Ailanthus altissima (Mill.) Swingle readily exploits disturbances, grows quickly into dense monocultures, and suppresses native plant species. The vascular wilt pathogen, Verticillium nonalfalfae Inderb., native to the eastern U.S., has been proposed as a biocontrol agent for the invasive A. altissima. Studies consistently demonstrate the safety and efficacy of the bioherbicide, but they also note that the selective nature of the fungus does not preclude other invasive plants that commonly co-occur with A. altissima from occupying the site. We quantified the standing plant community and seedbank at several sites across Virginia five years after inoculation with V. nonalfalfae to understand which species are present or being naturally recruited. A. altissima remained dominant in untreated areas but was nearly eradicated from the treatment plots. Other nonnative species made up a large portion of the plant community and seedbank across all study areas, with no differences in their respective cover and count between treatments. While variability in plant community composition is high and site-specific context is important for establishing effective management strategies, planting native species and mitigating other invasives will be crucial to ensuring native species successfully establish in bioherbicide-treated areas.

During the past 30 yr an impasse has developed in the discovery and commercialization of synthetic herbicides with new molecular targets and novel chemistries. Similarly, there has been little success with bioherbicides, both microbial and chemical. These bioherbicides are needed to combat fast-growing herbicide resistance and to fulfill the need for more environmentally and toxicologically safe herbicides. In response to this substantial and growing opportunity, numerous start-up companies are utilizing novel approaches to provide new tools for weed management. These diverse new tools broaden the scope of discovery, encompassing advanced computational, bioinformatic, and imaging platforms; plant genome–editing and targeted protein degradation technologies; and machine learning and artificial intelligence (AI)-based strategies. This review contains summaries of the presentations of 10 such companies that took part in a symposium held at the WSSA annual meeting in 2024. Four of the companies are developing microbial bioherbicides or natural product–based herbicides, and the other six are using advanced technologies, such as AI, to accelerate the discovery of herbicides with novel molecular target sites or to develop non-GMO, herbicide-resistant crops.

In this research paper the in vitro antimicrobial and antibiofilm activity of phage cocktail against the coagulase negative Mammaliicoccus sciuri was investigated. Three M. sciuri isolates obtained from clinical bovine mastitis samples were characterized and identified by 16S rRNA gene sequencing. Bacteriophages with lytic activity against M. sciuri isolates were isolated from dairy farm effluents. Two typical phages were isolated using standard enrichment and plaque assay techniques, purified by polyethylene glycol precipitation, and morphologically characterized based on shape and size using transmission electron microscopy. This was followed by determination of host range using spot tests and stability to varying temperature, pH and UV treatment. The phage cocktail suppressed bacterial activity within 30 min of exposure. Crystal violet assay showed that the tested phages and their cocktail significantly reduced the biofilm biomass of all three M. sciuri strains compared to the untreated control in vitro within 24 h with a single dosing. Transmission electron micrography of the purified phage particle revealed an icosahedral head and a rigid contractile tail, characteristic of the class Caudoviricetes. The findings open new avenues in phage-based antimicrobial approaches for controlling contagious and teat skin opportunistic bacteria causing bovine mastitis.

Galls function as provide shelter for gall inducers, guarding them against their natural enemies. Previous research has illuminated the interactions between galls, gall inducers, and their corresponding parasitoids within various caltrop plants. However, less is known about these relationships within Nitraria sibirica, particularly regarding the efficacy of parasitism. Therefore, this study aimed to identify the morphometric relationships among the swollen galls, gall inducers, and their parasitoids. Two species of gall inducers and three species of parasitoids were obtained from the swollen galls of N. sibirica. The correlations of the parasitization indexes, the lifespan of gall inhabitants, and temperature and the morphometric relationships between the galls and their inhabitants were analyzed. The dominant gall inducer identified was Contarinia sp. (Diptera: Cecidomyiidae). Furthermore, it was observed that three solitary parasitoids attacked Contarinia sp. in the swollen galls, with only Eupelmus gelechiphagus acting as an idiobiont ectoparasitoid. The dominant parasitoids were Platygaster sp. and Cheiloneurus elegans at sites 1 and 2, respectively, with Platygaster sp. displaying greater abundance than C. elegans in the swollen galls. The lifespan of the gall inhabitants shortened gradually as the temperature increased. Moreover, the optimal number of gall chambers ranged from two to four per swollen gall with maximized fitness, which can be considered the optimal population density for the gall inducer Contarinia sp. Morphometric analysis exhibited a strong linear correlation between gall size and chamber number or the number of gall inhabitants, as well as a weak correlation between gall size and body size of the primary inhabitants of swollen galls. Our results highlight the importance of the biological investigation of parasitoids and gall inducers living in closed galls with multiple chambers and may pave the way for potential application in biological control.

Some slug species are considered a nuisance in agriculture and horticulture worldwide, causing economic losses to growers. Phasmarhabditis is a genus of bacteria-feeding nematodes that can parasitize slugs and snails and thus potentially serve as a biological control agent. Canada had no record of Phasmarhabditis until a survey conducted in 2019 reported a Canadian strain of Phasmarhabditis californica from a single Arion rufus slug. To build on this discovery, we surveyed three major agricultural sites, ten greenhouses, and nurseries in Alberta from June to September 2021 to collect pest slug species and investigate their associated nematodes, specifically P. californica. Slugs were collected from the field and returned to the laboratory to check for emerging nematodes on White traps. We collected 1331 slugs belonging to nine species, with Deroceras reticulatum being the most common. Only 45 (3.38%) slug samples were positive for nematodes, and the majority were identified to species level: Alloionema appendiculatum, Caenorhabditis briggsae, Caenorhabditis elegans, Panagrolaimus subelongatus, and Mesorhabditis spiculigera. We did not isolate P. californica from any of the slugs collected from these survey sites, which included the original site where P. californica was discovered. However, four D. reticulatum slugs retrieved from a residential garden sample were infected with P. californica. These findings suggest the possibility of a fragmented distribution of P. californica across Alberta. Future research should focus on extensively surveying agriculture and horticulture sites and residential gardens in different provinces across Canada.

Temperature is one of the most important factors affecting soil organisms, including the infective stages of parasites and entomopathogenic nematodes, which are important biological control agents. We investigated the response of 2 species of entomopathogenic nematodes to different storage regimes: cold (9°C), culture temperature (20°C) and temperature swapped from 9 to 20°C. For Steinernema carpocapsae, cold storage had profound effects on chemotaxis, stress tolerance and protein expression that were retained in temperature-swapped individuals. These effects included reversal of chemotactic response for 3 (prenol, methyl salicylate and hexanol) of the 4 chemicals tested, and enhanced tolerance to freezing (−10°C) and desiccation (75% RH). Label-free quantitative proteomics showed that cold storage induced widespread changes in S. carpocapsae, including an increase in heat-shock proteins and late embryogenesis abundant proteins. For Heterorhabditis megidis, cold storage had a less dramatic effect on chemotaxis (as previously shown for proteomic expression) and changes were not maintained on return to 20°C. Thus, cold temperature exposure has significant effects on entomopathogenic nematodes, but the nature of the change depends on the species. Steinernema carpocapsae, in particular, displays significant plasticity, and its behaviour and stress tolerance may be manipulated by brief exposure to low temperatures, with implications for its use as a biological control agent.

Chrysoperla species include well-known predators of aphids and other soft-bodied arthropods. As such, they are considered important biological control agents of herbivorous pests in agroecosystems where many of green lacewings species occur. Despite the high number of species of the genus Chrysoperla, only a few have been assessed for the predation efficiency of their larvae against pests infesting plants, and even fewer are currently marketed for use in biocontrol practice. Difficulties in species identification within the Chrysoperla carnea complex species in particular has been related to varying success of commercial C. carnea s.l. releases in the field. In this study, we assessed the ability of two Chrysoperla species, Chrysoperla agilis a member of the carnea cryptic species group, and Chrysoperla mutata of the pudica group to consume aphid and mealybug individuals and suppress their populations in sweet pepper plants. We found that third-instar larvae of both species were able to consume a high number of aphids (approximately 120 nymphs per larva) and mealybugs (approximately 105 nymphs per larva) within 24 h. Furthermore, the release of second-instar larvae of both C. agilis and C. mutata was shown to be remarkably efficient in suppressing the pest populations in long-term greenhouse experiments. Aphid populations were suppressed by approximately 98% and mealybugs by 78% as compared to control plants. Our results highlight the predation efficiency and the biocontrol potential of two widespread Chrysoperla species for their use in pest control.

Cold storage effects on the female predatory thrips Scolothrips longicornis Priesner (Thysanoptera: Thripidae) fed on Tetranychus urticae Koch eggs for different time periods (5, 10, 20 and, 30 days) at 5 or 25 °C (control) on development and life table parameters were examined. Female adult duration and female total longevity were not influenced by the period of cold storage. The minimum mean female total longevity (28.1 ± 0.32 day) was observed in the 30-day treatment. The oviposition period decreased with increasing cold storage duration. All life table parameters of S. longicornis demonstrated a significant difference across treatments. Our results demonstrated that the female adult of S. longicornis could be maintained at 5 °C for 5-days with minimal reduction in the life-history process. This would be beneficial in the storage and mass production of S. longicornis in biocontrol programs involving T. urticae.

Aphidophagous hoverflies (Diptera, Syrphidae, Syrphinae) are common flower visitors and aphid predators in a range of flowering plants, including fruit crops. Here, we investigate whether aphid prey DNA can be detected in the gut contents of hoverfly larvae from a commercial strawberry field as a proof of concept that a molecular approach can be used to measure agricultural biocontrol. We used high-throughput sequencing (HTS) to target insect DNA and compared the resulting data to reference databases containing aphid and hoverfly DNA sequences. We explored what impact incorporating wildflowers within polythene-clad tunnels may have on aphid DNA detection rates in hoverfly larvae. In a randomized block experiment, coriander (Coriandrum sativum), field forget-me-not (Myosotis arvensis) and corn mint (Mentha arvensis) plants were inserted in rows of strawberries. Their effect on aphid DNA detection rates was assessed. Aphid DNA was found in 55 of 149 specimens (37%) validating the method in principle for measuring agricultural services provided by hoverflies. Interestingly, detection rates were higher near plots with forget-me-not than plots with coriander, though detection rates in control plots did not differ significantly from either wildflower species. These findings confirm that hoverflies predate aphids in UK strawberry fields, and that HTS is a viable method of identifying aphid DNA in predatory hoverflies. We comment on the need for further method development to narrow down identifications of both predator and prey. We furthermore provide some evidence that there is an effect of intercropping strawberry crops with wildflowers which may affect aphid consumption in hoverfly larvae.

The use of native entomopathogenic nematodes as biocontrol agents is a strategy to decrease the environmental impact of insecticides and achieve sustainable agriculture crops. In this study, the effect of the surface culture of Steinernema sp. JAP1 over two solid media at 23–27°C on infective juvenile (IJ) production and pathogenicity against Galleria mellonella larvae were investigated. First, the bacterial lawn on the surface of the media with egg yolk (P2) or chicken liver (Cl) were incubated in darkness at 30°C for 48 and 72 h, and 100 surface-sterilized IJs were added. Four harvests were conducted within the next 35 days and the mean accumulated production was superior on Cl (210 × 103 IJs) than on P2 (135 × 103 IJs), but the productivity decreased up to 10% when the incubation time of the bacterial lawn was of 72 h. The mean pathogenicity of in vitro- and in vivo-produced IJs were of 47–64% and 31%, respectively. It is worth noting that none of the two solid media had a statistically significant difference in IJ pathogenicity. Considering that the maximum multiplication factor of IJs on solid media was 2108 and that the pathogenicity against G. mellonella was outstanding, Steinernema sp. has a good potential for in vitro mass production.

Insect crop pests are a major threat to food security in sub-Saharan Africa. Configuration of semi-natural habitat within agricultural landscapes has the potential to enhance biological pest control, helping to maintain yields whilst minimising the negative effects of pesticide use. Fall armyworm (Spodoptera frugiperda, J. E. Smith) is an increasingly important pest of maize in sub-Saharan Africa, with reports of yield loss between 12 and 45%. We investigated the patterns of fall armyworm leaf damage in maize crops in Ghana, and used pitfall traps and dummy caterpillars to assess the spatial distribution of potential fall armyworm predators. Crop damage from fall armyworm at our study sites increased significantly with distance from the field edge, by up to 4% per m. We found evidence that Araneae activity, richness and diversity correspondingly decreased with distance from semi-natural habitat, although Hymenoptera richness and diversity increased. Our preliminary findings suggest that modifying field configuration to increase the proximity of maize to semi-natural habitat may reduce fall armyworm damage and increase natural enemy activity within crops. Further research is required to determine the level of fall armyworm suppression achievable through natural enemies, and how effectively this could safeguard yields.

Farming elements other than the crop, when integrated into the system, are supplementary, with multifold uses that include weed and pest management. Elements such as fish and poultry birds are integrated with transplanted wetland rice (Oryza sativa L.) for ensuring farmers’ livelihoods and the nutritional security and sustainability of the system. Integrated animal components such as poultry birds and fish also supplement the system with weed control. The role and efficacy of these animal components as tools for managing weedy rice (Oryza sativa L.) were explored, as weedy rice infestation is increasing. This threat of weedy rice is due to scarcity of water resulting from poor water management and improper field leveling. Grass carp (Ctenopharyngodon idella val.) produced the highest reduction of weedy rice biomass, 28% within 24 h under laboratory conditions. Polyculture of C. idella, mrigal (Cirrhinus mrigala Ham.), and silver carp (Hypophthalmichthys molitrix val.) reduced the biomass of weedy rice by 21% within 24 h. In laboratory studies, poultry manure at the highest concentration of 5% reduced the weedy rice seed germination 100% compared with rice seed germination at 91%. This conformed with microplot experiments in which poultry manure at 15.6 g d−1 resulted in a weed control index (WCI) of 8% in both years. However, poultry manure at 15.6 g d−1 in combination with herbicide application resulted in the highest control indices of weedy rice: 52% in 2017 and 2018. Integrating fish and poultry with PRE application of oxyfluorfen (0.25 kg ha−1) resulted in the highest WCI and grain yield in field experiments.

The use of nematophagous fungi is an alternative for the biological control of nematodes in ruminants. In this study, the compatibility of joint growth of the fungi Monacrosporium sinense and Pochonia chlamydosporia and the joint nematicidal activity of these fungal isolates on bovine infective larvae were evaluated. For that, tests of direct confrontation, the effect of volatile compounds and antibiosis were conducted. In order to carry out the tests, the fungi were inoculated in potato dextrose agar culture medium and, after the incubation period, the growth of the colonies, the formation of an inhibition halo and the effect of volatile metabolites were verified. The compatibility between fungi isolates M. sinense and P. chlamydosporia was confirmed and the nematicidal evaluation proved the best effectiveness was when both were used together, with a 98.90% reduction in the number of bovine nematode infective larvae under in vitro conditions. It was concluded that M. sinense and P. chlamydosporia presented synergistic action, suggesting that the joint application of the fungi increases the effectiveness of biological control of bovine infective larvae.

The potential of Melaleuca quinquenervia (Cav.) S.T. Blake to reinvade cleared areas was evaluated over a 13-yr period that included two wildfires and the introduction of biological control agents. The first wildfire occurred in 1998 and was followed by a mean of 591.5 recruited seedlings m−2. Recruits from that fire were cleared 7 yr later in July 2005 for a second experiment to evaluate seedling recruitment into cleared areas. Seed rain, seedling recruitment and mortality, and sapling growth rates were measured in four plots located around individual large reproductive trees. A second natural wildfire in 2007 burned through those plots, leading to increases in seed rain followed by a pulse in recruitment of 21.04 seedlings m−2, 96.5% fewer than after the 1998 fire. Recruits in half of the plots around each tree were then treated with regular applications of an insecticide to restrict herbivory by biological control agents, while herbivory was not restricted in the other half. There was no difference in seedling mortality between treatments 1,083 d post-fire (2007) with 96.6% seedling mortality in the unrestricted herbivory treatment and 89.4% mortality in the restricted herbivory treatment. Recruits subjected to the restricted herbivory treatment grew taller than those in the unrestricted herbivory treatment, 101.3 cm versus 37.4 cm. Many of the recruits were attacked by the biological control agents, which slowed their growth. Although solitary M. quinquenervia trees retain some capacity to reinvade areas under specific circumstances, there was a downward trend in their overall invasiveness at this site, with progressively smaller recruitment cohorts due to biological control agents. Land managers should prioritize removing large reproductive trees over treating recently recruited populations, which can be left for many years for the biological control agents to suppress before any additional treatment would be needed.

Cold winter temperatures significantly affect the biological control effort against water hyacinth, Pontederia ( = Eichhornia) crassipes Mart. (Pontederiaceae), in more temperate regions around the world. The population dynamics of the planthopper Megamelus scutellaris Berg. (Hemiptera: Delphacidae), a newly released biological control agent of water hyacinth, were recorded on the Kubusi River in the Eastern Cape Province (South Africa) over 15 months to determine the population recovery post-winter. Megamelus scutellaris incurred a severe population decline at the onset of winter when the water hyacinth plants became frost damaged. The combined effect of a population bottleneck and low minimum winter temperatures (6.12°C) below the agent's lower developmental threshold (11.46°C) caused a post-winter lag in agent density increase. Subsequently, the maximum agent population density was only reached at the end of the following summer growing season which allowed the water hyacinth population to recover in the absence of any significant biological control immediately post-winter. Supplementary releases of agents from mass-reared cultures at the beginning of the growing season (spring) is suggested as a potential method of reducing the lag-period in field populations in colder areas where natural population recovery of agents is slower.

Triatomine bugs carry the parasitic protozoa Trypanosoma cruzi, the causal agent of Chagas disease. It is known that both the parasite and entomopathogenic fungi can decrease bug survival, but the combined effect of both pathogens is not known, which is relevant for biological control purposes. Herein, the survival of the triatomine Meccus pallidipennis (Stal, 1872) was compared when it was coinfected with the fungus Metarhizium anisopliae (Metschnikoff) and T. cruzi, and when both pathogens acted separately. The immune response of the insect was also studied, using phenoloxidase activity in the bug gut and hemolymph, to understand our survival results. Contrary to expectations, triatomine survival was higher in multiple than in single challenges, even though the immune response was lower in cases of multiple infection. We postulate that T. cruzi exerts a protective effect and/or that the insect reduced the resources allocated to defend itself against both pathogens. Based on the present results, the use of M. anisopliae as a control agent should be re-considered.

The aim of this study was to investigate the foraging behavior of Aphidius matricariae (Haliday) (Hymenoptera: Braconidae) as a biological control agent of Myzus persicae nicotianae Blackman (Hemiptera: Aphididae), a key and cosmopolitan pest of tobacco fields. To achieve a strategy for the control of this pest and a mass-rearing program of the parasitoid, host stage preference, switching, functional response, and mutual interference of A. matricariae were investigated at 25 ± 1°C, 70 ± 5% RH and 16:8 h L:D photoperiod. The parasitoid showed a preference for third- and fourth-instar nymphs of tobacco aphid in both choice and no-choice experiments. Using the Murdach's model, switching behavior was observed in A. matricariae between different density proportions of third- and fourth-instar nymphs. Further, the parasitoid exhibited a type II functional response when it was offered to third-instar nymphs of M. persicae nicotianae at six densities (2, 4, 8, 16, 32, and 64). Based on the linear regression analysis, there was a significance difference between the logarithm of per capita searching efficiency and the logarithm of parasitoid density. As the wasp density increased, per capita searching efficiency decreased. The result of this study revealed that A. matricariae is an effective agent in the integrated management of M. persicae nicotianae. In addition, application of these results can be important in mass-rearing program of A. matricariae.

Candida lusitaniae and C. guilliermondii are perfect model organisms for the study of Candida genera behaviour in various conditions. Both of them are rare pathogens capable to cause candidiasis in the patients with weakened immune system and can undergo morphology switches related to the increased antifungal drug resistance. Candida genera yeasts are able to inhabit diverse range of ecological niches including space ships and space stations. During the long-term expeditions, astronauts are affected by various factors that can change the state immune system. In such conditions, the commensal usually non-pathogenic microorganisms can spread through the body of the host and cause infections. Weakened immune system and limited use of drugs in spaceships promote the search of the alternative methods for the biocontrol of microorganisms. Several studies demonstrate that microorganisms are altering their gene expression, physiology, morphology, pathogenicity and evolving resistance to the antifungals under microgravity conditions. Our research indicated that switch to the pseudohyphae morphology leads up 30-fold increased resistance to amphotericin B in C. lusitaniae and C. guilliermondii. Cultivation of yeasts in rotary cell culture system (RCCS) is related to the altered cell growth and resistance to the antifungal treatment. Our results showed that growth in the RCCS led to the extreme increase in cell resistance to amphotericin B as compared with the standard growth conditions. In our research, we applied electroporation for the biocontrol of two Candida species. C. lusitaniae and C. guilliermondii cells grown in RCCS exhibited significantly increased survivability after pulsed electric field (PEF) treatment in comparison with cells grown under routine conditions. We have shown that PEF bursts of 2.5–25 kV cm−1 of 100 µs × 8 duration display a dose-dependent permeabilization of both studied Candida species. Our research indicated that budding cells and pseudohyphae morphology cells, with increased resistance to amphotericin B, can be effectively inactivated after applying PEF higher than 15 kV cm−1.

Zygogramma bicolorata Pallister is a potential biocontrol agent of Parthenium hysterophorus L. (Asteraceae). This study was carried out to understand the effect of abiotic (temperature and moisture) and biotic factors (age and reproductive status) on the induction and termination of diapause in Z. bicolorata. We also evaluated the effect of diapause on longevity and fecundity of Z. bicolorata. In Z. bicolorata the induction of diapause occurred between the months of July and December. No diapause was observed in May and June, which coincided with the commencement of the monsoon rains. The percentage of diapause induction in Z. bicolorata was found to increase from one generation to another as well as with the age of adults. Diapause significantly increased the fecundity of females as compared to the fecundity in pre-diapause conditions. Soil moisture (80% RH) played an important role in providing the conditions for initiation and termination of diapause. Similarly, 18.4 and 12.5% of diapause adults resumed their activity in 6 and 5 days when exposed to temperatures of 40° and 45° C for 2 h every day, respectively. Exposure of adults to low temperatures, i.e. 5° and 10° C induced 94.3 and 92.5% diapause, respectively, with no adult mortality. Thus, our findings reveal suitable conditions for preventing and inducing diapause in Z. bicolorata, which is of great importance in the suppression of P. hysterophorus. We discuss the implications of these findings in the control of P. hysterophorus.

Aphthona spp. flea beetles were released in two ecological sites of the Little Missouri National Grasslands in southwestern North Dakota in 1999 to control leafy spurge. The change in leafy spurge density and soil seedbank composition was monitored to evaluate the effectiveness of the biological weed control agent and the associated change in plant communities 5, 10, and 15 yr after release in loamy overflow (valleys) and loamy sites (ridges). In 2014, 15 yr after release, leafy spurge stem density had decreased 94% from 110 to 7 stems m−2 in the loamy overflow sites and 88% from 78 to 9 stems m−2 in the loamy sites. Leafy spurge represented only 2% and 6% of the loamy overflow and loamy seedbanks in 2004, respectively, compared with nearly 67% and 70%, respectively, in 1999. There was a slow shift to reintroduction of native species into the seedbank over the last 15 yr. The number of desirable species increased to 21 by 2014 (more than three times the number of species in 1999) in the loamy overflow sites, and doubled to 14 species in the loamy sites, while less desirable forb species doubled in both sites. Desirable grass species doubled in the loamy overflow sites by 2014 but remained unchanged in loamy sites. Aphthona spp. successfully controlled leafy spurge for more than 15 yr without any additional control methods or costs to land managers and resulted in the slow return of a subset of native species.