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Florida researchers get funding to help tomato growers and breeders fight bacterial spot

“It’s really hard to manage this disease”

Florida scientists received a grant to investigate strategies to control bacterial spot in tomatoes. The disease creates major challenges for commercial production throughout Florida and across the United States.

Bacterial spot first affects the leaves of the plant, developing black spots the size of shotgun pellets. Then the leaves blacken and ultimately drop. The fruit is still edible but can develop little blisters, making them practically unmarketable.

The plant pathogen that causes bacterial spot in the southeast is called Xanthomonas euvesicatoria pv. perforans. The “pv.” abbreviation stands for “pathovar” and is used to designate a specialized group of bacteria with the same or similar characteristics within a species.


Courtesy UF/IFAS

Gary Vallad, professor of Plant Pathology at the University of Florida’s Gulf Coast Research and Education Center in Balm, said the pathogen has been problematic for the tomato industry since the early 1990s because it has developed a tolerance to copper-based pesticides, typically used for managing bacterial diseases.

“This pretty much limited the usefulness of copper, and without using other types of antibiotics, which we don’t use in the field, it’s really hard to manage this disease,” he said.

Hard to peel, hard to process
Other variations of the bacteria can also cause really large lesions, “which makes the tomato hard to peel mechanically, so processors don’t like that either, so that becomes a loss for them as well,” Vallad said.

That means the tomatoes can’t be canned or used for products like ketchup. There’s much that is unknown about the pathogen, Vallad said.

“A lot of that has been limited by our ability to differentiate strains of the bacterium. So, there’s been a lot of recent advances in our tools to be able to discriminate between different species based on sequencing of the pathogen’s genome,” he said.

“We can’t just look at the bacteria and say, ‘this is Bacteria A, and this is Bacteria B.’ This is what we kind of refer to as almost like cryptic species … they all look the same, so we have to actually … use molecular tools to really be able to differentiate between different strains.”

Vallad said he’s now interested in breeding a tomato with more resistance to the bacteria.

“We need to have a better understanding of the composition of that population, so breeders can actually identify resistance within a tomato that will actually cover all the strains or most of the strains,” he said. They also want to trace the movement of the strains throughout tomato production.

“We know different areas we can always find the bacteria, but we don’t know if the bacteria is exactly the same at every point,” Vallad said. “So, we’re trying to understand, to really look at the movement of the of these strains throughout the production system so we can find where in the production system is the best place to manage them.”

Xanthomonas euvesicatoria pv. perforans is also prominent bacterial species threatening tomatoes in the Midwest, Great Lakes, Northeast, and in neighboring areas of Canada, along with Xanthomonas hortorum pv. gardneri.

Thanks to $5.8 million from the National Institute of Food and Agriculture, Vallad and his team of scientists across Florida and the U.S. will spend the next four years identifying and understanding the different strains of the pathogen to help tomato growers and breeders manage the bacterial spot disease more successfully.

“These types of advancements are not just in this particular disease. It’s really impacting a number of plant diseases, animal diseases and human diseases,” Vallad said. “The exact same technology that was used to understand the COVID virus, we’re using to understand this particular pathogen on tomato.

“And this group of pathogens impact a number of other crops, not just tomato … Other Xanthomonas affect almost every crop we grow in the world. There is a Xanthomonas that can cause disease on it. So, understanding this group of organisms, tomato can be used as a model for other researchers for other crops as well.”

For more information:
WUSF News
www.wusf.usf.edu 

Publication date: Fri 4 Nov 2022

Bold jumping spiders

Home | Arts + Culture | Wild Things

Bold jumping spiders will attack larger prey, leaping four times the length of their body

By Jeanine Farley

Saturday, November 5, 2022

Bold jumping spiders are very hairy, with four pairs of eyes. (Photo: Claire O’Neill/Earthwise Aware)

What’s small and hairy and jumps? Perhaps a bold jumping spider, which is one of the most common jumping spiders in North America. These spiders are not dangerous. If you pick one up, for example, it probably will not bite you (but I make no guarantees). If it did bite you, its fangs would probably not penetrate your skin, and if they did pierce the skin, the venom is too weak to cause harm to humans.

The legs of adult bold jumping spiders sport bands of silver hairs, while juveniles have orange or yellow bands. (Photo: Joe MacIndewar/Earthwise Aware)

These spiders (Phidippus audax) are so named because they are fearless and quick to jump on and attack prey that is larger than they are. “Audax” is from the word audacity, meaning “bold” or “daring.” They prey on many insect pests, including mosquitoes. These little critters (one-quarter to three-quarters of an inch) are also able to jump four times their body length.

Probably the most prominent feature of jumping spiders is that they are hairy. Bold jumping spiders are mostly black with a white or reddish triangle and two small dots on their abdomens. Their fangs or mouthparts(chelicerae) are metallic green – a feature sometimes more noticeable on males.

Bold jumping spiders display metallic green fangs or mouthparts that are more pronounced in males. (Photo: Claire O’Neill/Earthwise Aware)

Bold jumping spiders hunt during the day. They sneak up on their prey and pounce, injecting venom that paralyzes their prey. We all know that spiders have eight legs; most spiders, including bold jumping spiders, also have eight eyes. This gives them the sharp vision they need to stalk their prey. In fact, jumping spiders – with eyes in a semicircle around the head, each pair of a different size, with the two in the middle being the largest – have the sharpest vision of all spiders. These two largest eyes give the spider good three-dimensional vision, while the other six eyes provide it with 360-degree views of the surroundings.

Bold jumping spiders are the state spider of New Hampshire, but this spider hunts on Prospect Hill in Somerville. (Photo: Claire O’Neill/Earthwise Aware)

Jumping spiders do not spin webs, but before they jump they attach a strand of silk to the surface they are on. If they jump and miss, they are still tethered to the tree or wall from which they jumped. They also use silk to make a cocoonlike resting place (in dried leaves, under rocks, in tree crevices) where they, eat their prey and protect their eggs.

Birds and dragonflies and small mammals prey on bold jumping spiders. If you have ever seen a bird digging an insect out from a tree fissure, you might have witnessed the demise of a bold jumping spider.

Juvenile bold jumping spiders have an orange-tinted triangle and two small dots on their abdomens. These spots become whiter in adults. (Photo: Joe MacIndewar/Earthwise Aware)

Similar to snakes, spiders shed their outer skin as they grow larger. Bold jumping spiders stop the process in the fall as adolescents and overwinter as sub-adults. In the spring, they finish growing to adulthood. They breed from spring to early summer; the female bold jumping spider produces an egg sac containing 30 to 170 eggs. (With six to eight egg sacs per season, that’s a lot of baby spiders.) She guards the egg sac until the baby spiders hatch; then the babies are on their own.

The spiders prefer flat vertical surfaces where they can see and easily pounce on their prey. Therefore, these spiders like broad-leaved plants such as milkweed, for example, or tree trunks, fenceposts and house siding. If you should happen to see a bold jumping spider inside your cellar or on your lawn furniture, let it be; it is shy and harmless, will most likely run or jump away if it detects you, and can help control insect pests.

Bold jumping spiders like this one in the Cambridge Highlands can detect vibrations from a great distance and jump four times its body length. (Photo: Claire O’Neill/Earthwise Aware)

whitespace

A bald eagle is spotted in Ball Square, Somerville, in mid-October. Its unusual left eye identifies it as KZ, the male of the nesting pair on the Mystic Lakes. (Photo: Jeanine Farley)

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Have you taken photos of our urban wild things? Send your images to Cambridge Day, and we may use them as part of a future feature. Include the photographer’s name and the general location where the photo was taken.


Jeanine Farley is an educational writer who has lived in the Boston area for more than 30 years. She enjoys taking photos of our urban wild things.


 

November 11, 2022

 

‘Wonder weevils’ released in Yorkshire waterways in fight against invasive floating pennywort

Biopesticides and Biocontrols 

‘Wonder weevils’ released in Yorkshire waterways in fight against invasive floating pennywort

   Delhi Bureau  0 Comments CABI  3 min read

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16 November 2022, America: Specialist weevils from South America have been introduced to two sites in West Yorkshire to control an invasive non-native plant choking waterways.

The floating pennywort weevils have been introduced on the Aire and Calder Navigation and one of the tributaries of the River Holme, in a collaboration by CABI, Yorkshire Water, Leeds City Council, River Holme Connections and a private landowner.

As reported by PA Media and syndicated to over 114 UK news outlets including the London Evening Standard, Belfast Telegraph, Glasgow Times and Oxford Mail, the bugs, which have evolved to only feed and develop on floating pennywort (Hydrocotyle ranunculoides), will target the plant where it is clogging up the waterways.

Floating pennywort is native to Central and South America, and was brought to the UK in the 1980s as an ornamental pond plant, but escaped into natural habitats where it can grow up to 20cm a day.

Back in May, CABI revealed how its research has been the forefront of a world-first after the weevil – a more than 10 years under study – started to be released in England to sustainably fight the floating pennywort.

The release was timed to coincide with Invasive Species Week 2022. Invasive Species Week is an annual national event to raise awareness of the impacts of invasive non-native species, the simple things that everyone can do to prevent their spread, and some of the fantastic work taking place across the UK, Ireland, Jersey, Guernsey and Isle of Man to protect the environment and reduce their impacts.

Since 2011, CABI, with Defra funding, has been investigating the potential use of a biocontrol agent for floating pennywort which has the ability to grow up to 20 centimetres each day. It forms dense rafts over rivers and harms native plant, fish and invertebrate species, through competition and cutting oxygen levels in water.

Floating pennywort – an ornamental pond plant originating from North America – also impedes navigation routes, disrupts recreational activities like fishing and canoeing and exacerbates flood risk.

Dr Steph Bradbeer, invasive species and biosecurity adviser at Yorkshire Water, said: “Invasive non-native species pose a very real risk to Yorkshire’s environment and wildlife.

“They can also impact on our ability to treat and distribute water to homes and return wastewater safely to the environment.

“Floating pennywort, if unchecked, can cause significant problems in slow-flowing watercourses and impact drainage systems.

“We hope the release of these specialist weevils will provide a way of tackling it without the need for mechanical or chemical intervention.”

Djami Djeddour, senior project scientist at CABI, said: “These weevil releases are the culmination of over a decade of collaboration with South American scientists and comprehensive safety and efficacy testing in our quarantine facilities, so it is thrilling to finally get them out into the wild.”

The weevils will be closely monitored, with their impact on the spread of floating pennywort carefully monitored.

It is hoped they will help improve local wildlife and water quality, reduce the plant’s impact on flood defences and control the spread of floating pennywort in rivers.

Related Posts:

DLNR NEWS RELEASE – NEW VIDEO HIGHLIGHTS HOW BIOCONTROL SAVED NATIVE WILIWILI TREES

Posted on Nov 16, 2022 in Latest Department NewsNewsroom

(HONOLULU) – A new animated video highlights the success story of how biocontrol, a process where a carefully selected living organism is used to control an invasive species, helped to save the native Wiliwili tree. The video, produced by the DLNR Division of Forestry and Wildlife (DOFAW) in collaboration with the Coordinating Group on Alien Pest Species, also shows how biocontrol can continue to be an important tool in managing invasive species in Hawaiʻi.

In 2005, a new pest, the erythrina gall wasp, made its way to Hawaiʻi and rapidly spread across the state, killing or severely damaging nearly all wild Wiliwili populations. “The sudden arrival of the erythrina gall wasp caught us all by surprise,” says Chipper Wichman, President of the National Tropical Botanical Garden. “Wiliwili is a keystone species in our dry forests, and nearly every part of this special tree is used by cultural practitioners. The impact of losing this species would have been profound.”

However in 2008, after extensive exploration in Africa for predators of the gall wasp and testing to make sure those predators didn’t impact other species, scientists were able to safely release a biocontrol agent: an even smaller parasitic wasp that preys on the gall wasp. The biocontrol agent successfully reduced the pest wasp numbers to levels that did not kill Wiliwili trees, saving them from the edge of extinction.

“Invasive species cost the state millions by reducing watershed benefits, degrading agricultural lands, threatening human infrastructure, and are one of the main drivers of the loss of biodiversity and native ecosystems in our state,” DOFAW Protection Forester Rob Hauff said. “Biocontrol has proven to be a safe, cost-effective, and essential tool. The success of the Wiliwili gall wasp biocontrol is one example of what we can expect if we continue to support this type of work.”

Prior to releasing a biocontrol agent, researchers perform years of exploration and analysis to ensure it won’t impact any species other than the target invasive species. Proposed biocontrols are also subject to careful review by specialists and regulatory officials, as well as the public. Since the focus on safety was implemented in Hawaiʻi in the 1970s, the biocontrol program has had a stellar record, with no non-target damages from any biocontrol released in the last 50 years.

Given the ongoing impacts of many invasive species currently in Hawaiʻi, new, updated facilities are needed to expand the capacity for biocontrol research. A coalition of state and federal agencies, including DLNR, the Hawaiʻi Department of Agriculture (HDOA), the University of Hawaiʻi, and the United States Forest Service and Agricultural Research Service, are currently discussing options for new facilities that can serve Hawaiʻi and other Pacific island neighbors, who often deal with similar invasive species.

While discussions on new facilities are ongoing, there are still new biocontrol agents that may be ready for release in the near future. Two insects, including a caterpillar targeting the weed miconia (Miconia calvescens), and a beetle targeting the weed cane tibouchina (Tibouchina herbacea), may be ready for release in Hawaiʻi within the year.

# # #

RESOURCES

(All images/video courtesy: DLNR)

Animated Video – Wiliwili Trees in Hawaiʻi: A Biocontrol Success Story: https://vimeo.com/764310295/75668bbed2

Photographs – Wiliwili Trees: https://www.dropbox.com/sh/26iq4inb956i1zc/AACHgND3m0E2RBeeUS0YsNRJa?dl=0

Biocontrol Hawaiʻi webpage: www.biocontrolhawaii.org

Media Contact:

Madison Rice

Communications Specialist

Hawai’i Dept. of Land and Natural Resources

Dlnr.comms@hawaii.gov

808-587-0396

Weevil may save Great Britain up to £16.8m a year in management of invasive aquatic fern

by CABI

Weevil may save Great Britain up to £16.8m a year in management of invasive aquatic fern
The invasive aquatic fern Azolla filiculoides. Credit: CABI

A new CABI-led study suggests that a tiny weevil (Stenopelmus rufinasus) has huge benefits in saving Great Britain up to £16.8m in annual management costs of the invasive aquatic fern Azolla filiculoides.

The research, published in the journal CABI Agriculture and Bioscience, estimates that without any biocontrol the expected yearly costs of managing A. filiculoides would range from £8.4m to £16.9m.

The scientists say that the impacts of naturalized S. rufinasus populations on A. filiculoides alone could be expected to reduce management costs to £800,000 to £1.6m a year.

However, they estimate A. filiculoides management costs to be lower still due to additional augmentative releases of the weevil that take place each summer, resulting in annual management costs of £31,500 to £45,800.

Azolla filiculoides, a type of floating water fern, was introduced to Great Britain at the end of the 19th century for ornamental use in ponds and aquaria. But its introduction into the wild has meant it has spread rapidly throughout England and Wales and to a lesser degree, Scotland.

The invasive aquatic fern outcompetes native species by forming a dense covering on the surface of the water. It blocks out light and can also deoxygenate water. A. filiculoides can also block canals, drains and overflows and may lead to an increased risk of flooding. It can affect irrigation systems—both by blocking their water supply and by reducing water quality.

It has been banned from sale in England and Wales since April 2014.

Its specialist natural enemy, S. rufinasus, was first recorded in 1921. It is suspected to have been introduced from America as a stowaway on A. filiculoides. Stenopelmus rufinasus is also reported to be present in numerous additional European countries where A. filiculoides is present.

The study sought to estimate the management cost savings resulting from the presence of S. rufinasus as a biocontrol agent in Great Britain. This includes the value of additional augmentative releases of the weevil made since the mid-2000s, compared with the expected costs of control in the absence of S. rufinasus.

Corin Pratt, lead author and Invasive Species Management Researcher at CABI, said, “The unintentional introduction of the weevil S. rufinasus to Great Britain is estimated to have resulted in millions of pounds of savings annually in management costs for A. filiculoides.

“Additional augmentative releases of the weevil provide further net cost savings, tackling A. filiculoides outbreaks and bolstering naturalized populations.

“The use of herbicides in the aquatic environment is likely greatly reduced due to A. filiculoides biocontrol. Although somewhat climate-limited at present in Great Britain, climate change may result in even more effective biocontrol of A. filiculoides by S. rufinasus.

“This has been observed in warmer regions such as South Africa, where the plant is no longer considered a threat since the introduction of S. rufinasus.”

The scientists conclude by arguing that in the absence of the specialist weevil S. rufinasus, A. filiculoides could be expected to be the dominant aquatic macrophyte in Great Britain. This would require extensive, costly management and likely widespread use of herbicides in the aquatic environment.

They state that the estimated benefit to cost ratio of augmentative S. rufinasus releases to be of 43.7:1 to 88.4:1.

More information: Corin F. Pratt et al, A century of Azolla filiculoides biocontrol: the economic value of Stenopelmus rufinasus to Great Britain, CABI Agriculture and Bioscience (2022). DOI: 10.1186/s43170-022-00136-0

Provided by CABI

Team IDs invasive tree dispersal patterns on Great Plains prairies

Nebraska Today

POCKET SCIENCE: EXPLORING THE ‘WHAT,’ ‘SO WHAT’ AND ‘NOW WHAT’ OF HUSKER RESEARCH

by Scott Schrage | University Communication and Marketing

Nebraska Sandhills

Craig Chandler | University Communication and Marketing

Cattle graze in the Sandhills near Whitman, Nebraska.

What?

As woody vegetation marches across grasslands — encroaching on prairies that wildlife and ranchers alike have come to depend on — ecologists are studying exactly how that invasive vegetation is populating and transforming formerly intact landscapes.

Mitigating the spread of invasive vegetation, including the eastern redcedar tree now threatening Nebraska’s prairies, means understanding the dispersal of seeds that eventually mature into new trees and bear seeds of their own. To date, though, no studies have analyzed how that dispersal may be shaping the patterns of encroachment seen on the Great Plains.

So what?

Husker researchers Dillon Fogarty, Dirac Twidwell and Robert Peterson recently investigated the issue at two sites in the Nebraska Sandhills: the Nebraska National Forest at Halsey and the Samuel R. McKelvie National Forest near Valentine. Both forests were hand-planted in the early 1900s and remain surrounded by the mixed-grass prairie native to the area.

Dillon Fogarty

Fogarty

The team began by randomly picking five treeless points around each of the two forests, then drawing lines from each of those 10 points to the nearest eastern redcedar planting — the oldest feasible source of seeds in the respective vicinity. Fogarty, Twidwell and Peterson proceeded to walk those 10 transects while marking the location, sex and height of any eastern redcedar tree they encountered. By using tree height as a proxy for age, the researchers were able to chronicle the encroachment of eastern redcedar over time.

Of the 961 eastern redcedar trees sampled by the team, more than half were growing within just 40 feet of the nearest seed-bearing tree, with their density declining rapidly beyond that distance. And more than 95% were located within 200 yards of the nearest seed source, delineating a zone in which grasslands are most vulnerable to woodland conversion.

Though most eastern redcedar occurred near seed sources, the farthest-flung outliers were found more than half a mile from those sources. The team suspects that the long-distance outliers stem from grassland birds foraging on eastern redcedar’s berry-like cones before flying to areas of treeless prairie and expelling the seeds.

Mature eastern redcedar trees produce up to 1.5 million seeds a year. Fogarty said the species’ one-two punch — with local seed dispersal driving swift conversion to woodland as long-distance outliers speed expansion across large tracts of land — makes eastern redcedar a serious threat to Nebraska’s prairies.

Now what?

Efforts to defend Nebraska’s already under-siege prairie against the further encroachment of eastern redcedar should especially focus on areas within 200 yards of mature trees, the researchers said. At the same time, managers should keep an eye on treeless expanses residing far from invasive vegetation. Early detection and rapid responses that eradicate the long-distance outliers from remote tracts will prove critical to safeguarding what remains of Nebraska’s pristine prairie, the team said.

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Grahame Jackson posted a new submission ‘Risk analysis and weed biological control.’

Submission

Risk analysis and weed biological control.

Authors: W. M. LonsdaleD. T. BrieseJ. M. CullenAUTHORS INFO & AFFILIATIONS

Publication: Evaluating indirect ecological effects of biological control. Key papers from the symposium ‘Indirect ecological effects in biological control’, Montpellier, France, 17-20 October 1999

https://doi.org/10.1079/9780851994536.0185


Abstract

Weed biological control and risk analysis are very powerful tools for land management and decision-making respectively. We explore the application of risk analysis to weed biological control. Recent criticisms of weed biological control have mainly centred on non-target impacts, attacks by the biological control agent on species other than the weed. In ecology, these are direct effects because they involve physical interactions between the species concerned. Indirect effects are those in which the species do not physically interact. In biological control terms, indirect effects include, on the positive side, the increase in pasture production or biodiversity resulting from successful biological control. On the negative side, they include the decline of a native species that had used the weed as habitat. The aim of weed biological control is then to maximize the ratio of desirable indirect effects to undesirable direct and indirect effects. Using a risk analysis approach, we show that the problems of weed biological control are less in the domain of science and more in that of communication and consultation. A well-conceived biological control project would aim for wide consultation to agree on the target weed with the community, so that negative effects are viewed as trivial against the positive ones. It would also use highly specific agents to reduce the risk of undesirable direct effects to a minimum. Lastly, biocontrollers themselves would merely be advisers on the decision to release.


Insects have a weak capacity to adjust their critical thermal limits. Sam England, Author provided (no reuse)

Insects will struggle to keep pace with global temperature rise – which could be bad news for humans

Published: October 3, 2022 11.01am EDT

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  1. Hester WeavingPhD Candidate in Entomology, University of Bristol

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Hester Weaving receives funding from a BBSRC studentship.

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Animals can only endure temperatures within a given range. The upper and lower temperatures of this range are called its critical thermal limits. As these limits are exceeded, an animal must either adjust or migrate to a cooler climate.

However, temperatures are rising across the world at a rapid pace. The record-breaking heatwaves experienced across Europe this summer are indicative of this. Heatwaves such as these can cause temperatures to regularly surpass critical thermal limits, endangering many species.

In a new study, my colleagues and I assessed how well 102 species of insect can adjust their critical thermal limits to survive temperature extremes. We found that insects have a weak capacity to do so, making them particularly vulnerable to climate change.

The impact of climate change on insects could have profound consequences for human life. Many insect species serve important ecological functions while the movement of others can disrupt the balance of ecosystems.

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How do animals adjust to temperature extremes?

An animal can extend its critical thermal limits through either acclimation or adaptation.

Acclimation occurs within an animal’s lifetime (often within hours). It’s the process by which previous exposure helps give an animal or insect protection against later environmental stress. Humans acclimate to intense UV exposure through gradual tanning which later protects skin against harmful UV rays.

One way insects acclimate is by producing heat shock proteins in response to heat exposure. This prevents cells dying under temperature extremes.

A ladybird drinking a speck of water on a narrow leaf.
Insects in warmer environments develop fewer spots to reduce heat retention. mehmetkrc/Shutterstock

Some insects can also use colour to acclimate. Ladybirds that develop in warm environments emerge from the pupal stage with less spots than insects that develop in the cold. As darker spots absorb heat, having fewer spots keeps the insect cooler.

Adaptation occurs when useful genes are passed through generations via evolution. There are multiple examples of animals evolving in response to climate change.

Over the past 150 years, some Australian parrot species such as gang-gang cockatoos and red-rumped parrots have evolved larger beaks. As a greater quantity of blood can be diverted to a larger beak, more heat can be lost into the surrounding environment.

A colourful red-rumped parrot perched on a branch.
The red-rumped parrot has evolved a larger beak to cope with higher temperatures. Alamin-Khan/Shutterstock

But evolution occurs over a longer period than acclimation and may not allow critical thermal limits to adjust in line with the current pace of global temperature rise. Upper thermal limits are particularly slow to evolve, which may be due to the large genetic changes required for greater heat tolerance.

Research into how acclimation might help animals survive exceptional temperature rise has therefore become an area of growing scientific interest.

A weak ability to adjust to temperature extremes

When exposed to a 1℃ change in temperature, we found that insects could only modify their upper thermal limit by around 10% and their lower limit by around 15% on average. In comparison, a separate study found that fish and crustaceans could modify their limits by around 30%.

But we found that there are windows during development where an insect has a greater tolerance towards heat. As juvenile insects are less mobile than adults, they are less able to use their behaviour to modify their temperature. A caterpillar in its cocoon stage, for example, cannot move into the shade to escape the heat.

Exposed to greater temperature variations, this immobile life stage has faced strong evolutionary pressure to develop mechanisms to withstand temperature stress. Juvenile insects generally had a greater capacity for acclimating to rising temperatures than adult insects. Juveniles were able to modify their upper thermal limit by 11% on average, compared to 7% for adults.

But given that their capacity to acclimate is still relatively weak and may fall as an insect leaves this life stage, the impact is likely to be limited for adjusting to future climate change.

What does this mean for the future?

A weak ability to adjust to higher temperatures will mean many insects will need to migrate to cooler climates in order to survive. The movement of insects into new environments could upset the delicate balance of ecosystems.

Insect pests account for the loss of 40% of global crop production. As their geographical distribution changes, pests could further threaten food security. A UN report from 2021 concluded that fall armyworm populations, which feed on crops such as maize, have already expanded their range due to climate change.

A damaged corn crop following an attack by fall armyworms.
The fall armyworm is a damaging crop pest which is spreading due to climate change. Alchemist from India/Shutterstock

Insect migration may also carry profound impacts on human health. Many of the major diseases affecting humans, including malaria, are transmitted by insects. The movement of insects over time increases the possibility of introducing infectious diseases to higher latitudes.

There have been over 770 cases of West Nile virus recorded in Europe this year. Italy’s Veneto region, where the majority of the cases originate, has emerged as an ideal habitat for Culex mosquitoes, which can host and transmit the virus. Earlier this year, scientists found that the number of mosquitoes in the region had increased by 27%.

Insect species incapable of migrating may also become extinct. This is of concern because many insects perform important ecological functions. Three quarters of the crops produced globally are fertilised by pollinators. Their loss could cause a sharp reduction in global food production.

The vulnerability of insects to temperature extremes means that we face an uncertain and worrying future if we cannot curb the pace of climate change. A clear way of protecting these species is to slow the pace of climate change by reducing fossil fuel consumption. On a smaller scale, the creation of shady habitats, which contain cooler microclimates, could provide essential respite for insects facing rising temperatures.

Davao del Norte banana farmers shift to corn due to Panama disease

A local executive from Davao del Norte has called on the Filipino national government to help small-scale banana farmers address the onslaught of Fusarium wilt or Panama disease. Mayor Roland Dejesica said the Panama disease has reached alarming levels, forcing farmers to shift to corn and endangering the long term viability of the town’s banana industry.

According to Dejesica, the town of Santo Tomas accounts for at least 70 percent of the total banana planted areas in Davao del Norte. About half of that area, he said, has been converted as corn plantation. For that he reason, he warned, the province’s billion dollar earner commodity of the province is on the brink of dying, because the Fusarium wilt has not yet been thoroughly addressed.

“We already asked the national government to look at our banana industry situation. We hope that they will extend help,” Dejesica said. He asks for the government to establish a research center, in order to study and understand the causes of Panama disease.

Source: pna.gov.ph

Publication date: Fri 28 Oct 2022

Bonwell: the multi-fruited mini cucumber with high resistance to CGMMV

In ‘The future is sky’ series, we show that shared entrepreneurship is of paramount importance. Blake Fischer, Head Grower at JEM Farms, discusses the partnership between JEM Farms and Rijk Zwaan in this second video. “It’s always great to have another set of eyes looking at your crop and pointing things out that we can all learn from”, says Blake Fischer.

Furthermore, JEM Farms shared their experiences with our high CGMMV resistant mini-cucumber variety, Bonwell. Curious to learn more about ‘The future is sky’ series or Bonwell?

Publication date: Mon 14 Nov 2022

With Xsect Xtra, Inveragro eliminates pepper pests

Inveragro, located in the valley of San Felipe, Guanajuato, and known for its tradition of producing and drying chili peppers, was having problems with pest control and humidity levels inside the greenhouse. With Xsect Xtra, they were able to reduce the entry of thrips by 50% while increasing their humidity by 15%, resulting in an ideal climate that promotes pepper growth.

Inveragro is a 10-hectare pepper greenhouse that started operations three years ago in the valley of San Felipe, Guanajuato, an area with different challenges for pepper growers due to its semi-arid climate and the presence of insects and pests such as whitefly, thrips, and weevils.

Germán Sandoval Barba, grower at Inveragro, was looking for a climate solution that would help him face these challenges. A year ago, he decided to try Xsect Xtra.

Ideal humid climate = healthier peppers
The pepper is a tropical crop that likes high humidity levels. Ideally the humidity inside a pepper greenhouse should be between 60% and 80%.

During the summer months, humidity inside Inveragro was between 45% and 50%, and it was necessary to keep the windows closed as a way to conserve humidity inside the greenhouse.

“Before installing Svensson’s insect control nets, I was worried that the temperature would rise too much and that it would affect the humidity. Once we tested the nets, the truth is that it was a very positive surprise the results that we had in terms of temperature and humidity”, says Germán Sandoval

Unlike last year when the windows were practically closed, now with Xsect Xtra, the windows are open between 20% and 30%, having a maximum temperature between 32 and 33 degrees. In addition, with Xsect Xtra, the humidity inside the greenhouse increased between 10% and 15%, compared to last year, achieving an ideal humidity between 60% and 75%, which benefits the growth of peppers.

“I thought that I was going to experience disadvantages with this insect control net because, for me, it was more important to sacrifice climate in order to reduce the entry of pests and insects. But to my surprise, I now have a better climate and fewer insects inside the greenhouse,” said Germán Sandoval.

Greenhouses with 50% fewer thrips
One of the biggest challenges for Germán is the entry of pests, and one way to control this problem is through hermeticity. Inveragro has four full-time employees dedicated exclusively to supervising any failure in the hermeticity of the greenhouses. “When I started looking for options to improve our hermeticity, I discovered the Svensson insect control nets, which would help us to improve our conditions,” says Germán Sandoval.

Before installing Xsect Xtra, during the fifth week of the production cycle, thrips were already seen inside the greenhouse, and it was necessary to apply pesticides and/or agrochemicals prior to the release of the biological control. “Now I can release the biological control we use Orius to control thrips, without pesticides and/or agrochemicals applications that could damage the biological control program,” says Germán, “since the installation of Xsect Xtra, 50% fewer thrips have entered the greenhouse”.

Powdery mildew was another climate problem at Inveragro, and it was necessary to apply agrochemicals at least once a week. During the first year with Svensson’s insect control net, Germán continued with the same program, but no powdery mildew was found inside the greenhouse.

“I’ve already modified my program for this year. I’m only going to apply preventive products every 15 days, which reduces by 50% the cost of powdery mildew throughout the year because now I have better climate conditions in terms of humidity, which is more controllable and promotes pepper growth”.

Germán has also noticed improvements in the beneficial program used to control thrips. He used to have 4 Orius per square meter, and this year he only has three orius per square meter, which means savings in this year’s beneficials budget.

“What Xsect Xtra has given me is improved humidity, fewer pests, and reduced phytosanitary diseases.”
 
Finally, Germán shared the following advice for all pepper growers: “I would tell growers who are afraid to try these nets not to be afraid. In the beginning, I hesitated, but it is something that will help them. What it can generate in the climate is minimal and what it can help them in the phytosanitary issue is very broad. The net pays for itself”.

For more information:
Ludvig Svensson

info@ludvigsvensson.com www.ludvigsvensson.com    

Publication date: Mon 14 Nov 2022