Canada thistle [Cirsium arvense (L.) Scop.] is an invasive perennial plant that threatens agricultural landscapes and natural ecosystems worldwide. The extensive regenerative root system of C. arvense complicates control efforts, with current strategies having limited success. Puccinia suaveolens (Pers.) Rostr (syn. Puccinia punctiformis (F. Strauss) Rohl), an obligate biotrophic rust fungus, has shown potential as a biological control agent by systemically infecting the root system, reducing root mass and shoot growth, and limiting vegetative regeneration; however, its efficacy when integrated with other control methods remains unclear. We conducted experiments from 2020 to 2022 at two sites in Colorado and Utah to evaluate P. suaveolens efficacy when applied alone and in combination with mowing, tillage, and herbicide. Treatments were applied in Fall (2020 and 2021), with monitoring of thistle stem density, vegetative cover, as well as P. suaveolens incidence before and after treatments through 2022. While P. suaveolens alone contributed to a decrease in thistle density, it was far less effective compared to herbicide treatments, and its impact when integrated with mowing or tillage was inconsistent. Herbicide application (alone and when combined with P. suaveolens) generated the greatest immediate reduction in thistle stem density and vegetative cover, although it resulted in the greatest amount of bare ground exposure. Grass coverage present within plots varied significantly between treatments, ranging from 0-75%, with the highest percentage observed in herbicide treatments in both years. Forb cover remained below 30% across treatments and years. Although P. suaveolens can contribute to C. arvense suppression, additional research is needed to remove barriers to its successful establishment, systemic infection and spread within populations, which could improve upon its efficacy, and optimization when integrated with other control strategies.

Steinernema carpocapsae is an entomopathogenic nematode with established efficacy against various agricultural pests. However, its impact on key lepidopteran pests, including Ostrinia furnacalis, Mythimna separata, and Spodoptera litura, remains underexplored, particularly at the pupal stage. This study evaluates the efficacy of the nematode through a combination of choice-based attraction assays, non-choice infection performance bioassays involving direct application to specific pupal body parts, and assessments of sublethal effects on adult survival and oviposition following pupal-stage exposure. S. carpocapsae exhibited a clear preference for pupae of all three pests over blank controls and for previously infected pupae over healthy pupae. When presented with different pupal genders, S. carpocapsae preferred female M. separata over males but showed no gender preference for O. furnacalis and S. litura. Infection performance varied by body part, with a higher infection performance on the abdomen and thorax compared to the head for O. furnacalis and S. litura, and on the abdomen over the thorax and head for M. separata. Adult survival probability was significantly lower when pupae were infected, and female oviposition was reduced when either member of a mating pair had been infected. These findings highlight the efficacy of S. carpocapsae as a promising biological control agent against these lepidopteran pests, particularly when targeting the pupal stage.

Outbreaks of Rachiplusia nu have occurred on soybean in Brazil as the first species resistant to the Bt soybean expressing only Cry1Ac protein, triggering a significant increase in insecticide use on the crop. This threatens one of the most important benefits of adopting Bt soybean cultivars – the reduction of chemicals. Therefore, this research studied the biology and parasitism capacity of Trichogramma pretiosum at 20, 25, and 30 ± 2 °C on R. nu eggs in order to evaluate the potential of releasing this egg parasitoid in soybean to manage R. nu. Parasitoid exhibited high biological performance on the R. nu eggs as observed in the lifetime parasitism of 24.9, 46.4, and 34.4 R. nu eggs at 20, 25, and 30 °C, respectively, and 100% emergence in both biology and parasitism capacity experiments. The sex ratio was statistically lower at 20 °C (0.4947), but at all studied temperatures, the production of female descendants was equal (sex ratio of 0.4947 at 20 °C) or higher (sex ratio of 0.6666 at 25 °C and 0.6524 at 30 °C). All other evaluated parameters were similar to previously positive recorded observations for T. pretiosum on other soybean pests, such as Anticarsia gemmatalis and Chrysodeixis includens, against which the parasitoid has already been commercially released in the fields as a biocontrol option. Therefore, T. pretiosum might also be released in soybean as an egg parasitoid against R. nu, what needs to be confirmed in future field trials.

Pieris brassicae (Linnaeus, 1758) (Lepidoptera: Pieridae), commonly known as the cabbage butterfly, is a major herbivorous pest causing significant damage to Brassica crops, which are widely cultivated for edible parts and economic uses such as oilseed production. Conventional chemical-based pest control methods pose risks to environmental and human health, prompting interest in sustainable alternatives like biological control using parasitoids. This study evaluated crop damage by P. brassicae larvae and the potential of the larval parasitoid Cotesia vestalis (Haliday, 1834) (Hymenoptera: Braconidae) in managing pest populations. Larvae and fertilized eggs of P. brassicae were collected and reared on four host diets (cabbage, cauliflower, turnip, and generic brassica) under controlled laboratory conditions. Larval growth, feeding behavior, and development were assessed, along with a feeding index for dietary efficiency. Parasitisation was introduced by exposing larvae to adult C. vestalis, and host-parasitoid interactions were statistically analyzed using one-way ANOVA and regression models. Results revealed that larvae had the highest feeding preference and weight gain on brassica, while turnip-fed larvae consumed the least. Parasitisation by C. vestalis significantly suppressed larval development, with a strong correlation between parasitisation rates and reduced host fitness. These findings highlight C. vestalis as a promising biological control agent for P. brassicae, offering an effective and eco-friendly alternative to chemical pesticides. Further research should focus on optimizing C. vestalis mass-rearing protocols and release strategies tailored to diverse Brassica cropping systems to promote sustainable pest management.

The predator Chrysoperla externa (Neuroptera: Chrysopidae) has great potential for its use in biological pest control programs. In order to assist future biological control programs that use Chrysopidae as a control agent, this research aims to study the behaviour of the green lacewing, C. externa, consuming two-spotted spider mites, Tetranychus urticae (Acari: Tetranychidae). In the laboratory, experiments were carried out to determine the predation behaviour of C. externa on different densities of adults of the two-spotted spider mite, T. urticae (1, 2, 4, 8, 16, 32, and 64 prey). For comparison purposes, the behaviour of C. externa was also studied using eggs from the alternative prey Ephestia kuehniella (Lepidoptera: Pyralidae). The functional response was determined by logistic regression of the number of mites consumed as a function of the initial number of prey using polynomial logistic regression. The random equation was used to describe the parameters of the functional response. The predator C. externa showed a type II functional response consuming both E. kuehniella eggs and T. urticae adults. The results obtained will allow to define the best strategy for the use of green lacewings in the biological control of the two-spotted spider mite, T. urticae.

Cydalima perspectalis (Walker, 1859) (Lepidoptera: Crambidae) larvae feed on Buxus. It is considered to be the most critical pest of boxwood trees. This study investigated whether different strains of Trichoderma harzianum had an effect on the biocontrol of larvae feeding on boxwood leaves whose nitrogen content was varied by fertilisation. Larvae were collected while feeding on boxwood seedlings in Rize parks and gardens in June 2021. In addition, G1 (no fertilisation), G2 (1.55%), and G5 (1.67%) leaves with different nitrogen concentrations obtained by nitrogen fertilisation were also used as food. As biocontrol agents, ID11D and YP1A strains of T. harzianum were applied in three doses: 50, 100, and 200 μL per water. In total, 21 different groups were created. The nutritional indices of the larvae belonging to the different groups were calculated. In addition, the activities of phenoloxidase, superoxide dismutase, catalase, and glutathione peroxidase activities were measured by taking haemolymph samples. In both strains, the enzyme activities increased with the dose applied. However, it was found that the enzyme activities of the ID11D strain applied were higher than those of the YP1A strain. It can be said that the ID11D strain is effective in controlling C. perspectalis larvae feeding on fertilised boxwood and the YP1A strain is effective in controlling larvae feeding on unfertilised boxwood.

The cold storage of biological control agents, such as parasitoids, is a valuable method utilised in mass rearing to ensure the availability of sufficient individuals when needed. This study evaluated the effects of storage temperatures of 9°C and 12°C, along with incubation periods of 7, 14, 21, 28, and 35 days, on the biological fitness of Bracon adoxophyesi Minamikawa (Hymenoptera: Braconidae). The results demonstrated that the survival rates of adult wasps exceeded 90.0% after being stored at both 9°C and 12°C for 35 days. At these temperatures, female wasps exhibited their longest lifespan at 14 days, whereas male longevity decreased progressively from 7 to 35 days. The parasitism rates observed were 43.0% at 9°C and 46.0% at 12°C after 7 days of refrigeration, with a subsequent reduction noted after 35 days. The fecundity of parasitic wasps decreased with the extension of storage time, but no significant difference was found in total egg production within 28 days of storage. Additionally, cold storage did not significantly affect the survival of the offspring; however, the proportion of females among the raised offspring was higher than in the control group. In comparing fitness parameters to the control, wasp vitality was notably higher after 21 days of storage at 9°C or 14 days at 12°C, indicating that these combinations of temperature and time are optimal. The findings of this study serve as a reference for optimising cold storage techniques and facilitating the large-scale application of B. adoxophyesi.

Asian corn borer, Ostrinia furnacalis Guenée (Lepidoptera: Crambidae), is a major pest in corn production, and its management remains a significant challenge. Current control methods, which rely heavily on synthetic chemical pesticides, are environmentally detrimental and unsustainable, necessitating the development of eco-friendly alternatives. This study investigates the potential of the entomopathogenic nematode Steinernema carpocapsae as a biological control agent for O. furnacalis pupae, focusing on its infection efficacy and the factors influencing its performance. We conducted a series of laboratory experiments to evaluate the effects of distance, pupal developmental stage, soil depth, and light conditions on nematode attraction, pupal mortality and sublethal impacts on pupal longevity and oviposition. Results demonstrated that S. carpocapsae exhibited the highest attraction to pupae at a 3 cm distance, with infection declining significantly at greater distances. Younger pupae (<12 h old), were more attractive to nematodes than older pupae, and female pupae were preferred over males. Nematode infection was highest on the head and thorax of pupae, with a significant reduction in infection observed after 24 h. Infection caused 100% mortality in pupae within 2 cm soil depth, though efficacy was reduced under light conditions. Sublethal effects included a significant reduction in the longevity of infected adults and a decrease in the number of eggs laid by infected females compared to controls. These findings underscore the potential of S. carpocapsae as an effective biocontrol agent for sustainable pest management in corn production, offering a viable alternative to chemical pesticides.

Hymenopteran parasitoids are an understudied group of insects despite being important in biological control programs globally. Little is known about the ability of parasitoids to control the passionvine hopper (Scolypopa australis (Walker); PVH), which was introduced to New Zealand (NZ) in the 1800s and has since become a major economic pest of kiwifruit. However, in their native Australia, this species has not reached pest status, likely due to the presence of associated parasitoids. Understanding the ecology of parasitoids associated with PVH in their native range is a critical step in identifying potential biological control agents that could be used in NZ. In this study, PVH presence and occupancy on different plant species was determined and the PVH parasitoid fauna of NZ compared with the Australian fauna. Collections were undertaken in and around Melbourne, Australia, between December 2021 and May 2023 in public and private gardens, roadside verges and parklands. Parasitoids were reared from the nymphs and eggs of PVH and identified. Ten species of parasitoid were discovered to parasitise PVH, eight of which were new host records. Three parasitoids, Dryinus koebelei, Neodryinus nelsoni, and Neodryinus koebelei, were reared from PVH nymphs and seven parasitoids were reared from PVH eggs: Ablerus sp., Anastatus sp., Centrodora sp., Cheilonoeurus sp., Ooencyrtus sp., and unknown species belonging to the families Figitidae and Platygastridae. These new data have made a significant contribution to understanding the ecology of PVH in their native range.

Eotetranychus kankitus is an important pest on several agricultural crops, and its resistance to pesticides has promoted the exploration of biological control strategies. Beauveria bassiana and Neoseiulus barkeri have been identified as potential agents for suppressing spider mites. This study aimed to investigate the pathogenicity of B. bassiana on E. kankitus and its compatibility with N. barkeri. Results showed that among the five tested strains of B. bassiana, Bb025 exhibited the highest level of pathogenicity on E. kankitus. Higher application rates (1 × 108 conidia/mL) of Bb025 led to a higher mortality rate of E. kankitus (90.402%), but also resulted in a 15.036% mortality of N. barkeri. Furthermore, preference response tests indicated that both E. kankitus and N. barkeri actively avoided plants sprayed with Bb025 compared to the control group that was sprayed with Tween-80. In a no-choice test, we observed that N. barkeri actively attacked Bb025-treated E. kankitus with no adverse effect on its predatory capacities. Furthermore, N. barkeri laid more eggs when fed on Bb025-treated E. kankitus compared to Tween-80-treated E. kankitus, but the subsequent generation of surviving individuals fed on Bb025-treated E. kankitus was reduced. These findings demonstrate that the Bb025 strain of B. bassiana is highly virulent against E. kankitus while causing less harm to N. barkeri. Consequently, a promising strategy for controlling E. kankitus could involve the sequential utilisation of Bb025 and N. barkeri at appropriate intervals.

Coccygidium luteum (Hymenoptera: Braconidae), a solitary larval parasitoid, is associated with the fall armyworm (FAW), in Africa. However, there is very limited information on reproductive biology, and other biological parameters that influence its life strategies. We conducted laboratory experiments to gain new insights into the biology of C. luteum reared on FAW as the host. Host age preference, reproductive biology, lifetime fecundity, life cycle, and adult longevity were studied under laboratory conditions of 28 ± 1°C and 70 ± 3% relative humidity. This study revealed that C. luteum prefer early (1st–3rd) instars of FAW for oviposition. The maximum parasitism rate was 80% at second instar larvae. A mean pre-oviposition period of 0.38 ± 0.51 days, oviposition period of 5.13 ± 0.64 days, and no post-oviposition period were observed. The mean lifetime parasitism rate of FAW larvae by female C. luteum was 49 ± 24. Longevity of unmated C. luteum was 14.44 ± 1.43 days for males and 12.83 ± 1.12 days for females. Mated ovipositing females lived for 7 days. Mean female and male progenies per adult female C. luteum was 28.11 ± 8.18 and 39.89 ± 4.76 respectively, with an overall sex ratio of 1.42 at 28 ± 1°C using second instar larvae. Total life cycle from oviposition to adult emergence was 23 ± 1 days. This study provides the basic information about C. luteum that could be utilised for mass rearing of this parasitoid under an augmentative biological control of FAW programme.

Johnsongrass [Sorghum halepense (L.) Pers.], an invasive tallgrass, actively inhabits grassland ecosystems of North America. The grasslands ecoregions of the Southern Great Plains are particularly susceptible to S. halepense invasion and dominance because of its preferential growth in continental climate zones coupled with its ability to readily colonize recent disturbances associated with declining livestock grazing and anthropogenic energy and housing development. Controlling S. halepense via chemical or mechanical inputs can reduce this plant species’ abundance temporarily, but are typically followed by S. halepense reestablishment. Sorghum halepense does, however, provide high-quality forage and appears to withstand the frequent drought and flooding events associated with climate change in Southern Great Plains ecosystems. In this review, the benefits and drawbacks of S. halepense in Southern Great Plains grassland ecosystems are discussed and areas where research on this species could be expanded are identified.

The present study describes the feeding effects of Neoseiulus cucumeris Athias-Henriot (Acari: Phytoseiidae) on western flower thrips (WFT), Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) and two-spotted spider mite (TSSM), Tetranychus urticae Koch (Acari: Tetranychidae). In addition, daily and total predation capacity, preference, and prey switching potential of this predator were studied on both pest species. WFT had a boosting effect on the biological parameters of N. cucumeris, primarily resulting in shorter developmental time, higher fecundity, and higher population growth potential than TSSM. Although immatures and males of N. cucumeris consumed significantly more TSSM than WFT, there was no significant difference in net predation rate, stable and finite predation rates of the predator between two prey species. We found an average of 10.58 and 7.93 TSSM and WFT are required to produce a single predator egg, respectively. WFT is preferred over TSSM by the predator. Negative switching behaviour was seen in N. cucumeris as it switched from the abundant prey to the rare prey. Both prey species were suitable for N. cucumeris, being able to develop successfully on them. The predator performed optimally on WFT compared with TSSM owing to its enhanced biological parameters as well as its preference, indicating that thrips are a more relevant resource than spider mites.

Mosquitoes, particularly Aedes aegypti, pose significant public health risks by transmitting diseases like dengue, zika and chikungunya. Bacillus thuringiensis var. israelensis (BTI) is a crucial larvicide targeting mosquitoes while sparing other organisms and the environment. This study evaluated the effects of sublethal BTI doses on Ae. aegypti larvae regarding mortality, development, adult emergence and size, using a wide-area spray application in an urban neighbourhood. Laboratory experiments with four BTI concentrations (0, 0.008, 0.02 and 0.04 ppm) assessed compensatory and over compensatory responses. The spray achieved over 90% larval mortality within 48 h, but accumulating sublethal doses could trigger compensatory and over compensatory effects, enhancing the fitness of survivors. A dose–response relationship was evident, with higher BTI concentrations leading to increased mortality, reduced longevity and fewer pupae. BTI exposure also skewed the sex ratio towards males and altered adult sizes, potentially affecting population dynamics and vectorial capacity. These findings highlight the effectiveness of BTI in Ae. aegypti control and the importance of understanding compensation, overcompensation and density-dependent effects. While wide-area BTI applications can reach inaccessible breeding sites and offer potent mosquito control, careful consideration of ecological and evolutionary consequences is crucial.

Multiple mating is a behaviour observed across various polyandrous insect species. It is suggested that, in ladybirds, this strategy of multiple copulations is used to enhance fecundity and fertility through sperm replenishment. Studies on sperm depletion need to correlate fertility with the presence of spermatozoa in the spermatheca. This study investigates the role of sperm replenishment in the ladybird Cryptolaemus montrouzieri. We hypothesised that females of this species exhibit fecundity and fertility rates proportional to the number of sperm replenishment opportunities (constant, periodic or absent). We observed oviposition behaviour and hatching rates over 30 days, and simultaneously tested for sperm depletion in females that copulated once. We dissected the spermathecae at four post-copulation moments to count spermatozoa under a microscope. Our results indicate that a single copulation suffices to maintain fertility for at least 30 days. Females with constant replenishment opportunities exhibited higher fecundity but lower fertility and increased mortality, suggesting a reproductive cost associated with frequent mating. Females with no replenishment during the experiment, exhibited the highest hatchability rate and lowest oviposition. Periodic copulation resulted in optimal female mating rate, with average fertility and fecundity. A plausible hypothesis would be that paired females choose to fertilise fewer eggs from a single male but are unable to control the effects of the oviposition stimulus induced by the male's presence. These findings have implications for the management and rearing of C. montrouzieri in biological control programmes, optimizing mating strategies for mass production.

Buffalobur (Solanum rostratum Dunal) is an invasive weed in China, and identifying its pathogens is crucial for developing effective biological control measures. In this study, leaf samples from S. rostratum showing typical disease symptoms were collected in Liaoning and Jilin provinces, China. The isolated fungal pathogens were identified based on their morphological characteristics and by using molecular biology techniques. Pathogenicity was assessed by artificially inoculating spore suspensions from the fungal pathogen onto the seeds, isolated leaves, and plants of S. rostratum. The safety of the fungal pathogens for eight other plant species was also evaluated. We then identified the following five fungal pathogens causing disease in S. rostratum in Liaoning and Jilin provinces: Alternaria alternata, Epicoccum sorghinum, Fusarium equiseti, Curvularia hawaiiensis, and Nigrospora oryzae. These fungal pathogens exhibited pathogenicity, with N. oryzae exhibiting the strongest pathogenicity and highest safety. Nigrospora oryzae demonstrated the highest inhibition rate against the radicle germination length of S. rostratum and showed robust pathogenicity toward both isolated leaves and plants. Notably, despite inducing mild reactions in corn (Zea mays L.), grain sorghum [Sorghum bicolor (L.) Moench], rice (Oryza sativa L)., and tomato (Solanum lycopersicum L.), N. oryzae did not have any detrimental effect on the growth of these plants.

The egg parasitoid Anastatus japonicus is a key natural enemy in the biological control of various agricultural and forestry pests. It is particularly used against the brown marmorated stink bug Halyomorpha halys and the emerging defoliator pest Caligula japonica in East Asia. It has been proved that the eggs of Antheraea pernyi can be used as a factitious host for the mass production of A. japonicus. This study systematically documented the parasitic behaviour and developmental morphology exhibited by A. japonicus on the eggs of A. pernyi. The parasitic behaviour of A. japonicus encompassed ten steps including searching, antennation, locating, digging, probing, detecting, oviposition, host-feeding, grooming, and resting. Oviposition, in particular, was observed to occur in three stages, with the parasitoids releasing eggs during the second stage when the body remained relatively static. Among all the steps of parasitic behaviour, probing accounted for the longest time, constituting 33.1% of the whole time. It was followed by digging (19.3%), oviposition (18.5%), antennation (9.6%), detecting (7.4%), and the remaining steps, each occupying less than 5.0% of the total event time. The pre-emergence of adult A. japonicus involves four stages: egg (0 to 2nd day), larva (3rd to 9th day), pre-pupa (10th to 13th day), pupa (14th to 22nd day), and subsequent development into an adult. Typically, it takes 25.60 ± 0.30 days to develop from an egg to an adult at 25℃. This information increases the understanding of the biology of A. japonicus and may provide a reference for optimising reproductive devices.

Many parasitoids alter their reproductive behaviour in response to the quality of encountered hosts. They make adaptive decisions concerning whether to parasitise a potential host, the number of eggs laid on an accepted host, and the allocation of sex to their offspring. Here we present evidence that Goniozus jacintae Farrugia (Hymenoptera: Bethylidae), a gregarious ectoparasitoid of larval tortricids, adjusts its reproductive response to the size and developmental stage of larvae of the light brown apple moth (LBAM), Epiphyas postvittana (Walker) (Lepidoptera: Tortricidae). Goniozus jacintae parasitises instars 3–6 of LBAM, but most readily parasitises the later, larger, instars. Brood sizes were bigger on larger hosts and brood sex ratios were female biased (proportion of males = 0.23) with extremely low variance (never >1 male in a brood at emergence), perhaps the most precise of all studied bethylids. Host size did not influence brood development time, which averaged 19.64 days, or the body size of male offspring. However, the size of females was positively correlated with host size and negatively correlated with brood size. The sizes of individual males and females were positively related to the average amount of host resource available to individuals within each brood, suggesting that adult body size is affected by scramble competition among feeding larvae. Average brood sizes were: 3rd instar host, 1.3 (SE ± 0.075); 4th instar, 2.8 (SE ± 0.18); 5th instar, 4.7 (SE ± 0.23); 6th instar, 5.4 (SE ± 0.28). The largest brood size observed was 8 individuals (7 females, 1 male) on the 6th instar of LBAM. These results suggest that later instars would give the highest yield to optimise mass-rearing of G. jacintae if used for augmentative biological pest control.