The Plantwise Blog

Maize lethal necrosis disease on the decline in Kenya


Plant clinic data collected by Plantwise countries in East Africa has corroborated a statement from the International Maize and Wheat Improvement Center (CIMMYT) which said maize lethal necrosis disease (MLN) is “under control but not eradicated”.

MLN is a destructive disease of maize caused by co-infection of Maize chlorotic mottle virus (MCMV) and any virus in the Potyvidrae family. Symptoms include mottling on leaves, leaf necrosis, stunted growth, dead heart, poor seed set, premature aging and death of plants. Early infection can result in total yield losses, further compounded by the possible disappearance of symptoms during the growing season, making disease detection more difficult. The disease can spread via insects such as thrips, aphids and beetles, as well as through seed contamination.

Originating in the Americas, MLN was first reported in Africa in Kenya in 2011. During 2012-2014, the disease spread rapidly throughout East Africa, threatening the livelihoods and food security of farmers in the region, as well as those in as yet unaffected areas across Africa. The effects of MLN are severe, as coupled with the losses of crops caused by the disease, trade is often embargoed between locations which are known to harbour infection and those that aren’t.

The table below demonstrates estimated current and future losses attributed to MLN in Africa. The potential scale of the destruction inspired a multi-organisational and -national response to prevent the disease taking hold in Africa, including efforts by CIMMYT, CGIAR, USAID, the Bill and Melinda Gates Foundation, and CABI to name a few.

Table of Economic Losses, MLN

Due to the rapid detection of MLN and the response of the countries involved, it has been reported that the disease is under control but not eradicated. “We have managed to contain the spread within the region but continue to monitor its movements” says Dr Prasanna, Director of CIMMYT’s Global Maize Program. This comes after survey work conducted in eastern and southern Africa in 2018, which showed no MLN in Malawi, Mozambique, Zimbabwe and Zambia, and incidence in Kenya is falling.

CABI has confirmed this by using Plantwise plant clinic data with no records of MLN in Malawi, Mozambique or Zambia. Diagnosis of MLN has indeed seen a fall in Kenya since 2014, despite more maize plants being seen in plant clinics than in previous years. This, along with the survey results, demonstrates the success of the governments, farmers and research institutions in Kenya to diminish the impact of MLN. Quarantining maize from infected regions; crop rotation; use of certified, clean seeds and hybrid, tolerant plants; stringent monitoring; and insecticide application to reduce transmission by insects were employed to minimise spread in Kenya.


Due to the potential rapid emergence of the disease, it can be “difficult to predict where it will be spotted next” claims Dr Prasanna, “hence the need to intensify awareness among farmers”. CABI Plantwise clinics are one of the ways this message has been shared, and a way of detecting new areas of the disease. In fact, MLN was first discovered in Rwanda when it was brought into a clinic. Materials for farmers, such as this flyer from CIMMYT and the CABI factsheets distributed at clinics are another way to increase awareness and vigilance. When plant doctors give advice at plant clinics, they select a “recommendation type” for that advice.


The majority of the advice was “cultural”, which is mostly delivering factsheets to farmers, helping to spread awareness and circulate the most current advice from relevant organisations on controlling the disease. The next most common recommendation was insecticide; promoted to prevent transmission, followed by monitoring and then the use of resistant varieties. The latter has been the subject of much research, and there are now seven hybrid, resistant varieties in Kenya.

As well as plant clinics helping in detecting and controlling the spread of emerging diseases, the resulting data collected can also be extremely useful to ensure surveillance of established diseases. When used in conjunction with data produced by other organisations, such as CIMMYT and CABI, it can help to substantiate these findings, as has been seen here; survey data from CIMMYT has been validated by the diagnoses being delivered in clinic, providing more depth and clarity to the picture being seen on the ground.

Although the picture at the moment is looking very positive, “absence of proof is not proof of absence”. The successes of the MLN interventions can’t lead to complacency. According to CIMMYT, the disease has spread to new areas in Uganda. Farmers, CABI, governments and other organisations  must keep up efforts to monitor and control MLN in Africa to minimise the effects on livelihoods throughout the continent.

Useful information:

Data correct as of 22/03/2019. Data analysed from 01/01/2011- 01/01/2019





For the fourth time All-Russian Institute of Plant Protection (VIZR), the leading center of the agricultural science in Russia and the head research institution for plant protection in Russia, will organize the All-Russian Plant Protection Congress with international participation, with the theme “Phytosanitary technologies in ensuring independence and competitiveness of the agricultural sector of Russia”

This year the Congress is dedicated to 90th anniversary of the Institute and will take place in the leading Congress Hotel of the city – Park Inn Pulkovskaya, September 09-11, 2019, St. Petersburg, Russia.

The Congress will bring together over 500 foreign and Russian scientists and plant protection specialists to share knowledge and experience, to present research results and to discuss plant protection innovations in agriculture and organic farming. All-Russian Plant Protection Congress will be composed of many various sessions and will tackle all important topics on plant protection and allied fields:

  • Phytosanitary monitoring and forecasting
  • Plant diseases
  • Biological plant protection
  • Arthropod pests
  • Biotechnology and molecular biology in plant protection
  • Plant resistance to pests
  • Chemical plant protection
  • IPM: engineering, organizational and economic issues

All main plant protection, plant pathology, entomology, mycology, microbiology societies and organizations, as well as keynote speakers, which have significant importance for plant protection in Russia will participate in the Congress. Also, leading private companies have joined the Congress and will present their stands and speakers: «Syngenta», «BAYER», «Schelkovo Agrochem JSC», «Shetelig Rus JSC», «HEMA Group of Companies», «Syntol», «Diaem», «Analytics and High Technologies Company», «AgroBioTechnology LLC». Main theme of the Exhibition is «Modern agrotechnologies in intensive crop production and organic farming».

We invite you to visit Saint Petersburg, one of the largest world centers of scientific cooperation, city with rich cultural and historical UNESCO world heritage!

Please visit our congress home page for more details:


Prof. Olga Afanasenko

IAPPS Coordinator Region II: Eastern Europe

E-mail: olga.s.afan@gmail.com



Welcome Letter

IV All-Russian Plant Protection Congress with international participation “Phytosanitary technologies in ensuring independence and competitiveness of the agricultural sector of Russia”

All-Russian Institute of Plant Protection is celebrating its 90th anniversary in 2019. Since the foundation of our Institute, many leaders of our nation, and ideologies changed, new technologies were introduced in agriculture, the intensity of land use transformed. However, the relevance of the plant protection research has always been extremely high and will remain so in the future.

Currently, the main mission of the Institute is providing the scientific background for the food security in Russia. In the Institute we undertake the research in almost all areas related to crop protection, which ranges from the fundamental biology to the development of measures, methods and systems of plant protection. We are proud to continue the work started by the founder of our Institute N.I. Vavilov and his associates.

The important component of our work is organizing the activities, where participants can share the achieved results, discuss them, inspire with new ideas and establish creative and business contacts. All-Russian congresses on plant protection have been held on the initiative of the VIZR in Saint Petersburg since 1995. The previous third Congress was held in December, 2013 and gathered nearly 200 specialists. According to our plans, the upcoming event should be more ambitious and eventful. On behalf of the organizing Committee, I invite you to take part in the Congress, which will be held on September 9-11, 2019!

The scientific program of the Congress covers all traditional areas of the research in the field of plant protection, and they are as follows: (1) monitoring of harmful and useful objects; (2) chemical, biological methods and integrated plant protection systems; (3) plant immunity; (4) agricultural biotechnology; (5) economy and agro engineering issues. We will have plenary and section presentations, as well as full poster session. For the first time the Congress will host an exhibition of the scientific laboratory equipment and products for plant protection, including biopesticides, chemical drugs, entomophages, and others. During the Congress, we will organize a special meeting on the biological control of the greenhouse pests, which will be attended by the scientists, farmers and manufacturers of natural and other plant protection products.

The Congress organizers will make every effort to form an interesting scientific and cultural program and to provide inspiring discussions and business networking!

Website: http://vizrcongress2019.ru/en/home/







Science Nordic

Fighting the insect apocalypse with hotels, flowers and dead trees

April 8, 2019 – 06:00

The news is full of stories about how the world’s insects are disappearing, whether from pollution, climate change, habitat losses or a combination of all three. But there are simple measures that people can use to fight back.


A honeybee collects pollen from a crocus. (Photo: Hallvard Elven, Natural History Museum)


Insects may be as bothersome as mosquitoes or as wonderous as honey bees, but whether small and troublesome or big and useful, insects across the globe are in trouble.

In recognition of alarming reports worldwide, Norwegian authorities last summer put into place a National Pollinator Strategy to monitor Norway’s insect populations.

But the average person can also do something about insect decline, experts say, even if they don’t have a big back yard or a farm at their disposal.

These actions can be as simple as making certain you don’t remove all dead wood from your yard, or something a little more involved, like building or buying an insect hotel.

An insect hotel at the University of Oslo’s Botanical Garden. The university’s Natural History Museum has plans to set up a number of insect hotels to study their usefulness. (Photo: Dag Inge Danielsen)


Researchers from the University of Oslo Natural History Museum and employees from the University of Oslo’s Botanical Garden have some suggestions for actions that can help.

Insect hotel for larvae and eggs

An insect hotel may sound like an odd concept, but at its most basic, this kind of structure provides protection for insect eggs and larvae.

Hallvard Elven, an entomologist at the University of Oslo’s Natural History Museum, says the most important feature of an insect hotel is that it offers lots of different-sized holes.

“The holes should be between 1 mm and I cm in diameter,” he says. “That makes the hotel attractive for different insect species.”

“Insects need flower blooms to survive,” says entomologist Hallvard Elven. “Many species also need open sandy soil and dead wood.”

He says if you make this structure yourself, you have to make sure that the holes don’t go all the way through — there should only be an opening in the front.

Find a sunny place

The insect hotel should be hung on a sunny wall or placed somewhere in your garden where it is good and warm during the daytime, and with flowers nearby.

The hotel should have some kind of netting to prevent birds from eating the inhabitants.

Other than that, you don’t need to do anything. In fact, you want to leave your insect hotel alone for the autumn and winter because the next generation of insects will climb out of their chambers during the following spring.

The hoverfly, Helophilus pendulus, is one of the species that is an important pollinator in Norway. (Photo: Halvard Elven/ UiO Natural History Museum)


“An insect hotel is primarily a place where wild bees and digger wasps, both of which are typically solitary, can nest. In nature these insects often have nests in hollow reeds or cavities in wood. For example, they use the chambers left in tree trunks by boring beetles,” says Elven.

The hotel’s cavities and entrances are visited by bees and digger wasps that pack food into the cavity, often in a row and inwards into the ‘tunnel’. The bees make food packs of pollen and nectar, while digger wasps use insects.

Females then lay an egg inside this food package. When the female is done, she crawls out and plugs the opening with clay, sawdust or wax. And that’s it. Eventually, the egg turns into a caterpillar, which feasts on the food that was left by the female.

During the summer or fall, this insect will pupate, still inside the hotel’s cavity. After a long and cold winter, when the sun is warm and the first flowers come out, the new insect emerges.

A Queen of Spain fritillary, Issoria lathonia, feeding from a yellow chamomile flower. (Photo: Halvard Elven/ UiO Natural History Museum)


Elven says there isn’t much research documenting the utility of insect hotels, but that he is working on setting up a study.

Provide blooms throughout the season

Another action you can take, if you have a yard, is to plant flowers and shrubs that bloom throughout the growing season, says botanist and museum lecturer Kristina Bjureke.

“Some insect species prefer open flowers where they can easily access the pollen. Others specialize in drinking nectar and have long tongues that can fit into deep, narrow flower tubes. Different varieties of plants and pollinating insects are adapted to each other over time and are mutually dependent on each other,” Bjureke says.

Bjureke has helped to develop specific plant lists for Norwegian gardeners so they know which plants are best for different insects. The website, in Norwegian, is at blomstermeny.no.

A garden bumblebee, Bombus hortorum, on a Siberian corydalis in the Oslo Botanical Garden. The garden bumblebee is one of the long-tongued bumblebee species. (Photo: Hallvard Elven / UiO Natural History Museum)

Flowers that provide both pollen and nectar are especially important, Elven said.

“Bees and bumblebees need both pollen and nectar,” he says. In addition to his research, he has also collaborated with Bjureke on different projects to preserve threatened habitats and inform the public about the value of the interaction between insects and flowers.

“Adult bees and bumblebees use nectar as fuel, while the larvae need pollen and nectar to grow. Other important pollinators are butterflies, which eat nectar, and beetles, which mainly eat pollen,” Elven says.

Protect meadows, old trees

One of the reasons that insects are disappearing is that meadows rich with native flowers are in increasingly short supply.

Botanist and lecturer Kristina Bjureke (right) collects seeds from a meadow in Oslo along with Gro Hilde Jacobsen from Bymiljøetaten, Oslo’s urban environment agency.

“A perfect lawn is of no interest to insects. Flower beds and pots with garden centre plants can help some species, but native meadow plants help many species,” Elven said.

Open sandy soil, old trees and dead tree trunks are also some of the most important habitat for insects, he adds. Death and decay, in fact, mean new life in the world of insects.

Many bees nest in sandy soil, but this soil is disappearing underneath trees and shrubs as meadows are overgrown, Elven said.

“That prevents bees from getting access to the sandy soil they need for nesting. This is one of the reasons why there are fewer bees,” he said.

The queen of a red-tailed bumblebee, Bombus lapidaries, on a dragon head. Dragon head flowers have characteristics that are typical of plants adapted to bumblebees, with blue flowers, a deep nectar tube and an opening that few other flower-visiting insects can pass through. (Photo: Hallvard Elven, UiO Natural History Museum)

Old, sick and dead trees are also important sites for a variety of insects and fungal species.

“For insects, an ordinary tree is more exciting after it is dead than while it is growing. Insects can live in a dead tree, and there are biotopes for hundreds of species,” he said.


Read the Norwegian version of this article at forskning.no



A honey bee collects pollen. Credit: James Nieh, UC San Diego

A recently approved pesticide growing in popularity around the world was developed as a “bee safe” product, designed to kill a broad spectrum of insect pests but not harm pollinators.

A series of tests conducted over several years by scientists at the University of California San Diego focused on better investigating the effects of this chemical. They have shown for the first time that Sivanto, developed by Bayer CropScience AG and first registered for commercial use in 2014, could in fact pose a range of threats to honey bees depending on seasonality, bee age and use in combination with common chemicals such as fungicides.

The study, led by former UC San Diego postdoctoral fellow Simone Tosi, now at ANSES, University Paris Est, and Biological Sciences Professor James Nieh, is published April 10 in Proceedings of the Royal Society B.

Pesticides are a leading health threat to bees. After years of growing concerns about systemic toxic pesticides such as neonicotinoids and their harm on pollinators, Sivanto was developed as a next-generation product.

Sivanto’s “bee safe” classification allows it to be used on blooming crops with actively foraging bees. Currently, pesticides are approved for widespread use with only limited testing. Perhaps most importantly, the interactions between new pesticides and other common chemicals such as fungicides are not fully tested. Sivanto’s product label does prohibit the pesticide from being mixed in an application tank with certain fungicides. However, bees can still be exposed to Sivanto and other chemicals (pesticide “cocktails”) that are commonly used in adjacent crops or that persist over time.

bee 2
Honey bee workers inside their nest. Credit: Heather Broccard-Bell

Starting in 2016, after reviewing documents describing Sivanto’s risk assessments, the scientists conducted several honey bee (Apis mellifera) studies investigating effects that were not previously tested, particularly the behavioral effects of chemical cocktails, seasonality and bee age. The scientists provided the first demonstration that pesticide cocktails reduce survival and increase abnormal behaviors. They showed that worst-case, field-realistic doses of Sivanto, in combination with a common fungicide, can synergistically harm bee behavior and survival, depending upon season and bee age. Bees suffered greater mortality—compared with control groups observed under normal conditions—and exhibited abnormal behavior, including poor coordination, hyperactivity and apathy.

The results are troubling, the researchers say, because the official guidelines for pesticide risk assessment call for testing in-hive bees, likely underestimating the pesticide risks to foragers. Honey bees have a division of labor in which workers that are younger typically work inside the colony (in-hive bees) and foragers work outside the colony. Foragers are therefore more likely to be exposed to pesticides.

“We found foragers more susceptible,” said Nieh. “They tend to be older bees and therefore because of their age they can suffer greater harm.”

The harmful effects of Sivanto were four-times greater with foragers than with in-hive bees, the UC San Diego study showed, threatening their foraging efficiency and survival. Both kinds of workers also were more strongly harmed in summer as compared to spring.

“This work is a step forward toward a better understanding of the risks that pesticides could pose to bees and the environment,” said Tosi, a postdoctoral fellow and project manager at the Epidemiology Unit. According to the authors, the standard measurements of only lethal effects are insufficient for assessing the complexity of pesticide effects.

bee 3a
A honey bee forages on flower. Credit: Heather Broccard-Bell

“Our results highlight the importance of assessing the effects pesticides have on the behavior of animals, and demonstrate that synergism, seasonality and bee age are key factors that subtly change pesticide toxicity,” Tosi said. Cocktail effects are particularly relevant because bees are frequently exposed to multiple pesticides simultaneously.

“Because standard risk assessment requires relatively limited tests that only marginally address bee behavior and do not consider the influence of bee age and season, these results raise concerns about the safety of multiple approved pesticides, not only Sivanto,” said Nieh, a professor in the Section of Ecology, Behavior and Evolution. “This research suggests that pesticide should be refined to determine the effects of commonly encountered pesticide cocktails upon bee behavior and survival.”

Sivanto is available in 30 countries in America, Africa, Asia and Europe, with 65 additional countries preparing to approve the product soon. Tosi points out that “because Sivanto was only recently approved, and no monitoring studies have yet investigated its co-occurrence with other pesticides after typical uses in the field, further studies are needed to better assess its actual environmental contamination, and consequent risk for pollinators.”

“The idea that this pesticide is a silver bullet in the sense that it will kill all the bad things but preserve the good things is very alluring but deserves caution,” said Nieh.



Public Release: 

Tiny traces of neonicotinoid pesticides impair insects’ ability to spot predators

University of Saskatchewan

IMAGE: Traces of neonicotinoid pesticides can impair a flying insect’s ability to spot predators and avoid collisions with objects in their path. view more 

Credit: University of Saskatchewan

Traces of neonicotinoid pesticides can impair a flying insect’s ability to spot predators and avoid collisions with objects in their path, new research by the University of Saskatchewan (USask) shows.

Residual traces of these widely-used pesticides can profoundly affect a flying insect’s ability to detect movement–a skill crucial to survival, according to the paper published in the journal NeuroToxicology.

Within an hour of being treated with tiny amounts of neonicotinoids or their metabolites (trace elements present after the insecticide begins to break down), the flying insects did not turn, glide or stop to avoid collision.

“Our findings suggest that very low doses of the pesticide or its metabolic products can profoundly and negatively affect motion detection systems that flying insects, such as locusts, grasshoppers and bees, need for survival,” said Jack Gray, an expert in neural control of animal behavior and Vice-Dean of Research, Scholarly and Artistic work in USask’s College of Arts and Science.

“Although they are found in the environment, and insects can be exposed to them, metabolites are not typically tested for toxicity. Our results suggest they should be.”

Neonicotinoid pesticides (or neonics) are the most widely used class of insecticides in the world and are neurotoxins. The European Union has restricted use of some neonics following concern over their impact on pollinators, including bees, and there have been proposals to restrict their use in Canada.

Although neonicotinoids break down into different compounds and can exist in trace amounts in the environment, these levels are typically not tested for toxicity.

Locusts exposed to trace elements of the neonicotinoid imidacloprid were unable to detect object motion in their field of view. When dosed with slightly higher amounts, the locusts were unable to fly straight or failed to take off at all.

The findings by researchers in the USask Department of Biology are part of a wider USask research program into the impact of trace elements of neonicotinoids on flying insects.

In tests on the locust’s nervous systems using electrophysiology, the USask biologists found their motion-detector neurons were less sensitive after being treated. Their ability to process and relay information quickly, and therefore respond quickly while flying, was also impaired.

Using a specially-designed wind tunnel, the research team measured a flying locust’s ability to navigate around simulated approaching objects–a skill crucial to avoiding predators and obstacles such as bushes and trees.

Good vision is crucial to insects’ survival as it allows them to see predators including larger insects and birds and avoid collisions with other insects or objects in their path.

The team will soon begin researching whether trace levels of neonicotinoids can disrupt navigation and flight behaviour in honeybees, affecting the neural mechanics which stabilize flight, control flight speed, altitude, and help insects calculate distance.

“Bees and other flying insects use similar neural mechanisms to process visual motion, and the ability to see movement is crucial not only for avoiding predators, but also for maintaining a steady flight path,” said Rachel Parkinson, a PHD biology student.


Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.


Public Release: 

How plants defend themselves

Plant immune system detects bacteria through small fatty acid molecules

Technical University of Munich (TUM)

IMAGE: Arabidopsis thaliana leaves are infected by simply pressure-infiltrating a solution containing the bacteria. view more 

Credit: Astrid Eckert / TUM

Like humans and animals, plants defend themselves against pathogens with the help of their immune system. But how do they activate their cellular defenses? Researchers at the Technical University of Munich (TUM) have now discovered that receptors in plant cells identify bacteria through simple molecular building blocks.

“The immune system of plants is more sophisticated than we thought,” says Dr. Stefanie Ranf from the Chair of Phytopathology of the TU Munich. Together with an international research team, the biochemist has discovered substances that activate plant defense.

Until now, scientists have thought that plant cells – similar to those of humans and animals – recognize bacteria through complex molecular compounds, for example from the bacterial cell wall. In particular, certain molecules composed of a fat-like part and sugar molecules, lipopolysaccharides or LPS for short, were suspected of triggering an immune response.

In 2015, Ranf’s team successfully identified the respective receptor protein: lipo-oligosaccharide-specific reduced elicitation, or LORE for short. All experiments indicated that this LORE protein activates the plant cell’s immune system when it detects LPS molecules from the cell wall of certain bacteria.

A throwback leads to the right track

“The surprise came when we wanted to study this receptor protein more closely,” recalls Ranf. “Our goal was to find out how LORE distinguishes different LPS molecules. For this we needed high-purity LPS. ”

The researchers found that only LPS samples with certain short fatty acid constituents triggered plant defense. Surprisingly, they found in all these active LPS samples also extremely strong adhering free fatty acid molecules. Only after months of experimentation was the team able to separate these free fatty acids from the LPS.

“When we finally succeeded in producing highly purified LPS, it became apparent that the plant cell did not respond to them at all! Thus, it was clear that the immune response is not triggered by LPS, but instead by these short fatty acids” said Ranf.

Targeting bacteria building blocks

The 3-hydroxy fatty acids are very simple chemical building blocks compared to the much larger LPS. They are indispensable for bacteria and are produced in large quantities for incorporation into diverse cellular components.

“The strategy of plant cells to identify bacteria through these basic building blocks is extremely sophisticated; the bacteria require these 3-hydroxy fatty acids and therefore cannot bypass the immune response,” summarizes Ranf.

Fitness program for plants

In the future, these results could help in breeding or genetically engineering plants with an improved immune response. It is also conceivable that plants treated with 3-hydroxy fatty acids would have increased resistance to pathogens.


The work was performed by an international and interdisciplinary collaboration of plant molecular biologists, chemists, and microbiologists. In addition to the Chair of Phytopathology and the Chair of Food Chemistry and Molecular Sensory Science of TUM, the Research Center Borstel (Leibniz Lung Center), the Helmholtz Zentrum München, the Austrian Gregor Mendel Institute for Molecular Plant Biology, the University of Maryland / USA, and the French University of Reims Champagne-Ardenne were involved in this work.

Stefanie Ranf’s research was funded by the German Research Foundation (DFG) as part of the Collaborative Research Center (SFB) 924 and the Emmy Noether Program.


Bacterial medium chain 3-hydroxy fatty acid metabolites trigger immunity in Arabidopsis plants

Alexander Kutschera, Corinna Dawid, Nicolas Gisch, Christian Schmid, Lars Raasch, Tim Gerster, Milena Schäffer, Elwira Smakowska-Luzan, Youssef Belkhadir, A. Corina Vlot, Courtney E. Chandler, Romain Schellenberger, Dominik Schwudke, Robert K. Ernst, Stéphan Dorey, Ralph Hückelhoven, Thomas Hofmann, Stefanie Ranf

Science, April 12, 2019 – DOI: 10.1126/science.aau1279

Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.