting one tablet on the ground in the drip zone of the juniper if it is 3 feet tall. For every additional 3 feet, you add another tablet– up to about 10 feet of tree height. The pellets can be applied when moisture is sufficient to dissolve them. The smaller trees tend to die all at once and the larger ones die by degrees until they completely brown and dead.
Cost per tree for this method is lower than using chain saws or heavy equipment, but the herbicide pellets may need to be repeated every 3-4 years to keep juniper contained. This is another option for people who don’t want to mechanically remove and then burn them. Ranchers can hike around and distribute the pellets, or do it from horseback while checking cattle, tossing pellets around the outside edges of the junipers.
Chains and excavators
Sullivan said one method still used in some parts of the West is chaining. An old ship anchor chain (with huge, heavy links) is secured between two big Cat tractors to mow down the trees. The heavy chain pulls on the trees and uproots them.
Another method is to tip the juniper tree over with the boom of an excavator. The machine can then grab it, pick it up and shake the soil off the roots so the trees can be piled easier. It costs more for this method but has the advantage of uprooting the trees without much damage to the surrounding terrain. “A machine can also be used to pile them and clean up the area afterward. This way you get some of the smaller branches that are underneath the soil; they pull up with the tree roots,” he said.
“This is probably one of the more expensive alternatives but leaves a cleaner site. Depending on your goals, budget, and equipment, one method may be more attractive than another.”
In his region many ranchers use chain saws and cut down the larger trees, then go back later to get the little ones—and pile them all up with machines.
“We try to keep abreast of research that keeps evolving on the impacts of these plants, and how to deal with them. Oregon State University has published a number of guidelines with advice on managing western juniper,” Sullivan said.
Do electrocution treatments have a place in weed control?
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Researchers used a tractor attachment called The Weed Zapper™ to electrocute eight types of weeds common in soybean crops, including herbicide-resistant waterhemp. (Stock photo via Ivan Radic, Flickr/Creative Commons)
COLUMBIA, Mo. — Researchers from the University of Missouri recently conducted two field studies to explore the effectiveness of electricity in weed control. They used a tractor attachment called The Weed Zapper™ to electrocute eight types of weeds common in soybean crops, including herbicide-resistant waterhemp.
The first study showed that control was more effective in the later stages of weed growth and was most closely related to plant height and the moisture in the plant at the time of electrocution. Once the weeds had set seed, the treatments reduced viability by 54 to 80 percent across the weed species evaluated. A second study showed electrocution reduced late-season, herbicide-resistant waterhemp plants by 51 to 97 percent.
At some stages of growth, the soybean crops exhibited yield losses of 11 to 26 percent following electrocution treatments – though researchers say those results likely represent a worse-case scenario. In late-season treatments, for example, the clear height differential between waterhemp and the soybean canopy means the electrocution device can treat the weed without sustained contact with the crop.
The net takeaway: When used as part of an integrated control program, electrocution can eliminate many late-season, herbicide-resistant weed escapes in soybean crops and reduce the number and viability of weed seeds that return to the soil seedbank.
Researchers from the University of Missouri recently conducted two field studies to explore the effectiveness of electricity in weed control. They used a tractor attachment called The Weed Zapper to electrocute eight types of weeds common in soybean crops, including herbicide-resistant waterhemp.
The first study showed that control was more effective in the later stages of weed growth and was most closely related to plant height and the moisture in the plant at the time of electrocution. Once the weeds had set seed, the treatments reduced viability by 54 to 80 percent across the weed species evaluated. A second study showed electrocution reduced late-season, herbicide-resistant waterhemp plants by 51 to 97 percent.
At some stages of growth, the soybean crops exhibited yield losses of 11 to 26 percent following electrocution treatments—though researchers say those results likely represent a worse-case scenario. In late-season treatments, for example, the clear height differential between waterhemp and the soybean canopy means the electrocution device can treat the weed without sustained contact with the crop.
The net takeaway: When used as part of an integrated control program, electrocution can eliminate many late-season, herbicide-resistant weed escapes in soybean crops and reduce the number and viability of weed seeds that return to the soil seedbank.
More information: Haylee Schreier et al, The Impact of Electrocution Treatments on Weed Control and Weed Seed Viability in Soybean, Weed Technology (2022). DOI: 10.1017/wet.2022.56
Would micro-ecology be damaged by a plastic film that kills a harmful soil insect?
by Higher Education Press
Chinese chive (Allium tuberosum) is a perennial herbaceous vegetable with medicinal qualities. Unfortunately, Chinese chive crops are severely damaged by the soil insect Bradysia cellarum. B. cellarum are mainly found in the surface soil to a depth of 5 cm. Department of Plant Protection, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences Investigator Youjun Zhang and his team showed that thermal treatment of B. cellarum adults, eggs, larvae, and pupae at 40 °C for 3 hours produced mortalities of 100%, 100%, 100% and 81%, respectively, and the fecundity of B. cellarum significantly decreased with increasing temperature and exposure time, completely inhibiting egg-laying at 37°C for 2 hours. These data suggested that B. cellarum is quite sensitive to elevated temperatures. As long as soil temperature to a depth of 5 cm is increased and remains over 40°C for 4 hours, the mortality rate of B. cellarum will be 100%. Therefore, the team has been studying how to improve soil temperature without destroying the ecological environment.
Youjun Zhang and his team had believed that applying a light blue anti-dropping film of 0.10 or 0.12 mm thickness would be enough to kill B. cellarum under a sufficient intensity of sunlight (e.g., between late April and mid-September in Beijing, China). The method was called soil solarization. However, it was not known whether soil solarization affects soil microbial diversity. If soil solarization can kill B. cellarum and also avoid affecting Chinese chive growth and the soil microbial ecological balance, it will be an environmentally friendly control technology.
In this study, Youjun Zhang and his team show that on the first day after soil solarization, 100% control of B. cellarum was achieved. Growth of Chinese chive was lower in solarized plots than in control plots over the first 10 days after treatment, but 20 days after treatment, plants in the solarized plot had recovered and leaf height and yields were equivalent among the treatments. Moreover, the soil microbial community diversity in the treatment group decreased initially before gradually recovering. In addition, the abundance of beneficial microorganisms in the genus Bacillus and in the phyla Proteobacteria, Chloroflexi and Firmicutes increased significantly.
Soil solarization is a promising strategy to control B. cellarum. It is simple to implement, pesticide-free and non-destructive to soil microbial diversity, and it may also promote the abundance of beneficial microorganisms. Soil solarization is practical and worth promoting as a new method of control of B. cellarum infestations in Chinese chive-growing regions.
More information: Effect of Solarization to Kill Bradysia Cellarum on Chinese Chive Growth and Soil Microbial Diversity, Frontiers of Agricultural Science and Engineering (2021). DOI: 10.15302/J-FASE-2021402