The Feed the Future Innovation Lab for Integrated Pest Management (IPM Innovation Lab) – a U.S. Agency for International Development (USAID)-funded organization housed at Virginia Tech – is implementing augmentative biocontrol in Nepal and Bangladesh to help manage the spread of fall armyworm (FAW), Spodoptera frugiperda. Thus far, the program has successfully trained numerous scientists and technicians across both countries on the process of mass-rearing and releasing FAW’s natural enemies.
In 2018, farmers in Asia could look at a leaf curled around an ear of corn and practically see through it. Translucent “windowpane” leaves, along with frass and round holes on the ear of corn itself, are signature marks showing that the invasive fall armyworm (FAW) pest has attacked and reached a field of one of the most important staple food crops in the world.
While the FAW attacks hundreds of plant species, the pest prefers to feed on maize, in which over 200 million people are dependent for food security every day. The FAW adapts to new environments quickly, is resilient to harsh conditions, can fly up to 100 miles in one night, and rapidly pushes out native insects. By 2023, the pest has reached more than 70 countries worldwide and has cost billions of dollars in crop losses.
FAW has cost billions of dollars in crop losses worldwide. Photos courtesy IPM Innovation Lab, Virgina Tech
At the time of FAW’s arrival in Asia in 2018, the IPM Innovation Lab had already started developing an augmentative biocontrol protocol – or the release of additional numbers of a natural enemy when too few are present to control a pest effectively – against FAW in Africa, where the fall armyworm had already begun
causing USD$6 billion in losses annually. Given the extremely replicable approach, the IPM Innovation Lab began surveying for natural enemies in Asia through its two associate awards, the Feed the Future Nepal Integrated Pest Management (FTFNIPM) program – implemented locally by International Development Enterprises (iDE) – and the Feed the Future Bangladesh Integrated Pest Management Activity (IPMA), a collaborative project with CIMMYT.
“The fall armyworm is a very resilient pest, so it requires a long-term, sustainable solution to mitigate it,” said Muni Muniappan, director of the IPM Innovation Lab. “Biocontrol of FAW is a valuable approach for many smallholder farmers who often cannot afford high-quality pesticides or who lack protective equipment to apply them. Biocontrol harnesses what nature is already doing for us – it increases the natural enemies already attacking FAW, and then, through targeted release, reaches the areas most impacted by the pest.”
Fall armyworm damage.
Over the last several years, FTFNIPM has scouted numerous FAW natural enemies in Nepal, including egg parasitoids Telenomus remus and Trichogramma chilonis; egg larval parasitoid Chelonus formosanus; larval parasitoids Charops bicolor and Cotesia spp.; and pupal parasitoid Brachymeria sp. In Bangladesh, IPMA has scouted egg parasitoids Telenomus remus, Trichogramma chilonis and Trichogramma pretiosum, andlarval parasitoids Bracon hebetor, Cotesia sp. and Campoletis chloridae.
Currently, FTFNIPM is supporting the production of Telenomus remus and Trichogramma chilonis in Nepal and IPMA is supporting the production of Telenomus remus, Trichogramma pretiosum, Trichogramma chilonis and Bracon hebetor in Bangladesh. The programs are harnessing a “satellite”
approach, which involves institutes such as the National Entomology Research Centre in Nepal and the Bangladesh Agricultural Research Institute to serve as nucleus centres that produce FAW parasitoids and subsequently provide training and technical support for universities and provincial laboratories to replicate the process.
Trainees identify FAW in the maize field.
Both FTFNIPM and IPMA develop “IPM Packages,” or suites of IPM strategies farmers can choose from based on their needs and conditions – the packages are also informed by farmer surveys, which assess constraints that limit the capacity of women, youth and marginalized groups to applying IPM strategies. For the IPM Package developed for maize, the programs have established a series of simple approaches farmers can apply both before and after FAW has reached their fields, including biocontrol. Corn seeds, the maize IPM Package recommends, should be treated with a systemic insecticide, which protects the crop up to four weeks from feeding by caterpillar pests, before sowing and setting up pheromone traps in the field. Immediately after first observing FAW moths in the pheromone traps, egg parasitoids reared in a lab can be released into the field. FAW moths will lay eggs on the systemic insecticide-treated plants and the caterpillars that emerge out of those eggs will die when they feed on the leaves. The egg parasitoids will continue to multiply in the field without interruption. By the time the systemic insecticide effect ends, there will be a substantial population of the parasitoid built up in the field.
Young FAW caterpillars that continue to emerge will feed on the maize leaf surface, causing insignificant damage, also known as giving the leaves a “windowpane” effect. However, when the caterpillars reach about an inch in length, they become cannibalistic and eat one another, leaving only one caterpillar on the plant. This caterpillar will feed on the leaves at night and hide in the whorl during the day, which does cause significant damage. For this FAW attack, the IPM Innovation Lab programs recommend treating just the affected maize whorls with neem, which forces the caterpillar out of the whorl, exposing it to the larval parasitoid Bracon hebetor and others.
Young FAW caterpillars feed on leaves at night and hide in the whorl during the day.
“Biocontrol, in combination with other environmentally sound techniques, is an important tool that will help us fight the fall armyworm, a pest that has the ability to wreak havoc across Asia for years to come,” said Madhab Chandra Das, IPMA Chief of Party. “It’s vital to remember just how essential maize is to the food security of communities across the continent. Asia’s millions of small-scale farmers, many of whom own less than an acre of land, have been disproportionately impacted by the
FAW’s invasion given their limited access to technology and that they have less land to depend on.”
In this piloting phase, FTFNIPM and IPMA are in the process of involving provincial government labs, cooperatives, universities, and private entrepreneurs to reach farmers with the biocontrol solution concept. In Nepal specifically, FTFNIPM conducted a study of 17 districts in seven provinces to assess the FAW’s spread in farmers’ fields – while FAW damage has significantly decreased since it first arrived five years ago, overall infestation of FAW is still 19 percent in the districts and continues to significantly impact food security.
Spodoptera caught by the pheromone trap.
The IPM Innovation Lab programs are working diligently to train emerging scientists, including a focus on training women scientists, on the FAW biocontrol technique. In addition, the programs collaborate with a FAW taskforce to prepare communities for FAW spread and conduct national workshops to increase awareness of the pest’s status, biology, management, and methods for engaging the private sector in its management. In Nepal, FTFNIPM supports research assistantships focused on FAW biocontrol to Master’s- and Bachelor’s-level agriculture students at Agriculture and Forestry University (AFU) and Far-Western University (FWU). In Bangladesh, IPMA trained both faculty and students at Patuakhali Science & Technology and Khulna Universities on rearing parasitoids and establishing a parasitoid-rearing laboratory.
“We’ve now helped conduct numerous trainings for scientists and stakeholders on FAW awareness as well as management, and it’s important to emphasize that a collaborative effort such as this will help sustain the management of the FAW pest over time,” said Lalit Sah, iDE Agriculture Program Lead. “We look forward to continuing to build capacity throughout Nepal and across Asia on biocontrol efforts so that it builds a foundation not only for managing FAW, but other caterpillar pests. IPM Innovation Lab support in Nepal and Bangladesh has contributed to the long-term viability of agriculture while reducing reliance on chemical pesticides and minimizing impact on the environment.”
Rasel Miah, an MS student, releases Bracon hebetor in the maize field.
In the coming weeks, five scientists from Nepal and two scientists from Bangladesh are undergoing training on rearing of natural enemies of FAW at the National Bureau of Agricultural Insect Resources at Bengaluru, India. Both programs also conduct exposure visits for Bangladesh and Nepal entrepreneurs, scientists, and extension staff to India to observe production and use of pheromone lures, biopesticides, and biocontrol on the ground. ●
As published in the Good Fruit Grower, the findings stem from a one-year demonstration project funded through the research grant program of the U.S.-based Washington State Wine Commission. The trial’s purpose was to evaluate a novel and sustainable IPM strategy that combinesdrone-released beneficials withuse of methyl salicylate, aninsect attractant.
The study, led by David James, Washington State University entomologist, was conducted in a commercial wine grape vineyard in Benton City, located in the Red Mountain AVA (American Viticultural Area). James specializes in spider and predatory mite studies and ways to enhance natural-enemy populations in grapes and hops. The drone release of beneficials was performed by UAV-IQ Precision Agriculture, a private companythat specializes in biological control through unmanned aerialvehicles (drones).
More than a decade ago, James extensively field-tested methyl salicylate in Eastern Washington vineyards. The compound, which is produced by many plant species and has a fruity, wintergreen odour, showed great promise then as a beneficial arthropod attractant. It is now commercially available under the trade name PredaLure, sold in the form of slow-release sachets.
In the new trial, James wanted to learn if the slow-release dispensers could improve the residence time and sustainability of drone-released beneficials as well as attract a diversity of naturally occurring beneficial insects and mites.
Two beneficial insects (obtained from a commercial insectary) were released by drone in the project: Cryptolaemus beetles, commonly called mealybug destroyer beetles, and the predatory mite Neoseiulus californicus. Drone releases of both species together were made in mid-June and mid-August.
James assessed the insectary beneficials for mortality and viability before and after drone release and determined the method did not appear to be a significant mortality factor. Yellow sticky traps were used throughout the trial to monitor the attractiveness of methyl salicylate to native beneficials. The trial had four treatments: untreated control, drone-released beneficials, drone-released beneficials plus attractant and attractant only.
Spider mite controlSpider mite populations were substantially reduced in all treatment blocks compared to the untreated control. The lowest numbers of spider mites – less than 25 mites per leaf – were counted in the methyl salicylate blocks, with and without drone application of beneficials. But the drone application blocks – averaging 60 mites per leaf – also were well below the number of spider mites in the untreated blocks, which averaged around 240 mites per leaf. Predator mite numbers were highest in the methyl salicylate treatments, with a mean of 2.5 predatory mites per leaf, followed by the drone-delivered methyl salicylate treatments, with a mean of 1.2 predatory mites per leaf. Few were found in the treatments without the attractant. This suggests that methyl salicylate dispensers could play a substantial role in improving biological control of spider mites by increasing populations of predatory mites.
Good suppression of spider mites was also observed in the drone-only treatments, even though few predatory mites were found in these treatments. Most of the predatory mites found during the sampling were native predatory mites and not the drone-released California species of predatory mites. While viability of the insectary-reared California species appeared to be reasonable immediately after release, their low numbers found during post-drone sampling suggest they did not persist well in the vineyard. The California species was chosen because of its significantly lower cost to purchase.
Mealybug observationsGrape mealybug populations were assessed by counting the number of mealybugs on sampled leaves and examinations of grapevine trunks. The number of mealybugs on sampled leaves was lowest in the drone treatment blocks, at 22-25 per leaf, and greatest in the methyl salicylate and control treatments, at 30-34 per leaf. Some data was collected on mature mealybugs, but it was difficult to make accurate counts of immature mealybugs. Although the data suggest that drone releases of the Cryptolaemus lady beetles had moderate impact on mealybug populations, the cooperating grower noted that mealybug population levels in the block were lower than previous years.
James was surprised by the higher number of mealybugs in the methyl salicylate treatment, because methyl salicylate is known to attract many kinds of mealybug predators, including lacewings. The proximity of treatments to each other may have obscured or minimized real effects.
Key findingsThe one-year evaluation demonstrated great potential for this
novel IPM tactic. One of the biggest surprises was the ability of methyl salicylate to attract substantial numbers of a diversity of beneficial insects and mites in wine grapes. Highlights of the data include:
Trend of reduced mealybug populations in blocks with drone-released mealybug destroyer beetles.
Substantial suppression of spider mite populations in all treatment blocks.
Methyl salicylate attracted a variety of native predators, including green lacewings, long-legged flies, lady beetles and big-eyed bugs.
The protocol for the combination tool of drone-released beneficials with an attractant could benefit from additional refinement, such as replacing the attractant sachets after six weeks instead of use all season long, using predator mites native to Washington, timing the drone releases to avoid high temperatures, and improved mealybug monitoring. ●
With drone company UAV-IQ, researcher David James’ research involved the release of beneficial insects by drone to aid in biological control of mealybugs and spider mites in wine grapes.Photo: UAV-IQ
Methyl salicylate dispensers could play a substantial role in improving biological control of spider mites by increasing populations of predatory mites.
Biotalys and Syngenta Crop Protection look to break new ground on bioinsecticides with a collaboration to research, develop and bring new products to the market. Luke Hutson spoke with Patrice Sellès, chief executive officer at Biotalys and Luc Maertens, chief operating officer, to find out more about the collaboration and provide an update on the company’s first product, Evoca.
Belgium-based Biotalys has formed a collaboration with Syngenta Crop Protection to research, develop and commercialize a new range of bioinsecticides.
The aim is to optimize how the protein-based technology of Biotalys, already in use to combat fungal disease such as Botrytis cinerea, could be used against insects.
But what would this mode of action be – contact? “I wouldn't go that far yet,” says Maertens. “We are just kicking off the research phase. So, I think it's a bit premature to narrow it down to a just contact.”
“At this stage, there are various options of what the mode of action will be. That’s the beauty of the platform,” adds Sellès.
The technology platform that Sellès is referring to is known as AGROBODY. What Biotalys calls an agrobody is a nanobody derived from the antibodies produced by a certain camelid.
Llamas produce a unique type of tiny antibody – called a heavy chain-only
antibody, from which the nanobody is derived. The nanobody is also known as a variable VHH (variable heavy homodimers). These heavy chain-only antibodies are smaller than human antibodies and are produced in large numbers in response to all sorts of antigens.
“Nature is doing the inventing for us through the immune system of the llama in creating these future proteins. This opens opportunities that we do not always foresee,” notes Sellès.
Patrice Sellès
Family focusThe collaboration with Syngenta will focus on one family of insect according to Sellès, although Biotalys is still free to explore other families of insect.
Sellès makes the point that there are fewer new modes of action coming to market. He cites a new product by BASF that was recently launched. It is the first Isopropanol-Azole on the market, with a FRAC (Fungicide Resistance Action Committee) code 3.
“It’s important to bring innovation on at a speed that outperforms the buildup of resistance, and this is what our platform is in position to do,” explains Sellès.
Biotalys’ first product, the biofungicide Evoca, was awarded its own FRAC code in May 2022.
“Peptides and enzymes are complementary because they bring innovation and new modes of action into the industry. And we need that because the chemistry cannot cope with the rate at which the resistance is building for the existing products today.”
Scaling upThe collaboration with Syngenta is the third major partnership for Biotalys. Since last year, Biotalys has been working on a research program funded by the Bill & Melinda Gates Foundation focused on leafspot disease for peas.
The company also has a partnership with Novozymes, with a successful feasibility study reported in October 2022. The objective was to explore the scaling up of Biotalys’s protein-based technology, which is turned into a product through a fermentation process. In October 2022, Biotalys reported that Novozymes had obtained proof of concept for a new manufacturing process that offers
potential significant cost of goods and scaling advantages.
“We have been producing at 35 cube [35,000 litres] and are continuously scaling up to above 40 cube. We have also done our first commercial production of Evoca,” says Maertens.
The commercial production run was done at 35 cube, confirmed Maertens, with the company aiming for production levels of around 100 cube.
In terms of the roll-out of Evoca in the U.S., final approval is still pending. Sellès says the product was put in the hands of the EPA at the end of 2020. The aim is to be launched in the U.S. by the end of 2023, except for California, where the registration process is typically longer.
“When we get the registration of Evoca in the U.S.,” explains Sellès, “we will go for what we call a market calibration. We do not expect to generate margins, but we will start creating the demand there as soon as we have that [calibration], and then we will move towards the next generation product to be launched as a fully commercial product by 2026.” ●
Luc Maertens speaking at New AG International’s Biocontrol & Biomes event in Madrid, December 2022. The next edition of the event will be held in Milan, 29-30 November 2023.Visit Biocontrol & Biomes for more detail
It’s important to bring innovation on at a speed that outperforms the buildup of resistance.
New AG International spoke with STK’s Global VP Sales Yair Nativ, and Dr. Eric Tedford, Field R&D Manager from Summit Agro, the exclusive distributor for STK in the U.S. to find out more about STK’s newly launched Yarden product.
The second hybrid fungicide from Israeli company STK has rolled off the production line.
Suitable for both the growing season and the post-harvest market, Yarden has been launched in Turkey by STK’s distributor Nufarm.
In Turkey, the product is approved for citrus as a post-harvest protection from rot disease, such as Penicillum spp., and in tomatoes for control of Botrytis cinerea and damping off (Rhizoctonia solani., Fusarium spp., Phythium spp.).
Yarden is a combination of tea tree oil (TTO) and fludioxonil, which is why it is described as a hybrid product using a combination of conventional chemistry with a natural ingredient.
STK’s Global VP Sales Yair Nativ says that Yarden has been on the market for six months. There are plans to take it to Colombia and then other markets in Latin America.
STK is looking to launch the product across Latin America in a period of one to three years. Nativ mentioned that it had been relatively easier to register a mixture in Turkey. In this market, growers can use only four actives in a growing season, so Yarden only counts as one active, not two, because of the tea tree oil: “This gives the growers more flexibility,” says Nativ.
Yarden is a combination of TTO and fludioxonil in a ratio of 100g: 125g, which is slightly different to STK’s first hybrid product Regev, which comes in a ratio of 2:1 of TTO and difenoconazole. The company also has reformulated version of Regev, known as Regev HBX, which comes in a 1:1 ratio, and is registered for use on pecans, soybeans and rice.
STK sources its tea tree oil from Australia. In January of this year, the company signed a collaboration agreement with Bio-Gene Technology (BGT) giving STK non-exclusive development and commercialization rights for Qcide for crop protection applications. Qcide is a natural oil product extracted from a rare cultivar of an Australian eucalypt.
Benefits of tea tree oilSummit Agro’s Dr. Eric Tedford explained that TTO contains eight different terpene hydrocarbons and so is more akin to conventional chemistry. “TTO has eight active ingredients with multiple mechanisms for its activity.”
Tedford has been instrumental in the prolific number of trials that STK/Summit have undertaken over the last three years, numbering a little more than 100.
“I want to go against the best that we are selling against, and be equal or better to the standard, and always better than the untreated,” said Tedford.
Regev has been tested for numerous crops in the U.S., including apples, in particular for protection against apple scab. The chart comes from a trial conducted by Chris Becker of Baar Scientific - Phelps, New York state in 2022. Commenting on the Regev trial on apples, Becker said: “Both fruit and leaves seemed to be well protected. Sometimes you see differentiation between foliar and fruit activity but in this trial both were equally controlled.”
Chart: Regev efficacy against apple scab in McIntosh apples. Competitor product names are covered
In the field trial for apple scab, the severity of the disease can be seen on the y-axis. Plant pathologists measure disease incidence and severity. Incidence is the number of units, such as fruits, trees, leaves, that are infected out of how many one observes. So, for apple, if you randomly rate 100 apples per tree and there are spots on 20 of the apples, this would be a 20 percent incidence. Severity is a measure of how bad the disease is. “You can best think of this as what percent of that apple is infected,” explained Tedford.
Bars that have the same letter above them, such as the orange untreated bar and the grey bar for a competitor product, means that they are not statistically different. “However, because the untreated has an “a” and Regev at 4 oz has a “b” – that indicates that Regev is providing a statistically significant reduction in apple scab over the untreated. This is why we replicate treatments so that we can measure variability among treatments and determine what differences are statistically significant or not,” expands Tedford.
“If you look at the application chart to the right of the plot snip you will see that applications were made on A – H timings with A being on 21 April and H being on 15 July. 38 DAH means the assessment was made 38 days after the H (July 15th) application,” added Tedford.
What’s in the pipeline?Nativ says that STK is looking for a product to take to European markets. The company’s broad spectrum botanical biofungicide Timorex is not registered within the members of the European Union. The product has its own FRAC code (46). Alongside this, the company is in advanced stages of a next-generation TTO product, which would be a straight TTO product, not hybrid. STK is also working on a plant extract for use in an insecticide. ●
Lemons and oranges treated with STK Yarden hybrid fungicide.
Yair Nativ, STK’s Global VP Sales
Dr. Eric Tedford, Dr. Eric Tedford, Field R&D Manager, Summit Agro
A study published in the journal Drones has determined the optimum height for a drone to fly and target desert locusts with biopesticides in order for it bemost effective as a tool to fight the crop pest.
Violet Ochieng, of the University of Nairobi (supervised for her PhD by Dr. Ivan Rwomushana, CABI’s senior scientist, invasive species management), found that a height of 10 metres is best for the drone to spray biopesticide on the desert locust below.
In 2019-20, according to the Food and Agriculture Organization (FAO), around 20 million people in Ethiopia, Kenya, Somalia, South Sudan, Tanzania and Uganda faced acute food insecurity due to swarms of desert locust, one of the most destructive migratory pests in the world. In Kenya, the outbreak represented the worst locust crisis in 70 years; by its peak, the country was tackling over 500 swarms in 28 of Kenya’s 47 counties.
The new study highlights that while current methods of control rely on conventional chemical insecticides during invasion, some environmentally friendly biopesticides based on Metarhizium acridum and insect growth regulators can also be deployed in preventative control operations.
“The successful use of drones to control pests such as fall armyworm, planthoppers, aphids, among others, makes it an attractive technology that has the potential to also improve locust management, especially in inaccessible areas. However, key parameters for the safe and optimal use of drones in
desert locust control were not documented before I began this study,” noted Ochieng. “Management of desert locusts by the use of drone technology appears promising when the biopesticides are applied at an optimum height of 10 metres and standard operating procedures are followed. Further research could also explore the gap in the effects of environmental parameters on flight application efficiency.”
To test the optimum height for spraying Metarhizium acridum on the locusts, the drone was flown at five different heights: 2.5 metres, 5 metres, 7.5 metres, 10 metres, and 12.5 metres. At each height, the drone sprayed the ink mixture on spray cards pinned to the ground to approximate the droplet density and compare it to the standard droplet density recommended for desert locust control.
To assess the efficacy of M. acridum and the effectiveness of drones in its application, 50 grams of spores were mixed in one litre of diesel and sprayed on caged live locusts of different stages (3rd and 4th instars, as well as the adults); they were monitored for 21 days in acontrolled room, and their mortality was determined.
Variation in droplet densitybetween the tested heights was significant, the scientists say. A height of 10 metres agrees withthe recommended standarddroplet density within the 45 droplets/cm2 range.
Mortality varied among the locusts’ developmental stages within and between heights. Survival probability varied between heights for 3rd instar, 4th instar, and adults. All the developmental stages of the desert locust were susceptible to Novacrid and the recommended target stage is the 3rd instar.
“This study has demonstrated that spraying desert locusts using a drone at any height below 10 metres may lead to over-deposition of the biopesticide, while heights above 10 metres may lead to under-application, which may limit exposure of the locusts to Metarhizium spores or pesticide molecules,” said Rwomushana, a co-author on the paper. “This study demonstrated that spraying a control agent from a specificheight is more effective than other heights tested.”
The scientists conclude that targeting the most susceptible early stages is also cost-effective in terms of the density of bands that will be controlled at once unlike the female adult desert locusts which can lay at least one egg pod before dying after an estimated 21 days of Novacrid application.
The research was conducted in partnership with fellow scientists from the University of Nairobi, CABI and Astral Aerial Solutions. ●
Violet Ochieng helps to prepare a drone for flight.Photo: CABI
A new study led by scientists from the Chinese MARA-CABI Joint Laboratory for Biosafety has discovered the optimum time to apply safer-to-use and more environmentally-friendly biopesticides to fight the Oriental migratory locust pest.
Locusta migratoria manilensis is deemed to be one of the most dangerous pests threatening crop production and food security in China. Crops at risk include maize, rice and peanut. Pastures can also be seriously damaged.
While there have been no major outbreaks in recent years, there are still high-density populations of the Oriental migratory locust in the marshlands of Jilin, Shanxi and Shandong Provinces which threaten food production and the region’s ecology.
Dr. Hongmei Li, lead author and senior scientist at CABI in China, together with fellow scientists including those from the National Agro-Tech Extension and Service Centre, Beijing, Zhejiang University and the University of Cordoba, Spain, suggest that the body heat of the locusts is key to effectiveness of the biopesticides.
The researchers highlight that entomopathogenic fungi (EPF) are widely promoted to reduce the amount of more harmful pesticides used to tackle the Oriental migratory locusts but that they tend to work better on insects with lower body temperatures.
Li and the scientists argue that biopesticides should be applied on younger locusts at dawn or dusk as they tend to show lower temperatures more suitable for EPF development – thereby minimizing the risk of a locust outbreak.
“Current pest management techniques would benefit from understanding the behavioural rhythms of the target pest and its body temperature, a critical aspect not well studied and potentially limiting the effectiveness of biopesticides under natural conditions,” noted Li.
The study – published in Frontiers in Physiology – sought to understand the behavioural patterns of different stages of hoppers and adults of the Oriental migratory locust and the environmental factors that modulated their body temperatures through field observation.
Intensive field sampling in two of the main breeding regions in China was carried out. This included recording the day and night body temperatures of 953 locusts as well as their morphological traits (stage, sex and size) and microhabitat.
“The results revealed that locusts preferred the ground as their main activity sub-habitat, particularly for hoppers,” said Li. “Adults tended to move upper in the reed canopy at two peaks – 10 am to 11 am and 2 pm to 3 pm. Locusts body temperature during the daytime increased with development stage and size, while the opposite pattern occurred at nighttime. Entomopathogenic fungi are more effective if the body temperature of the target pest is in a proper range without being too high or too low.
“The application of biopesticides, therefore, should focus on younger locusts – spraying in the morning or at dusk when the locusts have lower body temperatures.”
The scientists conclude by highlighting that the ground truth data of the pests that they have identified could in future also compliment advanced technologies used tackle crop pests. This includes earth observation and other agricultural-based applications. ●
Scientists measure the temperature of an Oriental migratory locust. Photo: CABI
Researchers in Singapore and the U.S. have developed the first-ever microneedle-based drug delivery technique for plants.
The method can be used to precisely deliver controlled amounts of agrochemicals to specific plant tissues for research purposes. When applied in the field, it could one day be used in precision agriculture to improve crop quality and disease management.
The work is led by researchers from the Disruptive and Sustainable Technologies for Agricultural Precision (DiSTAP) interdisciplinary research group at the Singapore-MIT Alliance for Research and Technology (SMART), MIT’s research enterprise in Singapore, and their collaborators from MIT and the Temasek Life SciencesLaboratory (TLL).
Current and standard practices for agrochemical application in plants, such as foliar spray, are inefficient due to off-target application, quick runoff in the rain, and actives’ rapid degradation. The novel silk-based microneedles technique circumvents this and other limitations by deploying and targeting a known amount of payload directly into a plant’s deep tissues, which can lead to higher efficacy of plant growth and help with disease management. The researchers state the technique is minimally invasive, as it delivers the compound without causing long-term damage to the plants.
Described in a paper titled “Drug Delivery in Plants Using Silk Microneedles,” published in Advanced Materials, the research studies the first-ever polymeric microneedles used to deliver small compounds to a wide variety of plants and the plant response to biomaterial injection. Through gene expression analysis, the researchers could closely examine the reactions to drug delivery following microneedle injection. Minimal scar and callus formation were observed, suggesting minimal injection-induced wounding to the plant.
The study optimized the design of microneedles to target the systemic transport system in Arabidopsis (mouse-ear cress), the chosen model plant. Gibberellic acid (GA3), a plant growth regulator in agriculture, was selected for the delivery. The researchers found that delivering GA3 through microneedles was more effective in promoting growth than traditional methods (such as foliar spray). They then confirmed the effectiveness using genetic methods and demonstrated that the technique is applicable to various plant species, including vegetables, cereals, soybeans and rice.
“The technique saves resources as compared to current methods of agrochemical delivery, which suffer from wastage. During the application, the microneedles break through the tissue barriers and release compounds directly inside the plants, avoiding agrochemical losses,” noted Professor Benedetto Marelli, co-corresponding author of the paper, principal investigator at DiSTAP, and associate professor of civil and environmental engineering at MIT. “The technique also allows for precise control of the amounts of the agrochemical used, ensuring high-tech precision agriculture and crop growth to optimize yield.”
Added Yunteng Cao, the first author of the paper and postdoc at MIT: “The first-of-its-kind technique is revolutionary for the agriculture industry. It also minimizes resource wastage and environmental contamination. In the future, with automated microneedle application as a possibility, the technique may be used in high-tech outdoor and indoor farms for precise agrochemical delivery and disease management.”
The work also highlights the importance of using genetic tools to study plant responses to biomaterials, said Sally Koh, the co-first author of this work and PhD candidate from NUS and TLL. “Analyzing these responses at the genetic level offers a comprehensive understanding of these responses, thereby serving as a guide for the development of future biomaterials that can be used across the agri-food industry.”
The future seems promising as Professor Daisuke Urano, co-corresponding author of the paper, TLL principal investigator, and NUS adjunct assistant professor elaborates: “Our research has validated the use of silk-based microneedles for agrochemical application, and we look forward to further developing the technique and microneedle design into a scalable model for manufacturing and commercialization. At the same time, we are also actively investigating potential applications that could have a significant impact on society.” ●
Silk microneedle array on a U.S. dime to show scale. Photo: SMART
Canada’s University of Saskatchewan (USask) opened its new University of Saskatchwan Insect Research Facility (USIRF), the first insect research facility with quarantine capabilities in a western Canadian university.
USIRF is specifically designed for research on beneficial insects and arthropod plant pests, including non-native insects and pathogens. The university stated the facility will boost Canadian agriculture, protect the environment, reduce risk to food security, and provide fundamental insight into insect ecology.
Located in the Agriculture Building on the USask Saskatoon campus, the 500-square-foot insect quarantine facility is designed to meet Canadian Food Inspection Agency (CFIA) Plant Protection Containment Level-2A requirements, allowing researchers to study non-native insects and pathogens that pose a potential threat to western Canadian crops.
“Insects are an important part of agricultural ecosystems but some present huge economic and environmental risk,” said Dr. Sean Prager, USask entomologist and USIRF research lead. “The USIRF provides us a space to pre-emptively study how these pests would work in our environment and with Saskatchewan crops before they become an issue. This facility also allows us to involve students in this research, which means we can train students at the highest level of entomological research.”
The bio-secure insect-rearing and quarantine facility employs mechanical and operating safeguards to prevent accidental release and cross-contamination of harmful species. The USIRF contains climate-controlled chambers for sustaining insects and infested plants, and space for conducting experiments.
The USIRF supports collaborations between pest researchers and USask Crop Development Centre plant breeders. With the increased research capacity, USask researchers will be able to develop proactive methods of managing insects, resulting in new ways to predict pest outbreaks, decrease pesticide use, and develop newpest-resistant crop varieties. ●
Research technician Ningxing Zhou (left) and graduate student Grace Onu-Odey (right) transfer a pea aphid in the new University of Saskatchewan Insect Research Facility. Photo: Kira Glasscock
Singapore-based Nutrition Technologies has launched a new bioactive organic fertiliser, Diptia, specifically designed and formulated to combat fungal plant diseases, and protect soil from infection.
Diptia is derived from black soldier fly (BSF) frass that has been composted and enhanced with a microbial biocontrol agent and insect chitin.
The company stated the bacteria was isolated from the BSF larvae itself, and has been shown to inhibit plant pathogens. The chitin is sourced from the exoskeleton of the mature insect pupae and is added to the product to increase the available chitin. These components work together to protect the plant root zone from phytopathogenic fungi while improving the plant's natural defences against disease.
Insect frass is a common nutrient source for plants in nature, and plants have complex mechanisms to benefit from frass. For instance, plants have receptors that recognize chitin in their environments – usually an indication of fungal attack – that stimulates the upregulation of their immune system in response.
“By reintroducing frass-based products back into agriculture, we are getting closer to the stability and resilience of a natural ecosystem,” stated the company in a news release. “The frass of the black soldier fly larvae (Hermetia illucens) has particularly powerful antifungal properties thanks to their life-history – a tropical insect that evolved in competition with fungi for access to the same nutrients. That evolutionary arms race gave the BSF powerful molecular and microbiological tools to inhibit fungi, and encourage beneficial microbes.”
Diptia also acts as an organic fertiliser with a NPK profile, carbon content and micronutrients, and the microbial activity of the product can improve both soil structure and health. ●
Researchers at INRAE, Sorbonne University, and the Chinese National Institute of Plant Protection have reconstructed the evolutionary history of a specific olfactory receptor in the Egyptian cotton leafworm, a crop pest. This receptor plays an essential role in moth reproduction because it allows males to recognize the female sex pheromone.
The scientists determined the receptor appeared around seven million years ago and that eight amino acids underlie receptor-pheromone binding. Published May 8 in PNAS, their findings can guide the development of biocontrol strategies directed against this pest.
The Egyptian cotton leafworm (Spodoptera littoralis) is found throughout the Mediterranean Basin as well as in Africa and the Middle East. Moth larvae are extremely polyphagous, and cause damage to diverse crop species (e.g., corn, legumes, cotton, tomatoes, peppers).
In 2019, these research collaborators identified OR5, an olfactory receptor in the Egyptian cotton leafworm that recognizes the main compound in the female sex pheromone blend. In this new study, the scientists explored the receptor’s evolutionary trajectory within Spodoptera to better characterize its functionality and specificity. They used a combined approach in which they resurrected ancestral receptors in the laboratory, with the help of computer analysis, and they modelled the 3D structure of the receptors. They were thus able to determine that OR5 appeared around seven million years ago.
The researchers also employed site-directed mutagenesis to explore OR5’s genetic fine-tuning, which allowed them to identify the eight amino acids (AAs) behind the receptor’s high degree of specificity. This finding is particularly unexpected, given that past research on receptor evolution has suggested just one or two AA substitutions suffice to change the functionality of ecologically important receptors.
“We must clarify how olfactory receptors emerge and acquire specificity over evolutionary time if we wish to anticipate the development of resistance to pheromone-based plant protection products,” stated a news release from INRAE. “This research advances the above goal and, additionally, clarifies the function of OR5, a highly specific receptor that is essential in the reproduction of two Spodoptera species – the Egyptian cotton leafworm and the tobacco cutworm (S. litura).”
The latter occurs mostly in Asia and is also polyphagous. The researchers maintain the discoveries will help spur the development of new biocontrol strategies that rely on (1) agonist molecules, which occupy receptors to the exclusion of the key pheromone compound, or (2) antagonist molecules, which block the receptor from being activated by the key pheromone compound. ●
Egyptian cotton leafworm (Spodoptera littoralis). Photo: INRAE - Michel Renou
Plant Products, a member of Biobest Group, opened a new U.S. facility in Canton, Michigan.
This new facility will allow Plant Products to further supplement their solutions-focused technical sales team with stronger customer service, and will streamline the company’s customer service team with all members working from the new facility.
At the same time, by tripling the warehouse space of its previous US location, the company is able to stock more items such as biopesticides, and to streamline the receiving, packing and shipping of Biobest beneficial insects and bumblebees.
The new facility has four-times the cooler space which allows Plant Products to store additional biopesticides requiring refrigeration
while at the same time potentially extending the shelf-life of these products. ●
(L-R) Alan Cartwright (operations manager), Andrew Byfield (sales manager) and Rob Lee (general manager) at site of Plant Products' new U.S. facility.
