The species composition of hymenopterous parasitoids attacking a garden pea leaf-miner fly, Chromatomyia horticola on garden pea plants was investigated at three locations in Japan. In Tsu, Mie Prefecture, Halticoptera circulus, Diglyphus isaea, Dacnusa nipponica, and Diglyphus minoeus predominantly emerged from C. horticola mines. D. nipponica was the dominant species in Fukuyama, Hiroshima Prefecture. Meanwhile, H. circulus, D. nipponica, Opius spp., and D. isaea were collected in large numbers in Koshi, Kumamoto Prefecture. These results revealed marked regional differences in parasitoid species composition. In addition, we compared these results with the results of corresponding surveys in other places.

A strain of Pythium oligandrum isolated from soybean, grown in a commercial field in Osaka, Japan, was characterized by species identification and suppression of soybean damping off caused by P. aphanidermatum and P. myriotylum. The morphology and hyphal growth temperature of the P. oligandrum strain corresponded with those of the original description of P. oligandrum. rDNA-ITS sequences of the P. oligandrum strain were highly matched to those of the type strain of the species. The P. oligandrum strain was mycoparasitic toward P. aphanidermatum and P. myriotylum, and significantly suppressed soybean damping off caused by them. This is the first report of the effectiveness of P. oligandrum on soybean damping off pathogens.

In order to elucidate the occurrence trends of resistant isolates of Botrytis cinerea and to conduct effective control, we collected isolates from 2015 to 2017 from tomato cultivation fields in Mie prefecture, Japan. We examined the chemical susceptibility of the isolates to major fungicides. In addition, we discussed the relationship between the application of fungicides and the occurrence of resistant strains.

In almost all of the investigation fields, resistant isolates to high-risk fungicides such as quinone outside inhibitors (QoI) and succinate dehydrogenase inhibitors (SDHI) were observed. The occurrence of resistance was frequent when using these fungicides. On the other hand, resistant strains to medium-risk fungicides, such as mepanipyrim, and to low-to-medium risk fungicides, such as fludioxonil, were not observed despite multiple sprayings. In other words, the occurrence trends of these major fungicides-resistant isolates were almost consistent with the risk defined by the Fungicide-Resistance-Action-Committee (FRAC).

In the fields where the generation of resistant strains was low, the use of protection fungicides such as tetra-chloroisophthalo-nitrile (TPN) and rotation spraying had been utilized.

We concluded that it is important to conduct susceptibility monitoring in order to verify the effect of the above measures against resistant isolates based on the FRAC risk.

Young shoots infested with mulberry tiger moth larvae Lemyra imparilis (Lepidoptera: Arctiidae) were observed on ‘Delaware’ grapevine in an open field in April 1997 and 1998. Larvae primarily fed on leaf tissue, and damaged leaves were observed in 89.4% of infested shoots. Additionally, damage due to feeding was observed in 42.6% and 38.3% of infested flowers and shoot tips, respectively. In 27.7% of infested shoots, larvae consumed all 3 tissue types (leaves, flowers, and shoot tips).

The effects of feeding damage were evaluated by investigating growth and fruit characteristics of: 1) shoots with natural injuries due to larval moth infestation and 2) shoots with artificial injuries due to manual excision. Shoots that were missing all their leaves had reduced numbers of berries per bunch. However, many of the shoots infested with larvae only had partial leaf damage. These shoots could be used for normal fruit production, because there were no observed effects on shoot growth or fruit characteristics. Shoots with flower damage caused loss of part or whole of the fruit bunches. Shoots damaged at the tip could produce bunches; however, growth was markedly reduced, so they could not be used for fruit production the next season. Therefore, shoots with flower and shoot tip damage should be removed by suckering early in the season.

We developed a technique to detect Perilla mosaic virus (PMoV), a pathogenic virus causing perilla mosaic disease, using the reverse transcription loop-mediated isothermal amplification (RT-LAMP) method. Although PMoV is widely distributed in Japan and is known to be composed two major clades on the basis of nucleotide sequences, all of the isolates tested were readily detected, by mixing two kinds of FIP and BIP primers corresponding to each clade. In addition, PMoV could be detected with an accuracy of 92.3% even with a simple template obtained by piercing symptomatic leaves with a needle. Furthermore, even in places where electric power is not available, PMoV could be detected on site by performing an RT-LAMP reaction using an automobile battery.

The effectiveness of control by the application of pyrifluquinazon against Thrips tabaci Lindeman and necrotic streak disease were evaluated using field tests on infested commercially grown Welsh onion plants. The population density of the adult and larval thrips were significantly lower in plots with pyrifluquinazon application than in the control plot, and the degree of leaf damage by thrips was maintained from about one-third to one-half in the treated plot compared with the control plot. Furthermore, the percentage and the number of leaves with necrotic streak disease were significantly lower in the pyrifluquinazon application plot than in the control plot. The number of necrotic streak disease spots was significantly lower in the treated plot compared with the control plot. These results indicated that pyrifluquinazon is an effective insecticide for the control of T. tabaci and necrotic streak disease.

Cletus punctiger is a seed bug that feeds on the grains of gramineous plants. Post-hibernating adults were collected in the field on April 23, 2018, in Shiga Prefecture, Japan. Twenty-four females and 32 males were reared separately in the laboratory at 25°C and with a 16-h photoperiod to study their longevity and fertility. The mean survival of females and males was 64.7 days and 133.3 days, respectively. Twenty-one of 24 females laid eggs, and the mean total number of eggs laid per female was 63.6. These females had already copulated before collection and subsequently laid the fertile eggs.

A immunochromatographic test can readily detect Ralstonia solanacearum in plants. Here we examined a method for detecting and estimating the density of this pathogenic bacteria in soil using an immunochromatographic test and tomato (Solanum lycopersicum) seedlings. We found that R. solanacearum could be detected after incubation in a water tank (27°C), and after 2 days incubation in artificially inoculated soil that contained 270–2700 CFU/g dry soil and in farm soil. We also found that the target that was captured by this method had pathogenicity toward tomato seedlings. These results suggested that this method will be useful for predicting bacterial wilt in the field.

The effectiveness of nine insecticides against Orius spp., an indigenous natural enemy of melon thrips, Thrips palmi Karny, was investigated in an eggplant field. Among the effective insecticides against twenty-eight-spotted ladybird (TSL), metaflumizone did not reduce the density of Orius spp., but indoxacarb reduced it by about half compared with control at 1 week after treatment. Among effective insecticides against two-spotted spider mite (TSM), pyflubumide, milbemectin, and spirotetramat did not reduce the Orius spp. density. Both acetamiprid and dinotefuran were effective against green stink bug (GSB), and emamectin benzoate and flometoquin were effective against melon thrips, reduced the Orius spp. density, but increased to about one-third to half density compared with the control by 2 weeks after treatment. Results show that, for conservation biological control of melon thrips, metaflumizone can be utilized for TSL control, and pyflubumide, milbemectin, and spirotetramat can be utilized for TSM control. Because acetamiprid and dinotefuran for GSB control reduced the Orius spp. density, spraying emamectin benzoate or flometoquin simultaneously is encouraged for the control of melon thrips until the Orius density recovers.

Races of tomato leaf mold pathogen, Passalora fulva, are rapidly and variously developed. For race identification of the pathogen, foreign cultivars have been used, although the seeds of these cultivars are not easily available in Japan. In this study, fixed lines of tomato were bred from Japanese cultivars harboring leaf mold resistance genes, Cf-2, 4, 5 or 9. The fixed lines were inoculated with 98 isolates of known races and resistance was as expected. Seeds of the fixed lines are open to all who need them in Japan.

The susceptibilities of female Tetranychus urticae (green form) collected in a strawberry field in Nagakute City, Aichi prefecture, Japan, against acaricides were examined at 2 and 10 hours after the onset of the light period, and in the dark period.

The mortality rates with emamectin benzoate emulsion, milbemectin emulsion, acequinosyl flowable, and reduced starch glycated solution applied at 2 hours after the onset of the light period tended to be lower than those in the other two treatment groups. Regarding cyenopyrafen flowable and cyflumetofen flowable, mortality after treating at 2 hours after the onset of the light period was higher than in the other two treatments. For the bifenazate flowable and sulfur, mortality did not differ among the treatment times. Furthermore, there was no apparent difference in mortality between treatment at 10 hours after the onset of the light period and that in constant dark conditions, with any acaricide.

Ovicidal effects of a variety of spiracles-blocking acaricides were examined against T. urticae collected in a strawberry field in Gamagori City, Aichi prefecture. Treatment of either highly refined machine oil emulsion or machine oil emulsion resulted in a substantial reduction in hatching rates, mainly due to the blocking of spiracles. Hatching inhibition effects were also observed with the rapeseed oil emulsion, fatty acid glyceride emulsion, and blended oil emulsion, but with the propylene glycol mono fatty acid ester emulsion, hydroxypropyl starch solution, and etoxazole flowable, hatching was almost never inhibited. The susceptibility of this population of T. urticae to etoxazole flowable was suspected to have decreased.

Spotted wilt disease caused by Tomato spotted wilt virus (TSWV) is one of the most important diseases affecting the production of bulbs and cut flowers of Dahlia variabilis in Japan. In Nara Prefecture, the main vector species of TSWV were thrips Frankliniella intonsa and Frankliniella occidentalis. The number of F. intonsa and F. occidentalis captured using blue sticky traps increased in late June and mid-May, and peaked in early July and late May to early June, respectively. TSWV viruliferous F. intonsa and F. occidentalis occurred throughout almost the entire production period in bulb production fields. TSWV might be transmitted by thrips, and the infection rates in dahlias reached up to 80% in a cut flower field. However, the use of insect proof nets greatly decreased the infection rates. In addition, the removal of dahlias with TSWV symptoms effectively decreased the rates of diseased plants. To prevent the spread of TSWV, it is important to prevent invasion of thrips using physical barriers. In addition, removal of the source of infection is an effective way to reduce the occurrence of disease.

We inoculated persimmon with Colletotrichum horii, causing anthracnose on the young twigs from the third week in April to the second week in June. The anthracnose lesions occurred in late April, and did not occur on lignified twigs. In addition, we inoculated the fruits with high and low levels of inoculation using twigs with lesions. In the high inoculation group, the occurrence of diseased fruits was as high as 41.6%. The results indicated that the application of fungicides should start after late April, and also that twigs with lesions should be removed and controlled using the application of fungicides.

In 2017, chrysanthemum downy mildew, which has not been reported in Japan since 1980, severely affected chrysanthemum production in Nara Prefecture, Japan. We investigated the occurrence of the disease at the fields in Nara Prefecture and the control efficacy of thermotherapy and fungicides against it. In the field survey, over 95 % of plants were diseased in seven cultivars, while no plants with the symptoms were observed in the other six cultivars. This suggests that some chrysanthemum cultivars had resistance to downy mildew. Chrysanthemum cuttings were treated with thermotherapy (treatment with hot water and hot air). The disease prevalence in both treatments was significantly lower than that in the non-treated. Severely diseased plants were sprayed with three fungicides (azoxystrobin, manzeb, and tolfenpyrad). While azoxystrobin and manzeb reduced the disease severity compared with non-treated, its efficacy was not so high. We concluded that the use of resistant cultivars and the application of thermotherapy can effectively control chrysanthemum downy mildew.

The effect of a predatory mite, Neoseiulus californicus (McGregor) release to control a population of two-spotted spider mite, Tetranychus urticae Koch, was investigated in a chrysanthemum greenhouse. After spider mite inoculation, we released N. californicus females at prey:predatory ratios of 20:1, 10:1, or 5:1. The population densities of spider mites began to decrease 4 weeks after predator release and reached almost 0 after 5 weeks. We found that N. californicus could reduce the population density of spider mites, when the N. californicus/T. urticae ratio was 10:1 or more.

In this study, the occurrence of perilla mosaic disease in Aichi prefecture, Japan, was evaluated by conducting a questionnaire survey among perilla farmers. About 90% of the farmers reported the occurrence of this disease in their crop, while about 30% reported the disease to have affected over 10% of their cultivation facility. The survey results suggested that the risk of disease development was significantly increased when perilla was planted in the field around the cultivation facility. In the local cultivation facility, we performed cultivar control by removing infected perilla planted in the field that had been the source of this disease during the cultivation period in summer 2016. As a result, the rate of this disease decreased compared with that during the cultivation in summer 2015, when no control measures were implemented. In addition, it was revealed that disease in the cultivation facilities was more often reported near the side windows, with higher incidences occurring from July to November. During the cultivation in summer 2017, after removing the source of infection and properly applying pesticide spray from July to November, the rate of the occurrence of perilla mosaic disease decreased further compared with that during the cultivation in summer 2016.

We evaluated the effects of pesticides on two native generalist phytoseiid species, Amblyseius eharai Amitai and Swirski and Euseius sojaensis (Ehara), collected in and around citrus orchards in Shizuoka Prefecture Japan. Test results indicated that ethiprole, pyrifluquinazon, etoxazole, chlorfenapyr, flufenoxuron, lufenuron, buprofezin, flometoquin, spirodiclofen, spiromesifen, cyenopyrafen, cyflumetofen, pyflubumide, cyantraniliprole, flubendiamide, flonicamid, imibenconazole, boscalid, mepanipyrim, kresoxim-methyl, pyribencarb, cyazofamid, copper(II)-hydroxide, and dithianon do not have harmful effects on adult females of these species or their oviposition. Comparison of our findings with those of previous studies suggested that pesticide effects on generalist phytoseiids differ not only among species but also among populations. Therefore, to establish effective regional IPM programs, it will be necessary to further evaluate the effects of specific pesticides on generalist phytoseiid mite populations living in and around target orchards.

The direct and residual efficacy of insecticides and the effect of different treatments (spraying or soil treatments) against three aphid species: Aulacorthum solani (Kaltenbach), Myzus persicae (Sulzer), and Aphis gossypii, collected from sweet pepper in Kagoshima Prefecture, Japan, were evaluated. Neonicotinoid insecticides: acetamiprid, imidacloprid, clothianidin, dinotefuran, thiamethoxam, and nitenpyram; and organophosphate: acephate; diamide: cyantraniliprole; and others: spirotetramat, pymetrozine, pyrifluquinazon, and flonicamid were tested by spraying or soil treatments (scattering of granules or drenching of wettable powder). Insecticides were applied to sweet pepper plants in a greenhouse (mean air temperature: 24.5°C), and sweet pepper leaves that were treated with insecticides were provided to aphids in the laboratory (25°C, natural day length) at 6 hours and 3, 7, 14, 21, 28, and 35 days after insecticide treatments. The mortalities of aphids were compared at 96 hours after rearing adults. The effect of insecticides did not differ significantly among the aphid species (GLM, P>0.05). The maximum mortality of aphids ranged from 80% to 100%, and all insecticides were effective against aphids. However, soil treatments resulted in higher mortalities (GLM, P<0.0001) and a longer periods if effectiveness than spraying. The mortalities were over 70% from 3 days to 28 days after applying six neonicotinoid as granules, and the same result was observed from 3 days to 35 days after acephate granule treatment.

We evaluated the effectiveness of an integrated pest management (IPM) program combining the predatory bug Nesidiocoris tenuis, verbena (Verbena × hybrida ‘Tapien’) as an insectary plant for N. tenuis, and a selective insecticide to control Bemisia tabaci in experimental greenhouse tomatoes. Testing was conducted from March to July 2015. We assigned three treatments to different sections of a tomato greenhouse: i) IPM treatment (N. tenuis + verbena + selective insecticide), ii) chemical treatment (insecticides only), and iii) control. The control treatment was intended to be grown without insecticides or N. tenuis, but we sprayed insecticide once because of heavy infestation of B. tabaci in mid-June. In the IPM treatment and the chemical treatment, the density of B. tabaci adults from late May to mid-June and the density of nymphs in June and July were significantly lower than in the control treatment. There was no significant difference in the density of B. tabaci between the IPM treatment and the chemical treatment throughout most of the growing period. Although N. tenuis populations became established and increased on both tomato and verbena, the density of N. tenuis adults on verbena was always low, suggesting that N. tenuis adults moved from verbena to tomato. No significant differences in the infection rate for Tomato yellow leaf curl virus (TYLCV) were observed among treatments. There were no significant differences in the number of fruits per truss among treatments, indicating that the plant-feeding behavior of N. tenuis did not affect tomato fruit production. Moreover, there were five insecticide applications in the chemical treatment but only one in the IPM treatment. These results indicate that an IPM program combining N. tenuis, verbena, and selective insecticides is a promising alternative to chemical control of B. tabaci in greenhouse tomato crops.

While surveying plant disease severity, we usually record the data in notebooks and enter them in spreadsheet software, such as Microsoft Excel, using keyboard input. However, this method has some problem concerning about the efficiency of working. In the present study, we evaluated the time-saving effect of voice input while surveying of plant disease. Two test subjects surveyed and recorded the disease severity of tomato powdery mildew using voice input. The time in voice input was 9.2% to 26.2% less than that in the control. The input time of the data into Excel in voice input was 58.1% to 67.1% less than in control. These results indicated that voice input could improve the efficiency of survey and input during plant disease experiments.

We investigated the efficacy of fungicides and differences among cultivars in resistance against strawberry powdery mildew. Ten fungicides were applied to strawberry plants, on three occasions, at seven days intervals. Relative to the untreated plants, disease severity was significantly reduced by eight of the fungicides after the second application, and by ten of the fungicides after the third application. Of the seven strawberry cultivars tested, the three with the highest disease resistance, from most to least resistant, were Yumenoka, Kaorino, and Akihime. These results indicate that multiple applications of fungicides and the use of resistant cultivars can effectively control strawberry powdery mildew.

Clubroot disease (CD), caused by Plasmodiophora brassicae, is one of the most economically important diseases affecting the Brassicaceae family of plants. We investigated the effect of CD on the yield of Hanana (Brassica rapa var. nippo-oleifera), a Brassica vegetable cultivated for young inflorescences and stalks as edible parts. Infested field plots with different severity levels of CD were prepared, and the disease was suppressed by pre-treatment with fungicide for nearly non-infested field plot as a control. As evaluation parameter, the fresh weights of edible parts and the plant top were measured. Assessment of plant growth and disease severity was done before harvest. Compared with the control, plant weight was significantly lower for plants grown in the plot with high disease severity. The yield of edible parts showed a tendency of decrease in the infested plots. A yield reduction of 65% was shown at the highest level of disease severity (99.4), whereas yield reductions were estimated at approximately 20% in plots with the moderate level (21.1–38.3). The present study quantified crop losses in a field of Hanana, and thus may be valuable for assuming the impact of CD specific to Hanana production.

The authors demonstrated sensitive detection of allium white rot pathogen (Sclerotium cepivorum Berkeley) using a nested PCR method for the ITS region of ribosomal DNA. A specific primer pair (SCITSF2 and SCITSR4) was designed for the consensus sequences lying on ITS1 and ITS2 among 5 isolates obtained from Shizuoka prefecture and 11 isolates of S. cepivorum. No cross reactions were observed in the PCR using SCITSF2 and SCITSR4 with any of the closely related non-target 10 fungal species of Sclerotiaceae (e.g. 3 Botrytis, Ciboria, Dumontinia and 5 Sclerotinia species) and Sclerotium rolfsii. Nested PCR in combination with primer pairs for the ITS region (OLPF1 and OLPR) and SCITSF2 and SCITSR4 made it possible to detect soil infestation with S. cepivorum, and asymptomatic infections of welsh onion with S. cepivorum, whereas the PCR using SCITSF2 and SCITSR4 partially failed to detect them. These results indicated that this method is capable of specific and sensitive detection of white rot disease infection in culture fields.

Control of secondary infections of tomato bacterial disease using calcium hypochlorite was evaluated. Effective concentrations of calcium hypochlorite differed between bacterial wilt and canker. In particular, even at 0.2%, calcium hypochlorite could not completely suppress bacterial canker. Furthermore, at concentrations of less than 0.2%, the control effect declined sharply. Alternatively, because concentrations of residual chlorine in calcium hypochlorite solutions decrease in light conditions, the control effects may deteriorate markedly depending on management.

The efficacies of several biocontrol agents against leaf blight caused by Cercospora chrysanthemi in garland chrysanthemum were investigated. Fungal mycelial disks were incubated on potato dextrose agar (PDA) plates spread with suspensions of each biocontrol agent, and were assayed for mycelial growth. Six kinds of Bacillus subtilis and one B. amyloliquefaciens agent potently inhibited C. chrysanthemi mycelial growth. The efficacies of these agents against leaf blight in potted garland chrysanthemum plants were tested. Of the agents, two of the B. subtilis agents and B. amyloliquefaciens stably reduced the disease severity relative to the control and showed promise for the control of leaf blight in garland chrysanthemum.

The coreid bug, Cletus punctiger, is widely distributed in Japan. This bug is a pest that sucks developing rice grains and causes pecky rice. Developmental zeros and effective accumulative temperatures of the bug were calculated from its developmental periods at different constant temperatures. The developmental zeros were 14.9°C in the egg stage, 13.8°C and 13.7°C in the egg and nymphal stages of female and male, respectively, and 16.6°C in the preoviposition period. The effective accumulative temperatures were 82.6 day-degrees in the egg stage, 400 day-degrees in the egg and nymphal stages of female and male, and 200 day-degrees in the preoviposition period. On the basis of these data, the number of annual generations of C. punctiger in Shiga Prefecture was estimated to be two.

Using onion thrips collected from Welsh onion fields in Nara prefecture, Japan, the toxicities of 11 insecticides were investigated. Treatment with imidacloprid, spinosad, abamectin, flometoquin, cyantraniliprole, and pyridalyl exhibited the greatest efficacy, with greater than 90% mortality and no leaf damage, followed by emamectin benzoate. Treatment with cypermethrin, dinotefuran, thiocyclam, and tolfenpyrad led to less than 60% mortality. Results suggested that spinosad, abamectin, flometoquin, and cyantraniliprole have utility for chemical control of onion thrips.

We revealed the toxicity of several insecticides on the adults of two species of ladybird beetles, Chilocorus kuwanae Silvestri and Pseudoscymnus hareja (Weise), predators of white peach scale Pseudaulacaspis pentagona (Targioni) in tea fields using a contacting method with tea branches. The results of test with C. kuwanae showed that chlorantraniliprole, cyantraniliprole, spinetoram and tolfenpyrad were not harmful, silafluofen was slightly harmful, and diafenthiuron and fluxametamide were seriously harmful. The results of test with P. hareja showed that chlorantraniliprole, cyantraniliprole, diafenthiuron, spinetoram and tolfenpyrad were not harmful, abamectin, dinotefuran and pyrifluquinazon were slightly harmful, fluxametamide was seriously harmful.

Stathmopoda masinissa Meyrick is serious pest in persimmon. For control of this pest, forecasting adults occurrence is important, because the optimum period for prevention is short. Forecasting results of the first occurrence day in first generation adults, calculated suing the effective accumulated temperature matched weel with actual occurrence. The optimum period of second generation larvae could be predicted using this forecasting method.

The control effects of 9 insecticides on diamondback moth, Plutella xylostella (Linnaeus), collected in Wakayama city, Japan, were investigated at the 3rd instar larvae using the leaf dipping method. Spinosad, emamectin benzoate, BT kurstaki, BT aizawai and cyantraniliprole exhibited high insecticidal activity. Indoxacarb and chlorantraniliprole were low effective. Cartap hydrochloride, and flometoquin were moderate effective.

Onion thrips, Thrips tabaci Lindeman, are a harmful pest of the genus Allium and also damage many other crops and fruits. In Japan, onion thrips developed resistance to pyrethroid and neonicotinoid insecticides, and they may also have developed resistance to other insecticides. We collected onion thrips in Osaka prefecture, Japan, from 2015 to 2018 and examined the effects of cypermethrin, dinotefuran, and spinosad insecticides on adult females using a laboratory bioassay. Most onion thrips populations showed resistance to cypermethrin and dinotefuran, except for a populations from Habikino city. All populations collected in 2015 and 2016 had no resistance to spinosad; however, the populations from Izumisano city collected in 2017 and 2018 and those from Kishiwada city collected in 2017 were found to be spinosad-resistant. This is the first report on the occurrence of spinosad-resistant thrips populations in Osaka.

We investigated the effect of ploughing on overwintering populations of Laodelphax striatellus nymphs in two successive periods. The population densities of L. striatellus were remarkably lower after ploughing. Almost identical results were recorded irrespective of the ploughing seasons (November or January). In addition, the population densities remained low until early spring when the examinations ended.

Acidic electrolyzed water (AEW) is used for the surface sterilization of fresh vegetables owing to its high bactericidal activity and food safety. AEW is also a specified agricultural chemical for the protection of vegetables from various disease. In this study, we demonstrated that a mist cooling system, including AEW, effectively reduced viable bacteria counts on the surface of eggplant. It was revealed that the mist cooling system including AEW is useful for labor-saving, hygiene control of farm products at the production stage.