Search Results (53)

A mutation affecting eye color was discovered in Macrolophus pygmaeus (Rambur) (Hemiptera: Miridae). This species is an important biological control agent used to manage whiteflies and other arthropod pests in greenhouse crops. Typically, these predators exhibit a dark eye coloration, ranging from garnet to black. However, individuals with bright red eyes have been identified within wild populations, making them easily distinguishable. The objective of this study was to study the mode of inheritance of the red eye color mutation observed. Additionally, a comparative analysis of key biological traits was conducted between individuals carrying the mutation and those from a wild-type population. From these specimens, a population carrying this eye color mutation, referred to as ruby, was established. Genetic analyses revealed that the red coloration is controlled by a single recessive allele located on an autosomal chromosome. Red-eyed individuals exhibited superior performance in biological traits, including greater body size in both males and females, as well as increased fecundity and longevity in females. The utilization of this red-eyed variant could be valuable as a visual marker in ecological and biological studies of population dynamics. Full article

The whitefly is among the main pests of crops, especially solanaceous and cucurbitaceous plants. The massive use of pesticides for its control has led to an increase in the pest’s resistance to different groups of insecticides and to environmental contamination. The use of biopesticides for its control is a sustainable alternative for the environment. The objective of this study was to evaluate the efficiency of two biopesticides based on entomopathogenic fungi against eggs, nymphs, and adults of whitefly in eggplant in a greenhouse. The treatments consisted of Cordyceps javanica, Beauveria bassiana, a commercial insecticide (i.e., Spirotetramat), and a control (no application). A completely randomized design was used with 16 repetitions per treatment, and the non-parametric Kruskal–Wallis test was applied. Mortality was recorded on five dates after application (DAA). The sampling data were transformed to efficiency (%). The biopesticides were found to be effective in controlling whiteflies in all developmental stages during the evaluation days. Full article

Bemisia tabaci is a major agricultural pest that affects both greenhouse and field crops by feeding on plant sap, which impairs plant growth, and by secreting honeydew, promotes sooty mold growth that further reduces photosynthesis. Additionally, these insects are vectors for viruses such as the cucurbit chlorotic yellows virus (CCYV), which causes significant damage to cucurbit crops. Traditional chemical pesticide treatments have limitations, including the development of resistance, harm to non-target organisms, and environmental contamination. Traditional chemical pesticides have limitations when it comes to controlling plants infested by CCYV and whitefly. However, the underlying reasons for these limitations remain unclear, as does the impact of entomopathogenic fungi on whitefly responses. This study explores the potential of using biological control agents, specifically Beauveria bassiana and Purpureocillium lilacinum, to manage whitefly populations and control CCYV transmission. Laboratory experiments were conducted to evaluate the pathogenicity of these fungi on non/viruliferous whitefly. The results indicated that both fungi effectively reduced whitefly populations, with B. bassiana showing particularly strong adverse effects. Whiteflies infected with CCYV exhibited a higher LC₅₀ to B. bassiana and P. lilacinum. Furthermore, bio-pesticides significantly altered the bacterial microbiome dynamics of the whitefly. Interestingly, CCYV increased the susceptibility of whiteflies to entomopathogenic fungus. The findings suggest that these biocontrol agents offer a sustainable alternative to chemical pesticides. Our study unraveled a new horizon for the multiple interaction theories among bio-pesticides–insects–symbionts–viruses. Full article

Passiflora edulis, introduced to the Republic of Korea in 1989 and commercially cultivated since 2012, has faced recent challenges due to viral infections impacting growth, yield, and quality. This study aimed to investigate the viral infections in P. edulis and surrounding weeds at cultivation sites in the Republic of Korea, examining possible correlations between the infections for sustainable agriculture. Over five years, P. edulis and weed samples were collected for virus diagnosis using PCR and RT-PCR assays, analyzing the infection status in both P. edulis and weeds and across weed species/families. The findings revealed infections with EuLCV, PaLCuGdV, CMV, and EAPV in both P. edulis and weeds, with PaLCuGdV showing the highest infection rate. Although no direct correlation was found between the presence of the same viruses in P. edulis and weeds, suggesting that there may be interactions among different viruses, the study highlighted that EuLCV infection could exacerbate symptoms when coinfected by other viruses. The study underscores the importance of implementing preventive measures within greenhouses to control virus transmission, offering insights for strategic management of viral diseases in P. edulis cultivation. These findings support the sustainable production of agricultural products by providing actionable strategies, such as the removal of weeds to eliminate habitats for vectors like whiteflies and aphids and the targeted management of high-incidence weeds from the Asteraceae, Solanaceae, and Oxalidaceae families to prevent and control the spread of EuLCV. Full article

In a greenhouse environment where tomatoes are grown, pests in yellow sticky traps need to be detected in order to control the pest population. However, tomato pests typically found on yellow sticky traps are small in size and lack distinct visual features, making it difficult for convolutional networks to extract sufficient contextual information, thereby rendering the tasks of localization and classification exceptionally challenging. In this work, an improved approach based on the advanced object detection model You Only Look Once version 7-tiny (YOLOv7-tiny) is introduced, aiming to enhance the accuracy of detecting small tomato pests while maintaining computational complexity. Firstly, a context information extraction block (CIE) based on a Transformer encoder is proposed, and this block aims to capture global context, explore potential relationships between features, and emphasize important characteristics. Secondly, an Tiny-ELAN fusion network is introduced, which enhanced the feature fusion ability of the network. Thirdly, the feature fusion part takes the P2 feature layer into account and adds a P2 small target detection head. Finally, the SCYLLA-IoU (SIoU) loss function is introduced, and its components are redefined to incorporate direction information, which enhances the model’s learning ability and convergence performance. Experimental results show that our method can accurately detect three insects: whitefly (WF), macrolophus (MR), and nesidiocoris (NC) in the yellow sticky trap images of tomato crops. Compared with Faster R-CNN, SSD, YOLOv3-tiny, YOLOv5s, YOLOv7-tiny, YOLOv7, YOLOv7-x, YOLOv8n, YOLOv8s, YOLOv10n, and RT-DETR, the mean average precision of our method increased by 3.14%, 11.8%, 4.7%, 4.7%, 4.4%, 3.5%, 2.9%, 4.6%, 4.4%, 4.2%, and 4.2%, respectively. Full article

Rhamnolipids (RLs), biosurfactants produced by Pseudomonas aeruginosa, have gained attention for their potential role in pest management. This study investigated the efficacy of RLs in controlling the two-spotted spider mite (Tetranychus urticae) and the whitefly (Trialeurodes vaporariorum), as well as a novel non-commercial essential oil-based product, Petir Kilat, on cucumber and tomato plants within a controlled greenhouse environment. The RLs were tested at concentrations of 1 mL/L and 2 mL/L, compared to commercial biopesticides including abamectin (ABAMAX) and Beauveria bassiana (NATURALIS). The results indicated that ABAMAX achieved the highest mortality rates for T. urticae and T. vaporariorum, with 100% mortality observed at 7 days. NATURALIS was also highly effective, particularly for whiteflies, though its efficacy declined over time. RLs showed a dose-dependent increase in mortality, with the higher concentration (2 mL/L) yielding more promising results, though not surpassing the commercial products. Petir Kilat, derived from orange essential oils, demonstrated significant control, particularly at higher concentrations, comparable to or exceeding the effectiveness of NATURALIS and ABAMAX in some cases. Statistical analyses revealed significant differences between treatments in most cases (p < 0.05). The findings underscore the potential of RLs and Petir Kilat as components of integrated pest management (IPM) strategies. While RLs are effective, their performance suggests they are best used in combination with other control methods. The study highlights the need for further research to optimize the application of RLs and essential oil-based products to enhance their role in sustainable pest management practices. Full article

Yellow sticky traps (YSTs) are common tools for monitoring the greenhouse whitefly (GWF), Trialeurodes vaporariorum Westwood (Hemiptera: Aleyrodidae), which can cause significant yield reduction in different greenhouse crops such as cucumber and tomato. In recent years, sticky traps equipped with green light-emitting diodes (LEDs) have also been (successfully) tested for catching GWFs. However, no study has observed GWF population dynamics at low population densities using such LED traps for early pest detection in crop stands. Therefore, a greenhouse experiment was conducted aiming to investigate the correlation between GWF populations on tomato crops (Solanum lycopersicum L. (Solanaceae)) and the numbers caught on yellow sticky traps and green LED traps, respectively. A small number of whiteflies was released into two pest-free greenhouse cabins, and populations on plants and traps were monitored for the duration of two months. The results show that the GWFs caught on LED traps correlate significantly positive with the population density on the tomato crops. Such a correlation was not found for standard YSTs. Moreover, the results indicate the possibility of early pest detection using LED traps. The findings are discussed in the context of the whiteflies’ ecology and population dynamics in greenhouses. Full article

Western flower thrips, Frankliniella occidentalis (WFT), is one of the most destructive insect pests of vegetables and ornamental crops globally. Ultraviolet-C (UV-C) exposure has been shown to reduce populations of arthropod pests, including whiteflies and two-spotted spider mites, but has not been fully assessed for WFT. The goal of this study was to determine if UV-C radiance could be a viable strategy for inclusion in integrated pest management (IPM) programs for WFT. The objectives were to (1) assess the relationship among UV-C dose (irradiance × duration) and mortality of WFT adults and second instar larvae, (2) determine the effect of UV-C on WFT fecundity and egg hatch, and (3) assess the effect of the WFT lethal dose of UV-C on three WFT-prone ornamental plants. A UV-C dose is measured in Joules, which equals power (watts) × exposure time. A dose-dependent relationship between UV-C exposure and mortality of WFT larvae and adults was observed. At the doses of 0.98 and 0.68 J/cm² (5 and 4 min exposure, respectively), 50% of the larvae died within 24 and 48 h, respectively. The UV-C dose needed to achieve 50% mortality was higher for adults than larvae, occurring at 5.2 and 4.4 J/cm² (35 min and 25 min exposure, respectively) within 72 and 120 h, respectively. The number of eggs laid by surviving WFT subjected to UV-C treatment was less than by those that were untreated, and the egg-laying period was significantly shorter among those treated with UV-C. When leaves containing WFT eggs were exposed to UV-C doses known to cause 30–40% mortality in adults, 86–98% fewer eggs hatched compared to untreated controls. Ornamental plants exposed to UV-C doses lethal to eggs, second instars, and adult WFT either showed no damage, or when damage occurred, plants recovered within 14–30 days. Additional studies under controlled greenhouse conditions are needed to elucidate the effectiveness of UV-C radiance against WFT over time and its compatibility with biological control and other IPM practices. Full article

Trialeurodes vaporariorum Westwood (greenhouse whitefly) are worldwide polyphagous pests of economic importance that damage solanaceous vegetables. Neonicotinoid pesticides and parasitoid Encarsia formmosa Gahan are the main management strategies applied worldwide, but precise control methods in greenhouse vegetables need to be developed to reduce the application amounts of pesticides and improve the suppression of whitefly populations. Therefore, we assessed the indoor acute toxicities and risk assessment of neonicotinoids for T. vaporariorum and E. formosa adults and pupae and compared the control effects of E. formosa and neonicotinoid acetamiprid. According to the acute toxicities results, most neonicotinoid insecticides were more toxic to E. formosa than T. vaporariorum, and pupae were much less susceptible than adults of both species. Moreover, acetamiprid had a low risk effect on E. formosa. Sole application of E. formosa and acetamiprid could effectively control T. vaporariorum, but their combined application resulted in antagonistic effects on the control of T. vaporariorum. The results showed that a combined application or sole use of E. formosa could reduce the use of insecticides, slow down the development of insecticide resistance in whiteflies, and improve the efficiency of controlling the growth of whitefly populations in greenhouse vegetable production. Full article

Nesidiocoris tenuis (Hemiptera: Miridae) is a generalist predator commonly used to control the whitefly Bemisia tabaci in Europe. This mirid has been found and established in South Texas, where it was initially observed feeding on nymphs of the psyllid Bactericera cockerelli (Hemiptera: Triozidae) in open tomato fields. B. cockerelli is the vector of the fastidious bacterium “Candidatus Liberibacter solanacearum” that causes diseases in several solanaceous crops, including zebra chip (ZC) disease in potatoes. There is a need to better understand how this predator impacts the control of important crop pests, such as potato psyllids. We assessed the interactions between N. tenuis and B. cockerelli in three different environmental settings. First, we estimated the numeric response of N. tenuis preying on B. cockerelli under laboratory and greenhouse conditions. Second, we evaluated the predator–prey interaction under controlled field cage conditions. Then, we exposed N. tenuis under controlled field release conditions to the natural occurrence of B. cockerelli. Finally, we assessed the compatibility between the use of N. tenuis as a biological control agent in a field study and its impact on ZC disease incidence, severity in potato tubers, and potato yield. Laboratory and greenhouse experiments resulted in diverse types of functional model responses, including exponential and linear mathematical models. Our findings revealed a significant predation effect exerted by N. tenuis, resulting in a reduction of more than fourfold in the number of B. cockerelli nymphs per cage. Specifically, the nymphal population decreased from 21 ± 3.2 in the absence of N. tenuis to 5 ± 1.6 when N. tenuis was present. Furthermore, the combination of N. tenuis with a reduced insecticide program increased potato yields, but only reduced ZC tuber incidence in one of two potato cultivars evaluated, and in one season. Findings from these studies indicate that N. tenuis could be effective as a biological control agent for B. cockerelli in potato production in South Texas. This is the first report of N. tenuis preying on immature stages of any psyllid species. Full article

Plants can respond to insect infestation and virus infection by inducing plant defenses, generally mediated by phytohormones. Moreover, plant defenses alter host quality for insect vectors with consequences for the spread of viruses. In agricultural settings, other organisms commonly interact with plants, thereby inducing plant defenses that could affect plant–virus–vector interactions. For example, plant defenses induced by omnivorous insects can modulate insect behavior. This study focused on tomato yellow leaf curl virus (TYLCV), a plant virus of the family Geminiviridae and genus Begomovirus. It is transmitted in a persistent circulative manner by the whitefly Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae), posing a global threat to tomato production. Mirids (Hemiptera: Miridae) are effective biological control agents of B. tabaci, but there is a possibility that their omnivorous nature could also interfere with the process of virus transmission. To test this hypothesis, this study first addressed to what extent the mirid bug Dicyphus hesperus Knight induces plant defenses in tomato. Subsequently, the impact of this plant–omnivore interaction on the transmission of TYLCV was evaluated. Controlled cage experiments were performed in a greenhouse setting to evaluate the impact of mirids on virus transmission and vector acquisition by B. tabaci. While we observed a reduced number of whiteflies settling on plants exposed to D. hesperus, the plant defenses induced by the mirid bug did not affect TYLCV transmission and accumulation. Additionally, whiteflies were able to acquire comparable amounts of TYLCV on mirid-exposed plants and control plants. Overall, the induction of plant defenses by D. hesperus did not influence TYLCV transmission by whiteflies on tomato. Full article

To enhance food security, food safety, and environmental health, a bio-based integrated pest management (BIPM) strategy was evaluated at two coastal locations in Lebanon as an alternative to toxic pesticide sprays in commercial high-arched plastic tunnels common in many countries. The evaluation occurred during two cucumber and pepper cropping seasons: spring and fall. At each site, two commercial tunnels were used; farmers’ conventional practices were applied in one tunnel, while the BIPM approach was followed in the second tunnel. In the farmers’ practices, a total of 14 sprays of insecticide/acaricide mixtures were applied during the spring growing season, and 6 sprays were applied during the fall. In the BIPM tunnels, hotspot releases of local strains of Amblyseius swirskii and Phytoseiulus persimilis were applied. By the end of the spring season, the number of whitefly nymphs (WFNs)/leaf and thrips/leaf in the pesticide treatment were 4.8 and 0.06, respectively, compared to 0.1 and 0.33, respectively, in the BIPM treatment. Similarly, at the end of the fall season, the WFNs reached 19.7/leaf in the pesticide control as compared to 1.2/leaf in the BIPM treatment, proving the efficacy of A. swirskii. Farmers using conventional acaricides during both cropping seasons failed to control Tetranychus urticae, the two-spotted spider mite (TSSM). However, hotspot releases of P. persimilis were successful in controlling TSSM. By the end of June, the number of TSSMs reached 7.8/leaf in the BIPM treatment compared to 53/leaf in the pesticide treatment. Likewise, in December, TSSM numbers reached 9/leaf in the BIPM treatment compared to 40/leaf in the pesticide treatment. Preliminary observations of pepper showed that both predatory mites (A. swirskii and P. persimilis) gave similar or better efficacy against the three pests. The two local predatory phytoseiid mites seem to be effective in controlling these three major pests and to be adapted to local environmental conditions. A rate of increase of 0.86 was observed for P. persimilis and 0.22 for A. swirskii, in June, when maximum temperatures were close to 40 °C. This also shows a compatibility between the two predators. In conclusion, our BIPM approach was efficient under a Mediterranean climate in arched plastic tunnels with relatively poor aeration. Full article

Cucurbit chlorotic yellows virus (CCYV), a Crinivirus transmitted by whiteflies, poses a significant threat to cucurbit crops globally. Summer squash (Cucurbita pepo L.), an important vegetable crop in the Southeastern United States, is particularly affected. The absence of commercially available resistant summer squash cultivars necessitates the exploration of resistant sources. Cucurbita germplasms with potential resistance to CCYV were previously identified through field screening. In this study, we describe the controlled greenhouse screening of these germplasm lines aimed at validating resistance to CCYV infection. The susceptible cultivar Gentry used as control exhibited early and severe symptoms in response to CCYV infection. In contrast, all the PI accessions tested, including PI 512749, PI 615141, PI 136448, PI 442312, PI 458731, and PI 420328, displayed delayed and less severe symptoms. Nevertheless, CCYV RNA accumulated in all the PI accessions. Lower symptom severity while harboring a considerable amount of CCYV indicates their inherent tolerance to the yellowing disease induced by CCYV. When comparing CCYV RNA accumulation in PI accessions with the commercial cultivar ‘Gentry’, lower virus titers were observed across all tested accessions. Specifically, PI 420328 and PI 458731 exhibited significantly reduced CCYV titers compared to the susceptible cultivar in both mass exposure and clip cage experiments. These accessions, displaying reduced symptoms and lower virus titers, hold promise as sources of resistance to CCYV in breeding programs. This study also highlights the importance of utilizing a reliable method to assay the resistance or tolerance of selected germplasm to infection by CCYV. Full article

Whiteflies cause significant crop losses through direct sap feeding, inducing plant physiological disorders and promoting the growth of sooty mold. Moreover, whiteflies can indirectly harm plants by transmitting plant viruses, particularly begomoviruses and criniviruses, resulting in severe viral disease epidemics. This study aimed to evaluate the physiological characteristics of susceptible and resistant soybean cultivars to B. tabaci. The experiments were conducted in a greenhouse. Eleven soybean cultivars were selected and infested with 100 adults of B. tabaci at the V3 stage. The evaluation of photosynthetic parameters, such as photosynthetic rate, leaf transpiration, stomatal conductance, and internal CO₂ concentration, revealed that B. tabaci infestation influenced gas exchange in soybean plants. The photosynthetic rate was higher in cultivars AS3810 and M8349 during the V6 stage. Infestations caused alterations in photosynthetic parameters, suggesting increased energy demand to maintain photosynthetic activity. However, the response to infestation varied among the different cultivars, indicating varying levels of resistance and tolerance to the whitefly’s damage. Furthermore, the infestation had a more notable impact during the vegetative phenological stage. In summary, infestation by B. tabaci has a discernible impact on the physiology of soybean plants, resulting in alterations in gas exchange parameters and water use efficiency. The reaction to infestation exhibited variations among different soybean cultivars, indicating potential differences in resistance to the pest. This study underscores the significance of assessing the physiological consequences of whitefly infestations on soybean crops. Full article

Some of the key pests of tomatoes are virus vectors, such as whiteflies, green peach aphids, and thrips, mainly because there is a lack of full resistance to the transmitted viruses. Alternatives to reduce this problem include the use of a push-and-pull strategy. Hence, this work assessed the association between Solanum habrochaites PI 1344117, used as a companion plant, and commercial tomato varieties over tomato virus vectors and the yield quality and quantity. Field and greenhouse trials were run during the 2015, 2016, 2018, and 2019 seasons. The treatments were BRS Tospodoro and BRS Tyão cultivated as monocrops and associated with PI-134417. The number of these insects was assessed by directly counting ten plants per plot and using captures on yellow sticky traps settled in the center of the plots. The yield and the number of irregularly ripening fruits (a symptom caused by whiteflies) were also measured. Both commercial cultivars gained from the protective effect of PI 134417, expressed by the significant reduction in the virus vectors on the plants. It was also noticed that there was a reduction in the number of irregularly ripening fruits, improving the fruit quality. These results encourage the use of wild and commercial tomato genotypes in association with implementing strategies to control tomato virus vectors, reducing the need to rely only on a chemical control. Full article