The effectiveness of controlling Scirtothrips dorsalis Hood by covering plants with red insect nets was evaluated by field tests on infested commercially grown tea plants in 2016 and 2017. The population density of S. dorsalis on the tea plants covered by the red nets was reduced from about one-tenth to one-fifth of that without the red insect nets, and the percentage of leaf damage caused by the thrips was maintained at no more than one-fourth to one-third when the red nets were used, compared to the percentage of damage without them. These results indicate that the red insect nets are an effective and economically efficient measure for the control of S. dorsalis.

Pythium aphanidermatum, P. coloratum, P. myriotylum, and Globisporangium irregulare (syn. P. irregulare), G. spinosum (syn. P. spinosum), and G. ultimum var. ultimum (syn. P. ultimum var. ultimum) are the causal pathogens of soybean damping-off in Japan. However, their temperature preferences have not been systematically investigated. In this study, we compared the soybean pathogenicity of these six species in low (15°C day/12°C night) and high (28°C day/25°C night) temperatures, under laboratory conditions (12h day/12h night). In the low-temperature treatment, G. irregulare, G. spinosum, and G. ultimum var. ultimum were highly pathogenic to the soybeans, whereas the other three species tested were weakly pathogenic. In the high-temperature treatment, P. aphanidermatum, P. myriotylum, G. spinosum, and G. ultimum var. ultimum were highly pathogenic, whereas G. irregulare was weakly pathogenic to soybean. P. coloratum showed no pathogenicity to the soybeans when compared to the non-inoculated control in the high-temperature treatment. These results demonstrate that the pathogenicity of P. aphanidermatum, P. myriotylum, and G. irregulare will be more temperature-dependent than those of P. coloratum, G. spinosum, and G. ultimum var. ultimum.

Sex pheromone lures usually attract the target species very specifically; however, non-target species are also often attracted. Non-target species attracted to a sex pheromone lure could lead to technical problems in pest monitoring. In this study, non-target lepidopteran species attracted to the sex pheromone lure for the beet armyworm Spodoptera exigua (Hübner) were examined at four sites in different environmental conditions in and around Tsu City, Mie Prefecture, Japan. In addition to attraction of the target species, three lepidopteran species (Athetis dissimilis (Hampson), Cucullia fraterna Butler, and Lithophane ustulata (Butler)) were specifically attracted to the lures for S. exigua. Of these, A. dissimilis was considered to be the species most likely to cause erroneous determination when S. exigua were counted mechanically or by inexperienced investigators.

To elucidate the cause of a severe outbreak of wheat red rust in Aichi Prefecture, a statistical analysis was performed on survey data from 2015 to 2019. The survey was conducted in local cultivation fields in Aichi Prefecture. The results showed that initial disease development in late April was related to the occurrence of severe epidemics in late May. Furthermore, using logistic regression analysis with the disease state in late April as the objective variable, we revealed that the number of days with an average temperature above 12 °C and rain from February 1 to March 31 were significantly related. Additionally, exposure to these conditions for more than 4 days was likely to increase the risk of severe disease occurrence. This discovery makes it possible to predict whether severe disease will occur during the appropriate control period. Thus, our findings could help ensure that this disease is effectively suppressed.

Toxicities of 31 insecticides were investigated after dilution to conventional concentrations for tobacco flea beetle adults collected from an eggplant field in Nara prefecture. The results show that the most effective insecticides were acephate, (MEP), permethrin, etofenprox, bifenthrin, imidacloprid, acetamiprid, dinotefuran, clothianidin, sulfoxaflor, spinosad, chlorfenapyr, indoxacarb, metaflumizone, cyantraniliprole, and fluxametamide. In the eggplant field, five peaks of adult occurrence were observed, suggesting four generations of tobacco flea beetles per year. The finding that adult beetles were most frequently observed on bottom leaves suggests the possibility of control by removing lower leaves in conventional cultivation practices.

We observed the behavioral activity of adult females and larval sap beetles Phenolia (Lasiodites) picta (MacLeay) in response to several potential attractant odors. We observed the arrival rates within 15 min of females and larvae to flavor components derived from yeast and fruits as attractants. All adult females and 93% of larvae arrived at the banana within this time frame. Adults were attracted to banana-flavored castella but displayed little attraction to other odor sources. Larvae showed attraction to the mixture, the essence, and pure ethanol. Larvae also showed lower activity in response to the castella than did adult females. Differences in adult and larval behavioral responses to various odor sources may reflect changes in feeding habits during progressive life stages.

An optimized method of anaerobic soil disinfestation (ASD) using sugar-containing diatomite or dried molasses was evaluated for efficacy against tomato bacterial wilt, tomato corky root, tomato bacterial canker, and root-knot nematode. The soil redox potential of both the diatomite and molasses treatments at a dose of 1 t/10 a was high at a soil depth of 40–50 cm (beyond the plowing depth). This indicates that the soluble carbon source in the treatments eluted and permeated into the deeper layer, leading to soil reduction. Populations of Ralstonia solanacearum and root-knot nematode decreased below the detection limit after ASD was completed. The occurrence of the four soil-borne pathogens monitored was not observed or was suppressed to low levels during tomato cultivation following ASD. In particular, protection against tomato bacterial wilt was enhanced by ASD, which was followed by the plantation of tomato seedlings grafted onto resistant rootstocks.

Detection of viruses and viroids is mainly conducted by RT-PCR using specific primers for the identification of plant pathogens. However, it is difficult and time-consuming to detect pathogenic viruses using these methods for new strains, unexpected species, or infection of new host plants; in these circumstances, different methods need to be employed. Messenger RNA sequencing technology (mRNA-Seq) detects a wide range of viruses and viroids in a single experiment. Here, we describe a model case in which we detected RNA viruses, DNA viruses, and viroids collected from Nara Prefecture fields using mRNA-Seq and developed an RNA extraction method and data analysis for the establishment of this system. The RNA extraction method was optimized to improve the quality of RNA in chrysanthemum plant tissue. The reduction of the plant tissue in the RNA extraction buffer resulted in the improvement of RNA yields and quality. By introducing the criteria for read number and genome coverage, we detected RNA viruses (cucumber mosaic virus (CMV), tomato spotted wilt virus (TSWV)) and viroids (chrysanthemum stunt viroid (CSVd), chrysanthemum chlorotic mottle viroid (CChMVd)), but not DNA viruses (tomato yellow curl leaf virus (TYLCV), dahlia mosaic virus (DMV)). In addition to the read number and the genome coverage, the average nucleotide sequence identity of reads detected by BLAST homology search and the average length of the identical region are important for judging whether the virus and viroid have infected the plants. These results indicate that the mRNA-seq could detect a wide range of RNA viruses and viroids in plants.

Haplothrips nigricornis Bagnall was found in a few species of Asteraceous weeds in Kyoto, Osaka, Wakayama, and Hyogo prefecture in Japan in 2019; however, little detail is known about its biology. We investigated the population of H. nigricornis and its seasonal occurrence by conducting a field survey in Osaka. Additionally, we investigated its feeding habits and destructive potential. We found 1 genus of Phlaeothripidae and 6 genera of Thripidae; the greatest number of H. nigricornis were collected from the inflorescence of Senecio madagascariensis. The seasonal prevalence of the occurrence of H. nigricornis appeared to be correlated with the blooming of S. madagascariensis. In comparison to other Thripidae species, it appears that this species may not be a strong flyer and, therefore, not particularly mobile. Consequently, H. nigricornis was thought to live mainly on S. madagascariensis and is not necessarily able to complete its lifecycle on other Asteraceous plants. Furthermore, we did not observe that this species caused obvious damage to any of the investigated plants (23 species in 6 families).

The efficacy of a combination of a predatory mite, Neoseiulus californicus (McGregor), and a spiracle-blocking insecticide, propylene glycol fatty acid monoester emulsifiable concentrate (Akaritouch), in controlling a population of the two-spotted spider mite, Tetranychus urticae Koch, was investigated. In laboratory experiments, when Akaritouch was sprayed weekly, the number of predatory mite females on leaf discs decreased. However, in the same experiments, the populations of N. californicus comprising eggs, immatures, and adults were maintained on the leaf discs because Akaritouch had no significant effect on the number of eggs and immature mites. In greenhouse experiments with strawberry and eggplant, we found that the use of N. californicus and Akaritouch spray in combination was effective in controlling the spider mite population. The effects were observed in the one-week interval application of Akaritouch.

Plum pox virus (PPV), the pathogen of ringspot disease of the Japanese apricot, is transmitted by aphids. To identify the best periods for aphid control, we investigated the population dynamics of winged aphids in Inuyama City, Aichi Prefecture, where the ringspot disease of the Japanese apricot is common, and emergency control measures are in place between March 2015 and March 2018. The number of winged aphids in each field varied with the time of the year, increasing temporarily during the low-temperature period (January to March), and decreasing thereafter. In each field, the number of winged aphids tended to increase from May to June and from September to November, and decrease from July to August. The peak season occurred 3–5 times in 2015, 5 times in 2016, and 4–5 times in 2017. Furthermore, the estimated field values were determined using the state-space model for occurrence and development in each field was based on the number of winged aphids over the past three years. In the observed values, the peak of occurrence detected 2–5 times a year was smoothed to 2-4 times a year, and the emergence periods, which differed from field to field, nearly coincided. We also investigated the detection of PPV viruliferous winged aphids, using nested-RT-PCR, from March 2016 to October 2017. In a study involving a total of 1,002 individuals in each field, no positive specimens were confirmed. This suggests that the density of positive specimens at this survey site may have decreased due to the removal of infected plants for emergency control.

The optimal timing for applying insecticides against Coccoidea species has been estimated using data from the nearest weather station in Aichi prefecture. However, such estimations were less accurate in areas far from weather stations. We developed models to estimate the optimal timing for applying insecticides against two Coccoidea species: Planococcus kraunhiae (Kuwana, 1902) Fernald, 1903 (Hemiptera: Pseudococcidae) and Comstockaspis perniciosa (Comstock, 1881) MacGillivray, 1921 (Hemiptera: Diaspididae), using the Agro-Meteorological Grid Square Data System. The models were verified by the occurrence of the two species in agricultural fields in 2018 and 2019. The “Triangle Method” was used on mesh agricultural weather data to calculate the total effective temperature, and hourly data were used for weather station data. The Meteorological Grid Square Data System showed high predictability for estimating appropriate control periods for both species. Implementing this method with a Python program provides appropriate control periods for a wide area, such as prefectures, and contributes to efficient pest management.

A combination treatment of dazomet with flooding was evaluated for its efficacy in soil disinfection of the deep layer. Following a typical treatment of dazomet (no flooding), the concentration of methylisothiocyanate (MITC) measured was very high in the plow layer, whereas it was below detection limits in the deep soil layer. On the other hand, a high concentration of MITC was detected in the deep soil layer when combined with flooding treatment. Using dazomet at a dose of 60 kg/10 a, tomato bacterial wilt (Ralstonia solanacearum) was well controlled, while a dose of 30 kg/10 a did not provide enough control. In an experiment in a severely infested plastic greenhouse in Hida-city, Gifu Prefecture, Japan, soil disinfection using dazomet reduced the percentage of wilted tomato (Solanum lycopersicum L.) plants to only 0%–2.8% when applied at 60 kg/10 a and combined with flooding, followed by planting tomato seedlings grafted onto highly resistant rootstocks. Our results indicate that the addition of a flooding treatment can transport dazomet deeper in the soil and improve the control of tomato bacterial wilt.

We investigated the toxicity of several insecticides to Arrhenophagus albitibiae Girault (Hymenoptera: Encyrtidae) parasitizing white peach scale, Pseudaulacaspis pentagona (Targioni-Tozettii) (Hemiptera: Diaspididae), in tea crops using three different laboratory assay methods. We checked the toxicity of 25 pesticides using the dry-film method and of 63 pesticides (55 insecticides + eight fungicides) using the contact method by spraying the pesticides on the tea branches. We also tested the toxic effect of 43 pesticides (40 insecticides and three fungicides) on the emergence of parasitoid pupae by dipping tea branches with the pupae into pesticide liquid. Moreover, we investigated the susceptibility of the parasitoid adults to four types of neonicotinoids using the contact method. The results of the dry-film test showed that many pesticides were more than moderately harmful to A. albitibiae, whereas organophosphate, pyrethroid, and avamectin/milbemycin insecticides were seriously harmful to A. albitibiae. The results of the contact test showed that most of the organophosphate, pyrethroids, spinosad, pyridaben, and milbemectin insecticides were seriously or moderately harmful, whereas insect growth regulators (IGRs), diamides, most acaricides, most other groups of insecticides (IRAC code: 2B, 9B, 11A, 12A, 13, 12A, 21A) and fungicides were only slightly harmful or not harmful to A. albitibiae. The toxicity test regarding the emergence of the parasitoid showed that only some organophosphates and pyrethroids were slightly harmful. The LC₅₀ values of the A. albitibiae adults under the four types of neonicotinoids were 5.6 ppm, 37.5 ppm, 176.1 ppm, and 177.7 ppm for clothianidin, imidacloprid, thiacloprid, and acetamiprid, respectively.

In this study, we examined the biological control potential of a nonpathogenic Xanthomonas sp. strain 11-100-01 (npX) against bacterial spot of lettuce caused by Xanthomonas axonopodis pv. vitians (Xav.). The results from field trials conducted over 3 consecutive years showed that npX had a significant control efficacy towards Xav on lettuce, which was comparable to that of basic copper sulfate. A re-isolation experiment using a spontaneous rifampicin-resistant mutant strain of npX revealed that it efficiently colonized the lettuce leaves, particularly the wounded sites, for at least 1 week after the spray treatment. Furthermore, the results of the in vitro antagonism assay demonstrated that npX produces antibacterial substances that effectively inhibit the multiplication of Xav. Altogether, our results strongly indicated that npX has the potential to be used as a biological control agent against bacterial spot in lettuce.

Recently, a new method to control the two-spotted spider mite Tetranychus urticae Koch with ultraviolet-B (UVB) irradiation has been established. Here, we employed UVB irradiation in combination with phytoseiid mites to control the two-spotted mite in high-bench strawberry cultivation in a commercial greenhouse for two years. We did not observe any adverse effects on the phytoseiid mites exposed to UVB at 26–79 mW/m² intensity at the top of strawberry plants for 2–3 h every night. Irrespective of the presence or absence of sheets to reflect UVB on the leaf surface, the combination of UVB irradiation and phytoseiid mites suppressed the two-spotted spider mite to a level below the control threshold from October to early April.

The authors determined the lethal conditions for sclerotia of Allium white rot pathogen (Sclerotium cepivorum Berkeley) during soil solarization. We found that during soil solarization at continual high soil temperature conditions (above 30°C daily average over 6 weeks), the green manure incorporation (GMI), with or without calcium cyanamide, was effective in reducing the living sclerotia in commercial fields, and was enhanced at higher soil moisture. To verify the conditions of this conventional soil solarization, GMI into soil with calcium cyanamide and temporal flooding of the treated soil space were performed using a simulated soil solarization method in a plastic bottle. The simulation was carried out in growth chambers set at approximately 36°C (14L/10D, 40/30°C), 30°C (12L/12D, 35/25°C), or 25°C (10L/14D, 30/20°C). Around 36°C, no living sclerotia were found after the 2-weeks incubation irrespective of the GMI. Around 30°C, on the other hand, living sclerotia were found after 6 weeks of incubation only in bottles without GMI. Around 25°C, living sclerotia were found even after 6 weeks in both treatments. These results indicate that this simulative method is capable of reproducing the lethal conditions of sclerotia during soil solarization.

Several experiments were conducted to establish an efficient system for controlling fruit rot when exporting Satsuma mandarin to Singapore. A total of 110 isolates of Penicillium digitatum obtained from 44 orchards in Wakayama Prefecture were assayed for sensitivity to thiophanate-methyl, benomyl, and iminoctadine triacetate. Of these isolates, 8.2 percent showed resistance to thiophanate-methyl and benomyl, and all isolates showed sensitivity toward iminoctadine triacetate. These three fungicides seemed to be effective. In a refrigerated maritime transport experiment in which Satsuma mandarin was taken from Japan to Singapore, spraying thiophanate-methyl wettable powder before harvesting suppressed the occurrence of fruit rot 19 days after devanning to about 41% of that of an untreated load. Addition of a paraffinic sticker adjuvant to thiophanate-methyl wettable powder or iminoctadine triacetate liquid decreased the rate of occurrence of fruit rot in an inoculation test of P. digitatum following artificial precipitation and reduced the occurrence of fruit rot 14 days after devanning in a refrigerated maritime transport experiment in which Satsuma mandarin was taken to Singapore. Adding a paraffinic sticker adjuvant to fungicides sprayed before harvesting was considered to improve the efficacy of fruit rot control after refrigerated maritime transportation of Satsuma mandarin from Japan to Singapore.

Two predatory bugs, Orius strigicollis (Poppius) and Nesidiocoris tenuis (Reuter), are indigenous natural enemies against thrips. We evaluated effective insectary plants for the conservation of these predators in open fields. We investigated the population dynamics of thrips and predators on 10 plants in 2016 (from summer to fall season) and 13 plants in 2017 (from spring to summer season), including French marigold Tagetes patula, sweet basil Ocimum basilicum, holy basil O. tenuiflorum, buckwheat Fagopyrum esculentum, and okra Abelmoschus esculentus. Population dynamics of O. strigicollis were significantly affected by the density of thrips; however, the relationship between the level of prey-predator densities on each plant was not completely proportional. As the suitability of supplementary foods (pollen or nectar) for O. strigicollis is known to differ among plants, we hypothesized that the qualities of flowers as foods might also affect the predators’ population density. On the other hand, the correlation between the population dynamics of N. tenuis and thrips was mutually unrelated, suggesting that occurrence of N. tenuis depends on plant species. The effective insectary plants in this study were buckwheat for O. strigicollis and garden verbena Verbena × hybrida ‘Hanatemari-Aya’ or holy basil for N. tenuis.

The effect of a combination of humidity control, using a heater control unit equipped with a dew condensation sensor, and fungicide spraying on the control of gray mold of tomato was examined. The relative humidity in the greenhouse decreased considerably with the use of the unit. Furthermore, the damage caused by the gray mold was reduced to 28.6% compared with fungicide spraying alone.

Isolates of Pythium aphanidermatum from the rotted roots of spinach grown in hydroponic culture in the Hiroshima Prefecture, Japan, were characterized based on morphology, hyphal growth temperature, and internal transcribed spacer (ITS)-rDNA sequences.

In September 2019, Pythium rot of ornamental cabbage (Brassica oleracea L. Acephala Group) occurred in Kinokawa City, Wakayama Prefecture, Japan. The causal agents were identified as Pythium aphanidermatum and P. myriotylum based on cultural characteristics and molecular analysis of ribosomal DNA internal transcribed spacer (rDNA-ITS) regions. An inoculation test confirmed that oomycetes were the causal agents of the disease. This is the first report of Pythium rot in ornamental cabbage in Japan.

In June 2014, bacterial shoot rot of ginger (Zingiber officinale Rosc.) occurred in Wakayama City, Wakayama Prefecture, Japan. Infected plants in fields were observed to have yellowish leaves and rot inside the pseudostem. Bacteria isolated from diseased tissues caused the same symptoms as those observed in the fields and were reisolated from the rotted tissue. Based on bacteriological characterization and sequence analysis of the 16S rRNA gene and gyrB gene, the bacteria were identified as Dickeya sp. This is the first report of this disease in Japan.

Ceratocystis ficicola is the causal agent of Ceratocystis canker in Japanese fig orchards. Ceratocystis canker is a soil-borne plant disease that causes wilting and mortality in fig orchards. Some rootstocks, such as “Celeste”, have been used to control the disease. However, these rootstocks are not perfect. Ficus erecta is highly resistant to Ceratocystis canker and might be suitable for use as a resistant rootstock. Unfortunately, the grafting compatibility between F. carica and F. erecta is extremely low. We successfully produced BC₁ lines, interspecific hybrids between F. carica and F. erecta as new rootstock candidates, and compared them with “Celeste” in relation to resistance to Ceratocystis canker infection via soil. Fig varieties, “Houraishi” and “Masui Dauphine”, were grafted on three BC₁ lines and the “Celeste” rootstock. Own-rooted cuttings of “Houraishi” and “Masui Dauphine” were also tested. All cuttings were planted in an orchard infected with C. ficicola. The roots, rootstock, and scions were sampled for C. ficicola and external symptoms were recorded. Infection and mortality occurred on 86.1% and 87% of the own-rooted “Houraishi” and “Masui Dauphine” cuttings, respectively. The infection rate on “Celeste” rootstock was 41.7%, but mortality was not observed; C. ficicola infection was restricted within the roots of “Celeste”. However, the disease was not detected in cuttings with BC₁ rootstock. These results indicate that BC₁ is more resistant to infection of C. ficicola via soil than existing resistant varieties like “Celeste”. Further investigation is required to select a suitable BC₁ line as a rootstock to control Ceratocystis canker and to achieve stable fig production.

The suppressive effects of metalaxyl-M and azoxystrobin against Pythium myriotylum, Globisporangium splendens, G. spinosum and an unidentified Globisporangium sp., which cause stem and root rot of Hydrangea macrophylla, were evaluated. The metalaxyl-M and azoxystrobin EC₅₀ values for the growth inhibition of the pathogens on potato-carrot agar were 0.02–0.12 ppm and 0.14–9.42 ppm, respectively. Soil treatments containing mixtures of metalaxyl-M and azoxystrobin showed significant inhibitory effects against the four pathogenic species.

Olpidium root rot is a disease of spinach grown in hydroponic culture. It causes browning of the roots of spinach, growth delay, and a serious reduction in yield. However, there is no information about control measures. Thus, we obtained preliminary data to explore the efficacy of fungicides and antifungal materials, which have potential to control Olpidium root rot. Azoxystrobin, oxathiapiprolin, phosphorous acid, and silver were found to be effective against Olpidium root rot.

The relationship between the presence/absence of arrehenotoky and sensitivity to pesticides was determined in the onion thrip Thrips tabaci using six populations collected in Mie. Three of the six populations exhibited high levels of arrhenotoky and were less sensitive to pesticides than the others.

Rice stripe disease is a serious problem in rice cultivation in Japan. We investigated rice stripe virus (RSV) acquisitions on small brown planthoppers, Laodelphax striatellus (Fallén), collected in autumn and the following spring in Hyogo prefecture from 2013 to 2019. We performed a correlative analysis of acquisition rates in autumn and the next spring. The correlation of linear expression was indicated (y = 0.5402 x + 0.7760, p < 0.001) (y: next spring, x: autumn). This prediction method may lead to more effective plant protection techniques for farmers.

The controlling effects of five insecticides on adult specimens of the five species of rice bugs that cause pecky rice in Shiga Prefecture, Japan, were investigated using a spraying system. Treatment with dinotefuran and ethiprole led to more than 85% mortality after 72 h for all 5 species. Treatment with MEP led to more than 95% mortality after 72 h, except in Cletus punctiger. Treatment with ethofenprox had limited effectiveness against Eysarcoris aeneus and Trigonotylus caelestialium. Sulfoxaflor showed slow-acting properties against Cletus punctiger, Leptocorisa chinensis, and Eysarcoris aeneus.

Nine insecticides were used as treatments against cucumber moth larvae on cucumber leaves. At three days after treatment, all insecticides were found to have high toxicity at commercial concentration, but flubenziamide, chrorantraniliprol, and acetamiprid were found to have low toxicity at 1/10 of commercial concentration. These results suggest that cucumber moths exhibit low susceptibility to two diamides.

The estimated occurrence dates of small brown planthoppers, Laodelphax striatellus (Fallén), from an agro-meteorological grid square data (AMGSD) at Hyogo Prefecture in Japan matched actual occurrence dates (error margin within 6 days), compared to those from an automated meteorological data acquisition system point. An accurate occurrence forecast of this pest can be obtained by using AMGSD.

The effects of five insecticides were investigated on five populations of flower thrips, Frankliniella intonsa (Trybom), collected from strawberry greenhouses in Nara Prefecture. Spinosad was the most effective insecticide in terms of corrected mortality and leaf damage. Cyantraniliprole showed low corrected mortality but low leaf damage. Acetamiprid results differed in terms of corrected mortality and leaf damage according to thrip population. Flometoquin and spirotetramat showed low corrected mortality and high leaf damage. These results suggest that spinosad and cyantraniliprole are effective insecticides against flower thrips, F. intonsa, from strawberry plants in Nara Prefecture.

The effects of six spiracle-blocking insecticides on the camellia spiny whitefly Aleurocanthus camelliae (Hemiptera: Aleyrodidae) in tea fields were evaluated. Compared with the protective value of the control insecticide, tolfenpyrad (100%), that of all the spiracle-blocking insecticides was lower. Of the six insecticides tested, hydroxypropyl distarch had the highest protective value (64.2%).

We investigated the residual toxicity of three insecticides (methidathion, bifenthrin, and clothianidin) against the parasitoid Arrhenophagus albitibiae Girault (Hymenoptera: Encyrtidae) parasitizing white peach scale Pseudaulacaspis pentagona (Targioni-Tozetti) (Hemiptera: Diaspididae) on tea trees. In addition, we investigated the effect of clothianidin on parasitism by parasitoids (including A. albitibiae) in a tea field. Tea branches were sprayed with the insecticides. Changes in insecticide toxicity and residues on tea branches and leaves were monitored. Methidathion was toxic to A. albitibiae adults for fewer than 10 days after the application, while residues on leaves and branches lasted approximately three weeks. The toxicity of bifenthrin lasted for less than 10 days after application. Bifenthrin residues on leaves were detected fewer than four weeks after application, while residues on branches were present for more than four weeks. Clothianidin was toxic for more than two weeks after application. Its residues on leaves lasted about one week, while residues on branches lasted for more than four weeks. Clothianidin application immediately after the peak of occurrence of the A. albitibiae slightly inhibited parasitism of P. pentagona by A. albitibiae.

Seasonal occurrence of male adults of the Comstock mealybug Pseudococcus comstocki was investigated using sex pheromone traps for four years in a commercial grape greenhouse in Osaka Prefecture. The first peak of the number of male adults captured on the traps was found in late March, with the second peak from late April to early May and the third peak from mid-June to early July. Thus, the sex pheromone trap for the mealybug could detect the peaks in the number of male adult in the grape greenhouse.

We determined the toxicity of insecticides by using the leaf-dipping method on two thrips species, Thrips palmi and Thrips tabaci. They were collected from 3 populations in Osaka Prefecture in 2017 and 2019, and the effects of 11 and 7 insecticides, respectively, for the two species were examined. The most effective insecticides against T. palmi were emamectin benzoate, fluxametamide, and flometoquin, whereas MEP and thiocyclam were effective against T. tabaci.