Bacterial rot of onion bulbs with autumn planting onion cultivation in Shiga prefecture occurs at storage facilities and shipment destinations, leading to complaints from processors and eventual disposal of bulbs. This study was conducted to elucidate the pathogenic bacteria of onion bulb rot that should be controlled for cultivation in Shiga prefecture. Bacteria were isolated from onion leaves and bulbs which exhibited bacterial rot symptoms during the growing period and after harvesting at various sites. Then the species were identified. Furthermore, to clarify the optimal temperature at which the bacteria cause rot, we investigated temperature effects on the onion scale lesion length and on the bulb rot percentage (number of rotten bulbs/number of bulbs sampled) during storage. Five species of pathogenic bacteria were isolated from the onion leaves and bulbs, but only Burkholderia cepacia, B. cenocepacia, and B. gladioli were isolated from the bulbs. Particularly, the highest isolated percentage of B. cepacia of surveyed sites was 52.6%. Onion scale lesions caused by the three Burkholderia species could not be confirmed at 10°C, but lesion formation was recognized at 15–20°C and higher temperatures. The lesions were longest at 25–35°C. Percentages of B. cepacia bulb rot were as low as about 10% at 15 °C and 20°C during storage, but were considerably higher at 30°C: about 41%. In conclusion, three Burkholderia species are the pathogenic bacteria to be controlled for autumn planting onion cultivation in Shiga prefecture. They can cause onion rot at 15–20°C or higher temperatures, but the optimal temperature for rotting is 25–35°C. These findings suggest that infection risks increase during April–June as temperatures rise after autumn planting onion cultivation in Shiga prefecture. Bacterial rot might be mitigated by storage at 10°C or lower temperatures.

In 2021, 83 isolates of Botrytis cinerea Pers. were collected from tomato fields in Nara Prefecture, Japan, and their sensitivity to fungicides was evaluated. The rates of isolates resistant to diethofencarb, penthiopyrad, thiophanate-methyl, and azoxystrobin were high and equalled 96.3%, 92.8%, 79.5%, and 46.3%, respectively. In contrast, the rates of isolates resistant to iprodione were low, amounting to 20.5%. No isolate resistant to mepanipyrim was detected. Only 4.1% of the isolates exhibited low sensitivity to fenhexamid. Tomato farmers in Nara Prefecture frequently used diethofencarb, penthiopyrad, thiophanate-methyl, and azoxystrobin though the resistance to those fungicides was observed in over 30% of the isolates. Our results suggested that mepanipyrim and fenhexamid could be effective fungicides. It was essential to identify effective fungicides via sensitivity experiments, to control Botrytis cinerea in production fields because of the frequent occurrence of isolates resistant to multiple fungicides.

The fruiting bodies and plasmodia of slime molds were found on small-flowered chrysanthemums (Chrysanthemum morifolium Ramat.) in an open field in Nara Prefecture, Japan. The damage was limited to the bottom leaves with fruiting bodies. The isolate was identified as Fuligo gyrosa (Rostaf.) E. Jahn based on its morphological characteristics and BLAST analysis. This is the first report of F. gyrosa causing slime mold disease in chrysanthemums.

Fusarium head blight (FHB) is a significant fungal disease of wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.) that can cause severe crop losses. The causal pathogens also produce toxins. In this study, 1,280 Fusarium graminearum Schwabe species complex (FGSC) isolates were obtained from sporodochia on symptomatic spikelets of wheat and barley in 437 fields in Mie Prefecture, Japan, from 2008 to 2021. The resistance of the FGSC isolates to methyl benzimidazole carbamate fungicides (MBC) was determined using the minimum inhibitory concentration method and testing for the presence of single nucleotide polymorphisms of the β2-tubulin gene coding region related to MBC resistance. The isolates established in this study had multiple amino acid mutations in the β2-tubulin gene-coding region. The F200Y and F167Y mutations were found among the highly resistant isolates, and the E198Q was found among the moderately resistant isolates. This is the first report of the E198Q mutation being detected outside of China. The isolates with the F200Y mutation, which showed high resistance to thiophanate-methyl, were only detected in 2008 and 2018. Additionally, the isolates with the F167Y mutation, which showed high resistance to thiophanate-methyl, were only detected in 2020 and 2021. In Mie Prefecture, which has a pest management system that controls the FHB once a year during the flowering period of wheat and barley, MBC-resistant strains are still low.

The use of Nesidiocoris tenuis (Reuter) (Hemiptera: Miridae) for control of Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) in the late period of winter–spring greenhouse tomato cultivation was evaluated in a demonstration test in Kumamoto Prefecture, Japan, from 2020 to 2021. Two adjacent greenhouses were used as a control plot and an N. tenuis-introduced plot. Insect-proof nets of 0.3–0.4 mm mesh were used for roof valleys and side walls of the N. tenuis-introduced plot, and 0.8–1.0 mm mesh were used for the control plot. Given the high risk of whitefly invasion in the immediate postplanting period, nonselective insecticides and repellents were used to control whiteflies in both plots initially, then N. tenuis and banker plants were introduced to the N. tenuis-introduced plot. The noncrop plants Cleome hassleriana (Chodat) (Brassicales: Capparaceae) and Verbena × hybrida hort. ex Groenl. & Rumpler (Lamiales: Verbenaceae) were planted as banker plants. N. tenuis introduction tended to suppress the increase in B. tabaci population in spring, the end of the cropping season, and had an indirect positive effect on the suppression of whitefly-transmitted viral diseases to the same or less level than the control. These results indicated that N. tenuis and banker plants, combined with insect-proof net of 0.3–0.4 mm mesh are effective control tools against B. tabaci even in the region which is at high risk for whitefly-transmitted viral diseases.

The fungicide sensitivity of 54 strains of gray mold fungus Botrytis cinerea, collected from tomatoes and strawberries in Aichi Prefecture from 2021 to 2022, were tested using primary kidney beans leaves for 16 fungicides, including QoI and SDHI fungicides. The bioassay results indicated that 22 (41%) and 17 (31%) fungal strains were resistant to the QoI fungicide azoxystrobin and pyribencarb, respectively. Moreover, 3 (6%), 2 (4%), and 2 (4%) strains were resistant to the SDHI fungicide penthiopyrad, isofetamid, and pyraziflumid, respectively. Interestingly, 23 (43%) were resistant to pyraclostrobin/boscalid, a combination of QoI and SDHI fungicides, while 8 strains (15%) were resistant to diethofencarb/thiophanate methyl. In addition, structural learning using a Bayesian network with lesion formation inhibition rate reported a probabilistic dependency relationship for QoI fungicides such as pyraclostrobin/boscalid, azoxystrobin, and pyribencarb. Correlation analysis (Spearman’s ρ) to the variation in lesion formation inhibition rate was shown, with 0.68 and 0.62. For SDHI fungicides, correlation analysis was found from penthiopyrad to isofetamid, with 0.5 correlation coefficient. These results suggest the possibility of cross-resistance between fungicides for the same strain in this prefecture.

Strains of satsuma dwarf virus (SDV) occurring in Mie Prefecture were examined, and at the same time, the disease symptoms on the rind of citrus mosaic virus (CiMV) sub-strain were also examined. SDV-free trifoliate orange (Poncirus trifoliata (L.) Raf.) rootstocks were planted in plots where the SDV strain, the CiMV sub-strain, and the navel orange infectious mottling virus (NIMV) strain occur. The relationship between the SDV strain and the infection rate was determined. The CiMV sub-strain occurred most frequently in Mie Prefecture, followed by the SDV strain. An isolate of the NIMV strain was detected in two orchards in Mie Prefecture. This is the second occurrence of the NIMV strain recorded in a field outside of the original field in Wakayama Prefecture, following an occurrence in Ehime Prefecture. This is also the first report of mixed CiMV sub-strain and NIMV strain infection in citrus. The results indicate that the CiMV sub-strain is widely distributed outside Wakayama Prefecture. Moreover, isolates of the CiMV sub-strain, which hardly induce mosaic symptoms in the fruit rind, were widely distributed. Trifoliate orange seedlings were planted near infected citrus trees growing on trifoliate orange rootstocks. SDV infection occurred within one year of planting. Whether the difference in infection rate was caused by differences in viral strains or by environmental factors in the field remains unknown.

The dynamics of the conidia of strawberry powdery mildew caused by Podosphaera aphanis (Wallroth) U. Braun & S. Takamatsu var. aphanis were examined during fungicide spraying. Although conidia were observed in the greenhouse even when sprayed with fungicides, the amount differed depending on the fungicide treatment. Spraying with 300-fold fatty acid glyceride + 750-fold sodium bicarbonate copper suppressed the amount of conidial scattering for 3 days, and spraying with 2,000-fold penthiopyrad and 3,000-fold pyriofenone suppressed the amount of conidial scattering for 4 days. A single treatment with 600-fold fatty acid glyceride + 1,000-fold sodium bicarbonate copper completely suppressed the regeneration of conidiophores. When 300-fold fatty acid glyceride + 750-fold sodium bicarbonate copper was sprayed at a rate of 300 L/10a, the incidence rate of the disease was significantly lower than that during no fungicide treatment.

In this study, we evaluated the efficacy of anaerobic soil disinfestation with incorporation of a vegetable oil refining byproduct (VORB) and sugar-containing diatomite (SCD). It was found that incorporation of VORB alone at a dose of 0.4 to 1.0 t/10 a could reduce the soil layer (0–30 cm depth) where VORB had been mixed, thereby disinfecting Ralstonia solanacearum. It was also found that incorporation of SCD at 0.5 t/10 a in combination with VORB at 0.7 t/10 a could effectively reduce the deeper layer (30–50 cm depth) of soil and suppress the development of tomato bacterial wilt.

The resistance of commercial sweet basil cultivars against basil downy mildew (BDM) caused by Peronospora belbahrii was assessed during pot and field experiments. In all experiments, var. “Campione” exhibited high resistance with no disease symptoms. In contrast, “Devotion” exhibited moderate resistance, and “TSGI-208” and “Obsession” exhibited low resistance. Furthermore, “Basil” was susceptible to the highest disease severity. According to these results, the combination of resistant cultivars and fungicide application could effectively control basil downy mildew.

The causal fungus of gray blight on tea [Camellia sinensis (L.) Kuntze] collected in Shiga Prefecture in 2019 and strains registered in the NARO Genebank as Pseudopestalotiopsis theae (Sawada) Maharachch., K. D. Hyde & Crous were reexamined. Phylogenetic and morphological examinations revealed that all strains were Pseudopestalotiopsis chinensis F. Liu & L. Cai.

To establish biological control for cucumber mosaic disease, we evaluated control effect of attenuated isolates of cucumber mosaic virus (CMV) and watermelon mosaic virus (WMV). In 2015 and 2017, cucumber seedlings were inoculated with the attenuated CMV-CM14 and WMV-WM14 isolates, and grown in greenhouses. When mosaic disease severity in the control plots increased to as much as 93.3–100%, the protective inoculation with the two attenuated isolates significantly suppressed cucumber mosaic disease. In 2023, the control of mosaic disease was evaluated in production fields using the CMV-CM14- and WMV-WM14-inoculated cucumber seedlings. The results showed that protective inoculation with the two attenuated isolates was effective to control the disease even under medium occurrence conditions. Our results suggest that protective inoculation with the two attenuated isolates can be effective to suppress the infections of CMV and WMV strains occurring in Kyoto Prefecture.

We investigated the effectiveness of Ultra violet B (UV-B) irradiation on controlling powdery mildew (Oidium matthiolae Rayss) and white rust (Albugo wasabiae Hara) of wasabi seedlings. The seedlings were irradiated with UV-B for 1 h from 23:00 to midnight at a distance of 100 to 200 cm from the irradiation source. The irradiance ranged from 2.4 to 40.8 μW·cm^–2. High efficacy was observed in this irradiance range for control of powdery mildew and not for the control of white rust. Furthermore, reduction of seed germination, growth inhibition or leaf damages of seedlings were not observed in this study.

Strawberry gray mold disease is one of the important diseases of strawberry caused by Botrytis cinerea. In this study, we examined the susceptibility of sixty-four isolates of this pathogen, collected from fifteen commercial strawberry fields in Osaka prefecture, Japan, to Qo inhibitor (QoI) fungicides (azoxystrobin and pyribencarb), succinate dehydrogenase inhibitor (SDHI) fungicides (penthiopyrad and pyraziflumid), methyl benzimidazole carbamate (MBC) fungicide (benomyl), dicarboximide fungicide (procymidone), phenylpyrrole fungicide (fludioxonil), and anilinopyrimidine fungicide (mepanipyrim).

Most of the isolates were resistant to azoxystrobin, while being susceptible to the QoI fungicide, pyribencarb. Additionally, most isolates showed a low sensitivity to SDHI fungicides and procymidone.

Effects of phosphite fertilizers and picarbutrazoxon on tomato root rot caused by Pythium cryptoirregulare Garzón, Yánez & G. W. Moorman and P. recalcitrans Belbahri & E. Moralejo were tested under pot condition. Soil drench of the phosphite liquid fertilizer at 100–1,000 ppm concentrations and picarbutrazox wettable powder at 500-fold dilution showed suppressive effects on root rot. However, the number of chemically damaged plants increased with increasing concentration and frequency of application of the phosphite liquid fertilizer, indicating that phosphite liquid fertilizer at a concentration of 100 ppm was considered suitable for the control of tomato root rot.

The two-spotted spider mite, Tetranychus urticae Koch, poses a critical challenge in rose cultivation owing to its reduced susceptibility to acaricides. Therefore, this study aimed to assess the efficacy of five distinct acaricides against adult female T. urticae inhabiting rose plants in 13 greenhouses located in the central region of Shizuoka Prefecture, Japan. The findings revealed substantial variations in the adjusted mortality rate of T. urticae, contingent upon the specific acaricides examined and the respective greenhouses from which they were sampled. The acaricides effectuating lower standardized fatality in T. urticae differed across the surveyed greenhouses. This observation suggested that the susceptibility of T. urticae to acarides is influenced not only by the type of acaricide used but also by the specific greenhouse environment, despite being confined to the same area.

In Japan, there is a cultural practice of consuming salted cherry leaves (Prunus speciosa), and edible cherry leaves are intentionally cultivated for this purpose. Synanthedon hector Butler, also referred to as the Japanese cherry tree borer, is a known pest of cherry trees. Its larvae feed on the tree trunks and cause serious damage. Hence, we investigated the disruptive effect on communication by employing mating disruptants using synthetic sex pheromones (synanthelure) and assessed the seasonal prevalence of S. hector adults in edible cherry leaf fields. In the fields treated with a mating disruptant, no S. hector male adults were attracted. In contrast, in untreated fields, S. hector male adults were attracted from late April to October, with peak attraction being observed in May, July, and September (multimodal type of occurrence). These results suggest that the communication disruption effect of pheromones on S. hector is extremely high. Moreover, this high communication disruption effect could continue until autumn if pheromones are installed by late April.

We investigated the chemical susceptibility of Kanzawa spider mites (Tetranychus kanzawai Kishida) and colonized exotic predatory mites (Phytoseiulus persimilis Athias-Henriot) collected from tea fields in Shizuoka Prefecture from 2019 to 2021.

The chemicals that caused in a corrected mortality rate of ≥90% in adult females and eggs of T. kanzawai across all populations were abamectin, milbemectin, acequinocyl, bifenazate, ethoxazole-pyrimidiphene, cyenopyrafen, cyflumetofen, and acynonapyr, out of the 16 chemicals tested.

Out of the 32 chemicals tested, profenofos, emamectin, abamectin, milbemectin, tebufenpyrad, pyridaben, tolfenpyrad, etoxazole, pyrimidifen, and fluxametamide were highly toxic to P. persimilis. In contrast, dinotefuran, clothiazinine, pyrifluquinazone, etoxazole, BPPS, chlorfenapyr, lufenuron, methoxyfenozide, acequinocyl, bifenazate, cyenopyrafen, cyflumetofen, pyflubumide, cyantraniliprole, chlorantraniliprole, cyclaniliprole, flubendiamide, flonicamide, and acinonapyr were less toxic to P. persimilis.

Moreover, acequinocyl, bifenazate, cyenopyrafen, cyflumetofen, and acinonapyr were highly effective against adult females and eggs of T. kanzawai, while having little negative effects on adult females P. persimilis. In contrast, spraying the three chemicals, emamectin, tolfenpyrad, and fluxamethamide, that are not applicable to T. kanzawai and highly toxic to P. persimilis in tea fields may lead P. persimilis population decreasing, while T. kanzawai increasing.

In a test cultivation of fig (Ficus carica L.) conducted in a closed-type plant cultivation room with artificial lighting, the damage of fruit pulp caused by thrips and eriophyid mites was investigated. Fig (cv. Masui Dauphine) trees were planted in plastic pots and continuously cultivated five times due to the renewal of bearing shoot. Pulp damage occurred in the fig fruits harvested from fourth and fifth cultivation. The overall incidence was 72% in the fourth cultivation and 85% in the fifth cultivation. The intrusion of onion thrips (Thrips tabaci Lindeman) into the fruit was detected as the cause. Many such infested fruits were observed where the adults and larvae of thrips co-existed, suggesting a high possibility of thrips generation alternation occurring inside the fruit. As thrips were hiding in the cracks of buds or in the soil, it was found that the thrips could not be eliminated from the cultivation environment by spraying pesticides and removing branches, which are the usual methods of pest management. Many cases were also observed where pulp damage occurred even though no thrips were present inside the fruit. Eriophyid mites were thought to be the main cause in this case. Eriophyid mites have been observed sporadically on the leaves, stems and surface of fruits since the first cultivation. In the fourth and fifth cultivation, many of them intruded inside the fruit and caused pulp damage similar to thrips. Thus, it can be concluded that the fate of these two types of pests in fig cultivation differs in a closed environment from that in open field cultivation; therefore it is necessary to develop new countermeasures to eliminate them.

We determined the toxicity of 10 insecticides on adult western flower thrips, Frankliniella occidentalis (Pergande) using the leaf-dipping method. Two different populations of the thrips were collected from an eggplant greenhouse in Kaizuka City and one from Habikino City in Osaka Prefecture. Flometoquin achieved more than 90% mortality while acetamiprid, tolfenpyrad, and cyantraniliprole showed low corrected mortality in all populations.

Conventional application of insecticides cannot successfully control loquat infection with the loquat psyllid, Cacopsylla biwa Inoue, because nymphs inhabit the crowded young fruit of loquat after flowering. We adopted insecticide application with a hand-held sprayer for each fruit at the time between the two cultivation practices: fruit thinning and bagging. Although this method requires more working time than the conventional treatment, it exhibits a higher control effect on the psyllids, resulting in less damaged fruits.

We investigated the susceptibility of second instar larvae and adult flower thrips (Frankliniella intonsa [Trybom]) collected from flat areas of Gifu Prefecture to 12 insecticides. Among the insecticides registered for controlling “thrips” on strawberries, spinosad, spinetoram, and fluxametamide demonstrated the highest efficacy against flower thrips. Conversely, spirotetramat and flometoquine were the least effective among the tested insecticides. Furthermore, among the insecticides not registered for thrips control on strawberries, emamectinbenzoate and chlorfenapyr show potential efficacy against flower thrips.