We investigated the effect of treatment with hot water extracts from the spent mushroom substrates (SMSs) of Lentinula edodes and Hypsizygus marmoreus on the resistance of rice leaves to Pyricularia oryzae infection. The spraying of the SMS extracts clearly suppressed the development of lesions caused by Py. oryzae infection. The accumulation of phytoalexins momilactones A and B, oryzalexin A, and sakuranetin was markedly induced by the spraying of extracts. The enhanced expression of defense related genes PR1b and PBZ was also found in leaves sprayed with the extracts. Treatments with the extracts also affected phytohormone levels. The levels of N6-(Δ2-isopentenyl)adenine and trans-zeatin markedly increased in response to treatment, whereas the levels of salicylic and jasmonic acids were largely unchanged.
Bemisia tabaci, a vector of cotton leaf curl virus disease, is among the most devastating pests causing huge economic losses due to reduced cotton yield and quality. The excessive use of chemical pesticides causes insecticide resistance. Entomopathogenic fungi (EPFs) have a role as mycoinsecticides. The combined use of these insecticides is a promising pest-control option to minimize adverse chemical effects. Thus, we have evaluated 10 EPFs under polyhouse conditions for their virulence against whitefly nymphs and their compatibility with chemical and botanical insecticides. The highest overall biological efficacy index was recorded with Ij-102, followed by Bb-4511, and Ij-089. An in vitro compatibility study was conducted to evaluate the effect of botanical and chemical pesticides on mycelial growth and spore production using the poisoned food technique. The effect of pesticides on the reduction of mycelial growth and conidial production ranged from −169 to 94.1% and −25.6 to 87.6%, respectively. However, Ij-089, Ij-102, Ma-1299, and Bb-4511 were found to be the most compatible with the chemical and botanicals evaluated. Comparatively, spiromesifen, diafenthiuron, buprofezin, pyriproxyfen, and flonicamid were more compatible with EPFs at half doses, as compared to the other chemical pesticides, namely imidacloprid, fipronil, profenophos, and triazophos. These results might provide the basis for future work and indicate that applications of EPFs showing the best virulence and compatibility have the maximum likelihood for the management of B. tabaci in the field in an integrated pest management system.
Glyphosate is a common herbicide used worldwide, but its adjuvant has not been studied much. A new adjuvant A-178®, based on the coconut shell extracts, has been developed for glyphosate (glyphosate isopropylamine salt: GP). The potency of the new adjuvant was compared with traditional adjuvant polyethoxylated tallow amine (POEA). Field study has shown that A-178® can improve the herbicidal effect of GP formulation, and, as compared with 41% GP mixed with 7% POEA (GPP), 41% GP mixed with 7% A-178® (recommended dose, GPA) is more effective for weed control. GPA improved herbicidal activity against GP alone by 79.27% and against GPP by 27.38% at 500 g a.i./ha. A-178® decreased the surface tension, increased the spreading area of GP, and improved the uptake of GP in cockspur (Echinochloa crus-galli L.). Our results indicated that the new adjuvant shows better ability to improve glyphosate efficacy than does POEA.
Effects of esfenvalerate on zooplankton and their recovery potential were studied using an indoor synthetic model ecosystem. Esfenvalerate was applied to the system by direct spiking to overlying water or the introduction of treated slurry soil to imitate drift and run-off exposure. Four zooplankton taxa, Daphnia magna (Cladocera), Heterocypris incongruens (Ostracoda), Cyclops sp. (Copepoda), and Brachionus calyciflorus (Rotifera), were exposed to esfenvalerate with Raphidocelis subcapitata (green alga). In a drift scenario, lower doses (0.02–0.5 µg/L) showed slight or negligible effects, but the results for the highest dose (5 µg/L) indicated direct effects, as remarkable population decreases were observed for three taxa (except rotifera). However, for the latter dose, results of weekly or single (Day-15) zooplankton re-introductions after dosing demonstrated resilient recovery. In a run-off scenario, a nominal dose of 20 µg/L, in which the measured water concentrations remained at 3–6%, had effects similar to those of the high drift exposure scenario for cladocera and ostracoda.
Broflanilide (1), discovered by Mitsui Chemicals Agro, Inc., has a unique chemical structure characterized as a meta-diamide and exhibits high activity against various pests, including Lepidopteran, Coleopteran, and Thysanopteran pests. Because broflanilide has a novel mode of action, the Insecticide Resistance Action Committee (IRAC) categorized it as a member of a new group: Group 30. The meta-diamide structure was generated via drastic structural modification of a lead compound, flubendiamide (2), and the subsequent structural optimization of meta-diamides on each of its three benzene rings led to the discovery of broflanilide. In the present study, the details of the generation of meta-diamides from the lead compound and the structural optimization of meta-diamides are described.
The brown planthopper, Nilaparvata lugens, and the white-backed planthopper, Sogatella furcifera, are significant pest insects for rice. Both species are able to survive year-round in northern Vietnam’s Red River Delta, which includes a large rice-producing region. This study aimed to evaluate insecticide use by farmers and its effect on the density of planthoppers in the region. Through interviews conducted with farmers in study sites in Nam Dinh (ND) and Vinh Phuc (VP) Provinces, we learned that farmers frequently used imidacloprid, fipronil, and emamectin-benzoate in ND and pymetrozine and thiamethoxam in VP. Farmers applied insecticides when the local government announcements regarding plant protection were broadcast. Generalized linear model analysis indicated that the selective insecticides applied did not contribute to reducing the densities of planthoppers in the farmers’ fields. Our results indicate the possible development of insecticide resistance by planthoppers or improper insecticide application by farmers.
The influence of clopyralid in soil on plant growth was investigated over time using three plants. The order of clopyralid sensitivity was as follows: Solanum lycopersicum>Solanum melongena>Momordica charantia, especially physiological disorder of S. lycopersicum were rapidly expressed as various serious symptoms with increasing concentration of clopyralid. In contrast, the clopyralid concentration of above-ground part was in the following order: M. charantia>S. lycopersicum, S. melongena, which differed from the order of sensitivity to clopyralid.