Search Results (11)

For pest control to be sustainable, the methods applied must be efficient and have a low environmental impact. Pest control failures bring economic and environmental problems. Phthorimaea absoluta is the main pest in tomato crops worldwide. Benzoylureas, diamides, and pyrethroids are among the insecticides with the highest reports of pest control failures, and Brazil is the country where this has been most observed. Machine learning models are suitable for predicting biological events. Thus, this study aimed to determine the risks of failures in the control of P. absoluta by insecticides in Brazilian biomes using the MaxEnt machine learning algorithm. The risks of pest control failures by benzoylureas and pyrethroids were higher in tomato crops located in the Cerrado and Atlantic Forest biomes, and annual precipitation was the critical variable associated with these failures. The risks of control failures by diamides were higher in crops located in the Caatinga, Cerrado, and Atlantic Forest, and temperature seasonality was the critical variable associated with these failures. In conclusion, the models determined in the study are robust to predict the regions with higher risks of P. absoluta control failures by insecticides, and they indicated the environmental variables associated with these risks. Full article

The tomato leaf miner Phthorimaea (syn. Tuta) absoluta (Lepidoptera: Gelechiidae) is invasive in many agricultural regions. Its larvae feed inside leaf mines and tomato fruits, causing yield losses. Repeated sprays of insecticides disrupt agri-ecosystems. Conducting three open-field tomato experiments, we assessed whether formulations of entomopathogenic nematodes could improve the efficacy of these promising biocontrol agents or whether other nature-based agents such as pyrethrin or spinosad would be the better option(s), as compared to a standard insecticide. Steinernema carpocapsae formulated in an alkyl polyglycoside polymeric surfactant, in canola oil, or mixed in both reduced 37 to 68% of pest larvae within two weeks post-treatment, followed by the botanical pyrethrin (48%). Neither spinosad nor lambda cyhalothrin achieved sufficient control. Increasing the frequency of treatments to every two weeks moderately increased efficacy. Positively, the nematodes can, if properly formulated and applied, still be recovered alive from leaf surfaces up to two hours after spraying, indicating that they have time to enter the leaf mines. A small proportion can even be still extracted alive from the leaf mines one week later. Despite these promising results, further research is needed to improve the efficacy of nature-based management options for use against this pest, with the aim of ultimately reducing reliance on chemical insecticides and minimizing the impact on agri-ecosystems. Full article

Phthorimaea absoluta, an important pest of tomato crops, has reportedly developed high levels of resistance to the insecticide chlorantraniliprole, which has a unique mode of action and high efficacy. This study evaluated the sustained multigenerational effects of chlorantraniliprole on P. absoluta, focusing on resistance development, growth, development, reproductive capacity, population parameters, and nutritional indicators. After continuous selection with sublethal chlorantraniliprole for eight generations (CX-Sub₈), bioassays showed that CX-Sub₈ had 225.37-fold higher resistance than the susceptible strain. The age-stage, two-sex life table analysis revealed that the preadult development time and mean generation time were significantly prolonged, while population reproduction and pupal weight were reduced. Moreover, the relative fitness of CX-Sub₈ was 0.62, and changes in the life table parameters correlated with an increase in the serial number of selection cycles. The second-instar larvae of CX-Sub₈ presented lower triglyceride, glycerol, trehalose, free fatty acid, and protein contents than the unselected strain (CX-S₈). Transcriptome analysis identified 2517 differentially expressed genes, with most being enriched in nutrient metabolism-related pathways, such as amino acid biosynthesis and fatty acid degradation metabolism. These results indicate that multigenerational sublethal chlorantraniliprole treatment disrupts the nutritional metabolism, and inhibits the growth, development, and reproduction of P. absoluta. Full article

Entomopathogenic fungi (EPFs) can influence plant–insect interactions through complex molecular and chemical mechanisms. This study investigates how EPF treatment of tomato plants modulates volatile organic compound (VOC) emissions and subsequent trophic interactions between tomato plants, the herbivorous pest Phthorimaea absoluta, and the parasitic wasp, Trichogramma chilonis. Our results demonstrate that EPF-treated plants exhibited reduced attractiveness to adult P. absoluta moths, which were actively repelled by EPF-induced VOCs. Conversely, these same plants showed enhanced recruitment of the parasitoid T. chilonis, which demonstrated positive chemotaxis toward the modified VOC profile. Chemical analysis revealed significantly elevated emissions of key VOCs in EPF-treated plants, particularly (E)-β-Caryophyllene, β-phellandrene, and α-Phellandrene. This increase is correlated with enhanced production of defense-related phytohormones, including JA, SA, and JA-Ile, which may regulate VOC biosynthesis pathways. Behavioral response studies using synthetic VOCs and electroantennogram (EAG) measurements confirmed that these EPF-induced VOCs elicited strong olfactory responses in both insect species. To summarize, EPF treatment reshapes multitrophic interactions by strategically modulating plant VOC emissions and activating defense signaling pathways in tomato plants, providing new insights for potential applications in sustainable pest management strategies. Full article

The tomato leaf miner Phthorimaea (syn. Tuta) absoluta Meyrick (Lepidoptera: Gelechiidae) is invasive in many agricultural regions. Its larvae feed inside leaf mines or tomato fruits and are difficult to reach with plant protection products. In contrast, entomopathogenic nematodes (EPNs) are highly virulent and can search for larvae. The challenge is to formulate EPNs to remain protected on a sprayed leaf surface until they enter the mines. We tested 11 formulations, including 2 oils, 4 gels or thickeners, 2 surfactants, 2 UV protectants, water, and combinations with and without the EPN Steinernema carpocapsae (Weiser) RW14-G-R3a-2 (Rhabditida: Steinernematidae), under non-closed low-humidity conditions. Six tomato leaf experiments with 1000 EPNs sprayed per leaf showed that EPNs in 0.25 to 0.5% canola oil or in 5% alkyl polyglycoside surfactant were the most effective (26 to 37%). Other formulations and an insecticide had less or no effect. Seven other bioassays showed that most formulations did not adversely affect EPN survival or pathogenicity. We assume that formulations of EPNs can be further improved, such as with other flowable gels or combinations, and encourage investment in the development of practical and economic protective sprayable formulations of EPNs against leaf miners to reduce reliance on chemical insecticides. Full article

The tomato (Solanum lycopersicum L.) leafminer, Phthorimaea absoluta (Meyrick) (Lepidoptera: Gelechiidae), is an extremely invasive pest and is threatening tomato production worldwide. Several strategies have been developed and implemented for managing P. absoluta. Effective pest control strategies based on integrated pest management (IPM) schemes include different cultural practices and techniques. This study seeks to (a) examine the perspectives, attitudes, and opinions of greenhouse tomato producers in Greece regarding different methods of P. absoluta management and (b) to determine whether the perceived damage caused by P. absoluta could be predicted by the implementation of various control management strategies. A questionnaire was employed to ascertain the views and beliefs of the participants. The questionnaire comprised five-point Likert scale questions. Principal component analysis (PCA) and binary logistic regression analysis were applied to examine the relationship between the reported perceived insect damage and the utilization of control techniques. The study findings indicate that greater adoption of alternative control methods and higher levels of adherence to preventive measures against P. absoluta are associated with a perception of reduced levels of damage. Conversely, individuals with a strong reliance on pesticides use are more likely to perceive a higher level of damage. Ultimately, as tomato growers are trying to deal with P. absoluta, more education and research on other alternatives could help the reduction of chemical use, promoting more environmentally friendly practices. The findings highlight integrated pest management over pesticides for sustainable tomato production. This can guide future research and extension efforts to develop tailored P. absoluta management approaches for Greek greenhouse growers and similar environments. Full article

Tomatoes are one of the predominant vegetable crops grown throughout the year in Tamil Nadu, India. Their perishable nature and resource-intensive cultivation make them susceptible to biotic stress. The damage caused by invasive insect pests, bacterial wilt during the rainy season, and viral diseases are major yield-limiting factors, and the farmers mostly depend on calendar-based insecticide applications for insect pest and disease management in tomatoes. The desired tomato hybrids grafted onto bacterial wilt-resistant eggplant rootstocks offer protection against bacterial wilt during the rainy season. The integrated pest and disease management (IPDM) practices consist of resistant grafted tomato seedlings (wild eggplant rootstocks EG 203 and TS 03), bioinoculants (Bacillus subtilis + Trichoderma asperellum + Purpureocillium lilacinum), pheromone traps (Phthorimaea absoluta and Helicoverpa armigera), botanicals (azadirachtin), microbial pesticides (Bacillus thuringiensis, Metarhizium anisopliae, and Beauveria bassiana), and bio-rationals, which were evaluated in four locations in two major tomato-growing tracts of Tamil Nadu. The results revealed that the treatment EG 203 eggplant rootstock-grafted tomato along with IPDM practices performed better across all experimental locations than the other treatment combinations viz., TS 03 eggplant rootstock-grafted tomato + IPDM, tomato + IPDM, grafted tomato + farmers’ practice and tomato + farmers’ practice. The EG 203-grafted tomato recorded a higher yield than the farmers’ practice with significantly superior biometric parameters. The treatment of EG 203-grafted tomato and IPDM practices can be adopted for safer tomato production by enabling a reduction in pesticide applications while enhancing productivity. Full article

Phthorimaea absoluta (Meyrick) is an invasive pest that has caused damage to tomatoes and other crops in China since 2017. Pest control is mainly based on chemical methods that pose significant threats to food safety and environmental and ecological security. Light-induced control, a green prevention and control technology, has gained attention recently. However, current light-trapping technology is non-specific, attracting targeted pests alongside natural enemies and non-target organisms. In this study, we characterized the phototactic behavior of tomato leaf miners for the development a specific light-trapping technology for pest control. In situ hybridization revealed opsin expression throughout the body. Furthermore, we investigated the tropism of pests (wild T. absoluta, Toxoptera graminum, and Bemisia tabaci) and natural enemies (Nesidiocoris tenuis and Trichogramma pintoi) using a wavelength-lamp tropism experiment. We found that 365 ± 5 nm light could accurately trap wild P. absoluta without trapping natural enemies and other insects. Finally, we analyzed the phototactic behavior of the mutant strains LW2^(−/−) and BL^(−/−). LW2 and BL mutants showed significant differences in phototactic behavior. The LW2^(−/−) strain was attracted to light at 390 ± 5 nm and the BL^(−/−) strain was unresponsive to any light. Our findings will help to develop specific light-trapping technology for controlling tomato leaf miners, providing a basis for understanding pest population dynamics and protecting crops against natural enemies. Full article

Potatoes hold the distinction of being the largest non-cereal food crop globally. The application of insecticides has been the most common technology for pest control. The repeated use of synthetic insecticides of the same chemical class and frequent applications have resulted in the emergence of insecticide resistance. Two closely related pests that feed on potato crops are the potato tuber moth, Phthorimaea operculella, and the tomato leafminer, Phthorimaea absoluta (syn. Tuta absoluta). Previous studies indicated the existence of insecticide resistance to various classes of insecticides including organophosphates, carbamates, and pyrethroids in field populations of P. operculella and P. absoluta. However, the exact mechanisms of insecticide resistance in P. operculella and to a lesser extent P. absoluta remain still poorly understood. Detecting resistance genotypes is crucial for the prediction and management of insecticide resistance. In this study, we identified multiple genetic mutations related to insecticide resistance in two species of Phthorimaea. An unexpected genetic divergence on target-site mutations was observed between P. operculella and P. absoluta. Three mutations (A201S, L231V, and F290V) in Ace1 (acetylcholinesterase), four mutations (M918T, L925M, T928I, and L1014F) in VGSC (voltage-gated sodium channel), and one mutation (A301S) in RDL (GABA-gated chloride channel) have been detected with varying frequencies in Chinese P. absoluta field populations. In contrast, P. operculella field populations showed three mutations (F158Y, A201S, and L231V) in Ace1, one mutation (L1014F) in VGSC at a lower frequency, and no mutation in RDL. These findings suggest that pyrethroids, organophosphates, and carbamates are likely to be ineffective in controlling P. absoluta, but not P. operculella. These findings contributed to a deeper understanding of the presence of target-site mutations conferring resistance to commonly used (and cheap) classes of insecticides in two closely related potato pests. It is recommended to consider the resistance status of both pests for the implementation of resistance management strategies in potatoes. Full article

Complex interactions between host plant resistance (HPR) and biological control agents, particularly omnivorous predators, can shape the outcome of an integrated pest management (IPM) program. However, such interactions are seldom explored during plant breeding programs. Therefore, in the present study, we compared the performance of the omnivorous biological control agent Orius laevigatus on six tomato genotypes with different levels of resistance to the tomato leaf miner Phthorimaea absoluta. We found that the O. laevigatus fitness components (i.e., egg deposition, egg hatching rate, and duration of egg, early nymphal, late nymphal stages, and their survival) were inferior on the wild resistant genotypes (LA 716 and LA 1777) in comparison to the resistant domesticated genotype EC 620343 and the susceptible genotypes (EC 705464 and EC 519819). It appears that the adverse effects of tomato genotypes on O. laevigatus are determined mainly by glandular and non-glandular trichome densities on the leaves. Comparison of O. laevigatus response to the tested tomato cultivars to that of P. absoluta revealed significant positive correlations in duration of the egg stages, development time of early and late larval stages, and overall immature mortality in both species. It appears, therefore, that defensive plant traits operate in a similar way on the pest and its predator in the system. Overall, the present study of the tomato-P. absoluta-O. laevigatus system provides experimental evidence for the need to optimize pest management by employing intermediate levels of crop resistance together with biological control agents. Full article

Invasive tomato leaf miner, Phthorimaea absoluta causes serious damage and yield loss in tomato production in open-field and protected cultivation. Use of chemical pesticides is uneconomical and adversely affects humans and the environment. Host-plant resistance is an effective, economical and eco-friendly alternative to chemical pesticides. In this study, four wild tomato accessions from the World Vegetable Center along with one susceptible check were evaluated for their antixenosis and antibiosis effects on P. absoluta. The accessions VI037241 (Solanum galapagense) and VI037240 (S. cheesmaniae) were highly resistant, leading to 85% larval mortality under no-choice conditions. Choice assay also showed less oviposition preference and reduced pupal weight. Both VI037241 and VI037240 showed the highest resistance under field conditions. The accessions of S. habrochaites (LA1777) and S. habrochaites var. glabratum (VI030462) demonstrated moderate resistance against P. absoluta. Wild accessions recorded significantly less eggs and leaf damage in field trials compared to the susceptible genotype, S. lycopersicum (CL5915). Trichome density, type and higher production of acylsugar contributed to the insect resistance. Acylsugar production in wild accessions was less during the rainy season but significantly higher than in susceptible genotype. These findings can be useful to develop P. absoluta-resistant tomato varieties in tropics. Full article