To establish an effective strategy for the chemical control of tomato Nectria blight, caused by Haematonectria ipomoeae, we evaluated the efficacy and timing of fungicide application to suppress infection through leaf-scar wounds. In vitro assays, seedling tests, and field trials showed that fludioxonil, pyribencarb, mandestrobin, ipflufenoquin, and a pyraclostrobin–boscalid mixture provided high control efficacy, with a protective value exceeding 70 (70% disease suppression compared with the untreated control) under field conditions. Infection markedly decreased when plants were inoculated ≥3 days after leaf removal, suggesting that wound healing at leaf scars restricted pathogen entry. These findings indicate that fungicide application within about 3 days after leaf removal effectively prevents initial infection and contributes to improved control of tomato Nectria blight.

Anthracnose caused by Discula theae-sinensis (I. Miyake) Moriwaki & Toy. Sato is the most serious disease of tea [Camellia sinensis (L.) Kuntze] in Japan. The pathogen retains its ability to form conidia on lesions on tea leaves that remained on tea plants for a long period. In this study, we examined conidial formation on diseased leaves that had fallen onto the ground. In the trial that began in June, conidial formation fell below the detection limit after 4 weeks. In contrast, in the trial that began in October, conidial formation was still observed in April. These results indicate that fallen leaves play only a minor role as infection sources during the tea growing season, but may serve as overwintering infection sources. Although diseased leaves remaining on the tree are regarded as the main infection sources, the potential contribution of fallen diseased leaves should also be considered.

To facilitate integrated pest management in Raphanus sativus (Daikon, Japanese radish), we surveyed two areas where R. sativus is cultivated in Shizuoka Prefecture, central Japan. We assessed the percentage of R. sativus plants colonized by leafminers on the leaves, parasitism rates by hymenopteran parasitoids on leafminers, and parasitoid species composition. The percentage of colonized leafminers ranged from 0.6–28.2 and 0–28.6% in the Mikatahara and Haibara areas, respectively. The majority of leafminers were Chromatomyia horticola, with a few Liriomyza trifolii. Additionally, the parasitism rate of parasitoids on leafminers varied from 8.3–79.5% (average 52.0%) in the Mikatahara area and from 0–48.6% (average 17.3%) in the Haibara area. These differences are likely because of variations in the surrounding crop cultivation conditions, wind speed, and pesticide application history in each area. The parasitoid community was primarily dominated by Diglyphus isaea, followed by Diglyphus minoeus (Eulophidae). Dacnusa sasakawai and Halticoptera circulus were the dominant parasitoids in the families Braconidae and Pteromalidae, respectively. The dominance of these parasitoid species was attributed to variations in their optimum temperature and pesticide susceptibility. Additionally, there were a few differences in species composition among the areas. These results indicate that natural enemy parasitoids significantly suppress leafminer density on R. sativus. Moreover, it was revealed that the parasitism rate of leafminer parasitoids varied significantly by region. The effective use of these natural enemy parasitoids requires identifying pesticides that minimally affect them and determining the optimal temperature for each parasitoid species.

In Shizuoka Prefecture, increased production of tencha—the raw material for matcha, whose exports are rising—has lead to expanded shaded tea cultivation, including in mountainous and hilly regions. However, tea blister blight disease has become an increasing problem in these areas, creating a need for effective control measures that also minimize pesticide residue. Accordingly, this study evaluated the effects of direct cover application and copper fungicide spraying on the incidence of blister blight. Field trials combining cover application and copper fungicide spraying were conducted at the Tea Research Center, Shizuoka Prefectural Research Institute of Agriculture and Forestry (Kikugawa City, Shizuoka Prefecture) and at a local organic tea plantation (Kawane Town, Shimada City, Shizuoka Prefecture). Disease incidence was assessed under each treatment condition. In a 2022 trial, cover application increased the number of blister blight-infected leaves. In contrast, no difference in disease incidence between covered and uncovered plots was observed in 2023, suggesting that the effect of cover application on blister blight may depend on prevailing weather conditions. In both years, copper fungicide application before or during sprouting reduced the number of infecetd leaves, although the magnitude of this effect also varied with weather conditions.

Frankliniella intonsa (Trybom) is a major pest in greenhouse-grown strawberries. Although red light-emitting-diode (LED) irradiation of crops suppresses the density of several thrips species, its effectiveness against F. intonsa in strawberries remains unknown. This study aimed to evaluate the effect of a red LED irradiation method, established for controlling Thrips palmi Karny on melons, eggplants, and cucumbers, on the density of F. intonsa on strawberries through greenhouse experiments in 2024 and 2025. Strawberry plants were irradiated with red LED light (peak wavelengths: 620–630 nm in 2024 and 660 nm in 2025) at 1.35–3.79 × 10¹⁸ photons/m²/s. In both years, no significant differences were observed in thrips densities on strawberry flowers between the non-irradiated control and red LED-irradiated plots. In 2024, the cumulative number of F. intonsa adults caught from ethanol-washed flowers was rather significantly higher in the red LED-irradiated plots than in the control plots, whereas no significant differences were observed in 2025. The results indicate that this red LED irradiation method did not suppress F. intonsa density in strawberries. Unlike a previous study, our findings suggest that red LED irradiation did not inhibit the settlement of F. intonsa on the plants. These differences may be attributed to various factors, including the irradiated plant species and their parts, variations in light susceptibility among thrips species, and irradiation intensity and conditions; thus, further investigations are necessary.

To evaluate the efficacy of slow-acting insecticides against Frankliniella intonsa, Frankliniella occidentalis, Thrips palmi, and Thrips tabaci, a bioassay method was developed and tested. We validated this bioassay method (dip test) using kidney bean (Phaseolus vulgaris L.) leaf discs placed on water-moistened cotton pads to maintain their freshness. Then we assessed the efficacy at two and seven days after treatment. The results demonstrated high applicability to only Frankliniella intonsa: control mortality was less than 10% after seven days. Emamectin benzoate and cyantraniliprole exhibited low efficacy two days after treatment, but both compounds showed high efficacy seven days after treatment, which indicated delayed action of these insecticides.

In contrast, this method was not appropriate for the other three species due to high control mortality (>20%) seven days after treatment.

These findings suggest that the method contributes to selection of effective insecticides, particularly for Frankliniella intonsa controls.

This study aimed to develop a rapid and efficient technique for the identification of Alternaria species isolated from field-infected broccoli plants exhibiting black spot symptoms. To achieve this, we focused on nucleotide sequences of the Alt a 1 region and designed species-specific primers capable of detecting four Alternaria species: A. japonica, A. brassicicola, A. brassicae, and A. alternata.

The specificity of the primer sets was evaluated using DNA extracted from standard strains of the four species. The results revealed that each species could be specifically detected. Furthermore, 102 Alternaria isolates obtained from broccoli and cabbage in Aichi Prefecture were identified using these primer sets. Genetic diagnostics enabled more accurate identification than morphological observations.

Sensitivity of an active component fungus, Verticillium lecanii of a biocontrol agent to 97 chemical pesticides was investigated on YPA medium as a low nutrient medium. Colony growth derived from conidia, or colony expansion was inhibited with multi-site activity inhibitors, mancozeb, thiuram, propineb, captan, TPN, and three agents of sterol biosynthesis inhibitor. Benomyl, azoxystrobin, tolclofos-methyl, fluazinum, pyriofenone, and flutianil also inhibited the growth. Pyrimidifen, an acaricide inhibited colony expansion. When these chemicals are mixed to V. lecanii agents, that may inhibit the biocontrol activity. Although, inhibitory effect of these chemicals to formulations of V. lecanii on plants is unclear.

‘Reikodai 1 go’ is a BC₁ line derived from the interspecific hybridization of the common fig, Ficus carica, with a wild fig, F. erecta that has resistance to Ceratocystis canker caused by Ceratocystis ficicola. We have confirmed that ‘Reikodai 1 go’ possessed the same resistance to Ceratocystis canker as F. erecta by an inoculation experiment in a previous study using only one strain of C. ficicola collected in Kure City (Hiroshima Prefecture). However, we are uncertain if the rootstock can be utilized for different strains of C. ficicola because the resistance level of ‘Reikodai 1 go’ to other strains is unknown. Therefore, we carried out inoculation experiments with different strains of the fungi using cuttings of ‘Reikodai 1 go’ and a susceptible common fig cultivar ‘Houraishi’. In addition to the Kure city strain, we employed C. ficicola strains collected in Fukuyama City (Hiroshima Prefecture), Habikino City (Osaka Prefecture) and Buzen City (Fukuoka Prefecture). By 30 days, all ‘Houraishi’ cuttings were dead, but all ‘Reikodai 1 go’ cuttings were still alive regardless of the origin of the fungi. Quantitative PCR showed that the amount of C. ficicola DNA was limited in ‘Reikodai 1 go’ cuttings relative to those in ‘Houraishi’ cuttings, regardless of the fungal origin. These results indicate that ‘Reikodai 1 go’ would be utilized anywhere in Japan.

The cold tolerance, and overwintering survival and fecundity schedules in winter of female adults of the five invasive pest thrips were examined and discussed in terms of the establishment potential and geographical distribution of overwintering population at outdoor conditions on the Japanese mainland. The mortality of female thrips molting into adults at 20°C in response to chronic low temperature exposure at −5°C was examined using a lethal time (LTime) approach. Such evaluation was carried by avoiding cold shock mortality where the samples were placed according to some intervals at the sequencing: One day at 15°C, two days at 10°C, one day at 5°C, and finally one day at 0°C, before exposure them to −5°C. Thrips tabaci had the longest LT₅₀ among the five invasive thrips tested, and Frankliniella occidentalis and Hercinothrips femoralis had longer LT₅₀ with overlapping 95% limits than both Echinothrips americanus and Thrips palmi. The order of cold tolerance at −5°C is likely to match marginal areas where each species could overwinter in Japan. In addition to adult females, survival of larvae that hatched at 20°C, in response to chronic low temperature exposure at −5°C was examined for four species of them, with the same acclimatizing procedure as the adult test. The result suggested that percentages of survival of E. americanus and T. palmi were lower than those of T. tabaci and F. occidentalis at the same low temperature period tested. The rearing trials throughout several generations under semi-outdoor conditions in Kyoto City were conducted from September of 2020 to April of 2021. Under semi-outdoor conditions, F. occidentalis and T. palmi were alive until the end of March, and both laid few eggs after January onwards. On the other hand, H. femoralis and E. americanus died on mid-December and the end of February, respectively, and they had stopped laying eggs in December.

Two types of electrolyzed water are available for agricultural use: slightly acidic and strongly acidic electrolyzed water. Both have been demonstrated to be effective in controlling plant pathogens. In this study, weekly applications of both types of electrolyzed water effectively suppressed strawberry powdery mildew caused by Podosphaera aphanis var. aphanis and gray mold caused by Botrytis cinerea. For powdery mildew, they showed higher disease suppression than fungicide applications at 10-day intervals. Furthermore, slightly acidic electrolyzed water exhibited higher control efficacy than strongly acidic electrolyzed water against both diseases, particularly against powdery mildew.

A newly invaded leafhopper, Singapora shinshana (Matsumura), gives a damage to leaves of Japanese apricot through sap-sucking, often causing early defoliation. We evaluated the control efficacy of nine insecticides by manual spraying using a power sprayer in the orchards. Cypermethrin, fenpropathrin, fluvalinate, acetamiprid and dinotefuran, were effective at 3, 7, and 14 days after treatment . We also conducted a study for labor-saving pesticide application using sprinklers or a multirotor unmanned aerial vehicle (UAV) because Japanese apricots are produced in sloped terraced orchards in Wakayama Prefecture. In case of applying acetamiprid, sprinklers or UAV achieved equivalent control effect to a conventional spraying.

The analytical method using ELISA was validated to determine residual oxolinic acid (OA) in ume, apricot and those processed liqueurs. OA was extracted with the buffer containing methanol. OA in the test solution was determined quantitatively using ELISA. Method validation was performed by recovery tests at 30 μg/g and 0.01 μg/g to evaluate the trueness, repeatability (RSD_r), and within-laboratory reproducibility (RSD_wr). The validation results exhibited sufficient trueness (80%～95%) and precision (RSD_r ≦ 9% and RSD_wr ≦ 13%). The interfering colorings were not observed in blank extracts. ELISA-based analytical methods can help inspect residual OA in ume, apricot and those processed liqueurs.

Nesidiocoris tenuis (Reuter) is an effective zoophytophagous predator of small insect pests in greenhouse vegetables such as tomato (Solanum lycopersicum L.). Sesame (Sesamum indicum L.) and cleome (Cleome hassleriana Chod.) plants fully support the development and reproduction of N. tenuis. Consequently, these non-crop plants are used as secondary plants (e.g., banker plants) for this mirid. However, the preferences of N. tenuis for crop and these non-crop plants remain unclear. In this study, we evaluated the plant preferences of this bug for tomato and sesame in dual-choice tests using potted plants. Individuals naively reared on a plant species [Crassula ovata (Mill.) Druce] unrelated to tomato or sesame exhibited no clear preference for either, suggesting that the innate preference of N. tenuis for both plant species was equal. In contrast, individuals with temporary (24 h) feeding experience on tomato or sesame showed an increased preference for the experienced plant species. These results indicate that plant preference in N. tenuis among these plant species is modulated by learning, suggesting that its plant preference may be artificially manipulated. These findings are consistent with results from a previous study conducted with tomato and cleome and may contribute to improving release strategies for this predator.

Pot and field experiments were conducted to evaluate the effectiveness of preceding cropping with several potential “bait crops” for suppressing clubroot disease in Hanana (Brassica rapa var. nippo-oleifera), which is a semi-traditional vegetable cultivated in Kyoto, Japan. Among the tested species, Guinea grass (Megathyrsus maximus; syn. Panicum maximum) exhibited a consistent suppressive effect on disease incidence, comparable to that of the known bait crop ha-daikon (Raphanus sativus var. longipinnatus), in pot experiments. Conversely, under field conditions, M. maximus did not reduce disease incidence compared with the untreated control. These findings suggest that the suppressive effect of M. maximus is confined to controlled environments and may depend on soil and management conditions. However, M. maximus confers advantages over ha-daikon as a bait crop in terms of vigorous growth and reduced pest damage during summer cultivation.

The efficacies of 15 insecticides at commercial concentrations were evaluated against Spodoptera litura (Fabricius) and Spodoptera exigua (Hübner) populations collected from production fields in Nara Prefecture, Japan during 2023–2025. For S. litura, spinetoram, lepimectin, chlorfenapyr, metaflumizone, indoxacarb, fluxametamide, broflanilide, and pyridalyl showed high efficacy 2–3 days after treatment. Methoxyfenozide was effective 5–8 days after treatment. For S. exigua, spinosad, spinetoram, chlorfenapyr, fluxametamide and broflanilide showed high efficacy 3 days after treatment, whereas methoxyfenozide was effective 5–8 days after treatment. In conclusion, several insecticides were found to have low efficacy against S. litura and S. exigua, but spinetoram, chlorfenapyr, methoxyfenozide, fluxametamide, and broflanilide were effective.

Sensitivity of Bacillus subtilis strain Y1336 in wettable powder formulation of a biological fungicide to 96 chemical pesticides was investigated on cucumber leaves. Mixtures of the biological fungicide and each of the chemical pesticides as concentrations registered in Japan were dropped onto the leaves. After a week incubation, rise and fall of colony forming units (cfu) of the strain was measured on agar medium. Without chemicals, cfu of the strain slightly decreased to 0.50–0.80 of cfu just after dropping the bio-fungicide without chemicals. Although 32 chemicals at concentrations registered inhibited colony growth of the strain on agar medium, only a fungicide, cyazofamid, and an insecticide, flonicamid, decreased the cfu to <0.10 on the leaves, and 5 fungicides fluazinam, mancozeb, propineb, captan and chinometionat and an insecticide hexiazox decreased the cfu to 0.10–0.20. Cyazofamid, flonicamid and hexiazox did not inhibited growth of the strain on agar medium. These 8 chemicals may interfere the fungicidal effect by the strain.

The seasonal occurrence of Pochazia shantungensis (Chou and Lu, 1977) was investigated through field observations conducted in Kinokawa City, Wakayama Prefecture in 2024 and 2025. This species overwinters in the egg stage. First-generation nymphs began to appear in early or mid-April. Adults emerged from mid-June and began to lay eggs in late June or early July. Second-generation nymphs began hatching in late July. Adults started to appear from late August, with oviposition beginning in mid or late September and continuing until late November. The eggs laid by the second-generation adults did not hatch until the end of December.

The number of adults captured by a light trap showed a bimodal pattern, with peaks occurring in early July for the first generation and in mid-September for the second generation. These results indicate that this species has two generations per year in Wakayama Prefecture.

In this study, we evaluated the efficacy of penthiopyrad, isopyrazam and pyraziflumid against Mycovellosiella nattrassii isolates. These isolates, collected from eggplants in Osaka Prefecture, Japan, in 2024, had previously shown reduced sensitivity to succinate dehydrogenase inhibitors (SDHI) in culture medium tests (Yasumatsuya et al., 2025). Three strains (N8, N9 and N10) were tested. N8 and N10 demonstrated low sensitivity to penthiopyrad, isopyrazam and pyraziflumid on culture medium, were resistant to these SDHI on plant body. N9, which was sensitive to pyraziflumid and resistant to penthiopyrad, isopyrazam on culture medium, was sensitive to pyraziflumid and resistant to penthiopyrad, isopyrazam on plant body.

The results of sensitivity to pyraziflumid on culture medium were consistent with the results on plant body. These results indicate the development of SDHI fungicide resistance in Mycovellosiella nattrassii (the causal agent of eggplant leaf mold) in Osaka Prefecture, and suggest the potential for the culture medium test to distinguish between sensitivity and resistance to pyraziflumid.

The seasonal occurrence of brown-winged green bug, Plutia stali SCOTT was investigated by light traps and pheromone traps for one season in Mino region of Gifu prefecture. To examine the seasonal fluctuation of mean body size, trapped bugs were measured in pronotum size and categorized in five size classes. The ratio of each size class fluctuated, and the proportion of relatively large classes increased in August for both traps. The mean body size of captured bugs decreased from September. Mean sex ratio of the captured bugs was investigated for each month to compare the attractive effect of traps. The ratio of female bugs was fluctuated and increased at the peak period of the number of bugs captured in each trap.