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.

Rachiplusia nu (Guenée) (Lepidoptera: Noctuidae) is a significant agricultural pest in South America infesting several crops, including soybeans. Bacillus thuringiensis (Berliner) (Bt) soybean, expressing Cry1Ac protein, is widely planted as a control method for numerous lepidopteran pests. However, insect resistance to Bt proteins poses a threat to its sustainability. Recent field reports from Argentina, Uruguay, and Brazil have documented unexpected injury to Bt soybean caused by R. nu populations, which may indicate the development of resistance to Cry1Ac in this species. This study aimed to evaluate the biological performance, reproductive parameters, and reproductive compatibility of two R. nu strains, one susceptible (SS) and the other exhibiting reduced susceptibility to Bt toxin (RR), when reared on Bt and non-Bt soybean. Reproductive compatibility between strains was investigated through parental and hybrid crosses, evaluating fecundity, fertility, and mating success. SS larvae fed with Bt soybean failed to complete their life cycle, whereas RR larvae exhibited higher survival rates. Egg and larval stages of RR larvae were longer when reared on Bt soybean. Pupal mass was lower for Bt-fed resistant strain, although this did not reflect on fecundity and longevity. Results on parental crosses revealed that Bt-fed RR strain displayed reduced mating success, fecundity, and fertility, compared to the non-Bt treatment. Hybrid crosses showed evidence for prezygotic and postzygotic incompatibility. These results suggest a shift in susceptibility of R. nu to Cry1Ac protein and highlight the importance of implementing robust insect resistance management strategies to maintain the effectiveness of Bt crops.

The whitefly, Bemisia tabaci is a cryptic species complex in which one member, Middle East-Asia Minor 1 (MEAM1) has invaded globally. After invading large countries like Australia, China, and the USA, MEAM1 spread rapidly across each country. In contrast, our analysis of MEAM1 in India showed a very different pattern. Despite the detection of MEAM1 being contemporaneous with invasions in Australia, the USA, and China, MEAM1 has not spread widely and instead remains restricted to the southern regions. An assessment of Indian MEAM1 genetic diversity showed a level of diversity equivalent to that found in its presumed home range and significantly higher than that expected across the invaded range. The high level of diversity and restricted distribution raises the prospect that its home range extends into India. Similarly, while the levels of diversity in Australia and the USA conformed to that expected for the invaded range, China did not. It suggests that China may also be part of its home range. We also observed that diversity across the invaded range was primarily accounted for by a single haplotype, Hap1, which accounted for 79.8% of all records. It was only the invasion of Hap1 that enabled outbreaks to occur and MEAM1’s discovery.

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.

The relationships between the Japanese beetle (JB) Popillia japonica Newman, 1841 and the grapevine agroecosystem were investigated in Piedmont in 2020 and 2021, to assess the impact of the species and its distribution within vineyards in relation to the proximity of environmental risk factors. Grubs were sampled by soil coring in the inter-rows of vineyards, whereas both adult beetles and defoliation were counted directly on grapevine plants. The presence of spatial autocorrelation was assessed and the influence of environmental variables (distance from woodlands, meadows and the margin of the vineyard, soil parameters, year of sampling, and year of first detection of the JB) was evaluated through generalized linear mixed models. Beetles and defoliation were more clustered at the edges of vineyards, whereas grubs were localized in few hot spots, generally close to meadows. Spatial autocorrelation was weaker for grubs with respect to adults and defoliation. Grub density depended on distance from meadows, and partially on soil features. Adults abundance was influenced by the proximity to meadows, woodlands, and their presence was clustered at the margin of vineyards. The JBs seem to rely on grapevine mainly as a food source rather than a reproductive site, preferring meadows for egg-laying: therefore, pest management in vineyards should be more focused on adult beetles rather than larvae in the vineyard inter-rows.

Rhopalosiphum padi is an important grain pest, causing severe losses during crop production. As a systemic insecticide, flonicamid can control piercing-sucking pests efficiently. In our study, the lethal effects of flonicamid on the biological traits of R. padi were investigated via a life table approach. Flonicamid is highly efficiently toxic to R. padi, with an LC50 of 9.068 mg L−1. The adult longevity and fecundity of the R. padi F0 generation were markedly reduced under the LC25 and LC50 concentrations of flonicamid exposure. In addition, negative transgenerational effects on R. padi were observed under exposure to lethal concentrations of flonicamid, with noticeable decreases in the reproductive period, adult longevity, total longevity, and total fecundity of the F1 generation under the LC25 concentration of flonicamid. Furthermore, the third nymph stage (N3), preadult stage, duration of the adult pre-reproductive period, duration of the total pre-reproductive period, reproductive period, adult longevity, total longevity, and total fecundity of the F1 generation were significantly lower under treatment with the LC50 concentration of flonicamid. The life table parameters were subsequently analysed, revealing that the intrinsic rate of increase (rm) and the net reproductive rate (R0) were significantly lower but that the finite rate of increase (λ) and the mean generation time (T) were not significantly different under the LC25 and LC50 concentrations of flonicamid. These data are beneficial for grain aphid control and are critical for exploring the role of flonicamid in the integrated management of this key pest.

Mango is a delicious tropical fruit with high economic value worldwide. The Forest-Savanna Transition zone of Ghana contributes significantly to the production of mangoes for both local and international markets. The zone is plagued with the fruit fly ‘menace’ like all mango-producing areas in Ghana. Not much has been done in terms of species monitoring. A 24- month fruit fly monitoring survey was conducted in eight mango orchards, to assess the composition of fruit flies associated with Mango and their damage levels. Four para-pheromone attractants (Methyl Eugenol, Terpinyl Acetate, Trimedlure, and Cuelure) were used to monitor fruit flies. Eight improvised water bottle traps (two per lure) were purposefully deployed in each orchard. A total of 18 tephritid species belonging to five genera were recorded. Bactrocera (one species), Ceratitis (six species), Dacus (eight species), Zeugodacus (one species) and Xanthaciura (two species). Bactrocera dorsalis was the most abundant species (90% of the collected samples), while the native mango fly, C. cosyra constituted 0.5%. Dacus fuscovittatus and Dacus pleuralis were for the first time captured and identified in Ghana. Dacus langi, Dacus carnesi, Dacus (diastatus?), Ceratitis silvestrii and C. quinaria were recorded for the first time in the zone. The zone recorded a diversity index of 0.41. Damage levels ranged from 41–91%. Ten out of the 18 species, are of economic importance on mango and must be watched. Periodic updates on seasonal fluctuations, species composition and new arrivals are key to the successful implementation of any management strategy.

We evaluated the lethal and sublethal effects of two novel Betaproteobacteria-based insecticides (Burkholderia spp. strain A396 as Venerate® XC; Chromobacterium subtsugae strain PRAA4-1 as Grandevo® WDG) and two neem-based insecticides (1.2% azadirachtin A and B as Azatrol and 3% azadiractin as Molt-X) on the cotton aphid, Aphis gossypii, and its natural enemy, Coccinella septempunctata. Aphids were given both residual and direct treatments, i.e. exposed to residues applied by leaf dipping, or by spraying the insects and foliage, while the predator was treated directly with insecticides. Well-established spirotetramat (Movento® 240 SC) was used as standard due to its effectiveness against a wide range of pests, its unique mode of action, and its systemic properties. All insecticides were effective against aphid mostly in concentration-dependent manner, as do exposure time, but at different magnitudes. Spirotetramat and Azatrol induced the highest toxicity to adult aphids, while spirotetramat and Molt-X were more noxious to aphid nymphs. C. subtsugae and Burkholderia were less effective, inducing only moderate levels of aphid mortality. Azatrol and spirotetramat were more detrimental to the fecundity of aphid compared to other products. Insecticides significantly increased the development time of nymphs surviving exposure to insecticides, except Burkholderia. Azatrol were more destructive to eggs, larvae and adult of Coccinella septempunctata, together with spirotetramat for young larvae and adults, relative to other treatment. The development time of predator larvae remained unaffected by treatment. New Betaproteobacteria- and neem-based insecticides except Azatrol seem to be a promising tool to suppress population of Aphis gossypii and integrate pest management programmes.

The effect of Wolbachia on the viability and antimicrobial activity of the ectoparasitoid Habrobracon hebetor was evaluated in laboratory experiments. Two lines of the parasitoid, Wolbachia-infected (W+) and Wolbachia-free (W−), were used. Parasitoid larvae were fed with a host orally infected with a sublethal dose of Bacillus thuringiensis (Bt) and on the host uninfected with Bt. Parasitoid survival was assessed at developmental stages from second-instar larvae to adults. At all developmental stages, there were no statistically significant differences in survival between lines W+ and W−, regardless of host Bt infection. In both W+ and W− lines, the expression of lysozyme-like proteins, antimicrobial peptides (AMPs), and Hsp70 genes was analysed in fourth-instar larvae fed with an infected and uninfected host. In addition, lysozyme-like activity and antibacterial activity were evaluated. The expression of AMPs was significantly higher in W− larvae and did not get induced during the feeding on the Bt-infected host. mRNA expression of lysozyme-like proteins and lysozyme activity were significantly higher in W+ larvae than in W− larvae and did not get induced when the larvae were fed with the infected host. In whole-body homogenates of H. hebetor larvae fed with the uninfected host, antibacterial activity against gram-positive bacteria (Bacillus cereus and Bacillus subtilis) was significantly higher in the W+ line and did not get induced during the feeding with the Bt-infected host. Therefore, there is no obvious immunostimulatory effect of Wolbachia in H. hebetor larvae when they feed on a host infected with an entomopathogenic bacterium.

Insects' development can be significantly impacted by various environmental factors, including temperature. Thus, this study aimed to investigate the effect of temperature on the predatory thrips, Scolothrips longicornis Priesner (Thysanoptera: Thripidae), which feeds on the strawberry spider mite, Tetranychus turkestani Ugarov and Nikolski (Trombidiformes: Tetranychidae). Under laboratory conditions (16:8 L:D, 75 ± 5% RH), the impact of various temperature regimens (15–37.5°C) on the development, population parameters, and mass production of S. longicornis was assessed. Additionally, an age-stage, two-sex life table of the species was constructed. The study revealed that S. longicornis' pre-adult developmental period decreased as temperature increased until 35°C, after which the developmental period increased. The longevity of both males and females displayed significant differences across the temperature range, with the longest lifespan observed at 15°C and the shortest at 37.5°C. At 26°C, the mean total fecundity of S. longicornis was significantly higher (53.52 eggs per female) than the fecundity observed at other temperature regimens. The intrinsic rate of increase (r) and finite rate of increase (λ) demonstrated the highest values at 35°C. While R0 increased as the temperature rose from 15 to 30°C, it rapidly decreased at 35 and 37.5°C. The findings of this study suggest that temperature plays a crucial role in enhancing the rate of development and reproduction of S. longicornis, and a temperature range of 26–30°C could be considered optimal for rearing and mass production of S. longicornis.

Ectropis grisescens Warren and Ectropis obliqua (Prout) are two morphologically similar sibling species with overlapping ranges. In this study, manipulative laboratory experiments were conducted to examine the possibility of reproductive interference in sympatric populations of E. grisescens and E. obliqua and the potential consequences of the mating interaction. Our results showed that the presence of males or females of different species could incur mating interference and significant reduction of F1 offspring. The reduction was not significant relevant to the initial relative abundance of E. grisescens and E. obliqua. Detailed observations of mating opportunity showed that female mating frequencies of both species were not significantly affected by the absolute species density, but the mating success of E. obliqua females with conspecific males depended on species ratio. In addition, adding males to the other species resulted in lower number of offspring suggesting that the males’ behaviour might be linked with mating interference. Males of both E. grisescens and E. obliqua could interfere the intraspecific mating of the other species, but the impact of the mating interference differed. These combined data indicated that asymmetric reproductive interference existed in E. grisescens and E. obliqua under laboratory conditions, and the offspring of the mixed species were significantly reduced. The long term outcome of this effect is yet to be determined since additional reproductive factors such as oviposition rate and progeny survival to adulthood may reduce the probability of demographic displacement of one species by the other in overlapping niches.