Journal of Pesticide Science最新文献

Adverse outcome pathway (AOP)-based computational models provide state-of-the-art prediction for human skin sensitizers and are promising alternatives to animal testing. However, little is known about their applicability to pesticides due to scarce pesticide data for evaluation. Moreover, pesticides traditionally have been tested on animals without human data, making validation difficult. Direct application of AOP-based models to pesticides may be inappropriate since their original applicability domains were designed to maximize reliability for human response prediction on diverse chemicals but not pesticides. This study proposed to identify a consensus chemical space with concordant human responses predicted by the SkinSensPred online tool and animal testing data to reduce animal testing. The identified consensus chemical space for non-sensitizers achieved high concordance of 85% and 100% for the cross-validation and independent test, respectively. The reconfigured SkinSensPred can be applied as the first-tier tool for identifying non-sensitizers to reduce. animal testing for pesticides by 19.6%.

A fluorescent labeled pyrazole derivative with a dansyl moiety (EH-DF) was synthesized. Design of EH-DF was carried out by using a dansyl moiety to substitute the naphthalene moiety of the parent compound (EH-1). At a concentration of 30 µM, EH-DF displayed biological activity on inducing a triple response in Arabidopsis seedlings. Compared with the non-chemical treated control, the hypocotyl length of EH-DF-treated Arabidopsis seedlings was reduced from approximately 9.2±0.7 mm to 2.4±0.2 mm. The length of the roots was reduced from 1.7±0.1 mm to 1.0±0.1 mm, and the curvature of the hook of Arabidopsis seedlings increased from 60±16 degrees to 245±35 degrees. The maxim excitation wavelength and emission wavelength of EH-DF were 350 and 535 nm, respectively. Data obtained via fluorescent microscope analysis indicated that intensive fluorescent signals of EH-DF were observed in the shoot of Arabidopsis seedlings.

Slow-acting fipronil is one of the best components for controlling invasive ants. However, its efficacy against invasive Lepisiota frauenfeldi, which recently invaded Japan, remains unclear. Here, its acute toxicity to Le. frauenfeldi was assessed, and its lethal concentrations were compared with those against other invasive ants (Linepithema humile and Solenopsis invicta). The LC₁₀ and LC₅₀ values of fipronil for Le. frauenfeldi were significantly lower than the previously reported values for Li. humile and/or S. invicta, and its LC₉₀ value against Le. frauenfeldi was in the same range as that required for Li. humile extermination. Additionally, Le. frauenfeldi can be more sensitive to fipronil than non-target arthropods. Therefore, recent fipronil-based Li. humile and S. invicta eradication/control programs may be effective against Le. frauenfeldi as well. Moreover, applying fipronil at dosages appropriate for Le. frauenfeldi would lead to effective Le. frauenfeldi extermination/control with low damage to other native species/ants.

Colletotrichum gloeosporioides species complex (CGSC) is the major pathogen causing strawberry anthracnose in Taiwan. Benzimidazoles and strobilurins are common fungicides used to control strawberry anthracnose. A total of 108 CGSC isolates were collected from five major strawberry-producing areas in Taiwan. The half-maximal effective concentration (EC₅₀) values of most CGSC isolates for benomyl (59 isolates), carbendazim (70 isolates), and thiabendazole (63 isolates) were higher than 500 µg a.i./mL. Strobilurin tests showed that the EC₅₀ values of most CGSC isolates for azoxystrobin (66 isolates), kresoxim-methyl (42 isolates), and trifloxystrobin (56 isolates) were higher than 500 µg a.i./mL. However, most CGSC isolates were sensitive to pyraclostrobin at 100 µg a.i./mL. Fungicide tests indicated that CGSC isolates show multi-resistance to benzimidazoles and strobilurins. Benzimidazole-resistant isolates were associated with a point mutation in codon 198 of the β-tubulin gene, and strobilurin-resistant isolates did not correspond with mutation in the cyt b gene or alternative oxidase activity.

The target site of the novel fungicide quinofumelin was investigated in the rice blast fungus Pyricularia oryzae. Quinofumelin-induced mycelial growth inhibition was reversed by orotate but not by dihydroorotate. Recovery tests suggested that the target site of quinofumelin was dihydroorotate dehydrogenase (DHODH), which catalyzes the oxidation of dihydroorotate to orotate. Quinofumelin strongly inhibited P. oryzae class 2 DHODH (DHODH II) (IC₅₀: 2.8 nM). The inhibitory activities of mycelial growth and DHODH II were strongly positively correlated, indicating that DHODH II inhibition by quinofumelin lead to antifungal activity. A P. oryzae DHODH II gene (PoPYR4) disruption mutant (ΔPopyr4), showing the same tendency as the quinofumelin-treated wild strain in recovery tests, was constructed, and disease symptoms were not observed in rice plants infected by ΔPopyr4. Thus, DHODH II, which plays an important role in pathogenicity and mycelial growth, is found to be the target site of quinofumelin.

The common pistachio psylla, Agonoscena pistaciae, is a serious global pest menacing pistachio orchards. Considering the dangers of using excessive chemical pesticides, it seems that using natural insecticides such as diatomaceous earth is a suitable way to lower the residual amount of highly hazardous pesticides. In this study, the effects of diatomaceous earth with different additives, including dipotassium hydrogen phosphate, polyurethane glue as a wood adhesive, and potassium silicate, were investigated in several concentrations over two years in orchard conditions. Although all treatments showed significant effects, the most effective treatments were (diatomaceous earth+dipotassium hydrogen phosphate) and (diatomaceous earth+polyurethane glue). Therefore, the use of diatomaceous earth combined with the additive materials mentioned can potentially be a safe method for the integrated management of the common pistachio psylla.

The extrapolability of the lysimeter test as a dissipation simulator in an actual paddy field was evaluated using mathematical models and their inverse analyses for predicting pesticide fate and transport processes in paddy test systems. As a source of experimental data, a four-year comparative experiment in lysimeters and paddy fields was conducted using various paddy pesticides. First, the dissipations for various active ingredients in granule pesticides under submerged applications were statistically compared using simple kinetic modeling. Second, the dissipation pathways, unobserved experimental components, and effect of the experimental setting were evaluated using a higher tier mathematical model with a novel inverse analysis protocol. Finally, owing to experimental constraints, the unobtainable parameters were extracted from the laboratory container test before being transferred to compare the outdoor experimental data under different formulation types.

The uptake experiments with pesticides were performed to clarify differences among plant species, and the influence of growth stages and conditions on the uptake and translocation ability of pesticides. There were 2-10-fold differences among plant species in the root and shoot concentrations of each pesticide, and shoot concentrations of pesticides in Brassica rapa L. var. perviridis were relatively high. In addition, the changes in shoot concentrations with growth stage of B. rapa were affected by root system development. The influence of temperature on uptake and translocation ability differed for each pesticide, while uptake and translocation ability were high for short day lengths. This indicated that plant uptake and translocation of pesticides were affected by root system development and growth conditions such as temperature and day length, not only the relationships to the chemical's properties and behavior of organic chemicals in the soil.