To reveal the nature of locusts’ visual reaction when stimulated by light, and to clarify the regulation characteristics of locusts’ phototactic visual physiology and obtain good spectral light features for locusts’ phototactic action, this study investigated locusts’ visual spectrum response by characterizing their photoreceptive reaction to LED light using an AvaSpec fiber-optic spectrometer system. Locusts’ phototactic response to spectral light was compared using this system. The results showed that locusts’ visual reaction characterization presents a photo-induced vision spectrum effect and that by offsetting the main wavelength of light and the spectral peak intensity, a time-varying bio-regulation effect emerges. In addition, locusts’ visual regulation ability to UV light is higher than that to violet light, whereas their reaction intensity is lower than to violet light, and the visual bio-regulatory force of locusts’ visual system absorbing orange light to react sensitively becomes gradually higher than when absorbing green light as time goes on. Moreover, corresponding to nominal illumination with the same radiant energy and a visual spectrum response stimulated by UV, violet, orange, and green light, it appears that the visual spectrum window is symmetrical around 382 nm, 400 nm, 602 nm, and 530 nm, respectively, with no obvious difference between spectral amplitudes and having a time-varying incremental characteristic with amplitude peak width. This indicates that the stimulus intensity of UV, violet, orange, and green light exceeds locusts’ visual tolerance, causing them to generate regulation inactivation as a visual physiological reaction, whereas the visual window response effect stimulated by UV light presents an illumination timeliness effect. Simultaneously, time-varying characteristics of locusts’ bio-behavior intensity show that light intensity can make up for locusts’ visual sensitivity differences at various spectral wavelengths. Presented with differential response time, photosensitive behavior intensity, and induction effect induced by orange light, time is superior for orange light, the stimulation effect caused by violet light is the strongest, and the phototactic synergy effect caused by UV light is the best. Keywords: Locusta migratoria manilensis, photoreceptive spectrum effect, visual reaction intensity, photosensitive activity effect, spectral illumination DOI: 10.25165/j.ijabe.20211402.4758 Citation: Liu Q H, Jiang Y L, Miao J, Gong Z J, Li T, Duan Y, et al. Photoreceptive reaction spectrum effect and phototactic activity intensity of locusts’ visual display characteristics stimulated by spectral light. Int J Agric & Biol Eng, 2021; 14(2): 19–25.

The loreyi leafworm Mythimna loreyi (Lepidoptera: Noctuidae) is a serious pest of agriculture that causes particular damage to Gramineae crops in Asia, Europe, Australia, Africa, and the Middle East. Low temperature is one of the important environmental factors that limits the survival, distribution, colonization, and abundance of M. loreyi. However, the metabolic synthesis pathways of cold-tolerant substances in M. loreyi and the key genes involved in the regulation under cold stress remain largely unknown. In this study, we sequenced the transcriptomes of three developmental stages (larvae, pupae, and adults) of M. loreyi to discover the molecular mechanisms of their responses to cold stress. In total, sequencing generated 120.64 GB of clean data from 18 samples, of which 19,459 genes and 1740 differentially expressed genes (DEGs) were identified. The enrichment analysis of Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) revealed that many DEGs were mainly enriched in pathways associated with energy metabolism and hormone metabolism. Among these, genes encoding multiple metabolic enzymes, cuticle proteins (CPs), and heat shock proteins (HSPs) were differentially expressed. These results indicate that there are significant differences among the three developmental stages of M. loreyi exposed to cold stress and provide a basis for further studying the molecular mechanisms of cold tolerance in insects.

Peanut Root Rot (PRR) is a devastating disease that significantly limits peanut production worldwide. Although PRR has been frequently reported in Henan Province of China, the predominant Fusarium species and their sensitivity to different fungicides remain unclear. Between 2021 and 2023, we surveyed 81 peanut fields across 17 cities in Henan Province, China, to assess PRR prevalence and Fusarium species distribution. A total of 1131 Fusarium isolates were identified based on the morphological characters and phylogenetic analyses and classified into 11 recognized Fusarium species: F. solani (56.06%), F. oxysporum (20.87%), F. neocosmosporiellum (13.62%), F. proliferatum (4.69%), F. acuminatum (1.33%), F. commune (1.15%), F. graminearum (1.06%), F. pseudograminearum (0.35%), F. ipomoeae (0.35%), F. lacertarum (0.26%), and F. armeniacum (0.26%). Pathogenicity assessments showed that all 11 Fusarium species were capable of causing PRR, with F. solani exhibiting the highest isolation frequency and widespread distribution in all areas. Furthermore, the four Fusarium species (F. solani, F. oxysporum, F. neocosmosporiellum, and F. proliferatum) were highly sensitive to the six fungicides, including prochloraz (EC₅₀ values of 0.02 ± 0.00~0.06 ± 0.01 mg/L), pydiflumetofen (EC₅₀ values of 0.31 ± 0.07~0.67 ± 0.06 mg/L), tetramycin (EC₅₀ values of 0.11 ± 0.02~0.58 ± 0.08 mg/L), tebuconazole (EC₅₀ values of 0.26 ± 0.07~0.65 ± 0.10 mg/L), prothioconazole (EC₅₀ values of 1.14 ± 0.16~3.15 ± 0.81 mg/L), and difenoconazole (EC₅₀ values of 0.62 ± 0.12~3.58 ± 0.76 mg/L). This comprehensive study is the first systematic documentation on the prevalence, virulence, and fungicide sensitivity of PRR pathogens in Henan Province. The findings of the current study will provide a theoretical basis for the effective management of peanut root rot in Henan, China.

Visual response effects of western flower thrips manipulated by different light spectra

Holotrichia parallela is among the world’s most destructive pests. For accurate qPCR and gene expression studies, the selection of stable and appropriate reference genes is crucial. However, a thorough evaluation of potential reference genes for use in H. parallela research is lacking. In this study, 11 reference genes (GAPDH, RPL32, RPL7A, RPS18, RPL13a, RPL18, Actin, RPS7, RPS3, VATB,and EF1A) were evaluated under different biological conditions and environmental stresses. The stability of 11 potential reference gene transcripts was evaluated through various computational tools, including geNorm, BestKeeper, NormFinder, theΔCt method, and the RefFinder program. Under various developmental stages and RNAi conditions, RPL18 and RPL13a exhibited the greatest stability. RPL13a, RPL18, and RPL32 were the most stable genes in both male and female adults. Under differing tissue conditions, RPL13a and RPS3 stood out as the most reliable. Moreover, under varying photoperiod conditions, RPL13a, RPS3 and RPL32 were the most stable genes. Lastly, Actin and RPL13a were the most stable genes across different temperatures. These findings offer essential criteria for selecting suitable reference genes across diverse experimental settings, thereby establishing a solid basis for accurate gene expression studies in H. parallela using RT-qPCR.