Ravenous insects in a warming world

Grasshoppers are among the insects predicted to grow hungrier and more populous in a warming climate, devastating U.S. corn crops.

James P. Blair/National Geographic/Getty Images

As the globe warms, farmers will face more drought, flooding, and crop-frying heat. But that may be nothing compared with the bugs. A new study finds that higher temperatures will produce more voracious grasshoppers, caterpillars, and other crop-devouring pests, with potentially catastrophic consequences for the world’s food supply.

The study is “a stark warning” for our future food security, says Robert Paxton, an insect ecologist at the Martin Luther University of Halle-Wittenberg in Germany, who was not involved with the work. But he notes that the computer model making the dire predictions omits other factors that might limit the toll.

Scientists became keenly aware of the insect threat 10 years ago. That’s when Curtis Deutsch, a biogeochemist at the University of Washington in Seattle, published a study showing that as temperatures rise, nearly all insects multiply and rev up their metabolisms. “When there’s more thermal energy in the environment,” says Deutsch, “all of the different chemical reactions in the complex soup of biochemistry inside living things start to speed up, and they need to consume more calories.”

To see what kind of damage this increased insect appetite might have on the global food system, Deutsch and his team built a computer program that combined physiological data on hundreds of insect species with climate models. When the planet warmed by an average of 2°C, as models predict will happen by 2100, if not sooner, wheat crops shrunk by 46%, rice by 19%, and maize (or corn) by 31%. Temperate, productive regions like the United States’s “corn belt,” wheat fields in France, and rice paddies in China were especially hard hit, the team reports today in Science.

For wheat and maize, the model predicted that the losses would continue to increase 10% to 25% for each extra degree of warming. Rice yields, however, might start to stabilize after a 3°C increase in temperature, as it is grown in many tropical environments where insects might begin to die off after too much warming.

“The modeling is robust, and the conclusions are sound,” says Paxton, who notes that German farmers are expected to lose one-fifth of their crops this year because of record-setting heat and lack of rainfall. But Paxton and Deutsch agree that the simplified model has left out many factors like how insects’ natural predators will respond to warming, whether the insects’ diets might change, and whether changes in farming techniques could keep the bugs at bay.

Still, Deutsch says it’s important to begin planning for the effects that climate change could have on the global food supply, because the people hardest hit by crop loss will likely be the world’s poorest households. According to recent United Nations estimates, at least 815 million people worldwide already go hungry each day, and maize, rice, and wheat are the main food sources for about 4 billion people.

“If we think about food supply as the pie we all get to eat, some us of get smaller slices than others,” Deutsch says. “If the pie begins to shrink, we need to find ways to stop it from shrinking and to carve it up more evenly so people aren’t left without.”

ICCP: Feeding the Future: Partners in plant health.

The recent International Congress of Plant Pathology (ICPP) in Boston brought together members of the plant health community from all over the world. Large events are a great place to forge new relationships, strengthen existing ones, or simply get everyone together in one place. The importance of working together is always emphasised when all corners of the community come together and find the space to discuss and discover common ground.

This was the focus of a session organised by CABI at ICPP titled Feeding the Future: Partners in plant health. Chaired by Plantwise programme executive, Washington Otieno with panelists Kirk Shirley from USDA Foreign Agricultural Service and Scott Heuchelin from Corteva Agriscience. The session highlighted the fundamental need for partnerships in plant health and food security.

With Plantwise representing the viewpoint of CABI as an international not-for-profit organisation, USDA as a food security donor, and Corteva the private sector, the session drew together diverse perspectives and valuable insights into how we all contribute to bringing plant health science from the lab to farmers’ fields; focusing on the importance of building genuine partnerships, leveraging on one another’s strengths to combat pests and diseases. But are these partnerships sustainable and future proof?


With essential objectives and funding streams often the main drivers, “partnerships are critical to address complex plant health issues in designing programmes,” said Kirk Shirley. USDA’s partnerships are enabling them to deliver, often remotely, in a range of diverse areas giving them a good overview of systemic issues in plant health. An example outlined by Mr Shirley is the distance learning project to bolster Pakistan’s sanitary and phytosanitary skills and knowledge. This project has been ongoing since 2011 with partners CABI and Texas A&M University, and earlier this year it was announced that the learning course would be going global and available in multiple languages including English, Spanish, and French.

Partnerships facilitate vital expertise and access to rural communities and enable programmes to reach as many beneficiaries as possible. However, there will always be restrictions due to funding or geopolitics and, as Mr Shirley pointed out, “phytosanitary issues don’t respect borders” which can create frustration and challenges often beyond the remit of control. Therefore “coordination and communication are absolutely crucial” to successful partnerships, concluded Mr Shirley.

Partnering with the private sector within agriculture may seem like a natural fit because agriculture is such a big business. Indeed, Dr Scott Heuchelin of Corteva Agriscience said that industry can and does contribute to a wide range of partnerships and gave a few examples of projects he had been involved with over the years including AWARD – professional development of African women, and BeCA – funding to support the creation of knowledge and expertise for capacity development.

Dr Heuchelin asserted that partnerships give both industry and collaborating partners opportunities to deal with pressing problems more effectively but it’s not something that is actually adequately demonstrated in terms of scale and impact. Corteva has extensive global capacity but potential partners must reach out with their needs. As Dr Heuchelin noted, “no individual entity whether government, philanthropic, or industry can achieve goals alone, we all need to work together,” adding that “creating a global plant pathology network is crucial.”

An integrated approach to managing plant health underpins what Plantwise is all about. Programme executive, Dr Washington Otieno took on a double role of chair and panellist in the session and described how Plantwise is implemented across 32 countries using partnerships in each one. Partnering not only with government departments such as extension, research, plant protection but also others such as academia, NGOs, and the private sector. Under Plantwise, CABI has driven the agenda of multi-stakeholder framework for managing plant health.

Dr Otieno made sure to emphasise that it’s vital to remember that primary beneficiaries have needs outside of plant pests and diseases such as advice on inputs or market linkages, and if these issues are outside your organisations core areas of strength, “partnerships are the only path to wider success.” Reminding the audience of plant pathologists that when “dealing with human beings, the science can only go so far,” and remembering this in programme design is crucial.


The theme of continuous communication, persistence, and coordination in order to maintain as much of the partnership as possible became the stand out theme from the audience members. What happens when a programme has reached is projected “end”, where does that expertise go?  Can we have better tracking methods and longer-term lines of communication? With the natural movement of people within and between organisations, former partners or experts aren’t always reachable further down the line.

Sustaining capacity requires not only full investment at the time of the project or programme; relationships should be future proof. As a starting point, individual organisations need to invest in keeping a good database on experts and their contacts. We can’t always rely on international conferences to bring us together again.

Global loss of wheat, rice and maize projected to rise 10-25% per degree of warming

Crop losses for critical food grains will increase substantially as the climate warms, as rising temperatures boost the metabolic rate and population growth of insect pests, new research says.

“Climate change will have a negative impact on crops,” said Scott Merrill of the University of Vermont, a co-author of the study published in Science. “We are going to see increased pest pressure from climate change.”

The research team looked at how the insect pests that attack three staple crops – rice, maize and wheat – would respond under a variety of climate scenarios. They found that rising global temperatures would lead to an increase in crop losses from insects, especially in temperate regions. Losses are projected to rise by 10 to 25% per degree of warming.

Just a 2-degree rise in global average temperature will result in total crop losses of approximately 213 million tons for the three grains, the researchers say.

Insects like it hotter – up to a point

The losses will come from an increase in insect metabolism, and from faster insect population growth rates. The link with metabolism is straightforward. “When the temperature increases, the insects’ metabolism increases so they have to eat more,” said Merrill, a researcher in UVM’s Dept. of Plant and Soil Science and Gund Institute for Environment. “That’s not good for crops.”

The link with population growth, however, is more complex. Insects have an optimal temperature where their population grows best. If the temperature is too cold or too hot, the population will grow more slowly. That is why the losses will be greatest in temperate regions, but less severe in the tropics.

“Temperate regions are not at that optimal temperature, so if the temperature increases there, populations will grow faster,” said Merrill, an ecologist who studies plant-crop interactions. “But insects in the tropics are already close to their optimal temperature, so the populations will actually grow slower. It’s just too hot for them.”

Key grain crops to take a hit

According to the study, wheat, which is typically grown in cool climates, will suffer the most, as increased temperatures will lead to greater insect metabolism, as well as increased pest populations and survival rates over the winter. Maize, which is grown in some areas where population rates will increase and others where they will decline, will face a more uneven future.

In rice, which is mostly grown in warm tropical environments, crop losses will actually stabilize if average temperatures rise above 3oC, as population growth drops, counteracting the effect of increased metabolism in the pests. “Rice losses will taper off as the temperature rises above a certain point,” said Merrill.

That means that the most substantial yield declines will happen in some of the world’s most productive agricultural regions. “The overall picture is, if you’re growing a lot of food in a temperate region, you’re going to be hit hardest,” said Merrill.

“I hope our results demonstrate the importance of collecting more data on how pests will impact crop losses in a warming world — because collectively, our choice now is not whether or not we will allow warming to occur, but how much warming we’re willing to tolerate,” said Curtis Deutsch of the University of Washington, who co-led the study with Joshua Tewksbury, director of Future Earth at the University of Colorado, Boulder.

France, China and the United States, which produce most of the world’s maize, are among the countries that are expected to experience the largest increases in crop losses from insect pests. France and China, as major producers of wheat and rice, respectively, are also expected to face large increases in losses of those grains as well. “The areas that produce the most grain, especially wheat and corn – the US, France and China – are going to be hit hardest,” said Merrill.

Reduced yields in these three staple crops are a particular concern, because so many people around the world rely on them. Together they account for 42% of direct calories consumed by humans worldwide. Increased crop losses will result in a rise in food insecurity, especially in those parts of the world where it is already rife, and could lead to conflict.

As farmers adapt to a changing climate by shifting planting dates or switching to new cultivars, they will also have to find ways to deal with pests, by introducing new crop rotations, or using more pesticides. But not all of these strategies will be available to all farmers. “There are a lot of things richer countries can do to reduce the effect, by increasing pesticide use or expanding integrated pest management strategies,” said Merrill. “But poorer countries that rely on these crops as staple grains will have a harder time.”

In addition to Merrill, Deutsch, and Tewksbury, study co-authors include Michelle Tigchelaar, David Battisti, Raymond Huey from University of Washington, and Rosamond Naylor of Stanford University. The research was funded by the National Science Foundation and the Gordon and Betty Moore Foundation.

Climate change: Insect activity and crop loss

FROM: James Urton

University of Washington


[email protected]

(NOTE: researcher contact information at end)

For Immediate Release

August 30, 2018

Climate change projected to boost insect activity and crop loss, researchers say

Newswise — Scientists have already warned that climate change likely will impact the food we grow. From rising global temperatures to more frequent “extreme” weather events like droughts and floods, climate change is expected to negatively affect our ability to produce food for a growing human population.

But new research is showing that climate change is expected to accelerate rates of crop loss due to the activity of another group of hungry creatures — insects. In a paper published Aug. 31 in the journal Science, a team led by scientists at the University of Washington reports that insect activity in today’s temperate, crop-growing regions will rise along with temperatures. Researchers project that this activity, in turn, will boost worldwide losses of rice, corn and wheat by 10-25 percent for each degree Celsius that global mean surface temperatures rise. Just a 2-degree Celsius rise in surface temperatures will push the total losses of these three crops each year to approximately 213 million tons.

“We expect to see increasing crop losses due to insect activity for two basic reasons,” said co-lead and corresponding author Curtis Deutsch, a UW associate professor of oceanography. “First, warmer temperatures increase insect metabolic rates exponentially. Second, with the exception of the tropics, warmer temperatures will increase the reproductive rates of insects. You have more insects, and they’re eating more.”

In 2016, the United Nations estimated that at least 815 million people worldwide don’t get enough to eat. Corn, rice and wheat are staple crops for about 4 billion people, and account for about two-thirds of the food energy intake, according to the UN Food and Agriculture Organization.

“Global warming impacts on pest infestations will aggravate the problems of food insecurity and environmental damages from agriculture worldwide,” said co-author Rosamond Naylor, a professor in the Department of Earth System Science at Stanford University and founding director of the Center on Food Security and the Environment. “Increased pesticide applications, the use of GMOs, and agronomic practices such as crop rotations will help control losses from insects. But it still appears that under virtually all climate change scenarios, pest populations will be the winners, particularly in highly productive temperate regions, causing real food prices to rise and food-insecure families to suffer.”

To investigate how insect herbivory on crops might affect our future, the team looked at decades of laboratory experiments of insect metabolic and reproductive rates, as well as ecological studies of insects in the wild. Unlike mammals, insects are ectothermic, which means that their body temperature tracks the temperature of their environment. Thus, the air temperature affects oxygen consumption, caloric requirements and other metabolic rates.

The past experiments that the team studied show conclusively that increases in temperature will accelerate insect metabolism, which boosts their appetites, at a predictable rate. In addition, increasing temperatures boost reproductive rates up to a point, and then those rates level off at temperature levels akin to what exist today in the tropics.

Deutsch and his colleagues found that the effects of temperature on insect metabolism and demographics were fairly consistent across insect species, including pest species such as aphids and corn borers. They folded these metabolic and reproductive effects into a model of insect population dynamics, and looked at how that model changed based on different climate change scenarios. Those scenarios incorporated information based on where corn, rice and wheat — the three largest staple crops in the world — are currently grown.

“Temperate regions are currently cooler than what’s optimal for most insects. But if temperatures rise, these insect populations will grow faster,” said co-author Scott Merrill, a researcher at the University of Vermont’s College of Agriculture and Life Sciences and the Gund Institute for Environment. “They will also need to eat more, because rising temperatures increase insect metabolism. Together, that’s not good for crops.”

For a 2-degree Celsius rise in global mean surface temperatures, their model predicts that median losses in yield due to insect activity would be 31 percent for corn, 19 percent for rice and 46 percent for wheat. Under those conditions, total annual crop losses would reach 62, 92 and 59 million tons, respectively.

The researchers observed different loss rates due to the crops’ different growing regions, Deutsch said. For example, much of the world’s rice is grown in the tropics. Temperatures there are already at optimal conditions to maximize insect reproductive and metabolic rates. So, additional increases in temperature in the tropics would not boost insect activity to the same extent that they would in temperate regions – such as the United States’ “corn belt.”

The team notes that farmers and governments could try to lessen the impact of increased insect metabolism, such as shifting where crops are grown or trying to breed insect-resistant crops. But these alterations will take time and come with their own costs.

“I hope our results demonstrate the importance of collecting more data on how pests will impact crop losses in a warming world — because collectively, our choice now is not whether or not we will allow warming to occur, but how much warming we’re willing to tolerate,” said Deutsch.

Co-lead author is Joshua Tewksbury, director of Future Earth at the University of Colorado, Boulder. Additional co-authors are Michelle Tigchelaar, a UW research scientist in the Department of Atmospheric Sciences; David Battisti, a UW professor of atmospheric sciences; and Raymond Huey, a UW professor emeritus of biology. The research was funded by the National Science Foundation and the Gordon and Betty Moore Foundation.


For more information, contact Deutsch at [email protected] or +1 206-543-5189 and the University of Washington News Office at +1 206-543-2580.

DOI: 10.1126/science.aat3466

Grant numbers: OCE-1419323, OCE-1458967, OCE-1542240, GBMF#3775


Water vital for economic growth and food security of Pakistan

Chairman Water and Power Development Authority (WAPDA) Lt. Gen Muzammil Hussain said that WAPDA being the biggest stakeholder is aware on water issues whereon economic growth, food security, development and security of Pakistan depend.

He added that Pakistan receives 145 million acre feet of water every year but only 14m acre feet of water is preserved. Due to soil gathering at the base of Tarbela and Mangla Dam, the storage capacity of the dam has decreased by 35 to 40 percent.

This was stated by Chairman WAPDA in his keynote address at a Roundtable on water scarcity in Pakistan at FPCCI Head Office Karachi, Capital Office Islamabad and Regional Office Lahore through Video conferencing. The discussion was organized by The Research and Policy Division of Federation of Pakistan Chambers of Commerce and Industry (FPCCI).

He said that at present the capacity of water storage is only for 30 days and 94 per cent of surface and groundwater is used for agriculture in Pakistan. He stated that lack of governance is the main problem as there are many anti-dams lobbies that are under control of donors. Pakistan need concrete steps for resolving of water issues like adoption of water efficient technologies, water safety and saving system in agriculture, as Pakistan ranked 46th out of 48th countries in water efficient usage country.

The aim of this roundtable was to discuss the water scarcity in Pakistan for minimizing risk and maximizing benefits. The session was graced by Lieut. General (r) Muzammil Hussain Chairman WAPDA and attended by Leaders of Business Community, Office Bearers of FPCCI, water research councils, stakeholders, representative of academia and trade bodies.

Earlier, in welcome address, Ghazanfar Bilour President FPCCI stated that Water scarcity presents a transnational and transboundary problem which seriously affects our agriculture and industrial sector productivity. He added that Pakistan has very little capacity of storage water compared to India, China and USA. Successful reforms in the water sector need to be accompanied by improvements in the agricultural production techniques, recycling plants and construction of small and large dams.

FPCCI Vice Presidents Mr. Tariq Haleem, Mr. Zahid Saeed, Mr. Waheed Ahmed, Mr. Karim Aziz, Mr. Arfan Yousuf, Mrs. SaeedaBano, Mrs. Shabnum Zafar and Mr. Shafique Anjum also highlighted water scarcity issues and emphasized on concrete steps for resolving the issues. In his remarks, S. M. Muneer Former President FPCCI stated that water scarcity is a serious issue in Pakistan which may dry-out Pakistan by 2025 because of over depletion, overexploitation and pollution of water resources.

14m cotton bales production expected

ISLAMABAD – Cotton crop output during the current season was expected to cross 14.23 million bales as the area under crop cultivation had witnessed over 2 percent increase during the period under review as compared the same period of last year.

Due to favorable weather conditions, suitable climate position for crop, better management and low intensity of pest attack in the Punjab and Sindh province as compared the last year were indicating significant growth in output, said Cotton Commissioner Dr Khalid Abdullah.

Talking to APP here on Tuesday, he said that white fly attacks on  cotton crop in the Punjab had reduced from 17 percent to 12 percent, where as jassid 13 percent against 15 percent of the last year.

The pest attack including cotton mealybugs, pink ball worm also reduced and it was reported at 23 percent as compared the 27 percent of same period of last year, he observed.

However, he said that the cotton crop in the Sindh had remained under water stress due to bellow normal rain falls in crop growing areas of the province, where as the water situation remained satisfactory in Punjab, which had supplemented the over all output for the season.

Dr Abdullah further informed that due to water stress, the overall 5-10 percent yield in Sindh was expected to reduce, adding that prices of local produces was remained stable and encouraging the growers.

The prices of above mentioned commodity in the international markets were recorded at 91 Cents, where as in local markets it was sold at Rs 4,000  per 40 kg, Cotton Commissioner added.

It may be recalled that cotton crop had been sown over 2.69 million hectares of land as against the fixed targets of  2.95 million hectares in order to produce over 14.37 million cotton bales during the crop season 2018-19.

The crop cultivation targets, which fixed for the current sowing season were achieved by over 91 percent as it went up by 2  percent as compared with the area under cotton crop cultivation during same period of last year.

Over all cotton sowing in the Province of Punjab  registered about 11 percent growth as it had cultivated the crop over 2.29 million hectares of land as against the set targets of 2.31 million hectares for the period under review.

However, crop sowing in the Sindh Province was decreased by 31percent and attributed the low sowing trend with dry weather during the crop sowing time as well as shortage of water for crop irrigation.

ECC to address root cause of Rs1.17 trillion circular debt

ISLAMABAD: The first meeting of the newly-reconstituted Eco­n­o­mic Coordination Committee (ECC) of the Cabinet did not take any conclusive decision on Wednes­day but appeared to be setting the stage for some serious business — to make fertiliser companies return Rs10 billion windfalls to the economy and to address the root cause of power sector circular debt.

Presided over by Finance Minister Asad Umar, a meeting of the ECC did not formally take up the difficult political decision for an increase in consumer-end gas prices by an average 30 per cent determined by the regulator a few months ago.

A senior official who attended the meeting told Dawn that the finance minister allowed everybody to express their views and give input and appreciated valid observations. After hearing them all, he desired that these be converted into written suggestions for an informed decision-making in a future meeting.

The meeting believed that the fertiliser industry had earned wind­falls last year when it was allowed subsidised gas for maximum fertiliser production for dom­estic agriculture. However, some participants viewed the subsidy was utilised for higher production that was later exported; otherwise there would have been no need for fertiliser import at this stage.

The summary under discussion demanded import of 600,000 tonnes of urea for the upcoming crop-sowing season. It was observed that the industry had earned Rs10bn extra windfalls out of subsidy and its export and should be made to pass on the amount to domestic farmers.

Mr Umar, who himself has a long practical background of the fertiliser industry, “expressed displeasure on the issue of fertiliser pricing and its export, taken by the previous government which was totally against the interests of the farmer community”, an official statement said.

He said the interest of poor farmers should be the supreme motivation for taking such decisions. The ECC was informed that the total requirement of fertiliser for this sowing season in the country would be around 600,000 tonnes.

The meeting decided to form a committee led by Adviser to the PM on Industry and Production Abdul Razak Dawood to hold discussions with the local fertiliser industry to ascertain the total domestic production. The committee will present its recommendations in the next ECC meeting to enable decision-making regarding import of urea.

In another summary, the power division of the ministry of energy demanded about Rs170bn to partially bail out the power sector that had developed a total circular debt of Rs1.178 trillion, with an addition of Rs30bn in July. It reported that fresh flow of circular debt stood at Rs566bn as of July 1, 2018, but had gone up to Rs596bn at the end of July.

Another Rs582bn were parked with the Power Holding companies under short-term financing facility arrangements, taking the total liability to Rs1.178trn. It was also reported that total receivables of the power sector had piled up close to Rs800bn.

It was agreed that habitual defaulters should be immediately shifted to pre-paid meters and areas with high incidence of default should be included in such a scheme. The major cause of concern was average power sector losses of about 18.5pc instead of 16.3pc allowed by the consumers. A committee was formed to address price gaps that develop on a quarterly basis because of currency indexation, etc., so that these do not pile up as circular debt.

It was also concluded that receivables should be reconciled with provincial governments, particularly Balochistan and Azad Kashmir, for settlement of their arrears and also to aggressively take up with K-Electric for recovery of Rs80bn arrears to the national grid.

As such, the meeting identified five-six key areas that accounted for the pile up of these liabilities and formed a few committees to work upon the reasons and formulate their suggestions to be presented in the next ECC meeting scheduled in the next week. The ECC will later present its suggestions to the cabinet for approval and decision on the future course of action.

The finance minister said all facts will be shared with the public to make the decision-making a transparent and inclusive exercise. He also deferred a decision on a summary regarding arrangement of funds for the Pakistan State Oil to dilute its receivables of about Rs330bn after initial discussion saying the subject was closely linked with the circular debt, and should be settled next week in a holistic manner.

DNA: Revolutionary advancement in agricultural pest surveillance

Brown marmorated Stinkbug nymph, Image by Photochem_PA

The use of DNA to detect a stinkbug invasion proposes a revolutionary advancement in agricultural pest surveillance following the success recorded on a piloted experiment conducted on farms in the USA. These interlopers attack all manner of produce, ranging from fruits to leafy vegetables.  However, the adoption of DNA techniques in detecting its early invasion may help to bring its assault to a halt, as opposed to the use of pheromone traps which may only be effective after the pest’s population are pronounced.

Originating from eastern Asia, the brown marmorated stink bug (halymorpha halys) was accidentally introduced into North America in the mid to late 1990s. With the initial discovery made in Pennsylvania, it has now been detected in 41 states and isolated populations have also been found in Canada.  In the USA, stinkbugs have become a particular nuisance pest in the mid-Atlantic region and Pacific Northwest, due not only to their destruction of important cash crops but also their overwintering behaviour of swarming people’s homes in large numbers.

It takes no time for farmer efforts to be rendered futile whenever stinkbugs invade their farmland. Their infestation cuts across the vegetative and reproductive stage of plant growth. As a recent article from Scientific American states, “If a farmer can grow it, a brown marmorated stinkbug can destroy it”.

Stinkbugs ravage a wide variety of fruits and vegetables by feeding on plant fluid through the insertion of its needle-like mouthpart into the stem, leaves, and seed pods. Entomologists from Kentucky University classified the damage caused by stinkbugs into 3 types, namely; the killing of small seedlings, stunted growth, and lastly enhancing production of tillers from the base of damaged plants.

Many food crops like corn, peaches, apples and tomatoes have been reported to be vulnerable to infestation from this invasive species and most times, remedies appear too late following detection. In 2010, about $37 million worth of apple fruit was lost due to stinkbug invasion. Likewise, the total loss of a Maryland peach harvest in 2012 was attributed to stinkbug invasion. Therefore, if not detected early, the introduction of control measures may not be effective enough to stop significant damage.

In this recent research, scientists have developed means to raise the stinkbug alarm at the earliest possible stage of its invasion by adapting genetic technologies used by scientists to detect aquatic invasive species. Early detection of the pest was achieved by sampling the water used by farmers when rinsing their crops before offering them for sale. This procedure helps to aggregate stinkbug DNA contained in body secretions that are left on crops by the insects. According to Dina Fonseca, a molecular ecologist and a member of the research team at Rutgers, “it would have been difficult to gather the DNA if crops were not rinsed. Reason being that, DNA contained in the pest’s secretions stick to a fixed position after it has been shed. Hence, the rinsing of crops was the saving grace to collecting the DNA.”

This method, which also included the use of pheromone traps to visually confirm the presence of the pest, was tested on two separate sites: a peach orchard in New Jersey known to harbour stinkbugs and a mixed produce farm in New Hampshire located just outside of the stinkbug’s known range. Both farms tested positive for stinkbug DNA in the water sample from rinsed crops, and stinkbugs were also caught in the pheromone traps. In light of these positive results, the researchers claim that the method could “revolutionize agricultural pest surveillance.”

However, contrary to the intriguing effectiveness of environmental DNA in detecting the early invasion of stinkbugs, Thomas Kuhar, a Professor of entomology at Virginia Polytechnic Institute who didn’t partake in the experiment, highlighted the importance of continuing to use the traditional method, that is, pheromone traps which are cheaper and better at both capturing pests physically and estimating their abundance. Although he does note that the environmental DNA method could be useful in regions like New Zealand where they do not currently harbor brown marmorated stinkbugs but are certainly at risk of invasion.

This research contributes to the growing body of work on stinkbugs and in the long-run could help to give farmers the upper hand in early detection of the pest.

To read more on this, follow the links below

Sunmbo Olorunfemi is a graduate of Sustainable Agriculture and Food Security and currently working as an intern with the Plantwise Knowledge Bank.

Plant viruses manipulate the feeding behavior of aphids

R. maidis feeds on a wheat plant. The team found that viruses manipulate the feeding behavior of aphids to improve their own ability to pass on their genomes to the next generation of viruses. Credit: J. Smith, Penn State

In the world of plant-feeding insects, who shows up first to the party determines the overall success of the gathering; yet viruses can disrupt these intricate relationships, according to researchers at Penn State.

“We found further evidence that manipulate more advanced organisms to improve their own fitness,” said Mitzy Porras, a recent doctoral graduate in entomology, working with Tomas Carlo, associate professor of biology, and Ed Rajotte, professor of entomology.” In other words, their ability to pass on their genome to the next generation of viruses.”

Porras and her colleagues studied the order of arrival of two species of aphids to wheat plants.

“Species that share the same limiting resource—in this case wheat plants—normally are expected to compete with each other for that resource,” she said. “But we found that the order of arrival to the host plant affects the outcome of the ecological interactions.”

Porras explained that in the absence of viruses, the aphid species Rhopalosiphum padi typically is the first to invade wheat plants, while Rhopalosiphum maidis arrives later. If the opposite occurs—R. maidis arrives first—then the success ofi R. padi is hindered. However, when R. padi infects the plant with barley (BYDV), two things change: the success of late-arriving R. maidis increases and, if R. maidis arrives first, then late-arriving R. padi has no trouble colonizing the plant.

“The increases nutrients in the plant, including sugars, sterols and amino acids, and may change the anatomy of the plant’s leaves, making the leaves easier for aphids to find and access the nutritious sap,” said Porras. “The aphids end up feeding for longer periods of time, which results in boosted reproductive success. The better the aphids do, the higher the probability that they will spread the virus to the and to other aphids.”

The findings appeared recently in Scientific Reports.

Porras and her colleagues designed a set of field and laboratory experiments in which they manipulated the presence of virus strains within aphids, along with the order of aphid species arrival to . They recorded the time it took for the aphids to start feeding, the duration of feeding and the reproductive health of the aphids. They also examined how aphid foraging affected the nutritional quality of host plants and plant virus strains.

“We placed electronic micro-sensors on individual insects and plants to measure feeding events with precision,” said Porras. “Specifically, we measured two key parameters of foraging—the time taken by aphids to reach the phloem (the nutritious plant sap), and the duration of ingestions.”

The team extracted viruses from plants, and used ELISA tests—which detect specific antibodies—to identify the types of viruses within the plants. In addition, they used a variety of gas chromatography and mass spectrometry techniques to analyze the for nutrient content.

“We learned that viruses play an important role in changing the nature of the interactions between and among species,” said Porras. “It’s fascinating that something as small as a virus with such a simple genome can manipulate more advanced organisms for its own benefit.”

Explore further: Aphids manipulate their food

More information: Mitzy Porras et al, A plant virus (BYDV) promotes trophic facilitation in aphids on wheat, Scientific Reports (2018). DOI: 10.1038/s41598-018-30023-6

Urban farming | Global Plant Protection News

Urban farming has been on a steady increase for many years now as space for agriculture creeps closer to cities and consumers look to reconnect with what they eat. As well as appealing to the health and environmentally conscious market, these systems often seek to achieve community benefits; providing opportunities and education for disadvantaged and minority groups. The size and purpose of urban agricultural systems can range enormously, encompassing: allotments, vertical farming, agroparks and community gardens, ranging from subsistence to industrial sized operations.

“Urban and peri-urban agriculture (UPA) can be defined as the growing of plants and the raising of animals within and around cities” FAO 2018

The main focus of urban agriculture is on the utilisation of underutilised spaces, including rooftops, walls and basements. CloudGro supplies lightweight modules designed to sit atop supermarkets, growing fresh produce on otherwise wasted space, which can then be monitored autonomously and brought down to shop level, creating a farmer’s-market style buying area. The system operates using the waste heat and CO2 generated by large superstores, helping to monetise waste products. The main advantage of inner city or supermarket based farming such as this is the reduction in transportation; saving time, emissions and extra packaging. Costs are reduced through the lack of need for refrigeration and transport, making fresh food more affordable for poorer consumers.

For the highest efficiency, in terms of space required for produce generated, controlled environment systems generate the greatest returns as they can be carefully calibrated to deliver optimum growing conditions for maximum yield. Vertical farming also allows farmers to increase efficiency by growing produce in stacked shelves or vertical planters. The kit used in controlled environment systems and vertical farming can range in complexity from simple roof-top set ups to highly optimised operations where even the wavelengths of light the plants are exposed to is monitored.

Hydroponics cultivates plants in water as opposed to soil, making it easier to maintain a constant supply of nutrition to the plants roots.

Aquaponics adds a second element to the hydroponic system by sourcing the crops nutritional supply from waste water generated by aquaculture; the waste is fed to a system of nitrifying bacteria which convert it into organic nitrogen for uptake by the crop roots. The now filtered water is then safe to return to the aquaculture container. This system makes more economical use of water in return for the production of two outputs; fish and vegetables, whilst creating a more efficient chain of nutrient usage.

Aeroponics involves the suspension of plant roots in a nutrient dense mist. This approach is touted to be even more efficient than hydroponics due to the higher oxygen availability for the crop roots.

For subsistence farming, these systems can be relatively simplified and require minimal inputs, providing a much needed nutritional enhancement and food security for the urban-poor. At the other end of the spectrum commercial operations are focussed largely on high value crops such as herbs and salad greens whose appeal is dependent on retaining freshness but are liable to transport spoilage.

Of course there are also disadvantages to urban farming’s swift rise; A lot of urban agriculture is unregulated and can occur on communal land, creating health risks from improper management of inputs. For the more high tech operations there is still some serious debate over whether the reduction in energy logically inferred through a reduction in transport distance does actually translate into a significant saving.

The expansion of urban areas means these forms of farming are likely to continue their increase in popularity across both the developed and developing world. As growth techniques become more refined, underutilised spaces may well become more productive than traditional agriculture for some leafy crops. With more commercial projects beginning to gain ground it is possible that in the next few years you the salad you eat may never have touched soil or even seen the sun. You may even have grown it in your own basement.


Find out more about urban agriculture projects here: