An ethanol-spray treatment was evaluated as a practical method for forecasting strawberry anthracnose caused by Glomerella cingulata in Nara Prefecture, Japan. Evaluations were conducted on latent infections of the pathogen to determine the disease occurrence in commercial strawberry nurseries from 2010 to 2014. The latent infection was highest in early July and corresponded highly to disease occurrence throughout the experiments. The results showed that the ethanol-spray treatment was a reliable and useful method for forecasting anthracnose in strawberry nurseries.
Imported kiwifruit affected by soft rot on Shanghai fruit market was selected for pathogen isolation and identification. The pathogenicity of different strains was compared. Morphological detection was combined with molecular tools to identify the main pathogenic strains as well as their biological characteristics. The results showed that Phomopsis was the main pathogen causing soft rot, and Phomopsis vaccinii (P. vaccinii) had the highest pathogenicity. Soft rot in kiwifruit caused by P. vaccinii was effectively inhibited under 5°C. This article is a first report of the pathogens causing soft rot in kiwifruit in Chinese market. Valuable experimental evidence is provided for the study on the pathogens carried by kiwifruit imported from New Zealand and on the occurrence of soft rot on the market.
Influence of cultivation pH of melon seedlings on transmission efficiency of Melon necrotic spot virus (MNSV) by the fungal vector Olpidium bornovanus was investigated. When melon seedlings were grown in plant culture medium, the transmission of MNSV was decreased under low pH values of 5.5 and 4.5. The application of 1% and 2% Ferosand (FeSO4·H2O) to decrease soil pH in artificially infested soil that was contaminated with O. bornovanus and MNSV, also decreased the transmission efficiency of MNSV. These results indicate that the transmission of MNSV by O. bornovanus is inhibited under low pH soil conditions.
Big rosette type brown-spot was found on tea (Camellia sinensis (L)O.Kuntze) leaves in 2013 and 2014. Fungi isolated from the diseased plants were identified as the Colletotrichum gloeosporioides species complex. Inoculation tests confirmed that this fungus was the causal agent of the disease. Big rosette brown-spot symptom is a special symptom of brown-blight disease on tea.
To estimate the initial infection period of Ceratocystis ficicola against fig cuttings via soilborne inoculum, one-year old cuttings were planted in a contaminated fig orchard. Two fig varieties, ‘Houraishi’ and ‘Masui Dauphine’ were employed in this study. Numbers of ‘Houraishi’ and ‘Masui Dauphine’ cuttings were 18 and 28, respectively. These cuttings were dissected at 69, 83, 97, 111, 125, 136, 150 and 171 days after planting, respectively. First infection of the fig plants was recognized at 97 days after planting, and then the infection rates of cuttings increased in both fig varieties. External symptoms, wilting and death, were not observed in the cuttings of either fig variety until three years after planting. These results indicate that infection of C. ficicola starts in the year of planting without any external symptoms. Soil applications of fungicide to prevent infection by C. ficicola should be carried out just after planting of fig cuttings.
Anthracnose was observed in Checkerberry plant (Gaultheriaprocumbens L.) in northern area of Hyogo Prefecture in October 2010. The causal agent was identified as Colletotrichum gloeosporioides on the basis of its morphology and molecular characteristics in an inoculation test, it was found to cause leaf rot. To the best of our knowledge,this is the first report on Anthracnose in Checkerberry plant in Japan.
Here, we investigated the effect of disinfection on seeds infected and damaged by Pyricularia oryzae parasitizing rice husk. In all the cases, seed disinfection was highly efficient in controlling the parasitic infection of the surface of rice seeds. Paticularly, application of a solution of benomyl, known for its fungicidal properties, had high efficacy in controlling this pathogen; however,sterol demethylation inhibitors had low efficacy. Further, the effect of disinfection on heavily damaged seeds showing later stages of infection was low.
We examined the effects of 10 fungicides in field conditions in order to establish an effective fungicide application program forsooty blotch in Japanese apricot. Captan, ditianon and difenoconazolewere more effective than the other seven fungicides tested duringtwo years of field testing. Therefore, we designed an effective fungicideapplication program, in which ditianon and captan were sprayed asthe initial application followed by difenoconazole. This is more efficientthan conventional fungicide application programs.
Control of bacterial soft rot in Chinese cabbage by fluazinam SC was evaluated in a vinyl-coated field. Fluazinam solution was applied onto the vinyl-coated field before or after opening the plantingoles. Both spray timings enabled to control bacterial soft rot. This application method can be used under the appropriate timing depending on the state of cultivation and can lead labor saving.
A population survey of thrips and of whitefly was conducted on eggplants and cucumbers in greenhouses with and without naturalenemies, Nesidiocoris tenuis and Amblyseius swirskii. Density of thrips and whitefly on cucumbers had been below the control threshold density (one individual per leaf) during survey period. Similarly, thrips density was below the control threshold density on eggplants in greenhouse with N. tenuis and A. swirskii. On the other hand, whitefly densities on eggplants were temporarily beyond the control threshold level. Nevertheless, no substantial economic loss was observed. Pesticide use in greenhouses with N. tenuis and A. swirskii was less than that in greenhouse without these natural enemies.
We investigated the effects of four insecticides on wolf spiders (Lycosidae). In the field, cypermethrin reduced spider populations until 1 week later, but acetamiprid, spinosad, and pyridalyl had no observable effect. In the laboratory, spinosad caused little harm to spiderlings of Pardosa astrigera L. Koch (Lycosidae).
Wild soybean consumption by four species of lepidopteran larvae was investigated to get basic data for an environmental assessment of Bt soybean. Fourteen species were preliminarily tested. The leaf area eaten by the last instar larvae were 295, 33.2, 17.3 and 16.3 cm2 for Cifuna locuples confuse, Pleuroptya ruralis, Paragabara ochreipennis and Archips semistructa, respectively.
Box-tree pyralid, Glyphodes perspectalis(Walker), is one of the serious lepidopterous insect pests of box trees. In late April 2014, this insect pest occurred and heavily injured the box trees in our center, which is located at Toyohashi city in Aichi Prefecture. Therefore, the susceptibility of G. perspectalis to 18 insecticides was evaluated by the leaf-dipping method. Of the 18 insecticides tested, 14 gave 100% mortality at their respective commercially used concentrations. In particular, fipronil, spinosad, and spinetoram exhibited very high insecticidal activity.
In addition, PAP, thiodicarb, flubendiamide, metaflumizone, and pyridalyl exhibited high insecticidal activity. Comparison of the insecticidal susceptibility of G. perspectalis with that of the common cutworm, Spodoptera litura (Fabricius), showed that G. perspectalis was more susceptible than S. litura except against lufenuron.
These results indicate that G. perspectalis can be easily controlled by using insecticides effective against S. litura.
The susceptibility of the white peach scale, Pseudaulacaspis pentagona (Targioni) (Hemiptera: Diaspididae) to pesticide was evaluated by potato tuber dipping method. Among nine pesticides tested on the white peach scale eggs, chlorpyrifos, DMTP (methidathion), pyriproxyfen, buprofezin, chlorfenapyr, and pyrifluquinazon caused high mortality. Among the 15 pesticides testedon first instar larvae, chlorpyrifos, DMTP (methidathion), fenpropathrin, pyriproxyfen, machine oil emulsion and chlorfenapyr were more toxic. Among the nine pesticides tested on second instar larvae, no pesticides were effective.
We designed two bioassay methods, leaf spraying and leaf dipping,to examine pesticide toxicity in the first instar larvae of melon thrips, Thrips palmi Karny. The corrected mortalities of the larvae for four pesticides (chlorfluazuron, flufenoxuron, spirotetramat, andpolyoxin AL) were 26.6–93.7% in the leaf spray method and 26.8–64.9%in the leaf dip method. Our methods could be used to evaluate pesticidetoxicity in the larvae of thrips.
The nematicide imicyafos applied to Malabar spinach (Basella alba) showed high control effect on the root-knot nematode. The agrochemical residues in the Malabar spinach were 0.04 ppm at the stems and leaves and 0.10 ppm at the broad leaves after 30 days of soil-mixing treatment; later, the imicyafos residues gradually decreased. Here we discuss the application for the registration of imicyafos for use in Malabar spinach.
The prevention of sweetpotato whitefly, Bemisia tabaci (Gennnadius) by combined application an entomopathogenic fungi, Paecilomyces tenuipes pesticide and physical control pesticides was examined under laboratory and greenhouse conditions. In the laboratory, the control effects by the combined application that two pesticides were mixed with under the half concentration of standard usage were higher than single pesticide treatment with standard concentration. Moreover, this effect was confirmed under low relative humidity, 40RH. Improvement of the control effect was confirmed under the greenhouse condition.
The diamondback moth (Plutella xylostella) is a serious pest to many cruciferous vegetables. Several entomopathogenic fungi were collected from the larvae of P. xylostella from fields in Gifu prefecture, Japan. We obtained four isolates of the entomophthoralean fungus, Erynia blunckii, which was considered a major natural enemy to P. xylostella in Japanese radish fields in Takasu, Gifu. The character of the fungus as a biocontrol agent was investigated. These isolates showed over 20 times higher conidia production than Zoophthora radicans isolates obtained from Takasu. A dose mortality assay on the E. blunckii isolate T10A showed that the LC50 value for 4th instar larva was 3.73 conidia/mm2.